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Download S013 - Rocks and minerals of Ontario
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Renseignements : POUR PLUS DE RENSEIGNEMENTS SUR VEUILLEZ VOUS ADRESSER À : la reproduction du contenu Services de publication du MDNM l'achat des publications du MDNM Vente de publications du MDNM les droits d'auteurs de la Couronne Imprimeur de la Reine PAR TÉLÉPHONE : Local : (705) 670-5691 Numéro sans frais : 1 888 415-9845, poste 5691 (au Canada et aux États-Unis) Local : (705) 670-5691 Numéro sans frais : 1 888 415-9845, poste 5691 (au Canada et aux États-Unis) Local : 416 326-2678 Numéro sans frais : 1 800 668-9938 (au Canada et aux États-Unis) PAR COURRIEL : [email protected] [email protected] [email protected] ONTARIO DEPARTMENT OF MINES HON. G. C. WARDROPE, Minister D. P. DOUGLASS, Deputy Minister J. E. THOMSON, Director, Geological Branch Rocks and minerals of Ontario By D. F. HEWITT Senior Geologist, Ontario Department of Mines Geological Circular 13 TORONTO 1966 Publications of the Ontario Department of Mines and pricelists are obtainable through the Publications Office, Department of Mines, Parliament Buildings, Queen's Park, Toronto, Ontario, Canada. Orders for publications should be accompanied by cheque, or money order, payable in Canadian funds to Treasurer of Ontario. Stamps are not acceptable. li—4,000—1964 2i—4,000—llOOmh—1964 3i—8000—E34—l 966 TABLE OF CONTENTS Geological Circular No. 13 PAGE Acknowledgments ...... ...... ...... ...... .... PART I ROCKS AND MINERALS ............................ Properties of Minerals ............ .. . .. ... ...... ........ Chemical Composition ......................... Physical Properties of Minerals ... ... ... ...... ..... ... Structure ........... ... ... .... ....... ........ Crystal Form ... ...... ..... .................. Cleavage .................................... Fracture ........... . .... ..... ..... .... ...... . Hardness ........ .... . .. ... ............ ..... . Colour and Streak ... ..... .... ................ Lustre ................. .......... ..... .. .. .. . Specific Gravity .... . .. . ..... ........ . . . ...... Magnetic Properties ..... ...... .... .. . ....... .. Other Properties .... ...... . ... .. ... .... ....... Common Minerals of Ontario ...... .. .... ...... ......... Composition, Characteristics, and Occurrence of Common Minerals ......................... Primary Rock-Forming Minerals ..... ................. Quartz ..... .... ...... ..... . . ................ .. . The Feldspar Group . ... ... ... .................... Orthoclase .. . . .. .. . .. .. .... . .. ... .. .. ... ..... Plagioclase .. ... ... . ..... ............ ......... The Mica Group ... ..... . .. . ... .. ... . ........... . Muscovite .. ..................... ...... ...... Phlogopite .. ... . . . . .. . . . .. . .... ......... ..... Biotite . ........... .... ...... ... . ...... ...... The Amphibole Group ... . ....... .............. .. Hornblende ...... .. ......... .... .. ........... Actinolite ... .. . .. . ...... .... ................. Tremolite .. . .... . .... . .. . ... . . ........ ....... The Pyroxene Group ....... ... . . ................ Augite ...... ... .. .... .. .. . . . .... . . . ......... Hypersthene ..... ... ..... .. . ... .. .... ... .... . Diopside .. .. . . .. . ... .. ... .... ..... ......... .. Olivine ..... .. . . .. .... .. .... .. . ... .............. Nepheline .. ......... . ..... . ... .. ... ........... . Garnet Group .. . . . .. .. . . .. ... .. ................. Garnet .. ... ... . .. . ... ..... .... .. ............ Staurolite ... .. ... . . . ... ...... .. ... ... ...... .. .. . Zircon ... .. .. .. .... .... ... .. . ......... ..... ... . Titanite .. ... . .. ... .. ... .. ..... .... ...... ....... Sphene ...................................... Secondary Minerals, often Formed by Alteration ...... Clay Group .. . . . ... .. . ... .... .. . ...... ......... . Kaolin ..... .... ..... ...... . . ... . ............ Serpentine Group . . . . . . . .. .. .. .. .. . . . . . . . . . . . .. . Serpentine .. . .. .. .. .. ... .... ..... ...... ..... . Chlorite Group . . . .. . . . . .. . .... .. ... . ........ .. .. Chlorite ... . .. .. ... . .. .. .. . .... .... .. ........ Epidote Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Epidote ... ..... .. .... ............ . .. .. . . . .. . Scapolite Group . . . . . . . . . . . .. .. .. .. . .. .. . . . . . . . . . Scapolite ........... ... .. .. ......... .. .. .... . Sedimentary Rock-Forming Minerals . . . . . . . . . . . . . . . . . . Calcite .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . Dolomite .. ... . .. ... . . . . ... ... .. .. ........... Gypsum . . . . . . . . . . . . . . . . . .. .. . .. . . . . . . . . . . .. . Halite . . . .. . . . . . . . . . . . . . . . . . . .. .. .. .. .. . . . . . lv x l 3 3 5 5 5 5 5 9 9 9 10 10 10 11 13 13 13 15 15 16 16 16 18 18 18 18 18 20 20 20 21 21 21 21 22 22 23 23 24 24 25 25 25 25 25 25 25 26 26 26 26 27 27 27 29 29 PAGE Metallic Ore Minerals ...... ........... .............. Iron Minerals ................................... Magnetite . ........ . ..... ................. ... Ilmenite .. ...... ... ..................... ..... Pyrite ..... .......... ........................ Pyrrhotite ........ ........................... Siderite ........... ........................... Hematite ......... .. ......................... Limonite .................... ................ Copper Minerals ..... .. ......................... Native Copper .. ............... ...... ........ Chalcopyrite ...... ........................... Bornite ............................. ...... ... Chalcocite ........ ................ .... ....... Azurite .............. ....................... Malachite ..... ... .............. ............. Nickel Minerals ... ... .. ... ........... ........... Pentlandite . .... . ...... ..... ... .............. Niccolite .. ... ...... .... .................... . Cobalt Minerals .. ... .......... ........ ..... ..... Cobaltite ........ ....... ..................... Smaltite ....... .... ..... ...... .. ........ ..... Lead Minerals ...... .. ... . .. ...... .. . . .......... . Galena ...................................... Zinc Minerals .. . .. . .. . .. . ... .. . .. . . . . ..... ..... . Sphalerite . . . . ... ... ....... .. .. . . .... ...... . . Gold Minerals . .. ..... . .. .... .... .. . .... . ...... . Native Gold . . . ... ........ .. . . ... . .. ......... Silver Minerals .. ... ... . ... . . . . ..... . . . ... .. .. .. . Native Silver ... . ... ..... . . ... ...... . ... . .... Argentite ........ ....... ...... . ........ ...... Molybdenum Minerals .. . . ... . .. ....... .. .... .... Molybdenite ..................... ............ Uranium Minerals . . . ... ... ....... ........ . ...... Uraninite .. ...... . ... ... .... .. ... . .. . . .. . . . .. Pitchblende ..... ............ .. ............ .. . Uranothorite .. ... .. ..... . ........ ............ Rare-Element and Radioactive Minerals ....... ..... . Columbite-Tantalite ...................... ..... Pyrochlore-Microlite ........... . .............. Allanite ..................................... Tungsten Minerals .. ............. ... ..... ... ..... Scheelite ................. ... ......... .... . .. . Beryllium . .. . . .... . ....................... .. ... Beryl ... ... ........ ... ... ............ ... .... Nonmetallic Minerals ............................... Apatite ......................................... Asbestos ...... .. ....... .... ........... ......... Chrysotile .... . ..... ...... ....... ... ...... ... Barium .. . ... ..... .......... ... . .. ... .... . . ... . Barite .. ....... ........... ...... ... . .. . ...... Brucite .............. .......... .... .. .... .... .. . Strontium ..... ........ .. ........... ..... ....... Celestite ....... ..... ........... ...... ..... ... Corundum ..... ... ...... .. ........... .... ...... . Fluorspar .. ...... ................ ...... .. ....... Fluorite ... ....... .. .. ....................... Graphite .... ......... .. ..... ................... Kyanite ........................................ Magnesite .. . ... .. ......... ... ... ............... Sodalite .... ........ ............................ Lithium ..... ........................ ........ ... Spodumene .................................. Talc ....... ..... ... ... ..... .. ........... ....... Tourmaline ......... .. .......................... Vermiculite ......... ............. ........ ...... . 29 29 29 29 30 30 30 30 31 31 31 31 32 32 32 33 33 33 33 33 33 33 34 34 34 34 35 35 35 35 36 36 36 37 37 37 37 37 37 38 38 39 39 39 39 41 41 41 41 41 41 43 43 43 43 45 45 45 45 45 46 46 46 46 46 47 PAGE Rock Classification . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . Igneous Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sedimentary Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . Metamorphic Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristics of Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . Igneous Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mode of Occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . Basis of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . Common Igneous Rocks in Ontario . . . . . . . . . . . . . . . . . Granite . .. . ... .... . . ...... ... . .............. Rhyolite . . . . . ... ... .. . .. .. .. .... . ............ Syenite ..... . ... .. . . . . .... .. .. .... .. ......... Trachyte .... ... . ...... ...... . . . .. ........... Granodiorite . . .... ... . ..... . .. ............... Diorite .. ... ... .. ... . .. ..... ....... .......... Diabase .. . .. . .... .. .. .. .... ........ ......... Andesite .. . .. ... . ..... .. . . .. .... .. ... ....... . Gabbro .. . . .. ... . . .. . ............. ....... ... Basalt .. . .. . .. . . . . ........ . ................. . Peridotite .. ... . .. .. . . .. ... . ........... ....... Sedimentary Rocks . . .. . . . . . .. . .. . .. . . . . . ...... . .. . . . Common Sedimentary Rocks in Ontario ... . . . . . . ... . Conglomerate .. . .. ... .. . ... ..... . .... ... ..... Sandstone . . . . . . ........ . .. .. .. ............... Greywacke . ... ... ... ... ... .......... ..... ... Shale . . . .. .... ..... .. . . .. ......... .......... Tillite .. ... . .. . ..... ... ..... .. .. .. .... .. ..... Limestone . . ... . .. . .. . ..... . ... .... ... .. .. ... Salt ... .... . . . ... .. .. ....... . ... . ... .. . ..... . Gypsum .. . . . . . .. . . . . .. .. .. . . ....... .. .. ..... Coal ...... ... .. ... . . .... . .. .. .. .. .... .. ..... Structures in Sedimentary Rocks .. . .. .. . . ........ . . Bedding ...... ... ... .. ... .... . ..... .... ...... Crossbedding ... .. ... .. . .. .... ............... Grain Gradation ... ... .. . .. .......... ........ Ripple Marks ... .. ... . ...,. ... ... ...... . . .. .. Mud Cracks . .. . . .. ... . ... . . . .. . .. ........... Fossils .. . . . . . . . . . . .. . . . . . . .. .. . . . .. . . . ... .. . Metamorphic Rocks ... .. . ........ ... ...... .. . . ...... Common Metamorphic Rocks in Ontario ... ... .. .... . Gneiss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . Schist . . . .. . . . . . . . .. . . . . . . . . . .. . . . . . . . . .. . . . . Slate . . . . . . . . . . . . . . . . . . . . .. .. . . .. . . . . . . . . . . . . Quartzite . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . Marble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Geologic Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Folds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unconformities . . . . . . . . . . .. .. .. . . . . . . . . . . .. .. . References and Further Reading . . . . . . . . . . . . . . . . . . . . . . . . PART II GEOLOGY OF ONTARIO ............... .. ..... ..... Geological Map of Ontario . .. . . . . . . . . .. .. .. .. .. . The Geological Time Scale . .. . . . . . . .. .. .. . . . . . . . .. .. . . . Geological Regions of Ontario . . . . . .. . . .. .. . . .. .. .. . . . . . The Precambrian Shield .. .... ...................... Archean Rocks .. . .. . . . . .. . .. . . . .. . .. . .... . ... .. . Volcanic Rocks . . . . . . . . . . . . . . . . . . .. . . .. .. .. .. . Sedimentary Rocks ... . ... . .. . ..... .... ...... . Basic Intrusive Rocks .. . . . . . . . .. . . . . . . .. ... .. . Acid Intrusive Rocks ... .... . . ... .............. Unconformity ................................ Proterozoic Rocks ..... ... ....... ....... ......... Older Sedimentary Rocks ...................... Younger Sedimentary and Volcanic Rocks ... ..... Basic Intrusive Rocks .. . ............... ....... vi 49 49 49 49 49 50 50 50 51 51 52 52 52 52 53 53 53 53 53 53 55 56 56 56 56 57 57 57 57 57 57 58 58 58 58 58 58 58 58 59 59 59 59 59 59 60 60 60 60 60 60 61 61 61 63 64 64 64 64 65 65 65 66 66 66 66 The St. Lawrence Lowland . . . . . . . . . . . . . . . . . . . . . . . . . . . The Ottawa-St. Lawrence Basin .. .......... .. Southern Ontario .......................... Paleozoic Rocks .............. .................. Upper Cambrian .. ........................... Ordovician ... ... ............. .... ..... ....... Silurian ............. ... . ... ................. Devonian ...... . ... ......... .. . . ............ . The Hudson Bay Lowland .......... . ... .............. Physiography and Pleistocene Geology ................. References and Additional Reading .... .. ..... ......... .. . 66 66 67 67 67 67 71 71 71 73 76 PART III ECONOMIC MINERAL DEPOSITS OF ONTARIO ..... ... Gold . . . . . . . . . . . . . . .. . .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . . Mineralogy and Occurrence . . . . . . . . . . . . . . . . . . . . . . .. . . Ontario Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . History . . ... .. . . . . . . . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . Geological Features . . . . . . . . . . . . . . .. .. . . . . . . . . . . .. . . . Porcupine Area . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . Kirkland Lake-Larder Lake Area . . . . . . . . . . . . . . . . . . Red Lake Area .. . ...... .. . . .. .... . ...... ....... Silver .. ....... .......... . . .. . .. . .. ..... .. .. . .. ...... . Mineralogy and Occurrence ............... ..... ...... Ontario Production ... ........ ... . .. ........... .... . History ............. . .. ......... . .. .. . .. . ... ..... .. Geological Features ... . . .. . .. .. .... . . . .. . . . ... .. . .. . Thunder Bay Area . .... ......... ....... ......... Cobalt Area .. ... ... .. ... .... .. ... .. . ......... .. Cobalt .................... ... ...... .......... . .... .. . Mineralogy and Occurrence . . . ..... ... . . ... ....... . .. Ontario Production ......... .. . .. . ........ ... .... . .. . History and Geological Features ... ... .. . .. ....... . . . . Nickel ........................ ........ .. .. . . ...... ... Mineralogy and Occurrence . . ..... . .. ....... ... .. . ... Ontario Production ....... . . ..... .... . .... .. .. ... .. . History ..... ... .. . . . . . . . . . .. . . . . . . .. .. .. . .. . .. . .. . Geological Features . . . . . . .. . . .. .... .. ...... .. .. .. ... Sudbury Area ....................... ... . . . ..... . Copper .............. ... .. .. . ..... ... ..... . .. ... ... .. . Mineralogy and Occurrence . . .. ..... .. .. . ...... . . .. .. . Ontario Production ....................... . . .. . ..... History . ... ...... . . . . . . . . . . . . . . . . .. . .. . . . . . . ... .. . Geological Features .. .. . . . ........ .. ........ ....... . Manitouwadge Area .. . . .... ... . .. . .. . ...... ..... . Zinc .......................... ... .. . .. ...... . .... . . -. Mineralogy and Occurrence . .... .. . ... . .... ...... .. .. Ontario Production ........ . .. . . . . .. . .. . .. . . . .. .... . History . . . . . .. . .. ... . .. . . . . . . . . . .. .. .. . . . . . . . . . .. . Lead ....................... . . . . .. .... ... .. .... ...... . Mineralogy and Occurrence . . . .. ... ... . . . .. ... ... . .. . Ontario Production ..... . .. . ... . . . . .. .. ...... .... ... Iron ...................... .. . .. . . .. .. . .. .. . . .. . . . . . . . Mineralogy and Occurrence . . . ... . . . .. . .. . . . . . .. . .. . . Ontario Production ..... . .. ..... . . .. ... . .. . . .. . ... . . History .. . .. . .. .. . . . . . . . . . . . .. . . . . . . . . . . . . . ... . . . . . Geological Features .. . . . . .. . ..... . .. ............. .. . Algoma Steel Corporation, Algoma Ore Division . .. . Steep Rock Iron Mines Limited ........ . . .. . . . ... . . . Marmoraton Mining Company Limited . . . . . . . . . . . . . Lowphos Ore Limited .............. ... .... . . .. .. . Jones and Laughlin Steel Corporation Limited . . . . . . . . Uranium ........................ ... ....... ... . .. . . .. . Mineralogy and Occurrence .. . .. .. . . .. . . . . .. . . . . .. . .. . Ontario Production . .. . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . History .......... .. .. . . . . . . . . . . .. . .. .. .. . . . ...... . Geological Features . . .. . .. . .... . . .. ... .. . . . . ..... .. . Bancroft Area .. .. . .. . .. . . .. . . . . .. . .. . . . . .. .... . Blind River Area .. . .. . .. .. . . . . . .. ... . .. . . . .. .. . 77 78 78 78 78 79 79 80 83 85 85 85 85 87 87 87 88 88 88 88 88 88 88 88 91 91 91 91 91 92 93 93 93 93 93 93 93 93 93 94 94 94 94 96 96 97 98 98 99 99 99 99 99 102 102 102 vii PAGE Magnesium .... . ..... . ........ . ........ ...... ......... Platinum Metals ... ............. ............ .... ....... Asbestos ............... .............................. Mineralogy, Occurrence, and Use ... ...... .... .. ... ... Ontario Production ...... ...... ..................... History of Production ....................... ....... Geological Features ..... .. .......... ............... . Feldspar .......... .............. .. . . ................. Mineralogy, Occurrence, and Use . . .. ...... ........... Ontario Production .............. ....... ......... ... Fluorspar ....................... ... ...... .. .... ... .... Mineralogy, Occurrence, and Use ... ............ ... .... Ontario Production ............. .. ... . ........... .... Graphite ............................................. Mineralogy, Occurrence, and Use .... ...... ............ Ontario Production ..... ............ . ... ..... ........ Gypsum .. ..................... ............ .. ...... ... Mineralogy, Occurrence, and Use .. . ..... .. .. .. ....... Ontario Production .. ...... ..... ..... ... ........ ... . Mica ...................... .... .. .. .... .. ............ Mineralogy, Occurrence, and Use .. ...... . . .... ....... . Ontario Production .. .... .. ....................... .. Nepheline Syenite ..... .. ...... . ..... ...... ... ......... Mineralogy, Occurrence, and Use ........ .... . . .. .... . Ontario Production ... ...... ...... ...... ....... .... . Salt ...... ......................... ...... ........... . . Mineralogy, Occurrence, and Use .. . .. ... . . . .. ......... Ontario Production ..... ... . ............ ....... ..... Silica ... ........... ...... .. ...... . . ... ............... Mineralogy, Occurrence, and Use . .. .... .. ... . . .. . ... . Ontario Production ....... ... ........ . ... .. . .. ....... Talc .. .... ..... ...... .... ............ ...... .......... Mineralogy, Occurrence, and Use ..... ............... Ontario Production .. . ... ........ .... .. .. . . ..... . ... Structural Materials ................................... Bibliography ...... ......... ... ... .. .. ..... .. . .. .. ..... 102 103 103 103 103 103 104 104 104 104 104 104 104 105 105 105 105 105 105 105 105 105 106 106 106 106 106 106 107 107 107 107 107 107 108 108 Tables 1 2 3 4 5 6 Average composition of rock of the earth's crust . .. ...... Average content of twelve useful metals in the earth's crust Classification of igneous rocks . . . .......... ........... Types of sedimentary rocks ... . . .. ...... .. ...... .... The geological time scale . . . . . . . . . . . . ... . .. . . . .. . .. . Table of formations for the Paleozoic rocks of southern Ontario .. .............. ............. . ........... 2 2 51 55 61 67 Photographs Cover Ouimet canyon; Dorion township, District of Thunder Bay. 1 Massive hematite ... ....... ..... ..... .... ..... . . ..... 4 2 Acicular tremolite .................. ................. 5 3 Well crystallized galena ..... .... ............ ........ 6 4 Prismatic crystals of pyroxene .. ...... . ........ ........ 6 5 Halite, showing cubic cleavage ....................... 7 6 Phlogopite mica, showing perfect basal cleavage .......... 7 7 Pyrite crystals ... ... ..... ........................... 7 8 Conchoidal fracture of quartz, showing glassy lustre ... .. . 8 9 Fibrous fracture of chrysotile asbestos ......... ..... ... . . 8 10 Twin crystals of calcite ........ ............... ........ 10 11 Quartz crystals ........... .... ............... ... .. .. . 13 12 Orthoclase feldspar, showing cleavages ................. 14 13 Perthitic feldspar ... ..... .......... ..... .... .. .. ..... 14 14 Plagioclase feldspar showing twinning striae .. . .... . .. .... 15 15 Hexagonal crystal of phlogopite mica ........... ........ 17 16 Asterated phlogopite .... .... .. . . .. ...... . .. . ......... 17 17 Tremolite-actinolite showing radiating structure ... ... .... . 19 18 Actinolite ........ .. ......... ... ... ....... .... ....... 19 19 Nepheline-albite pegmatite, pitted .. .. .... .. . ... . ... .. .. . 22 viii PAGE 20 — Garnet crystals ... ........ .......... ........... . .. ... 21 — Staurolite crystals showing cruciform twinning .... . ... ... 22 — Sphene crystal ..... ................................. 23 — Scapolite crystals ... .. .............................. . 24 — Calcite, cleavage rhomb, showing double refraction ...... 25 — Gypsum, variety selenite .............................. 26 — Halite, showing cubic cleavage ........... .... ....... .. . 27 — Botryoidal hematite .... .. ..... ...... ... ....... ....... 28 — Dendritic native copper ....... ... .................... 29 — Galena, showing cubic cleavage ............ .. ....... ... 30 — Gold ore from the Chesterville mine .. ... ....... ..... ... 31 — Dendritic native silver in dolomite ..................... 32 — Betafite crystals ...... ... ... ........ ................. 33 — Beryl crystal .. .. .. . . ... . .. .. . .. . .. ... . .. . ... . . .... . 34 — Apatite crystal in calcite ............................... 35 — Chrysotile asbestos .................................. 36 — Coarse platy barite ................................... 37 — Celestite ................ ........ ....... .... .... ..... 38 — Hexagonal corundum crystal ....................... ... 39 — Fluorite crystals, showing cubic habit ................ ... 40 — Graphite ... ........................................ 41 —Trigonal crystal of striated tourmaline, showing termination 42 — Exfoliated vermiculite ................ ................ 43 — Jointing in a Keweenawan diabase dike ... ........... ... 44 — Porphyritic texture in an igneous rock .. . ........ ....... 45 — Diabase dike cutting granodiorite ... .. . ...... . ...... ... 46 — Pillowed basic volcanic rock .. ... ... . ..... ... ........ 47 — Bedded varved clay ..... ... . . ........................ 48 — Timiskaming conglomerate ........ .... ... ........ ..... 49 — Gently dipping Rove shales .. ... ......... ....... ... ... 50 — Bedded limestone deposit .. ...................... ..... 51 — Wave ripple marks in sandstone ........................ 52 — Banded gneiss ... ...... .. .... .. . .. ............. .... . 53 — Sunderland esker ... . . .. . . .. . ... . .................... 54 — Vein breccia, Lake Shore gold mine, Kirkland Lake ... .. . 55 — Madsen Red Lake gold mine ..... .... . .............. . . 56 — Smelter of International Nickel at Copper Cliff .... . . . .. . . 57 — Geco mine in 1962, Manitouwadge . . . . . . . .. ... . ..... .. . 58 — Helen mine in 1955, Wawa ........... .... .. . .. . . . . ... 59 — Open pit; Steep Rock Iron Mines Ltd. ........... ....... 60 — Pronto mine in 1958, Ontario's first uranium producer, Blind River ...... .. .......... ..... ............. . 61 — Munro mine and mill in 1959, Matheson . . . . . . . . . . . . . . . 62 — Nepheline syenite quarries and mill in 1959, Nephton .... 63 — Bedded rock salt in the Ojibway mine, Windsor ... ..... . 64 — Plant of Lake Ontario Portland Cement Co., Picton ... . . . 22 23 24 26 27 28 28 31 32 34 35 36 38 39 40 40 42 42 43 44 44 47 47 48 50 52 52 54 55 56 57 58 59 76 82 84 89 92 96 98 100 103 106 107 108 Figures 1 — Face-centred cubic structure of gold ..... .............. 2 — Cross-sections of pyroxene and amphibole, showing cleavages 3 — Geological features in cross-section ................... 4 — Geology and age of rocks in southern Ontario . .. ... ... 5 — Geology of Ontario ................................. 6 — Relationship between Proterozoic and Archean rocks ..... 7 — Regional geology of southwestern Ontario ......... .. .... . 8 — Generalized columnar geologic section, southwestern Ontario 9 — Niagara Escarpment ................................. 10 — Ice-fronts at the time of Lake Whittlesey . ............... 11 — Moraines and kames of southern Ontario . . ... ... . ...... 12 — Drumlin fields of southern Ontario ..... ... .... .... . . ... 13 — Principal mining areas of Ontario .. . ......... .. . ..... . 14 — Gold mines of the Porcupine area .. .......... ,.... ... . 15 — Mines of the Kirkland Lake-Larder Lake area ..... ..... 16 — Gold mines of the Red Lake area .. ... .... ...... .. .. . 17 — Cobalt silver area .................................... 18 — Nickel-copper producers of the Sudbury area, 1963 . . . . . . 19 — Steep Rock Lake iron area ............. ....... .... ... 20 — Mines of the Blind River area, 1964 .. .. . . . . . . . . .. . . . .. . ix 3 20 49 62 63 65 68 69 70 72 74 75 77 80 81 83 86 90 97 101 ACKNOWLEDGMENTS The author wishes to express appreciation to more than twenty persons, companies, and agencies for making available a variety of photographs, figures, and tables for this publication. In particular, the author is indebted to Dr. L. G. Berry of Queen's University, Kingston, Ontario; Dr. V. B. Meen, Chief Mineralogist, Royal Ontario Museum, Toronto, Ontario; David E. Jensen of Ward's Natural Science Establishment, Rochester, N.Y., U.S.A.; and H. R. Steacy of the Geological Survey of Canada, Ottawa, Ontario, for providing many photos; and to Dr. Walter M. Tovell of the Royal Ontario Museum, Toronto, Ontario, for several figures of southern Ontario geological features. Credit and acknowledgment for photos, figures, and tables are due to the following: L. G. Berry and B. Mason (Mineralogy; W. H. Freeman and Co., 1959, San Francisco, Calif., U.S.A.). Photos 7, 10, 15, 17, 20, 21, 22, 28, 41. Canadian Johns-Manville Co. Ltd., 565 Lakeshore Road East, Port Credit, Ontario, Photo 61. S. A. Ferguson (Ontario Dept. Mines). Photo 47 G. L. Fletcher and T. N. Irvine (Ontario Dept. Mines). Photo 45. Geological Survey of Canada, Ottawa, Ontario. Photos 25, 29, 33, 38. Figures 7, 8. Table 3. G. R. Guillet (Ontario Dept. Mines). Photos 36, 39. G. A. Harcourt (Ontario Dept. Mines). Photo 43. Pat Hodgson Studio, Picton, Ontario. Photo 64. George Hunter, l Benvenuto Place, Toronto 7. Photos 55, 56. Hunting Survey Corporation Ltd., Toronto. Photos 58, 59. J Katherine H. Jensen, 199 East Brook Road, Pittsford, N.Y., U.S.A. Photos 11, 24. C. W. Knight (Ontario Dept. Mines). Figure 17. Lake Shore Mines Ltd., 199 Bay Street, Toronto. Photo 54. Sid. Lloyd, Walkerville, Ontario. Photo 63. B. Mason (Principles of Geochemistry; Wiley and Sons Inc., New York, U.S.A.). Table 2. V. B. Meen (Royal Ontario Museum), Toronto. Photos 2, 3, 8, 13, 14, 27. Ontario Department of Mines (Public Relations and Publicity). Photo 57. Ontario Department of Tourism and Information. Cover photo. E. G. Pye (Ontario Dept. Mines). Photos 31, 46, 49, 51. Figure 6. Royal Ontario Museum, 100 Queen's Park, Toronto. Photos 4, 23. J. Satterly (Ontario Dept. Mines). Photos 19, 32. Sudbury Daily Star. Photo 60. Jas. E. Thomson (Ontario Dept. Mines). Photo 30 W. M. Tovell (Royal Ontario Museum). Figures 4, 9, 11, 12. (Figures 11, 12, after Chap man and Putnam.) Ward's Natural Science Establishment Inc.. Rochester 9, N.Y., U.S.A. Photos 5, 6, 9, 12, 16 18, 34, 44. K. Wyatt, River Road South, Peterborough, Ontario. Photo 62. Part I — Rocks and Minerals The earth's crust is composed of rocks, which are aggregates of one or more minerals. Minerals are composed of one or more of the chemical elements, of which more than a hundred are known to exist. Although there are over a hundred elements, nine of them are found in such abundance in the earth's crust that they make up over 99 percent of the crustal rocks. Table l gives the average composition of crustal rocks, listing the ten most common elements in order of importance. The nine common elements in Table l exist in nature combined with oxygen as complex oxides. The most common oxide to be found in the earth's crust is silica, which forms more than 59 percent of the "average" rock of the crust; therefore, most of the common minerals are silicates. Silica itself, SiO2, exists widely in the earth's crust as the mineral quartz. Alumina is found in nature as the mineral corundum, A12O3, one form of which is the precious stone, ruby. Corundum is the second hardest mineral known, being only slightly softer than diamond. Alumina is more commonly found in complex combination with oxides of iron, sodium, potassium, magnesium, and silicon, in such minerals as feldspar, mica, hornblende, and pyroxene, all of which are among the most common rock-forming minerals. Iron oxides are found as the minerals magnetite, Fe3O4 , and hematite, Fe2O3, and in the hydrated state as limonite, Fe2O3 . *H2O. Lime, soda, and potash are not found as such in nature; these three, with magnesia, which is found in nature as the mineral periclase, most commonly form complex min erals with silica and alumina to form the rock-forming minerals mentioned above. Titania is found as black lustrous crystals of rutile, and often is combined with iron oxide in the mineral ilmenite, FeTiO3. Water, H2O, is one of our most common and useful minerals. Of the ten most common elements in the earth's crust listed in Table l, only iron is found as a solid mineral in the native state. Many of the metallic elements such as gold, silver, copper, lead, and zinc, are rare, as a percentage of the total content, in the crustal rocks of the earth; but they frequently are found in abundance, locally concen trated as ore deposits and orebodies, where they can be commercially exploited and extracted. Table 2 gives the average percentage of useful metals in the earth's crust, the min imum percentage necessary in a deposit for profitable commercial extraction, and the concentration necessary to produce an orebody. It is seen that a concentration of five times the iron in the average crustal rock will produce an orebody; gold must be con centrated 156 times its average occurrence, and tin 3,333 times its average occurrence in the earth's crust. A mineral is a naturally occurring inorganic compound whose chemical composition and physical properties are either uniform or variable only within definite limits. A rock is a naturally occurring unit of the earth's crust composed of an aggregate of one or more minerals. 1 Minerals are formed in one of three ways: by crystallization from a molten rock magma or lava on cooling, as in the case of igneous rocks; by crystallization and deposi tion from water as chemical precipitates, as in the case of some sedimentary rocks; or by recrystallization or alteration due to heat, pressure, or the processes of weathering. Table 1 Average composition of rock of the earth's crust ELEMENT SYMBOL Oxygen Silicon Aluminium Iron Calcium Sodium Potassium Magnesium Titanium Hydrogen O Si Al Fe Ca Na K Mg Ti H OXIDE FORM WEIGHT PERCENT 46.71 27.69 8.07 5.05 3.65 2.75 2.58 2.08 0.62 0.14 Silica Alumina Iron Oxides Lime Soda Potash Magnesia Titania Water SiO2 A1203 FeO, Fe2O3 CaO Na2O K2O MgO Ti02 HZO Total 99.34 Table 2 Average content of twelve useful metals in the earth's crust (after Mason; Principles of Geochemistry, p. 48; Wiley and Sons Inc., 1958.) A: minimum percent for profitable commercial extraction. B: concentration necessary for an orebody. PERCENT METAL IN EARTH'S CRUST Iron Titanium Manganese Chromium Nickel Zinc Copper Lead Tin Uranium Silver Gold 5.0 0.6 0.1 0.02 0.008 0.0065 0.0045 0.0015 0.0003 0.0002 0.00001 0.00000005 A 25 35 30 1.5 4 1 4 1 0.1 0.025 0.0000078 B 5 350 1,500 188 615 222 266 3,333 500 2,500 156 PROPERTIES OF MINERALS Among the more important diagnostic properties of minerals are the following ten. The last nine may be grouped as physical properties. Chemical composition Structure Crystal form Cleavage Fracture Hardness Colour and streak Lustre Specific gravity Magnetic properties Chemical Composition. Minerals are chemical elements or compounds, and each mineral has a definite chemical composition or a range of composition within definite limits. Quartz, for example, has the chemical formula SiO2, in which two atoms of oxygen are combined with one of silicon. Quartz has a fixed or definite chemical composition, and quartz anywhere in the world is essentially 100 percent SiO^. Because neither silicon nor oxygen can be replaced easily in this structure, the mineral has a constant and fixed chemical composition. Figure 1 — Face-centred cubic structure of gold. Gold has the chemical formula Au and is composed of a regular face-centred cubic structure of gold atoms as shown in Figure 1. However, gold is frequently found to be alloyed with small amounts of silver, which has a similar cubic lattice structure but a slightly smaller size of atom. Silver atoms may proxy for gold in the crystal lattice. We then say that gold and silver form a "solid-solution" series, and alloys of all ranges of composition from pure gold to pure silver may be formed. Thus, the mineral gold may have a range of composition, depending on the proportion of silver in it. Similarly the zinc mineral, sphalerite, has the chemical composition ZnS, zinc sulphide. However, atoms of iron (Fe) may proxy in the crystal lattice for zinc, and the formula may then be written (Zn, Fe)S. Not only do these minerals have a well defined and definite crystal structure but they also have a range of chemical composition within well defined limits. Silica combines with one or more of the other common oxides to form the common rock-forming minerals, the silicates. Among the commonest silicate minerals are the feldspars, and these are composed of the following three components: Orthoclase KAlSi3O8 or K2O . A12O3 . 6SiO2 Albite NaAlSi3O8 or Na2O. A12O3 . 6Si62 Anorthite CaAl2SL,O8 or CaO . A1263 . 2SiO2 Although the minerals albite and anorthite have definite chemical compositions, they form a complete solid-solution series, known as the plagioclase series, whose compo sitions range from pure NaAlSi3O8 to pure CaAl2Si2O8. The chemical composition of a mineral is frequently used in ascertaining its identity. In the field, chemical reagents and blowpipe tests are used in determining some aspects of the composition; in the laboratory, chemical or spectrographic analyses are frequently employed. Chemical composition is not always an infallible criterion in the identification of mineral species because some minerals that possess widely different properties and appearances have the same chemical composition. For instance, the diamond, a crystalclear gem of unsurpassed hardness, has the same chemical composition as graphite, the flaky soft black mineral we use in "lead" pencils; both are varieties of carbon and have the same chemical formula, C. The difference in physical properties of these two dimorphous minerals is due to the difference in molecular arrangement of the carbon atoms. In diamond, the carbon atoms form a face-centred cubic unit cell; but in graphite the carbon atoms are in sheets that are widely spaced along the c axis of the hexagonal structure. Other minerals having the same chemical composition but occurring in two different forms are: calcite and aragonite, CaCO3 ; pyrite and marcasite, FeS2 ; and sphalerite and wurtzite, ZnS. Occasionally a chemical compound may have as many as three different and distinct forms; titania, TiO2 may be found as rutile, octahedrite, or brookite. The common mineral quartz has high-temperature polymorphous forms called tridymite and cristobalite, both varieties of SiOo. Photo l — Massive hematite; Madoc, Hastings county. Physical Properties of Minerals Structure. The term "structure" refers to the outward shape and form taken by the mineral. Structure may be described in many ways: crystallized, showing crystal form or crystal faces; massive, not bounded by crystal faces; fibrous, as in the case of asbestos minerals; micaceous or platy, as in the case of mica, which can be easily split into thin plates or sheets; earthy, as in the case of limonite, an iron oxide mineral; granular, or formed of aggregates of grains as in certain varieties of apatite; radiating, as in some varieties of tremolite; acicular or needle-like, as in other varieties of tremolite. Crystal Form. Many minerals exhibit characteristic crystal form that is the outward expression of their internal molecular arrangement. For example, the minerals galena, halite (common salt), pyrite, uraninite, and many others belong to the cubic or isometric crystal system, and may form crystals that are cubic, octahedral, dodecahedral, or pyrito hedral in shape. Other minerals may show prismatic or pyramidal form as do zircon, rutile, barite, and some varieties of pyroxene and amphibole. Other minerals may be six-sided or hexagonal, as are apatite, beryl, mica, and corundum. Cleavage. The tendency of a mineral to split along certain smooth planes that have definite geometric relationships one to another is known as cleavage. Minerals may have one direction of cleavage that is singularly good, and this is called basal cleavage, as in mica. Some minerals show two good cleavage planes, as in the case of feldspar, or three good cleavages at right angles, as in the case of galena or halite. The latter is termed cubic cleavage, and splitting of a sample of the mineral produces perfect cubes of vary ing sizes. The mineral calcite exhibits rhombic cleavage; it splits in three good cleavage direc tions that are not at right angles, to produce rhombic faces. Fracture. If a mineral possesses cleavage, it splits easily along certain smooth planes; if it lacks cleavage in certain directions, it will break along irregular surfaces. The type of fracture resulting may be diagnostic. Fracture may be described in several ways: conchoidal, as in glass or some glassy or vitreous minerals; irregular; smooth; hackly, as in silver; fibrous, as in asbestos. Photo 2 — Acicular tremolite; Hastings county. Photo 3 — Well crystallized galena. (Courtesy of V. B. Meen.) Photo 4 — Prismatic crystals of pyroxene; Cardiff township. (Courtesy of Royal Ontario Museum.) Photo 5 — Halite, showing cubic cleavage. (Courtesy of Ward's Natural Science Establishment.) Photo 6 — Phlogopite mica, showing perfect basal cleavage. (Courtesy of Ward's Natural Science Establishment.) Photo 7 — Pyrite crystals. A: cube. B: cube and octahedron. C: pyritohedron. D: octahedron. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) Photo 8 — Conchoidal fracture of quartz, showing glassy lustre. (Courtesy of V. B. Meen.) Photo 9 — Fibrous fracture of chrysotile asbestos. (Courtesy of Ward's Natural Science Establishment.) Hardness. Hardness is an important diagnostic property of minerals. The hardness of minerals varies greatly, from the softness of talc to the hardness of diamond, and the degree of hardness of a mineral is measured by its comparative resistance to abrasion or scratching. Mineral hardness, designated by numbers from l to 10, is estimated by comparing the hardness of a specimen with the hardness of standard minerals of predesignated hardness. The Mohs Scale of Hardness, used by mineralogists, is as follows: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Talc Gypsum (selenite) Calcite Fluorite Apatite Feldspar Quartz Topaz Corundum Diamond In testing hardness, the following figures are useful: the fingernail has a hardness of about 2.5 and will scratch selenite but will not scratch calcite; a knife blade has a hardness of about 5.5 and will scratch apatite but will not scratch feldspar; glass has a hardness of about 6 and can be scratched by quartz. The mineral apatite, No. 5 in this scale of hardness, will scratch fluorite and the minerals l to 4, but apatite will be scratched by feldspar and the minerals 6 to 10 in this scale. The relation of l to 10 in the Mohs Scale of Hardness does not indicate, however, that diamond is ten times as hard as talc and twice as hard as apatite. The relationship is not an exact mathematical one: the diamond (No. 10) is actually about 4 times as hard as corundum (No. 9) and 6 times as hard as topaz (No. 8). Colour and Streak. Colour is sometimes an important diagnostic feature of certain min erals, as is the azure blue of the copper mineral azurite, or the bright green of the copper mineral malachite, or the golden yellow of chalcopyrite, or the silver-grey of galena. However, many minerals do not have a particularly characteristic colour because in many instances the colour may depend on the type and amount of impurities. A small propor tion of iron, for example in a mineral such as quartz or calcite, may impart a pink or reddish colour to the mineral. It is often difficult to determine the colouring agent in a mineral such as tourmaline, which may be black, brown, red, green or colourless. The streak of a mineral is the colour of the powder of the mineral, and this colour may sometimes be diagnostic. The streak is often obtained by rubbing the mineral on a granular porcelain streak-plate. Hematite, for example, has a characteristic brownish red streak, although the colour of the specimen may be silver-red, through brown, to black. Lustre. The character of the variation in the reflecting surface of a mineral is known as the lustre of the mineral. Minerals such as quartz have a glassy lustre; sphalerite has a resinous lustre, like resin. Other minerals have pearly lustre, like mother-of-pearl; ada mantine, like diamond; dull, like talc; waxy, as in varieties of pyrochlore. Photo 10 — Twin crystals of calcite; Sudbury. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) Specific Gravity. The weight of a mineral compared with the weight of an equal volume of water is its specific gravity. This property is frequently very helpful in mineral deter mination. For comparison, the specific gravities of some common minerals are: quartz and feldspar, about 2.5 to 2.8; magnetite 5; galena 7.5. Specific gravity is a helpful diag nostic feature of barite (4.5) and corundum (4), both of which are heavier than most other non-metallic minerals. Magnetic Properties. The magnetic properties of magnetite and pyrrhotite are diagnostic. A magnet will attract powdered magnetite or pyrrhotite. Other Properties. Other diagnostic properties such as twinning, fluorescence, phosphor escence, feel, odour, taste, tenacity, radioactivity, effervescence in acid, etc., may be helpful in certain circumstances. The introduction of the geiger counter, for example, made the property of radioactivity very important in prospecting for radioactive minerals of all kinds. A fluorescent lamp may be helpful in prospecting for fluorescent ore min erals such as scheelite (the tungsten ore) or willemite (the zinc ore). Hydrochloric acid is frequently used in the field to distinguish calcite from dolomite: calcite effervesces vigourously in cold hydrochloric acid, but dolomite shows little or no effervescence. 10 COMMON MINERALS OF ONTARIO Seventy-three of the more common minerals of Ontario are described here. They are conveniently listed below in five classifications and, where applicable, the group name is given. Primary Rock-Forming Minerals of Igneous and Metamorphic Rocks: Quartz Orthoclase, microcline } Plagioclase JFeldspar group Muscovite l Phlogopite V Mica group Biotite J Hornblende ] Actinolite ^Amphibole group Tremolite J Augite l Hypersthene ^Pyroxene group Diopside J Olivine Nepheline Garnet — Garnet group Staurolite Zircon Titanite (sphene) Secondary Minerals, often Formed by Alteration: Kaolin — Clay group Serpentine — Serpentine group Chlorite — Chlorite group Epidote — Epidote group Scapolite — Scapolite group Sedimentary Rock-Forming Minerals: Calcite Dolomite Gypsum Halite 11 Metallic Ore Minerals: Magnetite Ilmenite Pyrite Pyrrhotite Iron minerals Siderite Hematite Limonite J Native Copper Chalcopyrite Bornite Copper minerals Chalcocite Azurite Malachite Pentlandite l Vf . . , Niccolite J Nlckel Cobaltite l . Smaltite J Cobalt minerals Galena — Lead mineral Sphalerite — Zinc mineral Native gold — Gold mineral Native silver Argentite ^ Silver minerals Molybdenite — Molybdenum mineral Uraninite l Pitchblende Uranium minerals Uranothorite j Columbite-Tantalite 1 -. , Pyrochlore-Microlite Rare-element and Allanite j radioactive minerals Scheelite — Tungsten mineral Beryl — Beryllium mineral Nonmetallic Minerals: Apatite Chrysotile — Asbestos mineral Barite — Barium mineral Brucite Celestite — Strontium mineral Corundum Fluorite — Fluorspar Graphite Kyanite Magnesite Sodalite Spodumene — Lithium mineral Talc Tourmaline Vermiculite — Altered micas 12 Photo 11 —Quartz crystals. (Courtesy of Katherine H. Jensen.) Composition, Characteristics, and Occurrence of Common Minerals. The common pri mary rock-forming minerals of igneous rocks can be divided into two groups: the lightcoloured or leucocratic minerals such as quartz and feldspar; the dark-coloured ferro magnesian minerals such as amphibole, pyroxene, and biotite mica. Primary Rock-Forming Minerals QUARTZ Quartz silicon dioxide, Si(X Properties. Hardness 7. Specific gravity 2.6. Colour is variable: frequently colourless, white, smoky, but may be rose, blue, yellow, purple, etc. Lustre, glassy. Conchoidal fracture. Generally shows no cleavage. Occurrence. A very common leucocratic rock-forming mineral found in many igneous and metamorphic rocks such as granite, granodiorite, granite pegmatite, gneiss, etc. It forms the major mineral in many sands, sandstones, and quartzites; very common in veins. Ontario Localities. Beautiful clusters of piezoelectric-grade quartz crystals are mined at Lyndhurst (Leeds co.); these are found also at Marble Rock (Leeds co.). Rose quartz is found in a granite pegmatite near Quadeville (Lyndoch twp., Renfrew co.). Amethyst, the purple variety of quartz, is found in good crystals at Amethyst Harbour (MacGregor twp.) and Thunder Bay (Dist. Thunder Bay, on Lake Su perior). Agate is found filling cavities in basic volcanic rocks on islands in Lake Superior east of Sibley Peninsula (Lakehead area) and on Michipicoten Island (northeastern part of Lake Superior). Quartzite is quarried at Whitefish Falls (Curtin twp., Dist. Sudbury); at Killarney quarry (Killarney twp., Dist. Manitoulin), and at Sheguiandah (Howland twp. on Manitoulin Island). 13 Photo 12 — Orthoclase feldspar, showing cleavages at right angles. (Courtesy of Ward's Natural Science Establishment.) Photo 13 — Perthitic feldspar, an intergrowth of microcline and albite; Hybla, Hastings county. (Courtesy of V. B. Meen.) 14 Photo 14 — Plagioclase feldspar, showing twinning striae on a cleavage plane. (Courtesy of V. B. Meen.) THE FELDSPAR GROUP The principal members of the feldspar group are the potassium feldspar, orthoclase, and the soda-lime feldspars of the plagioclase series which includes albite, oligoclase, andesine, labradorite, bytownite, and anorthite. Orthoclase potassium aluminium silicate, KAlSi3O8 Properties. Hardness 6. Specific gravity 2.6. Two good cleavages at right angles. Colour frequently pink, red, white, grey, or buff. Streak is white. The variety microcline is triclinic, but orthoclase is monoclinic. Occurrence. Orthoclase is the most common rock-forming silicate mineral and an impor tant constituent of many igneous rocks, particularly granite and syenite. Common in metamorphic gneisses; also occurs with quartz in pegmatite dikes where micro cline is the common variety. Ontario Localities. Formerly mined extensively from granite pegmatites near Hybla (Hastings co.), near Verona (Frontenac co.), and near Perth (Lanark co.). Micro cline in these pegmatite dikes may grow in crystals 15 to 20 feet across and weighing up to 30 tons. The green variety of microcline, called amazonstone, is prized for gem-cutting and has been found at Hybla, Quadeville, Eganville, Mattawa, and on the shores of Lake Nipissing. The variety sunstone, showing a golden iridescence, is found near Hybla (Hastings co.) and Madawaska (Dist. Nipissing). The variety perthite is an intergrowth of microcline and albite and is named after its type locality near Perth (Lanark co.). 15 Plagioclase (a solid-solution series of which the two end members are albite and anorthite) Albite: Oligoclase: Andesine: Labradorite: Bytownite: Anorthite: sodium aluminium silicate, j 70-90 percent grades 50-70 percent to 30-50 percent j 10-30 percent calcium aluminium silicate, NaAlSi8Os NaA!Si3O8 NaAlSisOs NaAlSio,Os NaAlSi3O8 CaAlaSiL.Os Properties. Hardness 6. Specific gravity 2.6 to 2.76. Two good cleavages almost at right angles; twinning striations commonly seen on one cleavage face. Colour fre quently white, grey, blackish grey, green, pink. Streak is white. Distinguished from orthoclase by the twinning striations. A bluish iridescence may be present on cleav age faces in albite (variety peristerite) and labradorite. Occurrence. A very common rock-forming silicate mineral. Found in many igneous and metamorphic rocks including granite, diorite, gabbro, and gneiss. Also found in pegmatite dikes with quartz and microcline. Ontario Localities. Found commonly in granite pegmatites in the Perth, Hybla, and Verona areas. Good iridescent peristerite is found in Monteagle township (Hastings co.), Galway township (Peterborough co.); Bathurst township (Lanark co.), and Strong township (Dist. Parry Sound). THE MICA GROUP The three main members of the mica group discussed here are: muscovite (white mica) phlogopite (amber mica) biotite (black mica) Muscovite hydrous potassium aluminium silicate Properties. Hardness 2 to 2.5. Specific gravity 2.8 to 3. Perfect basal cleavage, splits into thin sheets; sheets are flexible or elastic. Colourless in thin sheets; silvery, brownish, or reddish in thick books. A good electrical insulator. Occurrence. A common rock-forming silicate mineral found in granite, syenite, and other igneous rocks, and in metamorphic rocks such as gneisses and mica schists; also common in granite pegmatite dikes. Ontario Localities. Found in many granite pegmatite dikes in Eastern Ontario. A bonanza muscovite deposit (the Purdy mine) was found in 1941 at Eau Claire (near Mattawa) where about 3,000,000 pounds of mica valued at S l,577,000 was mined during a 10-year period. One large mica crystal from the Purdy mine meas ured 9Vi by 7 feet and almost 3 feet thick; a sheet of this mica crystal is on exhibit at the Royal Ontario Museum, Toronto. Muscovite has also been mined at Caribou Lake (Dist. Nipissing); Methuen township (Peterborough co.); and Effingham township (Lennox and Addington co.). Curved crystals occur at Craigmont (Ren frew co.). 16 Photo 15 — Hexagonal crystal of phlogopite mica; Frontenac county. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) Photo 16 — Asterated phlogopite; Bedford township. (Courtesy of Ward's Natural Science Establishment.) 17 Phlogopite hydrous potassium magnesium aluminium silicate Properties. Same as muscovite but amber in colour; may be almost black in thick books. Occurrence. Commonly found in Grenville marble, serpentine, metamorphic pyroxenite, and basic pegmatite dikes, with diopside, apatite, and scapolite. Ontario Localities. Formerly extensively mined in eastern Ontario in North Burgess township (Lanark co.) near Perth, and in Bedford township (Frontenac co.). The most famous phlogopite mine was the Lacey mine near Sydenham (Frontenac co.), which produced for over 40 years. Crystals up to 7 feet across were mined. One of these is in the Miller Museum at Queen's University, Kingston. Triboluminescent and asterated phlogopite has been found in the Perth-Westport area. Biotite hydrous potassium magnesium iron aluminium silicate Properties. Hardness 2.5 to 3. Specific gravity 2.8 to 3.4. Perfect basal cleavage; splits into thin sheets that are flexible or elastic. Colour is black. Opaque to translucent. Distinguishable from other micas by its black colour. Occurrence. A common rock-forming ferromagnesian mineral found in granite, syenite, and other igneous rocks, and in metamorphic rocks such as gneisses and schists; also common in granite pegmatite dikes. Ontario Localities. Commonly found as good crystals in granite pegmatite dikes in parts of eastern Ontario. Large crystals of an unusual black mica are found in a calcite body at the Silver Crater mine (Faraday twp., Hastings co.); associated minerals are calcite, apatite, and betafite. Biotite crystals are common in the nepheline peg matites along the York River (Dungannon twp., Hastings co.). THE AMPHIBOLE GROUP The most important rock-forming mineral of the amphibole group is hornblende; it occurs in igneous and metamorphic rocks. The minerals actinolite and tremolite are common in metamorphic rocks. Hornblende hydrous calcium magnesium iron aluminium silicate Properties. Hardness 5.5. Specific gravity 3.2. Two good prismatic cleavages intersect at 56 0 and 124 0 . Vitreous lustre. Colour is black to dark green or brown. May often be found as six-sided prismatic crystals. Most easily distinguished from pyroxene by its cleavage angles. Occurrence. Hornblende is one of the most common rock-forming ferromagnesian min erals and occurs in granite, syenite, diorite, hornblendite, gneisses, and schists. Ontario Localities. Unusually large and well formed crystals are found lining the walls of calcite-apatite veins at Tory Hill (Haliburton co.) and near Eganville (Renfrew co.). Good crystals of hornblende are found at the Richardson feldspar mine (Bed ford twp., Frontenac co.), Fission mine (Cardiff twp., Haliburton co.); Silver Crater mine and Faraday uranium mine (Faraday twp., Hastings co.). Actinolite hydrous calcium magnesium iron silicate Properties. Hardness 5.5. Specific gravity 3.2. Perfect prismatic cleavage at 56 0 and 124 0 . Colour is light to dark green. Often found in fibrous or radiating crystalline masses. Distinguishable from hornblende by its colour and sometimes by its struc ture. 18 Photo 17 Tremolite-actinolife, showing radiating structure; Verona, Frontenac county. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) Photo 18 Actinolite; Barrie township. (Courtesy of Ward's Natural Science Establishment.) 19 Occurrence. More commonly occurs in metamorphic rocks such as marble, schist, gneiss; sometimes in metavolcanic rocks. An asbestiform mineral. Ontario Localities. Actinolite was mined for many years at the town of Actinolite (near Madoc, Hastings co.), for use as roofing granules. Good actinolite is found in the Tomahawk mine (Lake twp., Hastings co.), in Sebastapol township (Renfrew co.), and in Grimsthorpe township (Hastings co.). Tremolite hydrous calcium magnesium silicate Properties. Hardness 5.5. Specific gravity 3. Good prismatic cleavage at 56 0 and 124 0 . Colour is white to grey. Often in fibrous, radiating, or prismatic crystals. An asbes tiform mineral. Occurrence. More commonly found in metamorphic rocks such as schist, marble. Ontario Localities. Once mined in Blithfield township (Renfrew co.). Occurs with talc at Madoc (Hastings co.). "Cat's eye" variety at Wilberforce (Monmouth twp., Haliburton co.), near Denbigh (Denbigh twp., Lennox and Addington co.), and Hardwood Lake (Raglan twp., Renfrew co.). O.D.M.1556 Pyroxene Amphibole Figure 2 — Cross-sections of pyroxene and amphibole showing cleavage at 90 0 in the pyroxene and at 56 0 and 124 0 in the amphibole. THE PYROXENE GROUP Together with the minerals of the amphibole group, the pyroxenes form the most common rock-forming ferromagnesian minerals. Three common pyroxene minerals here described are augite, hypersthene, and diopside. Augite calcium magnesium iron aluminium silicate, Ca(Mg, Fe, Al) (Al, Si)2Oc Properties. Hardness 5.5. Specific gravity 3.3. Two good cleavages almost at right angles. Colour is dark-green to black. Lustre is vitreous to glassy. Characteristic 4- or 8-sided prismatic crystals. Distinguishable from hornblende by its right-angled prismatic cleavage, and often by its green colour. Occurrence. A very common ferromagnesian mineral in volcanic rocks, gabbros, py roxenite, and similar basic intrusive rocks. 20 Ontario Localities. In good crystals in eastern Ontario, particularly near Eganville (Ren frew co.), Hybla area (Hastings co.), Opeongo station (Dickens twp., Dist. Nipis sing), the Richardson feldspar mine (Bedford twp., Frontenac co.), and the Bathurst feldspar mine (Bathurst twp., Lanark co.). Hypersthene iron magnesium silicate, (Fe, Mg) SiO3 Properties. Hardness 5.5 to 6. Specific gravity 3.4 to 3.5. Good prismatic cleavage at right angles. Colour is grey, greenish, bronze-brown, to nearly black. Lustre is pearly to submetallic (bronzite). Occurrence. Common in norite; frequently found in metamorphic gneisses. Ontario Localities. In the Sudbury norite and other norite rocks. Diopside calcium magnesium silicate, CaMgSi2O0 Properties. Hardness 5.5. Specific gravity 3.3. Perfect prismatic cleavage at right angles. Colour is white, grey, or light green. Transparent to translucent. Occurrence. A common pyroxene mineral in metamorphic rocks, especially marble, pyroxenic amphibolites, and metamorphic pyroxenite. Common in basic pegmatite dikes with scapolite, calcite, phlogopite, and apatite association. Ontario Localities. Good crystals at Birds Creek (Hastings co.), Tory Hill (Haliburton co.), Dog Lake (Storrington twp., Frontenac co.), and in North Burgess township (near Perth, Lanark co.). OLIVINE Olivine iron magnesium silicate, (Fe, Mg)2 SiO4 Properties. Hardness 6.5 to 7. Specific gravity 3.3 to 3.6. Conchoidal fracture. Vitre ous lustre. Colour is olive to grey-green. Generally distinguishable by its green colour, conchoidal fracture, glassy lustre, and granular structure. Transparent to translucent. Occurrence. A common rock-forming mineral in basic and ultrabasic rocks that are deficient in silica, such as peridotite, dunite. Occasionally in basalt. Ontario Localities. Common in ultrabasic intrusives in the Matheson area of north eastern Ontario. Olivine crystals occur in a skarn zone at the York River (Dun gannon twp., Hastings co.). NEPHELINE Nepheline sodium aluminium silicate, NaAlSiO4 Properties. Hardness 5.5 to 6. Specific gravity 2.5 to 2.6. Subconchoidal fracture. Good prismatic cleavage. Greasy to glassy lustre. Colour is white, grey, pink. Distinguishable on weathered surfaces by its dove-grey pitted surface; the nepheline weathers more readily than the accompanying feldspar that stands up in relief. Occurrence. In alkaline igneous rocks deficient in silica; never found with free quartz. Most commonly in nepheline syenite, and nepheline gneisses, often with scapolite and feldspar. Ontario Localities. Commonly found in the Haliburton-Bancroft area of eastern Ontario where it is found in gneisses and in nepheline pegmatites. Excellent hexagonal prismatic crystals are found on joint surfaces near Bancroft. Good crystals are found at Nemegosenda Lake (Dist. Sudbury). 21 Photo 19 — Nepheline-albite pegmatite, showing grey pitted weathered surface of nepheline; Monmouth township. Photo 20 — Garnet crystals. A: trapezohedron. B: trapezohedron and dodecahedron. C: dodecahedron and trapezohedron. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) GARNET GROUP Garnet lime, magnesia, iron, alumina silicates Four of the more common members of the garnet group are: almandine, Fe3Al2Si3O ]2 pyrope, Mg3Al2Si3O 12 grossularite, Ca3Al2Si3Oi2 andradite, Ca3Fe2Si3O12 Properties. Hardness 6 to 7.5. Specific gravity 3.5 to 4.3. Conchoidal fracture; no cleavage. Transparent to translucent. Colour is red, brown, black, green, or yellow. Glassy lustre. Found commonly as dodecahedral (12-sided) crystals, but also found in massive or granular form. Occurrence. A common metamorphic mineral in schists and gneisses. Ontario Occurrences. At the Ruby mine (Ashby twp., Lennox and Addington co.). In large crystals near River Valley (Dist. Nipissing). At the Emily mine (near Gilmour, Tudor twp., Hastings co.). At Fishtail Lake (Harcourt twp., Haliburton co.). Massive garnet occurs on the York River in Monteagle twp., (Hastings co.), and in Raglan township (Renfrew co.). 22 Photo 21 ——Staurolite crystals, showing cruciform twinning. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) STAUROLITE Staurolite hydrous iron aluminium silicate, FeAl4Si2O 10(OH)2 Properties. Hardness 7.5. Specific gravity 3.7. Fracture subconchoidal; cleavage (010). Subvitreous lustre. Colour is reddish brown to brownish black. Translucent to opaque. Often found in good prismatic crystals sometimes twinned to form a cross. Occurrence. In typical brown crystals in schists and gneisses; a high-grade metamorphic mineral. Ontario Occurrences. Good crystals are found at Fernleigh (Clarendon twp., Frontenac co.) and Nipigon (Nipigon twp., Dist. Thunder Bay). ZIRCON Zircon zirconium silicate, ZrSiO4 Properties. Hardness 7.5. Specific gravity 4.7. Poor cleavage. Conchoidal fracture. Adamantine lustre. Colourless, yellow, brown, reddish brown in colour. Trans parent to translucent. Commonly found in characteristic prismatic bipyramidal crystals. Occurrence. A common accessory mineral in igneous rocks such as granite and syenite where it is found in minute crystals. Found as large crystals in granite, syenite, and nepheline pegmatite, and in metamorphic pyroxenite of the Grenville Province in eastern Ontario. Ontario Localities. Large tetragonal crystals common in pegmatites of the Bancroft region at Saranac mine (Cardiff twp.), Fission mine (Cardiff twp., Haliburton co.); Brudenell township (Renfrew co.), Lake Clear (Renfrew co.), Sebastopol township (Renfrew co.), and Hybla (Hastings co.). Crystals common in nepheline pegmatites, especially in Monmouth township (Haliburton co.) and Dungannon township (Hastings co.). 23 Photo 22 —Sphene crystal; Frontenac county. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) TITANITE (Sphene) Sphene calcium titanium silicate, CaTiSiO5 Properties. Hardness 5 to 5.5. Specific gravity 3.4 to 3.5. Prismatic cleavage; con choidal fracture. Resinous lustre. Commonly dark brown to honey-yellow in col our. Found in characteristically wedge-shaped or diamond-shaped crystals, some times massive; may be twinned. Transparent to opaque. Occurrence. In metamorphic rocks, schist, gneiss, marble, metamorphic pyroxenite. A common accessory mineral in granite and syenite. In pegmatites. Ontario Localities. In large crystals in the Haliburton-Bancroft area, and near Eganville (Renfrew co.), Sebastopol township (Renfrew co.), Lake Clear (Renfrew co.), Monmouth township (Haliburton co.), and near Westport (North Crosby twp., Leeds co.). 24 Secondary Minerals, often Formed by Alteration CLAY GROUP The clay minerals are commonly found in clay and shale deposits, of which they make up a large part. They are formed by the weathering and alteration of primary rock-forming minerals such as feldspar. Clay minerals are generally very fine-grained and are therefore very difficult to distinguish in hand specimens. The presence of clay minerals in a sample of fine-grained material is sometimes indicated by the plasticity of the material when it is moistened; plasticity is typical of wet clay soils. One of the com mon clay minerals is kaolin. Kaolin hydrous aluminium silicate, H4Al2Si2O9 Properties. Hardness 2 to 2.5. Specific gravity 2.6. Good basal cleavage, but this is rarely evident in fine-grained hand specimens. Lustre is dull to earthy. Colour is white to grey; may be stained brown or red by iron oxide impurities. Occurrence. A common alteration product of feldspar; found in clay soils, shales, etc. Ontario Localities. In the Perth area where it is an alteration of feldspar; in beds in the Cretaceous rocks of the Moose River basin in northern Ontario. SERPENTINE GROUP Serpentine hydrous magnesium silicate, H4 Mgp,Si2O0 Properties. Hardness 2.5 to 4. Specific gravity 2.5 to 2.6. Lustre greasy to waxy. Frac ture conchoidal or splintery; cleavage poor. Structure massive, platy, or fibrous. Colour is green, white, yellow, brownish red. Streak is white. Translucent to opaque. Often has greasy or slippery feel. Occurrence. Serpentine alteration commonly found in marble, peridotite, and dunite. Chrysotile asbestos is a variety of serpentine. Ontario Localities. In marbles in eastern Ontario as at Marble Bluff (Lanark co.). Serpentinized marble is found in a small quarry in Haliburton village, also near Madoc. In ultrabasic rocks in northern Ontario as at Matheson where the columnar variety picrolite is found in the Munro asbestos mine (Munro twp., Dist. Cochrane). CHLORITE GROUP Chlorite hydrous magnesium iron aluminium silicate Properties. Hardness 2 to 2.5. Specific gravity 2.6 to 2.9. Good basal (micaceous) cleavage. Vitreous to pearly lustre. Colour is generally green; sometimes black, brown, yellow. Usually found in foliated aggregates or pseudomorphs as an acces sory mineral of pyroxene, hornblende, and biotite. The folia are not elastic, and in this it differs from mica. Occurrence. A common metamorphic alteration of ferromagnesian minerals in intru sive and volcanic rocks. The green colour of "greenstones" so common in northern Ontario is usually due to chloritic alteration. Chlorite is found near Stanleyville (Lanark co.), in Tudor township (Hastings co.), and in Barrie township (Frontenac co.). 25 EPIDOTE GROUP Epidote hydrous calcium aluminium iron silicate Properties. Hardness 6 to 7. Specific gravity 3.3 to 3.5. Colour is often characteristic pistachio green; also yellow, brown, black. Transparent to opaque. Perfect basal cleavage; uneven fracture. Vitreous lustre. Often in striated prismatic crystals, or granular masses. Occurrence. A metamorphic alteration of basic intrusive and volcanic rocks, limy sedi ments, schists, and gneisses. Epidotized granites and syenites are not uncommon. Ontario Localities. Of widespread minor occurrence. In basalt near Madoc. Good crystals of epidote in Harker township (Dist. Cochrane). Epidote is also found at the Emily mine near Gilmour (Tudor twp., Hastings co.), at the Faraday mine (Faraday twp., Hastings co.), at the Marmoraton mine (near Marmora), and at Kaladar. SCAPOLITE GROUP Scapolite sodium calcium aluminium silicate with chlorine and carbonate Properties. Hardness 5 to 6. Specific gravity 2.7. Lustre vitreous to greasy. Prismatic cleavage. Subconchoidal fracture. Colour is white, grey, blue, green, pink. May fluoresce orange or yellow. Transparent to translucent. Often found as good prismatic crystals; also found in granu lar form. Occurrence. A metamorphic alteration in marble, metamorphic pyroxenite, gab bro, basic volcanic rocks, amphibolite, nepheline gneisses. A common contact metamorphic mineral in marble contact and skarn zones. Photo 23 — Scapolite crystals; Leeds county. (Courtesy of Royal Ontario Museum.) 26 Ontario Localities. Good large prismatic crystals associated with basic pyroxeneapatite-phlogopite pegmatites in meta morphic pyroxenite and marble near Perth and Verona. A common mineral in nepheline gneisses of the Bancroft area where some varieties turn blue on weathered surfaces. As does nepheline, scapolite easily weathers-out on exposed rock surfaces, causing pitting. Good crystals from Topspar mine (Harcourt, Cardiff twp., Haliburton co.), Monteagle township (Hastings co.), Craigmont (Renfrew co.), Old Spain mine (Griffith twp., Renfrew co.), and Drag Lake ,^ TT ,., . (Dudley twp., Haliburton CO.). Sedimentary Rock-Forming Minerals Calcite calcium carbonate, CaCO3 Properties. Hardness 3. Specific gravity 2.7. Perfect rhombic cleavage. Vitreous to earthy lustre. Colour is often white to colourless, but can be red, pink, blue, grey, black, yellow, etc. Opaque to transparent. Frequently is found as good prismatic or rhombohedral crystals. The transparent variety of calcite is called iceland spar and is used in optical instruments. Also common in massive aggregates. Effervesces vigorously with hydrochloric acid. Photo 24 — Cleavage rhomb of calcite, variety iceland spar, showing double refraction. (Courtesy of Katherine H. Jensen.) Occurrence. A very common mineral that is the chief constituent of limestone and marble. Also is found in veins. Good crystals are frequently found lining vugs or cavities in veins and limestone strata. Ontario Localities. Common throughout Ontario. Good crystals from Faraday mine (Faraday twp.) and Madoc (Hastings co.); in vugs in limestone at Amherstburg (Essex co.). Orange calcite is found at Macdonald mine (Monteagle twp., Hastings co.). Purple calcite is found at the Frontenac lead mine (Frontenac co.). Salmonpink calcite is found with apatite, near Perth Road (Frontenac co.). Good crystals at Sudbury, and at the Galetta mine (Renfrew co.). Dolomite calcium magnesium carbonate, Ca Mg (CO3)2 Properties. Hardness 3.5 to 4. Specific gravity 2.9. Perfect rhombic cleavage. Glossy to pearly lustre. Colour is white, grey, pink, brown, green, black. Opaque to trans parent. Found as rhombohedral crystals, or more commonly in aggregates. Effer vesces weakly in acid. Occurrence. Dolomite is one of the commonest sedimentary minerals because it makes up a large part of dolomitic limestones and nearly all of dolomite rock. "Dolomite" is a rock name for a monomineralic rock composed of the mineral "dolomite". Dolomitic marble is common. Also occurs in veins. Ontario Localities. Dolomite is mined for the production of magnesium metal at Haley Station (Ross twp., Renfrew co.) by Dominion Magnesium Limited. 27 Photo 25 — Gypsum, variety selenite. (Courtesy of Geological Survey of Canada.) Photo 26 — Halite, showing cubic cleavage; Windsor. 28 Gypsum hydrous calcium sulphate, CaSO4 . 2H2O Properties. Hardness 2. Specific gravity 2.3. Colourless variety selenite shows one excellent platy cleavage and two rhombic cleavages making angles of 66 0 and 114 0 with one another. Lustre is vitreous, pearly, or silky. Colour is white; can also be colourless, grey, reddish, or brown. Transparent to opaque. May be found as crystals, but is more commonly found as massive, bedded deposits. Sectile. Con choidal or fibrous fracture. Fibrous veins are called "satin spar." Ontario Localities. Found in mineable beds in the Salina Formation of Silurian age in southern Ontario. Mined at Caledonia (Seneca twp., Haldimand co.) and Hagersville (Brant and Haldimand counties). Good selenite comes from the Kingdon mine at Galetta, and from the Faraday mine (Faraday twp., Hastings co.). Halite (common salt) sodium chloride, NaCl Properties. Hardness 2.5. Specific gravity 2.2. Cubic cleavage. Transparent to trans lucent. Colourless or white; impure varieties may be reddish or yellow. Salty taste. Usually is found as massive beds, but sometimes as cubic crystals. Occurrence. A common mineral of sedimentary rocks; found as sedimentary beds asso ciated with gypsum, sylvite, and other chemical precipitates. Characteristic of a desert type of environment where evaporation exceeds runoff. Ontario Localities. Rock salt is mined at Windsor and Goderich, where it is found in beds up to 200 feet thick in the Salina Formation of Silurian age. The beds are at depths of 1,000 to 2,000 feet. Metallic Ore Minerals IRON MINERALS Magnetite iron oxide, Fe3O4 Properties. Hardness 6. Specific gravity 5.2. Found as octahedral crystals, cubes, or in granular or massive form. Metallic lustre. Colour is iron-black. Streak is black. Magnetic. Opaque. Can be distinguished from ilmenite by its strong magnetism. Occurrence. A common minor accessory in igneous rocks; also a common iron-ore mineral in magmatic segregation and contact metamorphic types of iron orebodies. Also occurs in "black sands." Often occurs in iron formation. Ontario Localities. Mined at Marmora in eastern Ontario; small deposits common in rocks of the Grenville Province in eastern Ontario. Good crystals from Bow Lake iron mine (Faraday twp., Hastings co.) and from Glamorgan township (Haliburton co.) Ilmenite iron titanium oxide, FeTiO3 Properties. Hardness 5.5 to 6. Specific gravity 4.7. Occurrence is massive or in crystals. Lustre is metallic to submetallic. Colour is iron-black. Streak is black to brownish red. Opaque. Distinguishable from magnetite by its lack of strong magnetism. Ilmenite becomes magnetic when heated. Occurrence. Same as magnetite. Often associated with magnetite in titaniferous iron orebodies. An ore mineral of iron, titanium, and titanium dioxide. Ontario Localities. Ilmenite is found at the Faraday mine (Faraday twp., Hastings co.) and in the Flinton area (Kaladar twp., Lennox and Addington co.) 29 Pyrite iron disulphide, FeS2 Properties. Hardness 6 to 6.5. Specific gravity 5. Occurrence is massive, fine granular, or as cubic crystals; crystals often striated. Lustre metallic. Colour is pale brassyellow. Streak is greenish black or brownish black. Opaque. Brittle. Fracture conchoidal. No cleavage. Distinguishable from chalcopyrite by its paler colour and superior hardness, and from gold by its hardness. Sometimes called "fool's gold." Occurrence. A common sulphide mineral found as an accessory mineral in igneous rocks, in massive sulphide deposits, and in sedimentary and metamorphic rocks. Frequently found in vein deposits where it may be associated with gold, lead, zinc, and copper minerals. In massive sulphide deposits it may be an ore of iron and sulphur. Used for the manufacture of sulphuric acid. Ontario Localities. In massive sulphide ores at Sudbury, Goudreau, Manitouwadge; with siderite at Wawa. Pyrite bodies are found widely in eastern and northern Ontario. Good crystals at the Levack mine (Sudbury), at the Macdonald mine (Hybla, Hastings co.), and at the Canada Talc mine at Madoc. Pyrrhotite iron sulphide, Fen S12 Properties. Hardness 4. Specific gravity 4.6. Occurrence is massive, or granular with irregular fracture. Metallic lustre. Colour is bronze-yellow to brownish red. Tarnishes rapidly. Streak is greyish black. Magnetic. Opaque. Recognized by its hardness, colour, and magnetism; has basal parting. Occurrence. Associated with pyrite in massive sulphide bodies; often associated with basic igneous rocks. Also found in vein deposits and in contact metamorphic de posits. Ontario Localities. Associated with the nickel ore mineral, pentlandite, at Sudbury. Pyrrhotite crystals are found at the Macdonald mine (Hybla, Hastings co.). Siderite iron carbonate, FeCO3 Properties. Hardness 3.5 to 4. Specific gravity 4. Good rhombic cleavage. Vitreous lustre. Colour is light to dark brown-grey. Can be found in cleavable masses, compact granular, and botryoidal (grape-bunch) masses; sometimes earthy. Dis tinguishable from calcite and dolomite by its colour and density. Occurrence. As a sedimentary carbonate in sedimentary and metamorphic rocks, par ticularly cherty iron formation; in veins. Ontario Localities. Mined as an iron ore at Wawa (Michipicoten area). Common in iron formations in northern Ontario. Hematite iron oxide, Fe2O3 Properties. Hardness 5.5 to 6.5. Specific gravity 4.9 to 5.3. Metallic to dull lustre. Colour is reddish brown to black. Streak is red. Translucent. Found as platy crystals, as earthy or botryoidal masses; or found as specularite, in foliated mi caceous silver-red crystals. Distinguishable by its characteristic red streak. Occurrence. An important iron ore mineral common in metamorphic and sedimentary rocks. Frequently found in residual iron ore beds. Ontario Localities. Mined at Steep Rock Lake. Good specimens from Madoc. Specular hematite found in Beatty township (Dist. Cochrane), and at Belmont Lake (Bel mont twp., Peterborough co.). 30 Photo 27 — Botryoidal hematite. (Courtesy of V. B. Meen.) Limonite hydrated iron oxide, FeO(OH). JtH2O Properties. Hardness 5 to 5.5. Specific gravity 3.6 to 4. Amorphous. Found in concre tionary, nodular, or earthy masses. Earthy limonite may appear to be quite soft. Colour is brown, black, yellow. Streak is yellow-brown. May have a vitreous lustre, but is usually dull to earthy. Occurrence. Frequently found as "bog iron ore." Formed by surface weathering of other iron minerals, as a secondary alteration. Ontario Localities. Mined at Steep Rock Lake from the dewatered bed of Steeprock Lake. COPPER MINERALS Native Copper copper, Cu Properties. Hardness 2.5 to 3. Specific gravity 8.9. Hackly fracture. Malleable. Dull lustre. Tarnishes readily. Copper-red colour. Found in wiry, branching, irregular masses. Easily recognizable by its malleability, high specific gravity, colour, and hackly fracture. Occurrence. A minor ore mineral of copper. Found in veins, and as hydrothermal de posits in volcanic flows and sediments as in the Keweenawan rocks of Michigan and Ontario. Ontario Localities. Mamainse Point, and Coppercorp mine in Mamainse Point area (Dist. Algoma). Copper boulders are sometimes found in the glacial drift south of Sault Ste. Marie. Chalcopyrite copper iron sulphide, CuFeS2 Properties. Hardness 3.5 to 4. Specific gravity 4.2. Generally massive. Metallic lustre. Colour is brassy to bronze-yellow. Tarnishes easily. Streak is greenish black. Dis tinguishable from pyrite by its softness, and from gold by its brittleness. Chalco pyrite powders on scratching, but gold is malleable. Occurrence. A common ore mineral of copper. Found in sulphide deposits of the magmatic replacement type and the hydrothermal type. Frequently found in veins. Ontario Localities. Mined at Sudbury and Manitouwadge. Massive chalcopyrite is mined at the Temagami copper mine (Lake Timagami). 31 Photo 28 —Dendritic native copper. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) Bornite copper iron sulphide, Cu.-,Fe S4 Properties. Hardness 3. Specific gravity 4.9 to 5.4. Metallic lustre. Brownish bronze in colour on fresh fractures, but quickly tarnishes to tones of iridescent purple. Streak is greyish black. Usually massive. Uneven fracture. Brittle. Occurrence. A common copper ore mineral often associated with chalcopyrite in sul phide mineral deposits. In veins. Disseminated in igneous intrusive rocks. Ontario Localities. Found in many copper deposits, at McGown mine (Parry Sound); Mamainse Point, and Coppercorp Limited in Mamainse Point area (Dist. Algoma). Chalcocite copper sulphide, Cu2S Properties. Hardness 2.5 to 3. Specific gravity 5.5 to 5.8. Metallic lustre. Colour is shiny lead-grey to black; tarnishes to dull black. Conchoidal fracture. Sectile. Commonly fine-grained or massive. Distinguishable by its colour, softness, and sectility. Occurrence. A common copper ore mineral frequently found in the weathered-surface portions of copper orebodies. Ontario Localities. Wilcox mine (Cowper twp., Dist. Parry Sound); Mamainse Point, and Coppercorp Limited in Mamainse Point area (Dist. Algoma). Azurite hydrous copper carbonate, Cu3(CO3)^(OH)2 Properties. Hardness 3.5 to 4. Specific gravity 3.8. Lustre is vitreous to dull. Azureblue colour is diagnostic. Effervesces in hydrochloric acid. Found as prismatic crystals, or as radiating masses or botryoidal (grape-bunch) masses. Occurrence. A secondary copper ore mineral found in the upper weathered oxidized portions of copper orebodies. A common "copper bloom". Ontario Localities. A surface alteration of many Ontario copper deposits. Found at Bruce Mines (Dist. Algoma). 32 Malachite hydrous copper carbonate, Cu2CO3(OH)2 Properties. Hardness 3.5 to 4. Specific gravity 3.9 to 4.0. Lustre is vitreous to dull. Bright green colour is diagnostic. Effervesces in hydrochloric acid. Found as pris matic crystals or as radiating masses or botryoidal masses. Often granular or earthy. May be found as green crusts of alteration, or stains. Occurrence. Same as azurite. Ontario Localities. A surface alteration of many Ontario copper deposits; found at Bruce Mines (Dist. Algoma). NICKEL MINERALS Pentlandite nickel iron sulphide, (Fe, Ni)0S,s Properties. Hardness 3.5 to 4. Specific gravity 4.6 to 5. Brittle. Metallic lustre. Yellowbronze colour. Bronze-brown streak. Occurrence is massive, or disseminated with other sulphides. Octahedral cleavage. Occurrence. The most common nickel ore mineral, found with pyrrhotite in massive and disseminated sulphide ore deposits that are frequently associated with basic intrusive rocks such as norite. Ontario Localities. Mined at the Sudbury nickel mines. Niccolite nickel arsenide, NiAs Properties. Hardness 5 to 5.5. Specific gravity 7.8. Metallic lustre. Pale copper-red colour; tarnishes to greyish black. Brownish black streak. Opaque. Usually mas sive. Brittle. Uneven fracture. Found often with sulphides. May show diagnostic "nickel bloom" alteration, which is light green. Occurrence. With other cobalt and nickel arsenides and sulpharsenides in massive and disseminated sulphide deposits, or in vein deposits. A minor nickel ore mineral. Ontario Localities. In vein deposits at Cobalt; at Silver Islet (Lake Superior) and at Sudbury. COBALT MINERALS Cobaltite cobalt sulpharsenide, CoAsS Properties. Hardness 5.5. Specific gravity 6.3. Metallic lustre. Silver-white. Greyblack streak. Commonly found as striated cubic or pyritohedral crystals, or in mas sive form. Perfect basal cleavage. Shows pink cobalt bloom alteration. Occurrence. A common ore mineral of cobalt found in vein deposits, or in massive sulphide deposits, in association with copper and nickel minerals. Ontario Localities. In veins at Cobalt; with massive and disseminated sulphides at Sudbury. Smaltite cobalt arsenide, CoAsH A variety of skutterudite, (Co, Ni) As3 Properties. Hardness 6. Specific gravity 6.5. Brittle. Metallic lustre. Colour is tinwhite to silver-grey. Streak is black. Opaque. Sometimes found as cubic crystals; more commonly massive, granular. Occurrence. A cobalt ore mineral occurring in vein deposits with silver ore. Ontario Localities. In vein deposits at Cobalt. 33 Photo 29 — Galena, showing cubic cleavage. (Courtesy of Geological Survey of Canada.) LEAD MINERALS The most common lead mineral is the lead sulphide, galena. The lead sulphate, anglesite, and the lead carbonate, cerusite, are not important lead ore minerals in Canada, although they may be important in weathered zones of ore deposits in deeply weathered areas. Galena lead sulphide, PbS Properties. Hardness 2.5. Specific gravity 7.5. Excellent cubic cleavage. Metallic lustre. Lead-grey colour and streak. Occurs as cubic crystals, or in massive form. Easily recognizable by its cubic cleavage, high density, softness, and lead-grey streak. Occurrence. The most important lead ore mineral, frequently found in sulphide replace ment orebodies, disseminated sulphide ores, and in veins. Frequently contains silver; often associated with the zinc sulphide, sphalerite. Ontario Localities. Kingdon mine at Galetta; Frontenac lead mine, Perth Road. Good crystals found in the Lockport Dolomite in southern Ontario. ZINC MINERALS The most common zinc mineral is the zinc sulphide, sphalerite. The zinc carbonate, smithsonite, is not quantitatively important in Canada. Sphalerite zinc sulphide, ZnS Properties. Hardness 3.5 to 4. Specific gravity 3.9 to 4.1. Good cleavage. Submetallic to resinous lustre. Colour is variable; frequently yellow, brown, black, red. Trans parent to translucent. Streak is white to yellow-brown. Frequently found in mas sive or granular form. Often recognizable by its lustre and cleavage. Occurrence. The most common ore mineral of zinc, it is often found associated with galena in massive and disseminated sulphide replacement deposits and in vein deposits. Ontario Localities. Mined at Manitowadge and in the Consolidated Sudbury Basin mine at Sudbury. In crystals in the Lockport Dolomite in the Niagara and Bruce penin sulas. 34 Photo 30 — Gold ore, showing pyrite mineralization; Chesterville mine, Larder Lake. GOLD MINERALS Although the common ore mineral of gold is native gold, it frequently occurs also as gold tellurides. Native Gold gold, Au Properties. Hardness 2.5 to 3. Specific gravity 19.3. Commonly found as irregular wiry masses, flakes, scales; rarely is it found in crystal form. Hackly fracture. Malle able. Very heavy. Golden yellow colour. Occurrence. Commonly found in quartz veins and in placer deposits; sometimes in association with sulphides in sulphide replacement deposits. Ontario Localities. Mined at Porcupine, Kirkland Lake, Red Lake, Little Long Lac. A by-product metal at Sudbury. SILVER MINERALS Native Silver silver, Ag Properties. Hardness 2.5 to 3. Specific gravity 10.5. Usually found as irregular wiry masses, plates, or scales; sometimes found in crystal form. Hackly fracture. Malle able. Metallic lustre. Silver-grey colour, tarnishes to black. Occurrence. Found in vein deposits frequently with cobalt and nickel sulphides. Gen erally, gold contains some silver alloyed with it. Silver also occurs in other minerals such as galena. Ontario Localities. Mined at Cobalt and Gowganda; formerly mined at Silver Islet (Lake Superior). 35 Photo 31 — Polished sample of dendritic native silver in dolomite; Silver Islet mine. Lake Superior. Argentite silver sulphide, Ag.,S Properties. Hardness 2 to 2.5. Specific gravity 7.3. Very sectile and can be cut with a knife. Lustre is metallic. Colour is blackish lead-grey. Opaque. Commonly found in massive form, or as coating; occasionally as cubic crystals. Poor cleavage. Subconchoidal fracture. Occurrence. An important ore mineral of silver; occurs in vein deposits with native silver. Ontario Localities. At Cobalt and Gowganda. MOLYBDENUM MINERALS The most common ore mineral of molybdenum is the sulphide, molybdenite. The secondary yellowish calcium molybdate, powellite, is frequently found as an alteration of molybdenite. Molybdenite molybdenum sulphide, MoS2 Properties. Hardness l to 1.5. Specific gravity 4.7 to 4.8. Excellent basal cleavage. Sectile. Flexible laminae. Lustre is metallic. Colour is silver to lead-grey; slightly bluish cast distinguishes it from graphite. Blue-grey streak. Opaque. Has greasy feel. Commonly occurs in platy crystals and in flakes. Foliated. Occurrence. In quartz veins; disseminated in igneous rocks and pegmatites. In basic metamorphic pyroxenites in eastern Ontario. Ontario Localities. Zenith mine (Renfrew co.), Cardiff township (Haliburton co.), Combermere (Renfrew co.), Echo township (Dist. Kenora). 36 URANIUM MINERALS Uranium mines in the Blind River and Bancroft areas have yielded an important part of Ontario mineral production. At Blind River the chief ore minerals are uraninite and brannerite. At Bancroft the chief ore minerals are uraninite and uranothorite. Uraninite uranium oxide, UO2 Properties. Hardness 5.5. Specific gravity 9 to 9.7. Occurs as cubic crystals. Submetal lic to dull lustre. Colour is steel-black to black. Streak is black. Strongly radio active. Irregular fracture. Occurrence. In granite and syenite pegmatites and in vein deposits. An important ore mineral of uranium. Ontario Localities. An important ore mineral in the Bancroft pegmatites; in veins at Wilberforce (Cardiff twp., Haliburton co.); at Blind River. Pitchblende uranium oxide, UO2 Properties. Hardness 5.5. Specific gravity 9 to 9.7. Found as massive to rounded botryoidal masses; this is the massive noncrystalline form of uraninite. Pitchy lustre. Colour is dark steely black to pitch-black. Black streak. Occurrence. A common ore mineral of uranium; found chiefly in vein deposits. Ontario Localities. At Theano Point (in Twp. 29 R.XIV, on Lake Superior). Uranothorite hydrous uranium thorium silicate Properties. Hardness 4.5 to 5. Specific gravity 4.0 to 4.5. Found as square prismatic crystals, or rounded to irregular grains. Pitchy lustre. Colour is black to yellowbrown or reddish brown. Highly radioactive. Irregular fracture. Distinguishable with difficulty from some varieties of pyrochlore. Occurrence. A common uranium ore mineral found in granite and syenite pegmatites, and in veins. Ontario Localities. A common ore mineral at the Bicroft mine and Faraday Uranium mine (Bancroft). Good crystals and massive material in several localities in Mon mouth and Cardiff townships (Haliburton co.). RARE-ELEMENT AND RADIOACTIVE MINERALS Columbite-Tantalite iron manganese niobate and tantalate, (Fe, Mn) (Nb, Ta)2Oc Properties. Hardness 6. Specific gravity 5.3 to 7.3. Subconchoidal fracture. Brittle. Submetallic to resinous lustre. Colour is black, brownish black, reddish brown. Streak is dark red to black. Distinct pinacoidal cleavage. Commonly found as distinctive platy prismatic, tabular to rod-shaped, crystals in pegmatite; sometimes as radiating crystals. Occurrence. In pegmatite dikes. Ontario Localities. At Quadeville (Lyndoch twp., Renfrew co.). 37 Pyrochlore-Microlite hydrous soda lime niobate and tantalate, (Na, Ca)2 (Nb, Ta),O6 (O, OH, F) Properties. Hardness 5 to 5.5. Specific gravity 4.2 to 4.4. Octahedral cleavage. Con choidal fracture. Brittle. Vitreous to resinous lustre. Colour is yellow-brown to blackish brown. Streak is brown. Translucent to transparent. In good octahedral crystals and grains. Occurrence. In pegmatite dikes; in carbonatite bodies. Ontario Localities. The variety betafite occurs in good octahedral crystals up to 3 inches in size in calcite at the Silver Crater mine (Faraday twp., Hastings co.); pyrochlore is found on the Manitou Islands (Lake Nipissing), Lackner Lake and Nemegosenda Lake (Dist. Sudbury), Firesand River and Scabrock Lake (Dist. Algoma), Big Beaver House (Dist. Kenora, Patricia Portion). Ellsworthite, a variety of pyro chlore, is found at the Macdonald mine (Hybla, Hastings co.). Inches i i Inches Photo 32 — Betafite crystals; Silver Crater mine, Faraday township. Allanite hydrous silicate of calcium, cerium, lanthanum, sodium, aluminium, mag nesium, thorium, and other rare earths. Properties. Hardness 5.5 to 6. Specific gravity 2.7 to 4.2. Subconchoidal fracture. Poor cleavage. Black to dark brown. Lustre is vitreous to resinous. Found as granular masses and individual grains; grains may show radial fracturing in the surrounding rock. Occurrence. In pegmatite dikes; veins. Ontario Localities. Massive allanite in Cardiff township (Haliburton co.), at Rosenthal (Renfrew co.), on the Pickerel River (Dist. Parry Sound), Madawaska (Dist. Nipissing). 38 TUNGSTEN MINERALS The most common ore mineral of tungsten is scheelite; wolframite, the iron man ganese tungstate, is not common in Ontario. Scheelite calcium tungstate, CaWO4 Properties. Hardness 4.5 to 5. Specific gravity 5.9 to 6.1. Lustre is vitreous. Good cleavage. Uneven fracture. Colour is white, yellow, brown, pink. Translucent to transparent. Found as octahedral crystals, and in massive granular forms. Distin guishable by its blue to yellow fluorescence. Occurrence. In high-temperature quartz veins, and in contact metamorphic deposits. Ontario Localities. Found in gold-quartz veins of the Porcupine camp (Timmins). Photo 33 — Beryl crystal; Lyndoch township. (Courtesy of Geological Survey of Canada.) BERYLLIUM Beryl beryllium aluminium silicate, Be3Al2Si6O 18 Properties. Hardness 7.5 to 8. Specific gravity 2.6 to 2.8. Poor cleavage. Uneven con choidal fracture. Brittle. Commonly found as six-sided hexagonal crystals. Colour is emerald-green, blue, yellow, white. Streak is white. Transparent to translucent. Glassy lustre. Distinguishable from apatite by its hardness. The gem varieties are known as emerald and aquamarine. Occurrence. In pegmatite dikes. Ontario Localities. Quadeville (Lyndoch twp., Renfrew co.), Eau Claire (Purdy mica mine near Mattawa), and in District of Kenora. 39 Photo 34 — Apatite crystal in calcite. (Courtesy of Ward's Natural Science Establishment.) Photo 35 — Chrysotile asbestos veins in dunite; Munro mine. Matheson. 40 Nonmetallic Minerals APATITE Apatite calcium phosphate, Ca5 (CI, F) (PO4)3 Properties. Hardness 5. Specific gravity 3.2. Basal cleavage. Conchoidal fracture. Brittle. Vitreous lustre. Colour is green, red, colourless, brown, blue, yellow. Streak is white. Transparent to opaque. Often recognizable by its six-sided hexa gonal crystals and fused appearance of crystal surfaces. Occurrence is massive, and as crystals. Occurrence. A common minor accessory in igneous and sedimentary rocks. In calcite veins with fluorite; in basic scapolite-pyroxene-phlogopite pegmatites associated with metamorphic pyroxenite. Ontario Localities. Formerly mined in pyroxenite pegmatites in the Perth area (Lanark co.), and in Bedford township (Frontenac co.). Good crystals are found in cal cite veins in Bancroft area (Faraday and Cardiff twps.), Sebastopol township and Eganville area (Renfrew co.). A large deposit of apatite associated with magnetite occurs at Nemegos (Dist. Sudbury). Uses. Source of phosphate for fertilizer and phosphorus chemicals. ASBESTOS Chrysotile hydrous magnesium silicate, H4 Mg3 Si2O9 Properties. Hardness 4. Specific gravity 2.2. Silky, fibrous, asbestiform. Found in cross-fibre veinlets. Has greasy lustre. Colour is grey-green to green, sometimes yellow. Translucent. Fibres flexible. Occurrence. Most frequently found in cross-fibre veinlets in serpentinized ultrabasic rocks such as dunite or peridotite. Ontario Localities. Mined at Munro mine (Matheson). Occurs in Deloro township (near Timmins), in Reeves township (Dist. Sudbury), Garrison township (Dist. Cochrane), and at Madoc. Uses. Asbestos-fibre goods, asbestos concrete, shingles, insulation. BARIUM Barite barium sulphate, BaSO4 Properties. Hardness 2.5 to 3.5. Specific gravity 4.3 to 4.6. Perfect basal and prismatic cleavages. Fracture uneven. Brittle. Vitreous to resinous lustre. Streak is white. Colour is white, grey, yellow, blue, red, brown. Transparent to opaque. Found as tabular to prismatic crystals; other occurrences may be massive, fibrous, lamellar, or granular. Distinguishable by high specific gravity. Occurrence. In sedimentary beds; in veins associated with lead, fluorite, etc. Ontario Localities. In veins at Madoc, at Tionaga (Penhorwood twp., Dist. Sudbury), in Langmuir township (Dist. Timiskaming), and on McKellar Island (Lake Superior). Uses. Barium greases, industrial fillers, well-drilling muds. 41 Photo 36 — Coarse platy barite. McKellar Island, Lake Superior. Photo 37 — Celestite; Bagot township. 42 BRUCITE Brucite magnesium hydroxide, Mg (OH)2 Properties. Hardness 2.5. Specific gravity 2.4. Good basal cleavage. Sectile. Pearly to vitreous lustre. Colour is white, grey to green, or blue. Transparent to trans lucent. May be crystalline, foliated, fibrous, granular, or massive. Distinguishable by its pitted weathered surface when found in marble. Occurrence. Disseminated in marble as a result of contact metamorphism. In veins in serpentine and ultrabasic rocks. Ontario Localities. Rutherglen (Dist. Nipissing); Hinchinbrooke township (Frontenac co.). Uses. In the manufacture of magnesia refractories. STRONTIUM Celestite strontium sulphate, SrSO4 Properties. Hardness 3 to 3.5. Specific gravity 4. Perfect basal and prismatic cleavages. Uneven fracture. Vitreous to pearly lustre. Streak is white. Colour is white, bluish, reddish. Transparent to opaque. Found as tabular, prismatic, and radiat ing crystals; other occurrences are fibrous or granular. Occurrence. In veins and cavities, usually in sedimentary rocks. Ontario Localities. Lansdowne township (Leeds co.), Amherstburg (Essex co.). White radiating masses in Bagot township (Renfrew co.); orange variety at Credit Forks; blue crystals in Lockport Dolomite at Dundas. Uses. Ore mineral of strontium. Photo 38 — Hexagonal crystal of corundum; Craigmont, Renfrew township. (Courtesy of Geological Survey of Canada.) CORUNDUM Corundum aluminium oxide, A12O3 Properties. Hardness 9. Specific gravity 4 to 4.1. Basal parting. Twinning striae may be prominent on basal faces. Fracture uneven. Brittle. Lustre adamantine to vitreous. Colour is blue (sapphire), red (ruby), yellow, brown, green, grey, white. Transparent to translucent. Occurs as hexagonal barrel-shaped crystals, or in gran ular or massive forms. Occurrence. Found in silica-poor rocks such as syenite, syenite pegmatite, nepheline syenite. Sometimes in marble. Ontario Localities. Burgess mine (Carlow twp., Hastings co.); Craigmont mine; Jewelville (Raglan twp., Renfrew co.). Blue variety on the York River (Dungannon twp., Hastings co.). Pink variety at Croft Uranium mine (Bancroft, Hastings co.). Uses. Used as an abrasive. 43 Photo 39 — Fluorite crystals, showing cubic habit; Madoc, Hastings county. Photo 40 — Graphite; Black Donald mine. Brougham township. 44 FLUORSPAR Fluorite calcium fluoride, CaF2 Properties. Hardness 4. Specific gravity 3.2. Frequently found as cubic crystals; found also in massive to banded form. Excellent octahedral cleavage. Colour is variable: blue, green, purple, colourless, rose, yellow. Lustre is vitreous. Transparent to translucent. Occurrence. A common mineral in vein deposits; occasionally an accessory mineral in granite. Ontario Localities. Madoc (Hastings co.), Silver Mountain (Dist. Thunder Bay). Purple fluorite in Cardiff township (Haliburton co.) and Ross township (Renfrew co.). Good crystals in the Lockport Dolomite at Niagara Falls. Uses. As a flux in metallurgical industries. GRAPHITE Graphite carbon, C Properties. Hardness l to 2. Specific gravity 2.2. Marks paper with a black streak. Lustre metallic to dull. Colour is black to steel-grey. Has greasy feel. Found as tabular crystals having perfect basal cleavage. Usually found in foliated masses or scales, but may be granular. Occurrence. A common mineral of metamorphic schists, gneisses, and marbles. May also be found in hydrothermal vein deposits. Ontario Localities. Black Donald mine (Calabogie); Timmins mine (near Perth); Gra phite station (Monteagle twp., Hastings co.); Harcourt (Cardiff twp., Haliburton co.); Lyndoch township; Desert Lake (Frontenae co.); North Elmsley township (near Perth). Uses. Foundry facing, lubricant, crucibles, pencils. KYANITE Kyanite aluminium silicate, Al2SiO5 Properties. Hardness 5 to 7. Specific gravity 3.6 to 3.7. Perfect basal and good pris matic cleavages. Irregular fracture. Lustre is vitreous to pearly. Colour is blue, white, grey, green. Streak is white. Translucent to transparent. Found character istically as bladed crystals, but sometimes columnar to subfibrous. Occurrence. A metamorphic mineral occurring in aluminous gneisses and schists. Ontario Localities. At Wanapitei (near Sudbury); in Butler and Antoine townships (near Mattawa); near Fernleigh (in eastern Ontario). Uses. In manufacture of refractories. MAGNESITE Magnesite magnesium carbonate, Mg CO3 Properties. Hardness 3.5 to 4.5. Specific gravity 3 to 3.1. Perfect rhombohedral cleav age. Conchoidal fracture. Brittle. Lustre is vitreous to silky. Colour is white, yellowish, grey, brown. Transparent to opaque. Found in granular or massive habit. Occurrence. Contact metamorphic deposits in serpentine marble; alteration zones in serpentinized dunite. Ontario Localities. Deloro township (near Timmins). Uses. Basic magnesia refractories. 45 SODALITE Sodalite sodium aluminium silicate with chlorine, Na4Al 3Si3O ];,Cl Properties. Hardness 5.5 to 6. Specific gravity 2.1 to 2.3. Dodecahedral cleavage. Uneven fracture. Brittle. Lustre is vitreous. Colour is blue, grey, green, yellow, white, pink. Transparent to translucent. White streak. Generally massive, granu lar, in veins. Occurrence. A hydrothermal alteration of nepheline in nepheline syenite and nepheline pegmatite. Often found as alteration zones along joints. Ontario Localities. Blue variety at the Princess Sodalite mine (Bancroft). Along York River in nepheline gneisses (Dungannon twp., Hastings co.). The pink variety, hackmanite, is found at the Davis quarry (York River, Dungannon twp.). Uses. Ornamental stone used for jewellery, lapidary work. LITHIUM Spodumene lithium aluminium silicate, Li Al Si2O6 Properties. Hardness 6.5 to 7. Specific gravity 3.1 to 3.2. Good Lamellar structure. Fracture is uneven to splintery. Brittle. Colour is greenish white, grey, yellow-green. Streak is white. elongate crystals. Occurrence. In granite pegmatites. Ontario Localities. Georgia Lake (Dist. Thunder Bay); District of Uses. Source of lithium, used for lithium chemicals. prismatic cleavage. Lustre is vitreous. Found as prismatic Kenora. TALC Talc hydrous magnesium silicate, H2Mg3 (SiO3)4 Properties. Hardness 1. Specific gravity 2.7. Perfect basal cleavage. Found as foliated or granular masses. Sectile. Lustre is pearly to greasy. Colour is white, pale green, yellow. Translucent. Has greasy feel. Occurrence. Commonly a hydrothermal secondary alteration in marble, serpentine rocks. Often associated with chrysotile asbestos, tremolite. Ontario Localities. Henderson mine (Madoc), Grimsthorpe and Cashel townships (Hastings co.), May township (Dist. Sudbury). Uses. As a filler. TOURMALINE Tourmaline complex hydrous boron aluminium silicate with calcium, sodium, mag nesium, iron Properties. Hardness 7 to 7.5. Specific gravity 3 to 3.2. Uneven to conchoidal frac ture. Poor prismatic and rhombohedral cleavages. Brittle. Lustre is vitreous to resinous. Colour is black, brownish black, blue, green, red. Streak is uncoloured. Transparent to translucent. Commonly found as long prismatic striated crystals with a 3-or 6-sided outline. Triangular crystal cross-section often diagnostic. Occurrence. Common in pegmatites and high-temperature veins. Ontario Localities. Ragged Lake (Wollaston twp., Hastings co.); Lyndoch township (Renfrew co.); Verona (Frontenac co.); near Enterprise; Wilberforce (Monmouth twp., Haliburton co.). Uses. A piezoelectric mineral used in pressure gauges. 46 Photo 41 — Trigonal crystal of striated tourmaline, showing termination. (Courtesy of Berry and Mason, Mineralogy, W. H. Freeman and Co., 1959.) Photo 42 — Exfoliated vermiculite. VERMICULITE Vermiculite altered micas Properties. Hardness 2 to 2.5. Specific gravity 2.6 to 2.8. Perfect basal (micaceous) cleavage. Lustre is pearly. Colour is generally buff, brown, reddish brown, silver, black. Transparent to translucent. Distinguishable from mica by its soft and pli able inelastic foliation plates, and by the fact that it expands greatly on heating. Occurrence. A secondary alteration of mica produced by hydrothermal or meteoric solutions; commonly found in schists, gneisses, pyroxenites. Ontario Localities. Stanleyville (near Perth); Catchacoma (Cavendish twp., Peterbor ough co.); Mattawa area; Cartier (near Sudbury). 47 Photo 43 — Jointing in a Keweenawan diabase dike; Schreiber area. District of Thunder Bay. 48 Figure 3 — Geological features in cross-section. ROCK CLASSIFICATION Rocks are classified into three main groups on the basis of origin. Igneous Rocks. Rocks formed by the cooling and crystallization of molten rock magma, either beneath the earth's surface as in the case of granite batholiths, or on the earth's surface as in the case of lava flows. Sedimentary Rocks. Rocks formed by deposition of mineral and rock material by water, wind, ice, etc. The material is derived by the decomposition or attrition of surface rocks by processes of weathering and erosion. The source rocks may be igneous, sedimentary, or metamorphic. Examples of sedimentary rocks are sandstone, limestone, and shale. Metamorphic Rocks. Rocks formed from previously existing igneous or sedimentary rocks by recrystallization due to heat and pressure within the earth's crust. Examples are: marble formed from limestone; slate formed from shale. CHARACTERISTICS OF ROCKS Rocks may be recognized from their characteristic features, such as structure, hardness, texture, colour, fracture. Igneous rocks frequently show a massive, jointed structure. Sedimentary rocks may be recognized generally by their bedded or stratified structure, produced when the detrital source material was laid down in beds by wind or water. Metamorphic rocks are frequently recognized by their foliated or schistose struc ture produced by the action of heat and directional pressure on the source rocks. Igneous rocks generally have an interlocking texture and may range from fine- to coarse-grained. Some igneous rocks show a porphyritic texture in which large crystals, often quartz or feldspar, occur in a fine-grained matrix. Lavas that have cooled rapidly may have a glassy texture. Sedimentary rocks may show a clastic texture in which fragments of the source rocks may be discerned; these fragments may be angular or rounded, depending on the distance of transportation before deposition. 49 Photo 44 — Porphyritic texture in trachyte porphyry, an igneous rock; Matachewan. (Courtesy of Ward's Natural Science Establishment.) Metamorphic rocks may show an interlocking texture, and frequently show pro nounced alignment of minerals. Other characteristics, such as hardness, fracture, colour, chemical composition, etc., assist in rock identification; the presence of fossils in a rock, for example, is evidence of a sedimentary origin. Igneous Rocks Mode of Occurrence. Igneous rocks are formed by the cooling and crystalization of molten rock magma. Where the magma has cooled beneath the earth's surface, the rock is said to be intrusive; where the magma was poured out as a lava on the surface of the earth, and there cooled and crystallized, the rock is termed extrusive. The intrusive rocks are frequently found in large irregular dome-shaped bodies called batholiths. Walllike or dike-like intrusive bodies cutting across the structure of the country rocks that they intruded are termed dikes. Where the intrusive rock is found as a sheet-like body parallel to the foliation or bedding of the sedimentary or metamorphic rocks that it intruded, it is termed a sill. Extrusive igneous rocks that were poured out as lava on the earth's surface formed flat sheets that are termed lava flows. These extrusive rocks are frequently referred to as volcanic rocks because they are the product of volcanic activity. Basis of Classification. Igneous rocks are named on the basis of three main features: mineral composition; texture and grain size; extrusive or intrusive occurrence. Igneous rocks are classified on the basis of the percentage of quartz, potash feldspar, plagioclase, and ferromagnesian minerals, and on the composition of the plagioclase, as shown in the accompanying table of classification of igneous rocks (taken from the Geological Survey of Canada). The most common igneous rock types met in the field in Ontario are subsequently described. 50 Table 3 AMOUNT OF QUARTZ Classification of igneous rocks (after Geol. Surv. Canada, 1958) MORE THAN 10 PERCENT FELDSPAR PROPORTION OF POTASH TO TOTAL FELDSPAR Composition of plagioclase Albite An,,- An u, Oligoclase An^-An*,, more than more than 10 GRANITE Rhyolite 2/3 QUARTZ MONZONITE V6 -2/3 Quartz latite percent quartz less than 1/3 less than 10 percent quartz Labradorite An.-,o-Anioo Andesine An:,,rAn.-,o MONOMINERALIC OR LESS THAN 10 PERCENT FELDSPAR GRANODIORITE QUARTZ DIORITE QUARTZ GABBRO Quartz latite Dacite Quartz basalt SYENITE more than ^ PERIDOTITE Trachyte PYROXENITE MONZONITE '/s-% Latite less than DUNITE SYENODIORITE DIORITE GABBRO Latite Andesite Basalt '/3 ANORTHOSITE COMMON CONTENT OF DARK MIN ERALS 0-10 10-40 40-70 percent percent percent COMMON IGNEOUS ROCKS IN ONTARIO Granite Composition. Granite is composed principally of quartz, orthoclase, and plagioclase, with a minor content of ferromagnesian minerals such as biotite and(or) horn blende. Orthoclase generally constitutes more than 2/^ of the total feldspar content. Quartz content often ranges from about 20 to 35 percent. The plagioclase is often albite. Colour. Light coloured, generally pink or grey. Texture. Generally equigranular, interlocking, granitoid; sometimes porphyritic (as in porphyritic granite). Grain Size. Generally medium-grained; the very coarse-grained variety having crystals over 5 centimetres in size is called granite pegmatite. Granite pegmatites are com monly found as dikes and may furnish a commercial source of feldspar and some times of mica, beryl, etc. Mode of Occurrence. Granite is an intrusive rock generally found as stocks, batholiths, dikes, and sills. 51 Colour. Generally pink or grey; sometimes slightly darker than granite owing to the higher content of ferromagnesian minerals. Texture. Same as granite. Grain Size. Same as in granite. Mode of Occurrence. Same as for granite. Diorite Composition. An intermediate intrusive rock composed primarily of andesine plagio clase and ferromagnesian minerals, mainly hornblende and biotite. Up to 10 per cent quartz may be present. If over 10 percent quartz is present, the rock is termed quartz diorite. Some orthoclase is frequently present. The ferromagnesian minerals range from 10 to 40 percent and generally constitute a much larger proportion than in granite or syenite. Colour. Pink, grey to dark grey, speckled with dark minerals. Texture. Same as granite (granitoid, equigranular). Grain Size. Same as in granite. Mode of Occurrence. Similar to granite; more common in smaller bodies such as stocks and sills. Diabase Diabase is a basic igneous intrusive rock in which the essential minerals are pyroxene and plagioclase. The plagioclase occurs as long lath-shaped crystals usually in random orientation. This is referred to as a diabasic texture. Andesite Andesite is the extrusive equivalent of diorite and is a very common volcanic flow rock in the Precambrian rocks in northern Ontario. Many of the so-called "greenstones" are andesitic lavas or basaltic lavas. Gabbro Composition. A basic intrusive rock composed of labradorite feldspar and pyroxene, with accessory hornblende, biotite, and magnetite. Orthoclase, if present, is a minor constituent. A little quartz is sometimes present. The ferromagnesian mineral con tent generally ranges from 40 to 70 percent. Colour. Dark, generally shades of grey, brown, or black. Texture. Granitoid, interlocking; sometimes contains laths of plagioclase. Grain Size. Medium to coarse grain size is common. Mode of Occurrence. As intrusive stocks, sills, dikes. Basalt Basalt is the extrusive equivalent of gabbro and is a fine-grained basic volcanic rock usually found as lava flows. Peridotite Composition. An ultrabasic rock composed essentially of olivine, with labradorite, py roxene, and sometimes amphibole or mica. 53 Photo 47 — Bedded varved clay laid down in glacial Lake Barlow-Ojibway; Timmins. 54 Photo 49 — Gently dipping Rove shales; Pigeon River, District of Thunder Bay. COMMON SEDIMENTARY ROCKS IN ONTARIO Conglomerate Conglomerate is a sedimentary rock formed by the consolidation of gravel deposits. It consists of aggregates of pebbles and boulders, frequently of many types, generally in a sandy or shaly matrix. The boulders and pebbles are generally rounded. If the frag ments are angular, the rock is termed a breccia. Sandstone Sandstone is a sedimentary rock formed by the consolidation of sedimentary material of sand size. Frequently the sand is quartz. If the sand is a mixture of quartz and feldspar, the rock may be termed arkose. The sedimentary material is often cemented by silica, carbonate, or iron oxides. Greywacke A sedimentary rock formed by the consolidation of a grit; grit is an impure variety of sandstone frequently made up of a large percentage of rock fragments. Greywacke is common in the Precambrian rocks of northern Ontario. 56 Photo 50 — Bedded limestone deposit; Beachville, Oxford county. Shale Shale is a sedimentary rock formed by the consolidation of clay. It is extremely fine-grained, and is generally grey, red, or black. It frequently has a conchoidal fracture, and may be scratched with a knife blade. Tillite Tillite is a sedimentary rock formed by the consolidation of a glacial till. This generally consists of an unsorted clayey to sandy matrix containing boulders of assorted sizes. The matrix is frequently a rock flour that is poorly sorted. Limestone A sedimentary rock composed mainly of calcite or dolomite. These rocks form by chemical precipitation of calcium carbonate, by mechanical deposition of calcium carbonate shells or organisms, or by the mechanical accumulation of detrital limestone from a previously existing limestone or shell bank. Limestones are soft and easily scratched with a knife blade. Calcitic limestones effervesce vigorously in hydrochloric acid. Limestones are frequently grey, buff, or brown. Salt Salt beds are chemical precipitates of sodium chloride laid down in a sea or basin in which there was excessive evaporation and no outgoing drainage. Salt beds are generally white, grey, yellowish, or pink in colour. Gypsum Gypsum deposits are chemical precipitates of calcium sulphate, frequently laid down in association with salt deposits. Colour ranges from white and grey, to pink, yellow, brown, or dark grey. Coal Coal measures form by the accumulation and lithification of vegetative organic material. 57 Photo 51 — Wave ripple marks in sandstone; Sault Ste. Marie. STRUCTURES IN SEDIMENTARY ROCKS The following features are characteristic and often diagnostic of sedimentary rocks. Bedding. A layered stratification of detrital material or chemical precipitates due to mechanical settling of particles, rhythmic precipitation, variations in the rate of supply of material, differences in the material supplied, and differences in colouring and organic content. Crossbedding. Cross-lamination as in deltaic deposits laid down at the mouth of a river. Grain Gradation. A sizing of material in individual beds from coarse at the base to fine at the top. Ripple Marks. Ripple marks are frequently preserved at the tops of beds that are later buried and preserved in the sedimentary series. Mud Cracks. Sometimes bedding surfaces of shaly sedimentary rocks show preserved mud crack patterns that were formed when the clay was drying on an exposed mud flat. Fossils. The presence of organic fossil remains in a rock gives much information on the sedimentary environment during formation. These fossils may prove useful in determin ing the age of sedimentary rocks and in assisting in their correlation with similar rocks in other places. Metamorphic Rocks Metamorphic rocks are formed from igneous and sedimentary rocks by heat, pres sure, and solutions within the earth's crust. The altered rock attains a new structure and frequently a new mineral assemblage, although some relict structures and assemblages may indicate its origin. Most metamorphic rocks show a pronounced foliation or alignment of mineral constituents owing to recrystallization under the effects of heat and pressure. The common metamorphic rocks encountered in the field in Ontario include those subsequently described. 58 Photo 52 — Banded gneiss; eastern Ontario. COMMON METAMORPHIC ROCKS IN ONTARIO Gneiss A foliated metamorphic rock composed of crystalline grains of quartz, feldspar, and ferromagnesian minerals oriented in a rudely banded structure. The individual grains are generally large enough to be recognized by the naked eye. These rocks com monly develop from granite, arkose, shaly sandstones, etc. Schist A foliated fine-grained metamorphic rock in which most of the materials are too fine to be identified by the naked eye. Minerals such as mica are frequently present and assist in giving the rock its foliated or schistose structure. These rocks commonly develop from shales. Slate A fine-grained metamorphic rock possessing good cleavage that allows it to be split into thin sheets. This slaty cleavage often cuts the bedding at an angle. Quartzite Quartzite is a metamorphic rock derived by the recrystallization of a quartz sand stone. It commonly has a glassy lustre, and a conchoidal fracture in which the break takes place across the quartz grains in contrast to the manner of fracturing of a sand stone. Marble Marble is a metamorphic rock produced by the recrystallization of a limestone. It is generally medium-grained, and frequently individual calcite grains can be discerned. It takes a polish and may be used as ornamental or building stone. Marble is commonly grey or white, but can be almost any colour owing to impurities. 59 Geologic Structures In addition to the terms already explained, geologic terminology often refers to folds, faults, joints, and unconformities, which are important geologic structures often encountered in the field. Figure 3, on page 49, illustrates geologic structures in crosssection. Folds. If bedded rocks are subjected to external pressures, they are frequently bent or warped into folds. A U-shaped or V-shaped fold is termed a syncline; an inverted Ushaped or inverted V-shaped fold is termed an anticline. Faults. Where rocks fail by rupture, the surface of rupture, along which the movement took place between the two broken portions of the rock body, is termed a fault. A zone of faulting along which movement and shearing has taken place is often termed a shear zone. Joints. When an igneous rock cools or a sedimentary rock is compacted and consoli dated, shrinkage often opens narrow hair-line cracks that are termed joints. Unconformities. Sedimentary rocks are formed by the processes of erosion, weathering, and attrition of the rocks exposed at the earth's surface, the subsequent transportation of the detrital material produced, and its final deposition in bedded formations; it will be immediately apparent that while this sedimentary deposition goes on in one place, there is a concurrent period of erosion or nondeposition at another place. The surface that marks a period of nondeposition or of erosion in the geologic column is called an unconformity. An unconformity may be recognized by a structural discordance between the underlying and overlying rocks, or by a gap or hiatus in the geologic column. The structural discordance may be marked by one of three or more features: folding in the rocks below the unconformity and by a lack of folding in the rocks above; channelling of the underlying rocks and deposition of the younger rocks on the eroded surface; old soil profiles on the surface of the unconformity; a difference in degree of metamorphism between the rocks above and below the unconformity; etc. A gap or hiatus in the geo logic column not indicated by structural discordance at the surface of unconformity may be indicated by such evidence as the absence of an expected series of beds, by a faunal break, by a discordance in age determinations, etc. REFERENCES AND FURTHER READING Dana's Manual of Mineralogy, by C. S. Hurlbut, Jr. 609pp. Wiley and Sons, 1959. New York, U.S.A. A Field Guide to Rocks and Minerals, by F. H. Pough. 332pp. Hougton Mifflin Co., 1960, Boston, Mass., U.S.A. Introductory Mineral Table, by H. R. Steacy. 13 pp. Price 25 cents; available from Queen's Printer, Ottawa. (Table is Appendix III of Prospecting in Canada, by A. H. Lang, Geol. Surv. Canada.) Getting Acquainted with Minerals, by G. L. English and D. E. Jensen. 362pp. McGraw Hill Book Co., 1958, New York, U.S.A. Petrography, by Howel Williams, F. J. Turner, and C. M. Gilbert. 406pp. W. H. Freeman and Co., 1955, San Francisco, Calif., U.S.A. Prospecting in Canada, by A. H. Lang, 400pp. Economic Geol. Series, No. 7, Geol. Surv. Canada, 1956, Ottawa; price S2.50. Mineralogy, by L. G. Berry and B. Mason. 630pp. W. H. Freeman and Co., 1959, San Francisco, Calif., U.S.A. 60 Part H — Geology of Ontario GEOLOGICAL MAP OF ONTARIO For the study of the geology of Ontario, the reader should provide himself with a copy of Map 1958b, The Geological Map of the Province of Ontario, published by the Ontario Department of Mines. THE GEOLOGICAL TIME SCALE Rocks are classified into eras and periods depending on their geologic age. Radio active age-determinations indicate that the oldest rocks of the earth's crust (early Pre cambrian) are about 4,000,000,000 years old. Fossils, indicative of plant and animal life, are common from Cambrian times (500,000,000 years ago) to the present; but, fossils are almost entirely absent in rocks of Precambrian age (550,000,000 to 4,000,000,000 years old). Table 5 The geological time scale PERIOD Cenozoic Recent Pleistocene Tertiary Mesozoic Cretaceous Jurassic Triassic Paleozoic Permian Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian Precambrian Proterozoic Archean AGE IN YEARS - l ,000,000 years - 70,000,000 years 135,000,000 years 180,000,000 years 220,000,000 years 275,000,000 years 330,000,000 years 355,000,000 years 410,000,000 years 430,000,000 years 490,000,000 years 550,000,000 years 2,000,000,000 years 4,000,000,000 years 61 o Q) X E c (D ^ 5 ^ c O S** O "~ So O)^ D -o o S s'l c c* tt) —r ^U D -D C O x O) J) o 0) O D) 62 D O U — PALEOZOIC *ND MESOZOIC Sedimentary rocks. PRECAMBRIAN l Mainly granitic rocks Scale of Miles Figure 5 — Geology of Ontario. GEOLOGICAL REGIONS OF ONTARIO Ontario is divided into three principal geological regions, namely: the St. Lawrence Lowland; the Hudson Bay Lowland; the Precambrian Shield. The St. Lawrence Lowland occupies an area in southern Ontario flanking the lower Great Lakes and the St. Lawrence River and is underlain by flat-lying Paleozoic rocks. The Hudson Bay Lowland consists of a low-lying area of Paleozoic and Cretaceous sedimentary rocks on the southwest shores of James Bay and Hudson Bay. The Precambrian Shield occupies more than 2A of the surface area of Ontario, and it is shown principally in pink on the Geological Map of Ontario (No. 1958b). 63 The Precambrian Shield The Precambrian rocks of the Precambrian Shield form the bedrock in most of Ontario except in the Hudson Bay and St. Lawrence lowlands where the Precambrian rocks are covered by a capping of Paleozoic rocks. The Precambrian rocks form the ancient crystalline basement rocks on which the younger rocks were laid down. The rocks of the Precambrian age are divided into two main subdivisions: the late Precambrian Proterozoic rocks; and the early Precambrian Archean rocks. The Archean rocks are generally highly metamorphosed, folded, and intruded by granitic rocks. Generally the Proterozoic rocks are less folded (often relatively flat-lying), less metamor phosed, and not as highly intruded by granitic rocks. The Proterozoic rocks frequently rest with unconformity on the Archean basement rocks. Proterozoic and Archean rocks, in turn, are divided into Groups and Series on the basis of lithology. These groups and series generally are named according to the geo graphic area in which they were first described. The subdivisions of the Proterozoic and Archean rocks shown on the Geological Map of Ontario (No. 1958b) are as follows: PRECAMBRIAN PROTEROZOIC Basic intrusive rocks (Keweenawan). Younger sedimentary and volcanic rocks (Keweenawan, Animikie). Older sedimentary rocks (Cobalt, Bruce, Huronian). ARCHEAN Acid intrusive rocks (Algoman, Laurentian, Killarnean). (May include some Proterozoic intrusive rocks.) Basic intrusive rocks (Haileyburian, and others). Sedimentary rocks (Timiskaming, Sudbury, Couchiching, Grenville, and others). (Includes some volcanic rocks.) Volcanic rocks (Keewatin Series: includes minor sedimentary rocks). ARCHEAN ROCKS Volcanic Rocks. Examination of the Geological Map of Ontario indicates the pre dominance of Archean rocks (shown in pink, green, grey, and purple). The oldest Archean rocks are the volcanic rocks of the Keewatin Series (shown in green on Map 1958b); these consist mainly of basic volcanic rocks ("greenstone", basalt, and andesite). The Keewatin Series also includes some intercalated basic sills and minor amounts of sedimentary rocks, mainly greywacke, schists, and iron formation. Generally, these formations have been highly folded, metamorphosed, and intruded by granitic rocks. The Keewatin rocks are found as infolded "greenstone belts" (shown on Map 1958b as linear and discontinuous green bands). They are important prospecting areas; many of the gold and base metal deposits are found in these greenstone belts. Sedimentary Rocks. Of younger age (and shown on Map 1958b in grey) are the Timiskaming Series of sedimentary rocks, consisting mainly of greywacke, arkose, quartzite, and conglomerate. Minor volcanic flows and tuffs are included in some areas. The Timiskaming sedimentary rocks are also highly folded, metamorphosed, and intruded by basic and acidic rocks, but they lie with unconformity on the Keewatin volcanic rocks and are younger. The Timiskaming rocks are found as infolded remnants in the granitic Archean rocks of the Precambrian Shield, as are the Keewatin rocks. They are found in the Kirkland Lake and Porcupine areas where they are often the host rocks for gold deposits. Archean sedimentary rocks that may be correlated with 64 Figure 6 — Block diagram illustrating the relationship between the Proterozoic and Archean Precambrian rocks. the Timiskaming Series are found in many places in northern Ontario; the Sudbury, Couchiching, and Seine series of northern Ontario are examples of these. In southern Ontario the rocks that are shown in grey on Map 1958b within the Precambrian Shield area belong to the Grenville Series. They consist of marble, paragneiss, amphibolite, and quartzite. These are intruded and replaced by granite, syenite, and gabbro. Commercial deposits of uranium, magnetite, apatite, fluorite, mica, feld spar, nepheline syenite, talc, gold, lead, copper, and molybdenum have been found in these rocks. Basic Intrusive Rocks. The oldest Archean intrusive rocks are generally basic or ultra basic rocks, mainly diorite and gabbro, with some anorthosite, peridotite, and dunite (these are shown in purple on Map 1958b). Iron and base metal deposits may be found associated with some of these basic intrusive rocks. Asbestos deposits in the Matheson area of northeastern Ontario are in ultrabasic rocks of this age. Acid Intrusive Rocks. A large part of the Archean basal complex in Ontario is composed of granitic rocks ranging from massive granite batholiths to extensive areas of granitic gneisses of hybrid origin. Granodiorite, syenite, monzonite, and porphyry are common in this group. The gold deposits of the Porcupine and Kirkland Lake areas are thought to be associated in age with Algoman intrusive rocks that cut the Timiskaming Series. Unconformity. At the end of Archean times, there was a period of mountain-building and of folding. The rocks were intruded and highly metamorphosed. Then followed a long period of erosion during which the area was worn down to a peneplane. The younger Proterozoic rocks were then laid down above this erosional unconformity on the surface of the folded Archean rocks. This unconformity and the difference in structure and metamorphism between the Archean and Proterozoic rocks may be well seen in the Cobalt and Kirkland Lake areas where the Proterozoic Cobalt Group of sedimentary rocks rests on the Archean. 65 PROTEROZOIC ROCKS Older Sedimentary Rocks. The older Proterozoic sedimentary rocks are shown in brown on the Geological Map of Ontario, and they occupy an area extending from Sault Ste. Marie to Cobalt in northern Ontario. The two main groups recognized are the Bruce Group and the Cobalt Group. The Cobalt Group is younger and rests on the Bruce Group. The Bruce Group consists of conglomerate, quartzite, greywacke, and limestone. The uranium ore horizons at Blind River are in the Mississagi Quartzite Formation of the Bruce Group. The Cobalt Group consists of conglomerate rocks, greywacke, and quartzite, and is generally almost flat-lying. The Cobalt silver ores are found in the rocks of the Cobalt Group. The Bruce and Cobalt Groups together are termed "Huronian" in much of the geologic literature of the north shore of Lake Huron. The Huronian of the Lake Superior area in the U.S.A. contains many large iron deposits. Younger Sedimentary and Volcanic Rocks. The younger sedimentary and volcanic rocks that are shown in yellow on the Geological Map of Ontario comprise the Ke weenawan Series and the Animikie Series. These rocks are found on the north shore of Lake Superior in the Nipigon-Port Arthur area, on Michipicoten Island, and on the east shore of Lake Superior north of Sault Ste. Marie. The Keweenawan Series consists of conglomerate, sandstone, shale, and interbedded lavas. It was named on Keweenaw Point, Michigan, and is the host rock for the important Michigan native copper deposits. Keweenawan copper deposits are found in Ontario near Mamainse, north of Sault Ste. Marie. The Animikie Series is found in the Port Arthur area and consists mainly of conglomerate, quartzite, sandstone, slate, iron formation, and limestone. Basic Intrusive Rocks. The basic intrusive rocks of Proterozoic age are shown in orange on the Geological Map of Ontario, and they are common in the Port Arthur-Nipigon area and in the Sault Ste. Marie-Sudbury-Cobalt area. The basic intrusive rocks consists mainly of gabbro, diabase, and norite. The Sudbury Norite, with which the Sudbury nickel-copper deposits are associated, is of Proterozoic age. The Nipissing Diabase of the Cobalt area (which is thought to be the source-rock of the silver-cobalt deposits) is also Proterozoic. As already mentioned, the Keweenawan type of copper deposits are also Proterozoic in age and are associated with Keweenawan intrusive activity. The St. Lawrence Lowland The St. Lawrence Lowland is underlain by Cambrian, Ordovician, Devonian, and Mississippian rocks of the Paleozoic system. These are flat-lying sedimentary rocks consisting mainly of limestone, dolomite, shale, and sandstone, with some minor beds of gypsum and salt. The Paleozoic rocks of the St. Lawrence Lowland are divided into two parts by Precambrian rocks that extend southeast to the St. Lawrence River between Kingston and Brockville. This arch of Precambrian rocks is called the Frontenac Axis. The Ottawa-St. Lawrence Basin The Paleozoic area northeast of the Frontenac Axis is called the Ottawa-St. Law rence basin and is occupied by Cambrian sandstones (shown in light purple on Map 1958b) and Ordovician limestones and shales (shown in pale blue on Map 1958b). The Nepean or Potsdam Sandstone Formation is the main Cambrian formation in the basin, and it is found on the flanks of the Frontenac Axis beneath the Ordovician rocks. This sandstone formation is mainly composed of high-purity silica sand and is a potential source of commercial silica sand. 66 Of the Ordovician rocks in the Ottawa-St. Lawrence basin, the most important, commercially, are the Black River-Trenton limestones that are quarried in the Ottawa and Cornwall areas as a source of crushed stone and concrete aggregate. Southern Ontario The whole of southern and southwestern Ontario, south of a line extending from Midland on Georgian Bay to Kingston on Lake Ontario, is underlain by Paleozoic rocks. These Paleozoic formations also extend, as may be seen on Map 1958b, up the Bruce Peninsula and across into Manitoulin, Cockburn, and St. Joseph islands. The formations of the Paleozoic rocks in southern Ontario are set out in Table 6. Table 6 SYSTEM Table o] formations for the Paleozoic rocks of southern Ontario LITHOLOGY FORMATION OR GROUP Mississippian Port Lambton Formation Grey to black shale, sandstone. Devonian Kettle Point Formation Hamilton Formation Oriskany Formation Black shale. Grey shale and argillaceous limestone. Limestone and dolomite. Sandy limestone and dolomite. Brown limestone and dolomite. Limestone, dolomite, chert, sandstone. Sandstone. Silurian Bertie Akron (Bass Is.) Formation Salina Formation Guelph-Lockport Formations Clinton-Cataract Groups Buff dolomite. Dolomite, shale, gypsum, salt. Dolomite. Shale, sandstone, dolomite. Ordovician Queenston Formation Meaford-Dundas Formations Collingwood Formation Trenton-Black River Groups Red shale. Grey shale. Grey to black shale. Limestone. Upper Cambrian Potsdam Formation Sandstone. Delaware Formation Columbus Formation Detroit River Group Bois Blanc Formation PALEOZOIC ROCKS Upper Cambrian. The Potsdam Sandstone of Upper Cambrian age is exposed sparingly on the west flank of the Frontenac Axis in Frontenac county. The colour of the rock is grey to buff. The Lake Superior Sandstone is found in the Sault Ste. Marie area, where it has been used for building stone. It is also of Upper Cambrian age. It is red, grey, buff, or red and grey variegated in colour. Ordovician. Ordovician rocks (shown in pale blue on Map 1958b) are exposed in a wide area extending northeastward from the Niagara Escarpment to the Precambrian contact that runs from Midland to Kingston. The lowermost formations of Ordovician age are the limestones of the Black RiverTrenton groups. These occupy a wide band extending from the Precambrian contact to 67 o "D O C o u •t. o x d) k. to "5 ao '5 .o "o O) O t. O) 6c O) l/) 4) O) ^ o V O) "o c o '5) 0) K 0) t3 O) 0- v-;--7-' 6OOn PORT LAMBTON -I-I- KETTLE POINT ----— — i — HAMILTON DUNDEE DEVONIAN AND MISSISSIPPIAN LEGEND li DEVONIAN Limestone 1000- -p 1 | Shaly limestone DETROIT RIVER ''il ^anc^y limestone 1500- BOIS BLANC feU \ i f ORISKANY BASS ISLAND '-i^^Ci. -r r- j\ Dolomite \ 1 . J \ G 2000- \ ' -i : -~\ Sandy dolomite F | - - | Shale . D ^~ SALINA SILURIAN 2500VERTFEETICAL OF SCALE ill \: '—'. Sandy shale or shaly sandstone B A-2 3000- ife a-o w -a * o*o sfe^ft ^-T- A-i GUELPH, LOCKPORT-AMABEL [.'.'.'.'.l Sandstone get CLINTON l '^-' .' -J- '1 Sandstone, limestone, LJ—L-J—J 3nd dolomite I^f: CATARACT I f1 QUEENSTON -,— ; .-r.' rr: 3500 4000- |^1 ^-~-~ | MEAFORD-DUNDAS, BLUE MOUNTAIN GLOUCESTER^ 'COLUNGWOOD' | Chert ORDOVICIAN Gas producing horizon . . . . - . . — —— ' Ir ) w A| ,, L j , L, r }v\ Metamorphosed rocks . . tt — Oil producing horizon . . . . . . . . . . . . . . . . . . . . . . . * 4500 —— — Oil and gas producing horizon...... ........tt TRENTON. BLACK RIVER * Show of oil and gas....,-...,......., ...... * 5000 - - - - -. V AC-P 5500- *" EAU CLAIRE, MT. SIMON, JACOBSVILLf CAMBRIAN f* i, v 7 r " A ^ Vi METAMORPHOSED ROCKS PRECAMBRIAN G.S.C. 225 Figure 8 — Generalized columnar geologic section for southwestern Ontario. (Courtesy of Geological Survey of Canada.) a line roughly from Collingwood to Port Hope. The Black River and Trenton lime stones are widely used for crushed stone, concrete aggregate, portland cement manu facture, lime manufacture, and flux stone for the metallurgical industries. Above these limestones lie a series of Ordovician shales, the Collingwood, MeafordDundas, and Queenston formations, that occupy the area between the Niagara Escarp ment and the Trenton limestones. In the Toronto area, which is underlain by the Dundas and Queenston shales, these shales are used for the manufacture of brick and tile. 69 Figure 9 — Niagara Escarpment. (After W. M. Tovell.) 70 Silurian. The Silurian rocks (shown in blue on Map 1958b) occupy a wide belt from Niagara Falls and Fort Erie to Bruce Peninsula and Manitoulin Island. A prominent topographic feature in southern Ontario is the Niagara Escarpment that extends from Queenston through Dundas, thence north through Orangeville to the Bruce Peninsula. The resistant rock member that forms the caprock of the Escarpment is the Lockport Dolomite of Silurian age, and the entire Escarpment is composed of rocks of Silurian age. The lower parts of the Niagara Escarpment are composed of shales, sandstones, and minor dolomite of the Cataract and Clinton groups. The Medina Sandstone of the Clin ton group is exposed in the lower part of the scarp, particularly in the Milton-George town-Credit Forks area, and this sandstone is quarried extensively as a building stone. The (old) Toronto City Hall and the main building of the Ontario Parliament Buildings at Queen's Park in Toronto are built of Medina Sandstone. The Guelph-Lockport Dolomite that forms the caprock of the Niagara Escarpment is buff to brown high-purity dolomite, and is quarried for building stone, crushed stone, concrete aggregate, flux stone, and dolomitic lime production. Above the Guelph Dolomite lies a thick band of Salina Dolomite and Shale. This formation is important because the gypsum deposits of the Caledonia and Hagersville areas are found within it. In the southwestern part of Ontario (the Windsor-SarniaGoderich area) where the Salina Formation is from 1,000 to 1,800 feet underground, there are extensive beds of rock salt up to 600 feet in thickness. These salt beds in the Salina Formation are worked either by underground mines (as at Windsor and Goderich) or by brine wells (as at Windsor, Sarnia, and Goderich). The uppermost formation of Silurian age is the Bass Island Dolomite, a buff to grey impure dolomite. This is quarried in the Port Colborne, Dunnville, Cayuga, and Hagersville areas as a source of crushed stone. Devonian. The Devonian rocks (shown in grey on Map 1958b) occupy all of south western Ontario west of the Silurian rocks. Because those Paleozoic rocks already described dip gently to the southwest throughout this part of Ontario, as we progress southwest across the strike of formations we cross progressively younger and younger formations. The oldest and lowermost Devonian formation is the Oriskany Sandstone; however, because this formation is present only in the Cayuga area, throughout the remainder of the area the Bois Blanc Limestone rests directly on the underlying Bertie Akron Dolomite of Silurian age. The Bois Blanc Limestone, although it is cherty, is quarried for crushed stone at Port Colborne and Hagersville. The limestones of the Detroit River Group lie above the Bois Blanc Formation and are exposed in the Beachville area. Near Woodstock they are quarried as a source of high-purity limestone that is used for chemical lime, flux, and portland cement. This formation is exposed also at Amherstburg where it is quarried for lime manufacture. Above the Detroit River Group are the limestones and dolomites of the Delaware Formation. The Delaware Limestone is quarried at St. Marys for the production of portland cement. The upper Devonian and Mississippian shales (the Hamilton, Kettle Point, and Port Lambton formations) are not used commercially, although parts of the Hamilton Shale are suitable for the manufacture of brick. The Hudson Bay Lowland The low-lying plain flanking Hudson Bay and James Bay is underlain mainly by Ordovician, Silurian, and Devonian limestones, dolomites, and shales of Paleozoic age. These rocks have not been given much examination, but there has been some prospecting 71 O) J* o sO 01 O) -C o in C o 0) ^ l o O) D o for oil and gas in the area. Deposits of high-purity gypsum of possible commercial interest are to be found in the Devonian rocks at Gypsum Mountain, at Moose River Crossing, and along the Cheepash River. Cretaceous deposits of clay, sand, and lignite are indicated (in light green) on the Geological Map of Ontario. These form a basin of considerable extent in the Missinaibi, Mattagami, and Abitibi river basins. Prospecting for kaolin and lignite deposits has been carried out in this area, but there is no current commercial production. Physiography and Pleistocene Geology The physiography of Ontario is, to a large extent, a reflection of the underlying bedrock formations. The Hudson Bay lowland, which is underlain by flat-lying Ordo vician, Silurian, Devonian, and Cretaceous sedimentary rocks, is a low-lying plain show ing little relief. The plain slopes gently to Hudson Bay; drainage is poor, and much of the area is covered by muskeg. Rock exposures are sparse and are generally limited to the river valleys. The principal rivers, such as the Moose, Albany, and Attawapiskat, show a dendritic pattern of drainage. The Precambrian Shield underlies 254,000 square miles or about 62 percent of Ontario. The ancient crystalline rocks of the Precambrian Shield have been peneplaned, and relief rarely exceeds 1,000 feet. The highest ground is found north of Sault Ste. Marie on the eastern shores of Lake Superior where elevations approach 2,200 feet above sea-level. Prominent highlands exist in the vicinity of Port Arthur, where Thunder Cape has an elevation of 1,850 feet above sea-level, standing 1,250 feet above the waters of Lake Superior. Highlands in Algonquin Park and other parts of eastern Ontario reach 1,900 feet in elevation. A feature of the Ottawa valley is a series of prominent fault scarps trending northwest. These are part of the Ottawa-Bonnechere graben. The Mount St. Patrick scarp (in Renfrew co.) is one of this series and shows a relief of more than 1,000 feet. A similar down-faulted graben structure may exist in the Lake Timis kaming basin where an outlier of Paleozoic rocks is preserved. The St. Lawrence and Great Lakes lowland of southern Ontario is also underlain by relatively flat-lying Paleozoic rocks, and relief is low. A low scarp generally marks the Precambrian-Paleozoic contact that runs from Midland on Georgian Bay to Kingston on Lake Ontario. A second prominent topographic feature is the Niagara Escarpment that runs from Niagara Falls to the Bruce Peninsula. This is a cuesta formed by a cliff of resistant Lockport Dolomite that stands in relief above the softer Ordovician shales that lie east of it. During Pleistocene times, Ontario was covered by ice-sheets. Field work indicates that there were four main glacial stages when great ice-sheets spread southward across Ontario. These glacial stages were followed by an interglacial period of warm weather when the ice-sheets retreated. It is considered that we are now in a warm interglacial stage. The last advance of the Wisconsinan glacier, the youngest of the glacial stages, took place about 27,000 years ago, and by 20,000 years ago the ice had spread well south into Ohio and covered the whole of Ontario. Field work indicates that all of southern Ontario was covered by ice until about 14,000 years ago. The first land to appear above the melting and retreating ice-sheets was the highland area northwest of Orangeville. The ice-sheet had three recognizable lobes: the Lake Ontario lobe, which occupied the basin of Lake Ontario and spread southwest; the Lake Simcoe lobe; and, the Lake Huron lobe in the basin of Lake Huron. Along the margins of the first land to appear, large glacial meltwater streams deposited a heavy load of sand and gravel to form the kame-like accumulations typical of the Orangeville and Waterloo moraines. Glacial spillways formed along the margin 73 74 Photo 53 — Sunderland esker; Ontario county. of the land-area between the land and the ice. These fed southward into the glacial lakes Whittlesey and Warren, precursors of the present Lake Erie. The Georgetown and Paris spillways were formed in this way and are now the sites of important gravel pro duction. Shorelines of the glacial lakes Whittlesey and Warren have been mapped across southwestern Ontario. As the Lake Ontario ice-lobe retreated eastward and stood at the Niagara Escarp ment, a large interlobate moraine was built between the Lake Simcoe and Lake Ontario lobes. This is the Oak Ridges moraine that extends across Ontario from Oak Ridges to Trenton. Many of the major eskers of eastern Ontario were probably formed at this time. As the ice retreated from the Lake Ontario basin, glacial Lake Iroquois was formed in the Lake Ontario basin. It was larger than present-day Lake Ontario, and its shoreline can be traced across the country some miles inland from the present shoreline of Lake Ontario. In the Huron basin, another major glacial lake, Lake Algonquin, was formed. Beaches of the glacial lakes Iroquois and Algonquin have been sources of commercial sand and gravel deposits. As the ice retreated northward, the St. Lawrence valley was uncovered, and the land east of Pembroke and Brockville was flooded by the Champlain Sea. Marine clay deposits were laid down in this sea. Eventually the ice melted back to free the NipissingOttawa valley, and Lake Algonquin ceased to exist because of free drainage to the east. The drainage of Lake Algonquin and the earlier part of the Champlain Sea has been dated about 10,000 years ago. As the ice-sheet retreated into the Hudson Bay area, a great glacial lake, Lake Barlow-Ojibway, was formed in northern Ontario. The flat clay plains of the Ontario "clay belt" were formed in this glacial lake. Gradual uplift of the land and retreat of the ice-sheet have brought conditions to the present state. This description of the Pleistocene history of Ontario is taken largely from P. F. Karrow in "Sand and Gravel in Ontario" (Indust. Mineral Rept. No. 11, Ontario Dept. Mines, 1963) by D. F. Hewitt and P. F. Karrow. Many of the surficial physiographic features of Ontario landscapes, such as kames, eskers, moraines, raised beaches, and drumlin fields, owe their presence to Pleistocene glaciation. REFERENCES AND ADDITIONAL READING Geological Map of Ontario, Map 1958b. Ontario Dept. Mines; Price S 1.00. Geology and Economic Minerals of Canada, by Officers of the Geological Survey. 517 pp., edit ed by C. H. Stockwell. Economic Geology Series, No. 1; Geol. Surv. Canada, Ottawa, 1957; price S4.00. (This report also gives a very useful description of the economic mineral deposits of Canada, but is technical in nature and presupposes some knowledge of geology and mineralogy.) 76 Part III—Economic Mineral Deposits of Ontario o Geraldton O AU Beardmore Au Manitouwadge 0Cu,Zn.Ag. Pb Au \ Porcupine oMatheson -Renabie Au,Cu o AJ? Virginiatown OAU Kirkland Lake0 O. AU Wawa J Au-F* : NOT LOCATED Sand and gravel, clay and shale pits Limestone and other quarries. Ag Asb Au Co Cu Fe — —— — — — — Silver Asbestos Gold Cobalt Copper Iron FI Gyp Ne Mi Pb Pd — — — — — — Fluorspar Gypsum Nepheline syenite Nickel Lead Palladium Figure 13 — Principal mining areas of Ontario. 77 The more important metallic mineral deposits of Ontario include gold, silver, cobalt, nickel, copper, zinc, lead, iron, uranium, magnesium, and the platinum metals. Non metallic mineral deposits of Ontario include asbestos, feldspar, fluorspar, graphite, gyp sum, mica, nepheline syenite, salt, silica, and talc. Large tonnages of the construction materials, sand and gravel, stone, clay products, cement, and lime, are produced in the province. GOLD Mineralogy and Occurrence Gold is found in the native state or as gold tellurides, frequently associated with sulphide minerals such as pyrite and arsenopyrite. It is commonly found in vein type deposits in a gangue of quartz and carbonates. Quartz veins containing gold mineral ization are thought to have been formed by hot aqueous solutions travelling along fis sures, cracks, or shear zones. It is commonly assumed that these solutions originated from acid intrusive bodies, and there is often a spatial association between gold quartz veins and acid intrusive stocks. Ontario Production Production of gold in Ontario from 1866 to 1962 totalled 94,477,152 ounces valued at 33,059,429,652. Production from the three principal gold camps to the end of 1962 has been as follows: Porcupine S l,471,953,467 Kirkland Lake — Larder Lake l ,004,421,162 Red Lake 232,546,147 History Gold was first discovered in Ontario in 1866 on the farm of John Richardson, lot 18, concession V, Madoc township, Hastings county, near the village of Madoc. A gold rush developed, and subsequently gold was found in a number of places in a belt 70 miles long extending from Belmont township in Peterborough county, across the counties of Hastings, Frontenac, and Lennox and Addington, into Lanark county. Gold was mined in eastern Ontario from more than a dozen mines from the early 1890s until about 1917, with a total production of about S750,000. The principal mines were at Cordova and Deloro. The discovery of gold in the Lake of the Woods area came in 1878. The main producers in the Kenora district were Cameron Island, Cedar Island, Kenricia, Mikado, Regina, Straw Lake Beach, and Wendigo. A total of about S5,000,000 worth of gold was produced. Ontario's greatest gold camp, the Porcupine, was discovered in 1907, and in 1909 the Hollinger, Mcintyre, Dome, and Vipond properties were staked. Production from the Porcupine area began in 1910 and has continued to the present. The initial gold discovery at Kirkland Lake was made by W. H. Wright on the Wright-Hargreaves property in 1911, and gold production from this mining camp began in 1913. The principal mines that have operated at Kirkland Lake are Macassa, Kirk land Lake Gold, Teck-Hughes, Lake Shore, Wright-Hargreaves, Toburn, and Sylvanite. 78 Gold was discovered at Larder Lake in 1906 by Dr. Reddick, but it was not until 1938 that the Kerr-Addison mine began commercial production. Gold was discovered at Red Lake by Lorne Howey in 1925, and the Howey mine was developed in 1930. Subsequently Mackenzie Red Lake, Red Lake Gold Shore, Madsen Red Lake, Cochenour-Willans, McMarmac Red Lake, Dickenson Red Lake, and Campbell Red Lake mines came into production. Substantial amounts of gold were produced by mines in the Thunder Bay District from 1905 to the present, notably from Little Long Lac, McLeod-Cockshutt, and Leitch mines. Geological Features Gold-bearing quartz veins are found in Archean rocks of the Keewatin and Timis kaming Series and are usually closely associated with Algoman granite and syenite por phyries. The Keewatin series of rocks is dominantly volcanic in origin and consists chiefly of basic flows with minor tuff, agglomerate, and iron formation. The Timis kaming Series, which overlies the Keewatin volcanics unconformably, is composed prin cipally of slaty greywacke, quartzite, and conglomerate, with some interbedded acid to intermediate volcanic rocks. Both these series of rocks have been metamorphosed and folded and are intruded by pink and grey granite and syenite porphyry of Algoman age. Structural conditions favourable for the deposition of gold-bearing quartz veins fre quently are found in the greenstones and sedimentary rocks in the vicinity of such Algoman intrusive rocks, especially where shearing and alteration are evident. Rusty gossan zones may occur at the surface where sulphide-bearing gold veins have been weathered, and such gossans should be panned for gold. PORCUPINE AREA The gold deposits at Porcupine are found in a belt of folded Keewatin and Timis kaming rocks forming a syncline pitching gently northeast. Stocks of Algoman quartz porphyry intrude the margins of the syncline. The principal vein systems are found within zones of shearing and fracturing developed near the porphyry intrusions. The Hollinger, Mcintyre, and Coniaurum mines lie on a shear zone 500-1,500 feet wide, striking N.60 0 E. The veins vary greatly in size and shape, but the vein system has been worked to depths greater than 6,000 feet. The veins are composed of quartz mineralized with gold, pyrite, pyrrhotite, arseno pyrite, sphalerite, chalcopyrite, and tellurides. Tourmaline, scheelite, albite, and ankerite are present in the veins and scheelite has been produced commercially. The veins com monly cut the shear zone at a small angle and strike about N.50 0 E. The average width of the veins is about 10 feet. The Dome mine lies on the south side of the Porcupine syncline. The ore shoots on the upper levels have ranged from 15 to 150 feet wide and up to 600'feet long. The veins on the upper levels lie principally in a narrow band of conglomerate and grey wacke lying between Keewatin greenstone on the north and porphyry on the south. Large tonnages of ore have been developed in the lavas at lower levels and the mine is now developed to depths greater than 4,000 feet. In 1961 the average grade of ore mined at Porcupine was S8.45 per ton. Gold mines in active production in 1963 in the Porcupine camp included Mcintyre, Hollinger, Dome, Paymaster, Preston, Delnite, Aunor, Broulan Reef, Hallnor, and Pamour mines. 79 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Aunor Gold Mines Ltd. Broulan Reef Mines Ltd. Delnite Mines Ltd. Dome Mines Ltd. Hallnor Mines Ltd. Hollinger Consolidated Gold Mines Ltd. Hugh-Pam Porcupine Mines Ltd. Mcintyre Porcupine Mines Ltd. Pamour Porcupine Mines Ltd. Paymaster Consolidated Mines Ltd. Preston Mines Ltd. Figure 14 — Gold mines of the Porcupine area. KIRKLAND LAKE-LARDER LAKE AREA The seven principal producing mines at Kirkland Lake Area were: Macassa, Kirkland Lake Gold, Teck-Hughes, Lake Shore, Wright-Hargreaves, Sylvanite, and Toburn; they lie along a 2 Vi-mile length of the Kirkland Lake "main break", a thrust fault striking N.67 0 E. and dipping steeply south. The country rocks are steeply folded Timiskaming sedimentary and volcanic rocks cut by Algoman syenite and syenite por phyry. The gold-bearing quartz veins are found along the faulted zone, which provided access for the ore-bearing solutions. Some ore contains only a small percentage of quartz, and in this case it is the brecciated rock itself that is mineralized. The width of orebodies ranges from a few feet to more than 100 feet. Post-ore faulting displaced the veins by as much as 650 feet, making it more difficult to follow the ore in mining. The 80 O) .i 3 E sis s'* i* cs s T, 2 -2 o S "o,? El 5) O U O a co J:" S 'c U w i O P . O rn D (U O (U -^ O -i O) -D ^ i .M: D "D < < 'i E l E J -D 2 ,.o 0"-2^ -lg Z CO--. •^ Q. E -D .3 li 2 U ^ •D -c O J2 —i — 0) "2 o 81 Photo 54 — Vein breccia; Lake Shore gold mine. Kirkland Lake. (Courtesy of Lake Shore Gold Mines Ltd.) deepest mines in Ontario are at Kirkland Lake where workings extend to depths of more than 8,300 feet below the surface. At Larder Lake the principal gold mine is Kerr-Addison Gold Mines Limited, which has been in production since 1938. The orebodies lie within and south of a strongly sheared carbonate zone cutting Timiskaming volcanic rocks. Gold ore occurs in quartz stockworks in the carbonate zone and in adjacent mineralized and silicified volcanic flows. In the flow-type orebodies, pyrite mineralization contains most of the gold. There is minor chalcopyrite, galena, sphalerite, scheelite, and arsenopyrite. In 1961 the average grade of ore mined in Kirkland-Larder area was S12.00 per ton. 82 1. 2. 3. 4. 5. Campbell Red Lake Mines Ltd. Cochenour Willans Gold Mines Ltd. Dickenson Mines Ltd. McKenzie Red Lake Gold Mines Ltd. Madsen Red Lake Gold Mines Ltd. Figure 16 — Gold mines of the Red Lake area. RED LAKE AREA Red Lake occupies an infolded basin of Archean volcanic and sedimentary rocks surrounded and intruded by Algoman granitic and porphyritic rocks. Geological con ditions vary in the mines of the Red Lake camp. Orebodies at the Campbell and Dicken son mines are in silicified fracture zones in Keewatin greenstones. The strike length of the ore zone is 2,500 feet and the vein systems have been explored to a depth of 3,600 feet at the Dickenson mine. At Cochenour-Willans mine, the ore is found in or adjacent 83 Photo 55 — Madsen Red Lake gold mine. (Courtesy of George Hunter.) to two tuff beds along a flow contact in the volcanic rocks. Orebodies consist of short narrow quartz veins containing native gold and sometimes arsenopyrite, stibnite, sphale rite, and pyrite. The orebodies at the McKenzie mine are in a series of two or three crescent-shaped shear zones in the McKenzie granodiorite stock. Within the shear zones, some individual quartz veins two to three feet wide persist for hundreds of feet, but only portions of the veins are of ore-grade material. The veins have been fractured and mineralized with gold tellurides and sulphides, chiefly pyrite, sphalerite, arsenopyrite, pyrrhotite, chalco pyrite, and galena. The mine has been worked to a depth of almost 2,000 feet. At Madsen mine, most of the ore is in silicified zones in the Austin tuff-breccia; this tuff-breccia is a member of the Keewatin volcanic rocks and lies between the rhyolitic phase of the welded tuff and the underlying basalt. The gold content varies directly with the degree of silicification. Pyrite and pyrrhotite are the main sulphide minerals; minor arsenopyrite, magnetite, ilmenite, chalcopyrite, and sphalerite are present. The ore zone, which has a length of about 4,000 feet at surface, rakes to the northeast. Development has been carried out to a depth of 4,000 feet. The average grade of ore mined at Red Lake in 1961 was S16. l O per ton. 84 SILVER Mineralogy and Occurrence Silver commonly occurs in the native state, often alloyed with gold; it is found also as the silver telluride, hessite (Ag2Te), as the silver sulphide, argentite (Ag2S), or as the silver sulphosalts, pyrargyrite, and proustite. A substantial percentage of Ontario silver production is a by-product of base metal and gold mining. In 1961 almost two million ounces of silver were recovered from Ontario ores of base metals, mainly from Sudbury. More than 400,000 ounces of silver were recovered in refining gold ores. Silver also occurs in carbonate veins with cobalt and nickel minerals. At Cobalt these vein deposits are genetically and structurally associated with Nipissing Diabase sills. Ontario Production Production of silver in Ontario to the end of 1962 totalled 596,948,356 ounces valued at S377,148,752. This silver production came mainly from the Cobalt and Gowganda silver mines, the Sudbury nickel mines, and Ontario gold mines. History There have been two principal silver-mining areas in Ontario: the Thunder Bay area on the north shore of Lake Superior near Port Arthur; and the Cobalt-Gowganda area. Silver was discovered at Spar Island about 24 miles south of Port Arthur in 1846, but silver mining began at Thunder Bay in 1866 with the discovery of a rich silverbearing vein by Peter McKellar. The Shuniah mine was found in 1867, and the famous Silver Islet vein in 1868. The Silver Islet vein was discovered on a small rocky island, measuring 90 by 90 feet, lying off Thunder Cape in Lake Superior. Mining operations began in 1868 and continued until 1884; total production was worth about S3,250,000. A very interesting account of this pioneer silver mining venture is given by T. W. Gibson (1937, pp. 44-51). Silver production from the Thunder Bay area slackened off toward 1880, but renewed impetus was given when the Rabbit Mountain vein was discovered in 1882. The Rabbit Mountain, Beaver, Porcupine, Badger, and Silver Creek mines were opened. The Silver Mountain deposits were found in 1884, and mining flourished until 1892 when the price of silver fell. There was renewed production from 1898 to about 1903 when mining ceased. In August 1903, during construction of the Temiskaming and Northern Ontario Railway north from North Bay, silver was discovered near what later became the Cobalt silver camp. Two lumbermen, James H. McKinley and Ernest J. Darragh, cruising the Booth timber limits for tie timber, found veins containing a heavy metal that later proved to be silver. Claims were staked, and the McKinley-Darragh mine was opened in 1904 on the shore of Long (later Cobalt) Lake. In September another discovery of silver was made by a blacksmith, Fred LaRose. T. W. Gibson, director of the Ontario Bureau of Mines recognized the occurrence of niccolite in samples from this vein, and, in October 1903, Provincial Geologist Willet G. Miller examined the discovery. He immediately identified silver as well as cobalt and nickel minerals in three veins that had been uncov ered. About this time, Tom Hebert discovered the Nipissing mine and, in November 1903, Neil King made the initial discovery on what became the O'Brien property. 85 O U O) 86 A geological survey was carried out by Dr. Miller in 1904. A report describing the new Cobalt silver deposits was published, and this soon created interest in the new mining camp. In May 1904, William G. Trethewey began prospecting at Cobalt and within a very short time discovered what became the Trethewey and Coniagas mines. Word of rich silver shipments from the new mines at Cobalt inspired a major prospecting rush that reached a peak in 1905 and 1906. Production increased until 1911 when 31,507,791 ounces of silver came from the Cobalt area. In 1907 and 1908, rich silver discoveries were made near Gowganda. Silver production from the Cobalt-Gowganda areas has continued to the present time, and Cobalt recently celebrated its 60th year as a mining camp. Geological Features THUNDER BAY AREA In the Thunder Bay mines, native silver, argentite, and silver sulphosalts are found in veins in a gangue of quartz and carbonate with minor amounts of fluorite and barite. The fissure-filling veins have a northeasterly strike and dip 60 0-900 . The veins cut black slate of the Animikie Series and are usually in slates near the base of a Keweenawan diabase sill or in the sill itself. Flatly dipping diabase sills cap the hills, such as Silver Mountain and Rabbit Mountain. The association of the silver veins with the diabase sills suggests a genetic relationship. The veins are generally narrow, their widths ranging from a few inches to a few feet. Rarely, veins 20 feet in width were found. Silver orebodies were irregular and erratic, and rarely extended more than 400 feet vertically. The Silver Islet mine was worked to a depth of l ,250 feet, but most of the ore is reported to have occurred above 400 feet. COBALT AREA At Cobalt, native silver and cobalt-nickel arsenides are the main ore minerals and are found in calcite veins and in mineralized wallrock. Vein widths average 3 to 4 inches; but, with disseminated ore in the wallrocks and with parallel mineralized frac ture systems, ore widths up to 85 feet have been mined. Vein systems are rarely more than a few hundred feet in length. Silver usually is found in ore shoots of great richness separated by extensive barren or low-grade sections. The principal rocks of the area are gently dipping Cobalt conglomerate, greywacke, and quartzite lying on an irregular erosion surface of Keewatin volcanic rocks and iron formation. These are intruded along a warped plane by a sill of Nipissing Diabase about 1,000 feet thick. In the most productive part of the camp in Coleman township west of Cobalt Lake where the Hudson Bay, Nipissing, Trethewey, Coniagas, Buffalo, City of Cobalt, and Townsite mines are located, the diabase sill has been eroded and the Cobalt sedimentary rocks are exposed. The silver veins are spatially and genetically associated with the diabase sill and generally are found within 300 feet of the upper or lower contact of the sill. Ore also appears to be spatially associated with the Keewatin-Cobalt unconformity. Silver-bearing veins may also be found in Keewatin volcanic rocks and in Nipissing Diabase, but are more common in the Cobalt sedimentary rocks. The bulk of the Cobalt silver ore has come from the upper 500 feet of mine workings. Exploration below l ,000 feet in depth has generally been unproductive, but two mines in the Gowganda area have exceeded 1,000 feet in depth. 87 COBALT Mineralogy and Occurrence Cobalt commonly occurs as cobaltite, CoAsS, and smaltite, (Co,Ni)As3.x. Cobalt minerals are associated with the silver mineralization at Cobalt and Gowganda where cobalt is recovered as a by-product. After exposure to the atmosphere, cobalt minerals develop a characteristic pink oxidation called "cobalt bloom". Cobalt minerals were not found in commercial quantities in the Thunder Bay silver mines. Cobalt is recovered from the nickel copper ores of the Sudbury area. Most of the cobalt at Sudbury occurs in solid solution in the mineral pentlandite, (Fe,Ni)0S8, which averages about one percent cobalt. Ontario Production Production of cobalt in Ontario to the end of 1962 totalled 70,160,598 pounds valued at S103,802,381. This production came principally from the Sudbury and Cobalt mining areas. In some of the mines at Cobalt, cobalt is the principal ore mineral. History and Geological Features The history and geological features of the Cobalt camp are described under the heading Silver (see pp. 85-87). NICKEL Mineralogy and Occurrence Nickel commonly occurs as the nickel iron sulphide, pentlandite, (Fe,Ni)9S8, which contains 34-35 percent nickel. Pentlandite is usually intergrown with the iron sulphide, pyrrhotite, Fe7S8, which itself may contain as much as two percent nickel. Other nickel minerals are: the nickel arsenide, niccolite, NiAs; the nickel antimonide, breithauptite, NiSb; gersdorffite, NiAsS; and the nickel sulphide, millerite, NiS. At Sudbury the nickel minerals are found with other sulphides in massive or disseminated sulphide ore replacements frequently associated with basic intrusive rocks such as norite. At Cobalt the nickel minerals are found in the silver-bearing calcite veins. Ontario Production Production of nickel in Ontario to the end of 1962 totalled 9,534,061,759 pounds valued at 54,006,511,810 principally from the Sudbury area. Total mineral production from the Sudbury area to the end of 1962 was S6,847,370,000; this includes substantial amounts of nickel, copper, cobalt, gold, silver, and platinum metals. History The first mine that was located in the Sudbury area was the Murray mine; it was discovered in 1883 along the right of way during construction of the Canadian Pacific Railway. A gossan zone was observed in a rockcut and copper mineralization was iden tified. The mine was opened in 1889, and the ore was smelted and refined at Swansea in Wales. From 1884 to 1890 prospecting continued in the Sudbury area and during 88 Photo 56 — Smelter of The International Nickel Company of Canada Limited; Copper Cliff. (Courtesy of George Hunter.) those first few years many of the major deposits of nickel-copper ore, including the Frood, Creighton, Stobie, and Copper Cliff mines, were discovered. In 1886 Samuel J. Ritchie and associates organized the Canadian Copper Company, forerunner of The International Nickel Company of Canada Limited, and purchased the Copper Cliff, Stobie, Lady Macdonald, McArthur, Creighton, and Frood mines. The discovery of nickel in the copper ore was made in 1887 at the Orford Copper smelter in New Jersey, U.S.A. The Mond Nickel Company, established in 1900, merged with other interests to become The International Nickel Company of Canada Limited in 1929. In 1928 Falconbridge Nickel Mines Limited was formed to mine a deposit discovered by geophysical methods by Thomas Edison. The story of the early history of nickel and copper mining in the province is given by Gibson (1937, pp. 71-104). Many discoveries have since been made in the Sudbury area and recently The Inter national Nickel Company of Canada Limited has operated the Frood-Stobie, Creighton, Levack, Garson, Murray, and Copper Cliff North mines. Falconbridge Nickel Mines are operating the Falconbridge, East Hardy, Boundary, Onaping, Strathcona, and Fecunis Lake mines. Nickel is also mined at the Gordon Lake mine of Nickel Mining and Smelting Corporation Limited near Kenora. 89 4) O c c 'i'i U _ o c i O 90 U c * -2 c ^ . o! J l "E .5 c w l ™ - ^ o "i 1 "5 '5 Q o * E uit O J3 Geological Features SUDBURY AREA The nickel-copper sulphide orebodies at Sudbury are closely associated in age and location with the Sudbury Norite, one member of a composite irruptive rock of Keween awan age. The nickel irruptive is an elongate basin-shaped intrusive sheet about 37 miles long and 17 miles wide. The outcropping width of the intrusive rim of the basin varies from l to 3V2 miles wide. The intrusive sheet dips southerly along the north rim of the basin, and steeply to vertically along the south rim. The intrusive sheet is divided into three layers; from the top down these are micropegmatite, transition zone, and norite. The layering is apparently due either to differentiation in place or to composite intrusion. Quartz diorite is present as lenses in the norite and in dike-like offsets that in some cases extend for some miles from the footwall contact of the irruptive. Economic mineraliza tion is frequently found to be associated with the quartz diorite phase of the intrusion. The nickel-copper sulphide orebodies are found along the footwall contact of the norite in mineralized shear zones or in mineralized embayments of quartz diorite. These are called "contact" or "marginal" deposits; Creighton, Falconbridge, Levack, Murray, and Garson are of this type. Orebodies also are found in the quartz diorite offsets. The Frood-Stobie, Worthington, Victoria, Nickel Offset, and Copper Cliff orebodies are of the offset type. Three main types of ore are recognized: disseminated sulphides largely in quartz diorite; massive sulphides along zones of shearing and brecciation; sulphide veins, and stringers in sheared and brecciated quartz diorite and country rock. The ore may lie in either the quartz diorite or the adjacent footwall country rocks. Both the Creighton and Falconbridge mines have been developed to depths greater than 6,500 feet. The principal ore minerals are pentlandite, nickeliferous pyrrhotite, chalcopyrite, cubanite, niccolite, gersdorffite, maucherite, and sperrylite. The average grade of ore is about 2 percent nickel and 2 percent copper, but it varies from orebody to orebody. The country rocks within the Sudbury basin are volcanic and sedimentary rocks of Precambrian age. The country rocks along the south rim of the irruptive are mainly older Precambrian volcanic and sedimentary rocks. The north rim of the irruptive is largely flanked on the north by an older granite complex. COPPER Mineralogy and Occurrence Copper may occur in the native state, as it does in the copper deposits of the Mamainse area north of Sault Ste. Marie. However, more commonly copper occurs as: chalcopyrite, CuFeS2, containing about 34 percent copper; cubanite, CuFe2S3, containing about 22 percent copper; chalcocite, Cu2S; and bornite, Cu5FeS4 . The secon dary copper carbonate minerals, malachite and azurite, are found in the upper weathered portions of copper deposits, but these minerals are not quantitatively important in Canada. Copper sulphide minerals most frequently are found as vein deposits or in massive and disseminated sulphide replacement orebodies. Ontario Production Production of copper in Ontario to the end of 1962 totalled 9,814,742,656 pounds valued at S l,905,721,934. Production was principally from the Sudbury area, but the 91 Photo 57 — Geco mine in 1962; Manitouwadge. following companies also produced copper concentrates in 1962: Geco Mines Limited and Willroy Mines Limited at Manitouwadge; Kam-Kotia Porcupine Mines Limited and Mcintyre Porcupine Mines Limited near Timmins; Temagami Mining Company Limited at Timagami Island; Rio Algom Mines Limited (Pater mine) near Blind River; Ethel Copper Mines Limited near Elk Lake; North Coldstream Mines Limited near Kasha bowie; and Nickel Mining and Smelting Corporation Limited at Gordon Lake near Kenora. An important new copper-zinc orebody was found in 1964 near Timmins by Texas Gulf Sulphur Company. History Copper mining at Bruce Mines on the north shore of Lake Huron began in 1847 and continued intermittently for more than 50 years. Copper has been found at many places along the north shore of Lake Huron, but the only producing mine is now the Pater mine near Blind River. Near Mamainse, copper mining began about 1860. Native copper here occurs in volcanic and sedimentary rocks of the Keweenawan Series. By far the largest copper-mining district in Ontario is the Sudbury area whose his tory has been briefly described under nickel (see pp. 88, 89). The copper-zinc mines of Manitouwadge were discovered in 1953, and production began from the Geco and Willroy mines in 1957. Initial exploration at Geco mine is reported to have indicated over 15,000,000 tons of ore grading 1.7 percent copper, 3.5 percent zinc, and 1.7 ounces of silver per ton. A new townsite with access roads and railroads was built. 92 Geological Features Geological features of the Sudbury area are described under Nickel (see p. 91). MANITOUWADGE AREA The Geco orebody at Manitouwadge is a sulphide replacement body in Keewatin muscovite-quartz schist that lies between granodiorite gneiss to the north and hornblendebiotite gneisses to the south. The orebody consists of massive sulphide ore enclosed in an envelope of disseminated ore. The massive ore is principally pyrite and pyrrhotite, with variable amounts of chalcopyrite and sphalerite. The disseminated ore in muscovitequartz schist consists of pyrite, pyrrhotite, chalcopyrite, and minor amounts of sphalerite. The orebody dips vertically and strikes east-west. It is developed to depths greater than 2,500 feet. The orebody has a length of more than 2,700 feet and a width in places more than 150 feet. The Willroy orebody at Manitouwadge is a tabular body of disseminated sulphide ore consisting of pyrrhotite, pyrite, chalcopyrite, and some sphalerite, in biotite-sillimanite-muscovite-quartz schist. ZINC Mineralogy and Occurrence Zinc commonly occurs as the zinc sulphide, sphalerite, ZnS. Sphalerite often is found with the lead sulphide, galena, in vein deposits and in sulphide replacement deposits. Ontario Production Ontario production of zinc to the end of 1962 amounted to 570,250,142 pounds valued at S66,339,547. History Zinc production in Ontario was of minor and intermittent character until the dis covery of the copper-zinc mines of Manitouwadge in 1953. Since 1958 a substantial production of zinc has come from the Geco and Willroy mines, and in 1962 production exceeded 100,000,000 pounds. LEAD Mineralogy and Occurrence Lead is commonly found as the lead sulphide, galena, PbS, which is often asso ciated with sphalerite. Galena occurs as vein deposits and sulphide replacement bodies. Ontario Production Production of lead in Ontario to the end of 1962 amounted to 100,545,074 pounds valued at 58,095,484. Production in 1962 was 2,287,000 pounds valued at S226,879. This production came principally from the Geco and Willroy mines. A small production of lead concentrates has come from mines of the Cobalt area. Many small lead mines have operated from time to time in Ontario, among the better known of which are the Kingdon mine at Galetta, the Frontenac lead mine in Loughborough township, the Hollandia mine in Madoc township, and the Jardun mine near Sault Ste. Marie. 93 IRON Mineralogy and Occurrence The principal iron ore minerals are magnetite, hematite, limonite, siderite, pyrite, and pyrrhotite. Magnetite deposits are of three main types: magmatic magnetite deposits associated with basic intrusive rocks; contact metamorphic magnetite deposits; and magnetite iron formation of sedimentary origin. The magnetite deposit at Marmora is of the contact metamorphic type. The Moose Mountain deposit of Lowphos Ore Limited is magnetite iron formation. Hematite, limonite, and the associated hydrous iron oxide mineral, goethite, are commonly found in sedimentary and lateritic iron deposits, and sometimes in hydro thermal or metasomatic deposits. The iron mines near Steep Rock Lake are of the sedimentary type in which hematite, limonite, and goethite are the principal iron min erals. Hematite is the common ore mineral of the Lake Superior iron ranges. Both hematite and magnetite occur in Precambrian iron formations. Siderite and pyrite are found in banded chert-pyrite-siderite sedimentary iron for mation of the Michipicoten type. This type of ore is mined at the Helen mine near Wawa. Pyrite and pyrrhotite from massive sulphide deposits are a source of commercial iron ore. The International Nickel Company of Canada Limited at Sudbury produces pelletized iron ore, grading about 68 percent iron, from pyrrhotite. Ontario Production Production of iron in Ontario to the end of 1962 totalled 70,569,699 tons valued at S538,840,809. Production of iron ore in Ontario in 1962 amounted to about 6Vi million tons. In 1963 six iron mines were in production: Algoma Ore Division of the Algoma Steel Corporation in the Michipicoten area operated the Sir James open pit, the Geo. W. MacLeod mine, and the Goudreau pyrite mine; Steep Rock Iron Mines Limited, Caland Ore Company Limited, and Canadian Charleson Limited produced at Steep Rock Lake; Marmoraton Mining Company Limited operated the Marmora open pit; Lowphos Ore Limited produced from an open pit at Moose Mountain. The Adams mine of Jones and Laughlin Steel Corporation has scheduled iron ore production for 1964 from its Kirkland Lake property. Pelletized iron ore is produced as a by-product of the nickel mines of the Sudbury area by The International Nickel Company of Canada Limited and Falconbridge Nickel Mines Limited. The iron is recovered by roasting of nickeliferous pyrrhotite. Nickel, cobalt, and copper are recovered from the sinter by leaching with ammonia. The pel letized iron oxide grades about 68 percent iron. Almost a million tons of iron ore pellets are produced annually. History Mining of iron ore in Ontario dates back to 1800 when a blast furnace was built at Furnace Falls (later Lyndhurst) on the Gananoque River to smelt bog iron ore. Other blast furnaces were built in 1813 at Charlotteville in Norfolk county to smelt bog ore, in 1820 at Marmora and in 1837 at Madoc to smelt magnetite and hematite ores from Peterborough and Hastings counties, and in 1882 at Burnt River to smelt magnetite ores from Snowdon and Glamorgan townships. During the last half of the 19th century more than 40 small magnetite and hematite mines were operated in eastern Ontario. These included a large group in Hastings county: the Seymour, Sexsmith, Wallbridge, Eldorado, Nelson, and Dufferin mines in Madoc township; the St. Charles, Lee, Baker, Emily, and Orton mines in Tudor town94 ship; the Ridge, Coehill, and Jenkins mines in Wollaston township; and others. The Blairton and Ledyard mines were operated in Belmont township (Peterborough co.); the Pusey, Paxton, Howland, and Imperial mines in Glamorgan, Lutterworth, and Snow don townships; the Wilson, Calder, Gildersleeve, Ravenhurst, Wilbur, Lavant, and Mis sissippi mines in Lavant and Palmerston townships; the Glendower mine in Bedford township (Frontenac co.); the Caldwell mine in Bagot township; the Radnor mine in Grattan township; the Chaffey mine near Newboro; and others. From about 1902 to 1913 the Bessemer, Rankin, and Childs mines were active in Mayo township (Hastings co.). Total production from all these small mines in eastern Ontario up to the year 1900 probably did not exceed 1,000,000 tons. Iron production increased notably after the discovery in 1897 of the Helen mine near Michipicoten; during the period from 1900 to 1923 when the Helen, Magpie, and Moose Mountain mines were in production, about 3 1A million tons of iron ore were produced. There was a lapse of 16 years from 1923 to 1938 during which time there was little or no iron ore production in Ontario. A new era of iron-ore mining began in 1939 when Algoma Ore Properties, now Algoma Ore Division of The Algoma Steel Corpora tion, resumed production in the Michipicoten area. Production from these mines from 1939 to 1962 exceeded 25,000,000 tons of sinter ore valued at more than S175,000,000. The presence of hematite boulders on the south side of Steeprock Lake led geol ogists to predict the presence of a hematite orebody beneath Steeprock Lake. In 1938 drilling from the ice of Steeprock Lake disclosed the presence of high-grade hematite ore in the basin of the lake. Later drilling indicated probable reserves of several hundred million tons of direct-shipping ore, and in 1944 production was begun by Steep Rock Iron Mines Limited after the diversion of the Seine River and the draining of Steeprock Lake. The Errington open pit orebody was opened in 1944; mining went underground in 1953 on the orebody. The Hogarth open pit came into production in 1953 and under ground development was begun a few years later. Stripping was commenced on a third open pit, the Roberts, in 1961. Shipments of ore from Steep Rock Iron Mines Limited from 1945 to the end of 1962 totalled 26,235,183 tons valued at S265,999?002. The C ore zone on the East Arm of Steeprock Lake was leased to Inland Steel Company. After drilling proved a large tonnage of high-grade direct-shipping ore, the property was prepared for production by Caland Ore Company Limited, a Canadian subsidiary of Inland Steel. In 1960, production began and is expected to eventually reach 3,000,000 tons annually. Oglebay Norton Company's Canadian Charleson mine has been producing hematite ore since 1958 from a gravel deposit on the south side of Steeprock Lake. The glacial gravels that average 10-20 percent iron were derived from the Steeprock orebodies and transported by ice and glaciofluvial action. The hematite is concentrated by jigging. The annual rated capacity of the plant is about 200,000 tons. As a result of an aeromagnetic survey carried out by the Ontario Department of Mines and the Geological Survey of Canada in 1949, a magnetite orebody was dis covered near Marmora. The property was drilled by Bethlehem Steel Corporation. A subsidiary company, Marmoraton Mining Company Limited, was formed to develop the mine. A high-grade magnetite is produced and pelletized. Production began in 1955 at the rate of approximately 400,000 to 500,000 tons of pellets per year. The Moose Mountain iron range 35 miles north of Sudbury has been known for many years. The Moose Mountain mine was operated from 1909 to 1920. The ore is a siliceous magnetite iron formation. In 1953 Lowphos Ore Limited, a subsidiary of Hanna Iron Ore Division of National Steel Corporation, acquired the property and pro duction of magnetite concentrates began in 1959. A pelletizing plant was recently com pleted and now produces a product grading 58-60 percent iron. 95 Photo 58 — Helen mine in 1955; Algoma Ore Division, The Algoma Steel Corporation Limited, Wawa. (Courtesy of Hunting Survey Corp. Ltd.) Jones and Laughlin Steel Corporation is preparing to bring the Adams iron mine into production in Boston township, six miles south of Kirkland Lake. The deposit is a banded siliceous magnetic iron formation of Keewatin type, grading about 25 percent iron. Milling tests have indicated that a high-grade magnetite pellet can be produced. Production is scheduled for 1964. With six iron mines now in production, and a seventh scheduled to commence production in 1964, Ontario's iron ore industry is flourishing as never before. Aero magnetic surveys of northern Ontario have indicated the presence of many low-grade iron ranges grading from 20 to 35 percent iron. Exploration work has been carried out on at least 20 new properties and reserves of over 6,000,000,000 tons of potential ore have been indicated. Geological Features ALGOMA STEEL CORPORATION, ALGOMA ORE DIVISION The Keewatin sideritic iron formations of the Michipicoten area extend for a distance of about 11 miles from Wawa Lake to Hawk Junction. Five separate iron ranges are recognized; from west to east these are the Helen, Eleanor, Lucy, Ruth, and Josephine-Bartlett ranges. These are thought to be faulted segments of a single iron formation. At the Helen mine the pyritic siderite band strikes east-west and dips 70 0 S. to vertical. The footwall is banded silica, and the hangingwall is volcanic pyroclastic rocks. The maximum thickness of the siderite member of the iron formation at the 96 Figure 19 — Steep Rock Lake iron area. Helen mine is about 240 feet. The formation can be traced for more than a mile alongstrike. The Helen orebody is 2,600 feet long and the nearby Victoria orebody is 2,000 feet long. The Helen mine has been operated to a depth of nearly 1,000 feet. A sink-float plant removes a high-silica fraction from the siderite ore. About IV2 tons of siderite ore are required to produce l ton of sinter averaging about 51 percent iron. The pyrite content of the ore saves fuel in the sintering process. STEEP ROCK IRON MINES LIMITED The goethite-hematite ore zones at Steeprock Lake strike northwest and dip steeply to the southwest. The footwall of the ore zone is the Steeprock limestone of probable sedimentary origin. The hangingwall of the ore zone is basic volcanic and pyroclastic 97 Photo 59 — Open pit mining in 1963; Steep Rock Iron Mines Limited, Steep Rock Lake. (Courtesy of Hunting Survey Corp. Ltd.) rocks. A granite batholith lies to the north. Steeprock Lake has an M shape and the orebodies lie in the lake basin on the northwest-trending arms of the M. A. W. Jolliffe has suggested that the two ore zones represent the faulted arms of a single ore formation. This iron ore zone has a length of several miles and a width of 100-300 feet. Ore reserves in the Steeprock iron range are estimated at 300,000,000 tons per 1,000 feet of depth, and deep drilling has indicated ore to over 2,000 feet in depth. There is some controversy over whether the ore is of sedimentary lateritic origin or hydrothermal origin, but the former seems more likely from recent information. MARMORATON MINING COMPANY LIMITED The Marmora magnetite orebody is a contact metamorphic skarn deposit asso ciated with a syenite intrusion invading Grenville crystalline limestone. The orebody pitches southwesterly, and has a length of approximately 2,400 feet and a width of slightly more than 400 feet. It averages about 37 percent iron. The Precambrian ore body was covered by 110 feet of Paleozoic limestone that was stripped to expose the ore. LOWPHOS ORE LIMITED Concentrations of magnetite are found in lenticular bands of Keewatin siliceous iron formation that lie within a Keewatin greenstone complex in Hutton township. The ore zones range in length from 300 to 4,000 feet and have an average width of 150 feet. 98 JONES AND LAUGHLIN STEEL CORPORATION The Boston township iron range, 7 miles southeast of Kirkland Lake, extends for a length of about 6 miles in the northeastern part of Boston township. Iron formation, interbedded with lavas and pyroclastics, occurs over a width of 4,000 feet in places. The Keewatin iron formation consists of alternating layers of siliceous magnetite, massive magnetite, quartzite, and chert. The formation is usually highly folded and contorted. At the Adams mine the grade of the iron formation averages 25 percent. URANIUM Mineralogy and Occurrence Uranium commonly occurs as uraninite or uranothorite in the granitic and syenitic pegmatite deposits of the Bancroft area, or as uraninite and brannerite in the pyritebearing quartz-pebble conglomerates of the Blind River area. Ontario Production Ontario production of uranium oxide (U3O8) from 1955 to the end of 1963 amounted to 101,957,747 pounds valued at S l,052,796,601. This production came from the Blind River and Bancroft uranium areas. Mines that produced at Blind River include: the Nordic, Milliken, Panel, Quirke, Lacnor, Pronto, Buckles, and Spanish American mines of Rio Algom Mines Limited; the Denison and Can-Met properties of Denison Mines Limited; Stanrock Uranium mine; and Stanleigh Uranium mine. Uranium mines that produced at Bancroft include: Faraday Uranium Mines Limited (now Metal Mines Ltd.), Bicroft Uranium Mines Limited (now Macassa Gold Mines Ltd., Bicroft Division), Canadian Dyno Mines Limited, and Greyhawk Uranium Mines Limited. History In 1847 J. L. LeConte, a geologist from U.S.A., described the first known occur rence of uranium in Canada at a locality on the east shore of Lake Superior about 70 miles north of Sault Ste. Marie. The locality was not re-discovered until the fall of 1947 when Robert Campbell, a prospector, made a discovery of pitchblende at Theano Point. This precipitated a prospecting rush to the area but no commercial production ensued. In 1922 W. M. Richardson discovered uraninite on what is now the property of Fission Mines Limited at Wilberforce. From 1929 to 1931, Ontario Radium Corpora tion and its successor, International Radium and Resources Limited, did underground exploration on the Richardson find. A 150-ton mill was built but did not operate suc cessfully. The property was reopened by Fission Mines Limited in 1949, and further exploration was carried out in 1954 and 1955. No production resulted. From 1932 to 1936 and from 1939 to 1942, Canada Radium Mines carried on underground exploration and development on a property near Cheddar in Cardiff town ship (Haliburton co.). In 1939 and 1940 a 100-ton mill was built on the property but was closed after test runs. Uranium prospecting began in earnest in Ontario about 1948 after the widespread introduction of the geiger counter as a prospecting tool. One of the early finds in the Bancroft area that became a productive mine was the Faraday mine. Discovered in 1949 by Arthur Shore, a prospector, the mine is in Faraday township (Hastings co.). In 1952 the property was taken over by Newkirk Mining Corporation, and Faraday Uranium Mines Limited (now Metal Mines Ltd.) was formed. Production began in April 1957 and was continued until 1964. 99 Photo 60 — Pronto mine in 1958; Ontario's first uranium producer; Blind River. (Courtesy of Sudbury Daily Star.) In 1952 G. W. Burns discovered the Bicroft uranium mine in Cardiff township (Haliburton co.). The property was acquired by a Toronto syndicate under the direction of C. C. Huston, and Centre Lake Uranium Mines was formed; it later became Bicroft Uranium Mines Limited, and is now Macassa Gold Mines Limited, Bicroft Division. The mine went into production in October 1956 and closed in 1963. There were two other uranium producers in the Bancroft area: Canadian Dyno Mines Limited was discovered in 1953, came into production in May 1958, and closed in 1960; Greyhawk Uranium Mines Limited in Faraday township opened its mine in August 1957 and closed in March 1959. The initial discovery of uranium in the Blind River area was made in 1948 by Karl Gunterman in Long township where radioactivity was indicated in a pyrite-bearing con glomerate. Although the discovery was examined by several geologists and engineers, no development resulted due to the low assays. Among those who examined the dis covery was Franc Joubin, a geologist. In 1952 Joubin postulated that the surface exposures of radioactive conglomerate in Long township may have suffered surface leaching and decided to re-examine the area. In May 1952 Joubin and associates staked 36 claims in Long township. Peach Uranium Syndicate was formed to explore these claims and diamond-drilling was carried out in 1953. Pronto Uranium Mines Limited was organized to develop the deposit and production began in September 1955. The uranium mine was closed in April 1960, but the mill continued to operate on copper ore from the Pater mine. After discovery of the uranium-bearing conglomerate ore in Long township, Joubin and associates decided to prospect the extension of the quartz-bearing pebble conglo merate in the townships to the north where the extent of the formation was indicated on W. H. Collin's geological map of the area. Several more uranium discoveries were staked in 1953 by Joubin and associates, and later in 1953 a major staking rush devel oped in the Elliot Lake area. The finds resulted in the discovery of many uranium orebodies, and twelve mines came into production in 1955, 1956, and 1957. Four mines were still in production in 1964. 100 Geological Features BANCROFT AREA At Bancroft the uranium minerals, uraninite and uranothorite, occur in pegmatitic granite dikes. These are the only deposits of the pegmatitic type to produce uranium in Canada. Grades average about 0.1 percent U3O8. The dikes are complex composite pegmatitic granite bodies of irregular and branching shape, cutting and replacing the country rocks. Contacts with the country rocks are sharp to gradational. More than one lithologic facies is generally present in the dike; marked lithologic changes are abrupt across and along the dikes. The uranium minerals are concentrated in ore shoots that generally favour the footwall or hangingwall constrictions or zones of shattering. At the Bicroft mine, the dikes lie within a zone of syenitized paragneiss and amphi bolite striking N.I O 0 E. and dipping 50 0 east. The zone has a strike length of 16,000 feet on the Centre Lake property. Dikes range from 5 to 100 feet wide and up to several hundred feet in length. Ore shoots range from a few feet to 200 feet in length. Slopes were opened in dozens of different ore shoots on various levels in the mine. The mine was developed on 13 levels to a total depth of 1,843 feet. At the Faraday mine, the pegmatitic granite and syenite dikes cut metagabbro and gabbroic amphibolite. There are many lenticular, pod-shaped, and irregularly branching dikes trending east-west, parallel to the gneissic structure of the country rock. The dikes generally dip 40 0 -60 0 S. Ore shoots range from a few feet to more than 300 feet in length and from l to 35 feet in width. The mine has been developed to a depth of 1,455 feet. The strike length of the ore-bearing zone is about 3,000 feet. BLIND RIVER AREA In the Blind River area the uranium minerals, uraninite and brannerite, occur in pyrite-bearing quartz-pebble conglomerate members of the Mississagi formation of Lower Huronian age. Two of the major ore zones are on the north and south limbs of the Quirke Lake trough, a westerly-pitching syncline of Huronian sedimentary rocks lying on a pre-Huronian granitic basement. Ore zones in the various mines range from 7 to 35 feet in thickness, and these follow the bedding direction in attitude. Average tenor of ore is about 0.12 percent U3O8 . Ore-bearing zones are exposed in outcrops on the surface on the north and south limbs of the Quirke Lake trough and can be traced down-dip to depths of more than 3,500 feet. The shaft at the Milliken mine, for example, has a depth of 3,400 feet. At the Denison mine the ore zone consists of two conglomerate bands each up to 12 feet thick, separated by 3 to 6 feet of low-grade quartzite. Locally the beds pinch and swell. Most geologists believe that these uranium deposits are of placer origin and were formed at the time of deposition of the conglomerates in troughs or depressions in the Precambrian rocks. MAGNESIUM Magnesium metal is produced from high-purity crystalline dolomitic marble of the Grenville Series at Haley by Dominion Magnesium Limited. The plant was opened in 1941 to produce magnesium from dolomite by the Pidgeon process, which involves the reduction of magnesia by ferrosilicon in a retort. Calcium, barium, thorium, strontium, and lithium have also been produced by the company. 102 Denison Mines Ltd. 1. Can-Met mine. Closed April 1960 . . . . . . . . . . . . . . . . . U 2. Denison mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . U Preston Mines Ltd. 3. Stanleigh mine. Closed November 1960 . . . . . . . . . . . . . U Rio Algom Mines Ltd. 4. Buckles mine. Closed October 1958 . . . . . . . . . . . . . . . . U 5. Lacnor mine. Closed July 1 960 . . . . . . . . . . . . . . . . . . . . U 6. Milliken mine. Closed June 1964 . . . . . . . . . . . . . . . . . . . U 7. Nordic mine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . U, Th 8. Panel mine. Closed June 1961 . . . . . . . . . . . . . . . . . . . U 9. Pater mine. (Pronto Division) . . . . . . . . . . . . . . . . . . . .Cu 10. Pronto mine. Closed April 1960 . . . . . . . . . . . . . . . . . . U 11. Quirke mine. Closed December 1960 . . . . . . . . . . . U, Th 12. Spanish American mine. Closed February 1959 . . . . . . . .D Stanrock Uranium Mines Ltd. 1 3. Stanrock mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . U Figures 20 — Mines of the Blind River area, August 1964. 101 Photo 61 —— Munro mine and mill in 1959; Canadian Johns-Manville Company Limited, Matheson. (Courtesy of Canadian Johns-Manville Co. Ltd.) PLATINUM METALS There is a substantial production of metals of the platinum group each year from the Sudbury mines. These metals include platinum, palladium, iridium, rhodium, and ruthenium. In 1961 the production of platinum metals from Sudbury amounted to 418,278 ounces valued at S24,534,349. Selenium and tellurium are also produced. ASBESTOS Mineralogy, Occurrence, and Use Chrysotile is the principal asbestos mineral mined in Ontario. It is commonly found in cross-fibre veinlets in serpentinized dunite or peridotite. Chrysotile asbestos is used in making asbestos cloth, packing, electrical insulation, brake linings, clutch facings, asbestos cement products, floor and wall tile, boiler and roofing cements, and many other products. Ontario Production The total Ontario production of asbestos up to the end of 1949 was 233 tons valued at S102,456. In 1950 the Munro mine of Canadian Johns-Manville Company Limited came into production near Matheson. Ontario production of asbestos to the end of 1962 amounted to 307,473 tons valued at S49,929,525. History of Production The small production of asbestos in Ontario prior to 1950 came from three deposits in northeastern Ontario: the Slade-Forbes Asbestos Company produced in 1917 from a deposit in Deloro township (Dist. Cochrane); in 1923 to 1926 the Bowman mine, also in Deloro township, produced 194 tons of asbestos; in 1937 and 1939 Rahn Lake Mines Corporation produced 19 tons of asbestos from a property in Bannockburn township (Dist. Timiskaming). In 1948 the chrysotile deposit in Munro township (Dist. Cochrane) was acquired by Canadian Johns-Manville Company and production began in 1950. The company holds other properties in Garrison township (Dist. Cochrane) and Reeves township (Dist. Sudbury). 103 Geological Features The serpentinized dunite sill, which is the host rock for the A orebody at the Munro mine, strikes N.65 0 W. and dips 70 0 N. It lies conformably within a series of Keewatin volcanic rocks. The sill has a maximum width of 1,000 feet and has been traced for more than 3V2 miles along-strike. The A orebody within the sill has a max imum width of about 250 feet and a length of 1,600 feet. The orebody consists of three separate elliptically shaped ore pods plunging vertically and separated by 100-200 feet of waste rock. The host rock is medium to light granular serpentinite cut by crossfibre veinlets of chrysotile from Vsz to 3 inches in width. There are two major sets of fibre veins, one set parallel to the strike of the sill and other set normal to strike. The production is principally group 4 fibre. Production began from the open pit in 1950, and in 1959 the mine was switched over to an underground operation. The main shaft reaches a depth of 1,204 feet. The grade of ore is reported to be approximately 6-7 percent. FELDSPAR Mineralogy, Occurrence, and Use Both orthoclase (the potash feldspar) and plagioclase (the soda-lime feldspar) have been mined in Ontario. Commercial deposits of feldspar are found mainly in granite pegmatite dikes where the feldspar crystals may grow to gigantic size. Single feldspar crystals weighing up to 50 tons have been quarried at Ontario feldspar mines. Feldspar is used principally in the manufacture of glass, whitewares, glazes, and enamels. Ontario Production Total feldspar production in Ontario until the end of 1954, when Ontario produc tion ceased, amounted to 661,990 tons valued at 54,205,604. Mines were located prin cipally in eastern Ontario, with quarries near Bancroft, Perth, Verona, Madawaska, Burks Falls, and Sudbury. The largest feldspar mine in Ontario was the Richardson mine in Bedford township (Frontenac co.), near Verona. This mine operated intermittently from 1900 to 1948 and produced 228,690 tons of feldspar or more than 34 percent of Ontario's total ton nage. The mine was worked as an open pit that reached a depth of 120 feet. FLUORSPAR Mineralogy, Occurrence, and Use The mineral fluorite, CaF2 is found in tabular fissure-filling vein deposits cutting varied types of country rock. Calcite and barite are frequently associated with the fluorite. Fluorspar is used as a flux in the steel, glass, and enamelling industries, and in the extraction of aluminium from bauxite ores. Ontario Production Ontario fluorspar production to the end of 1962 amounted to 121,919 tons valued at S3,421,825. This came principally from the mines of the Madoc area in eastern Ontario. Fissure-filling fluorspar veins at Madoc cut Ordovician limestones as well as the underlying Precambrian rocks that range from marble to granite. The deepest mine workings are about 300 feet in depth. The veins have widths up to 15 feet. Ore shoots are rarely more than a few hundred feet in length. The main vein systems at Madoc are found along faults that strike northwest. 104 Photo 62 — Nepheline syenite quarries and mill in 1959; Indusmin Limited, Nephton. (Courtesy of K. Wyatt.) NEPHELINE SYENITE Mineralogy, Occurrence, and Use Nepheline syenite is an intrusive igneous rock composed of nepheline, albite, and microcline, with minor amounts of biotite and magnetite. It is used in the manufacture of glass and ceramics. Ontario Production Ontario production of nepheline syenite from 1935 to the end of 1962 amounted to 2,781,986 tons valued at S30,905,114. Production has come principally from Blue Mountain in Methuen township (Peterborough co.). SALT Mineralogy, Occurrence, and Use Beds of rock salt are laid down as chemical precipitates in saline bays or inland seas that lack outgoing drainage. In Ontario, salt beds having an aggregate thickness of up to 600 feet are found in the Salina Formation of Silurian age in southwestern Ontario. Salt is used in the chemical and food processing industries and as a de-icing agent. Ontario Production Ontario production of salt to the end of 1962 amounted to 34,541,777 tons valued at S184,352,658. Mines are operated at Windsor and Goderich. Brine wells produce salt at Amherstburg, Windsor, Sarnia, and Goderich. 106 GRAPHITE Mineralogy, Occurrence, and Use The mineral graphite is commonly found in Grenville paragneisses and marbles in eastern Ontario. Graphite concentrations of commercial grade and size are often the result of hydrothermal deposition. Graphite is used in the manufacture of crucibles, ladle stoppers, retorts, and other refractory articles used in metal foundries. Graphite is used in lubricants, brushes for electric motors, batteries, lead pencils, foundry facings, and many other products. Ontario Production Production of graphite in Ontario to the end of 1962 amounted to 95,156 tons valued at S6,l 14,768. The principal producing mine in Ontario was the Black Donald mine near Calabogie (Renfrew co.). This mine produced from 1896 to 1954 when it was exhausted. It produced 94 percent of Ontario's graphite. GYPSUM Mineralogy, Occurrence, and Use Gypsum beds are laid down as chemical precipitates in bays or inland seas in a desert type of environment. Gypsum beds up to 12 feet thick are found in the Salina Formation of Silurian age in south-central Ontario. Gypsum beds are also found in the Moose River basin of northern Ontario. Gypsum is used for the manufacture of plaster and wallboard, and as a retarder in portland cement. Ontario Production Ontario production of gypsum to the end of 1962 amounted to 7,752,140 tons valued at 326,322,368. Principal production has come from mines at Hagersville and Caledonia south of Hamilton. MICA Mineralogy, Occurrence, and Use The white mica, muscovite, is found in crystals up to 10 feet in diameter in granite pegmatite dikes. The amber mica, phlogopite, is commonly found in books up to about 8 feet in diameter in basic pegmatites (metamorphic pyroxenite) with calcite and apatite. Mica is used as an electrical insulator, and as a filler in paints, rubber goods, and wallpaper. Ontario Production Ontario production of mica up to the end of 1962 amounted to 96,131,757 pounds valued at S4,556,079. About a third of this production came from the Purdy mica mine at Eau Claire, a muscovite mica mine of great richness, discovered at the beginning of World War II near Mattawa. The two principal phlogopite mining areas were in eastern Ontario near Kingston and Perth. 105 Photo 63 — Bedded rock salt; Ojibway mine. Canadian Rock Salt Company Limited, Windsor. (Courtesy of Sid. Lloyd.) SILICA Mineralogy, Occurrence, and Use Silica commonly occurs in the form of quartz, SiO2 , mainly in sandstone, quartzite, vein, and pegmatite deposits. Silica is used as a flux in metallurgical industries, and for the manufacture of glass, ferrosilicon, and silicon carbide. Ontario Production Ontario production of silica to the end of 1962 amounted to 40,766,782 tons valued at 536,844,291. Production has come principally from the Lorraine Quartzite of Precambrian age quarried in the District of Manitoulin at Whitefish Falls, Killarney, and Sheguiandah. TALC Mineralogy, Occurrence, and Use The hydrous magnesium silicate, talc, is found as a hydrothermal alteration product of dolomitic marble. Commercial talc deposits are found in marble of the Grenville Series in eastern Ontario near Madoc. Talc is used as a filler in paint, rubber goods, roofing, insecticides, paper, toilet preparations, and foundry facings. It is also used in the ceramic industry. Ontario Production Ontario production of talc to the end of 1962 amounted to 699,164 tons valued at S7,799,261. Most of the talc production has come from the mines of Canada Talc Industries at Madoc. 107 Photo 64 — Plant of Lake Ontario Portland Cement Company Limited, Picton. (Courtesy of Pat Hodgson Studio.) STRUCTURAL MATERIALS A large part of Ontario's mineral production is made up of crushed stone, sand and gravel, clay products, portland cement, and lime. Annual production of these materials in 1961 exceeded 5130,000,000. BIBLIOGRAPHY (Additional references are listed on pages 60 and 76.) Gibson, T. W. 1937: Mining in Ontario; Ontario Dept. Mines, Publications Office (S 1.00). Hewitt, D. F., and Karrow, P. F. 1963: Sand and gravel in southern Ontario; Ontario Dept. Mines, Industrial Mineral Rept. No. 11. (S2.00) Mason, B. 1958: Principles of geochemistry; Wiley and Sons Inc., New York, U.S.A. 108 -t- 7'- ,3~t inches t inches t x •x* '",, -'^ w* i- 'J-p "--- . 'Ta3r^LV^* -s?l3*m. ." ~ . ijjw,-"** , .**--.F: ' A." V t ^^XiiXi&.-a "".''V^kHi . i-J (O1 '' T- ^ "*^~ , Sr f. ' ,.?***--L;~' ^-' V" *^*-. t ' . \ * -'- - ^ ,-, * J ' '*- *vi, -**- -'-' " ' 'Ill Photo 45 — Two-foot Keweenawan diabase dike cutting granodiorite; Emo area. Photo 46 — Pillowed basic volcanic rock; near Jackfish, District of Thunder Bay. Rhyolite Rhyolite is the extrusive equivalent of granite. Rhyolite is found principally as volcanic flows with composition similar to that of granite. Rhyolite is light coloured and its texture is fine-grained to porphyritic. Syenite Composition. An intrusive rock composed principally of orthoclase and plagioclase feld spars. Orthoclase exceeds plagioclase in quantity. Quartz is less than 10 percent. Hornblende, biotite, and pyroxene are common ferromagnesian accessories but rarely make up more than 10-20 percent of the rock. Colour. Generally light coloured: grey, pink, buff to yellow-brown. Texture. Same as granite; may be porphyritic. Grain Size. Same as in granite. Mode of Occurrence. Same as for granite. Trachyte Trachyte is the extrusive equivalent of syenite and is found as volcanic flows similar to rhyolite but lacking quartz. Granodiorite Composition. Composed primarily of quartz, orthoclase, and plagioclase. The plagio clase is more calcic than in granite and is generally oligoclase. Granodiorite may contain 10-30 percent ferromagnesian constituents, mainly biotite, hornblende, or pyroxene. 52 Photo 48 — Timiskaming conglomerate; Kirkland Lake. Sedimentary Rocks Sedimentary rocks are produced by the weathering and erosion of the rocks of the earth's crust, the subsequent transportation of the detrital material produced, either mechanically or in solution, and the final deposition of this material in bedded deposits by mechanical deposition, organic processes, or chemical precipitation. The sedimentary rocks are divided into three main classes, depending on their origin. If the sedimentary rock is formed by the mechanical accumulation of detrital material, it is termed a clastic or detrital rock. If the sediment is produced by chemical precipitation, as in the case of salt beds, gypsum beds, and some types of limestone, the rock is termed a chemical precipitate. If the sediment is produced by the accumula tion of organic material, such as shells as in the case of limestones, or vegetative material as in the case of coal measures, the sedimentary rocks are called organic. The more common sedimentary rocks are shown in the accompanying table, and most of the common types met in the field in Ontario are subsequently described. Table 4 ORIGIN Types of sedimentary rocks UNCONSOLIDATED DEPOSIT CONSOLIDATED DEPOSIT Mechanical Gravel Sand Grit Clay Till Conglomerate Sandstone Greywacke Shale Tillite Chemical Marl Limestone Salt Gypsum Organic Limestone Coal Measures 55
