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ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks MAGMA = molten rock + suspended mineral grains + dissolved gases Origin – in asthenosphere, or Base of lithosphere Migrates up - Lava (at surface) http://volcano.und.nodak.edu/vwdocs/HawaiiQuest/gen_hawaii_volcs/bar_graph.gif ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks Crystallization Bowen’s Reaction Series http://imnh.isu.edu/digitalatlas/geo/rocks/bowens/bowens.jpg ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks Igneous Rocks http://www.outreach.canterbury.ac.nz/resources/geology/glossary/igneous.jpg Table 1: Igneous Rock Classification Chart Mineral Composition Always: K-feldspar Quartz Always: Hornblende (= Sometimes: biotite plagioclase Muscovite Plagioclase fine to coarse (crystals < 3 cm) Granite Diorite pegmatitic (crystals > 3 cm) Pegmatitic Granite Mineral Composition Texture Phaneritic (crystals big enough to see) amphibole) Sometimes: biotite quartz augite Aphanitic (crystals too small to see) Rhyolite Andesite Porphyritic (mix of crystal sizes) Porphyritic Rhyolite Porphyritic Andesite Glassy (no crystals, looks like glass) Vesicular (“holes” in rock, remnant gas pockets) Color Always: Plagioclase Augite (=pyroxene) Sometimes: olivine hornblende Gabbro Always: Augite (or other pyroxene mineral) Olivine Periodite Basalt Porphyritic Basalt Obsidian (usually black, gray or red) Pumice Scoria (small tubular vesicles) (round or elliptical vesicles) light or red intermediate colors Always: Olivine dark or green Dunite http://www.physicalgeography.net/fundamentals/images/igneous_classification.gif Fractional Crystallization Bowen’s Reaction Series http://imnh.isu.edu/digitalatlas/geo/rocks/bowens/bowens.jpg Fractional Crystallization – remaining melt composition changes as crystals form Fractional Crystallization – remaining melt composition changes as crystals form Relates magma composition to volcano type and eruption style ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks Metamorphism http://pasadena.wr.usgs.gov/office/given/geo1/lecturenotes/MetaRx_files/image017.gif http://myweb.cwpost.liu.edu/vdivener/notes/meta_rx.htm http://myweb.cwpost.liu.edu/vdivener/notes/meta_rx.htm New minerals can form with increased heat and/or with “fluids” http://hays.outcrop.org/images/rocks/metamorphic/lutge8e/FG07_18.JPG Table 1: Metamorphic Rock Classification Chart Texture Mineral Content Nonfoliated (no alignment of mineral grains) crystals too small to see not banded breaks into wrinkly pieces with sheen Slate minerals not visible may appear grainy crystals big enough to see wavy texture may be banded banded Foliated (alignment of mineral grains) breaks into flat fragments alternating dark and light bands pebbles visible a crystalline texture similar to igneous rocks, but termed granoblastic texture variable variable variable (mica minerals common) variable variable quartz Note Anthracite coal not on chart. minerals not visible Likely Protolith shale siltstone shale siltstone basalt shale siltstone sandstone Metaconglomerate conglomerate Porphyroblastic sandstone granite or other Schist igneous rock (augen gneiss) Schist Gneiss (quartz, feldspar, hornblende, and biotite common) calcite or dolomite generally fine-grained, but may appear grainy Phyllite Greenstone (metabasalt) (mica minerals common) pebbles visible contains some large crystals (porphyroblasts), wavy texture Rock Name sandstone granite or other igneous rock Metaconglomerate conglomerate quartz sandstone Quartzite (metaquartzite) limestone Marble dolostone Greenstone (metabasalt) basalt ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks Crystallization Bowen’s Reaction Series http://imnh.isu.edu/digitalatlas/geo/rocks/bowens/bowens.jpg Oxidation 4Fe+3 + 3O2 2Fe2O3 hematite Hydrolysis 2KAlSi3O8 + 11 H2O Al2Si2O5(OH)4 + 4H4SiO4 + 2OH- + 2 K2+ potassium feldspar clay mineral (kaolinite) Carbonic acid action H2O + CO2 H2CO3 CaCO3 + H2CO3 Ca+2 + 2 HCO-3 calcite http://hays.outcrop.org/images/weathering/press4e/table-07-02.jpg http://hometown.aol.com/rhaberlin/images/mwmech.gif http://piru.alexandria.ucsb.edu/collections/geography3b/p-s/ps06-05a.jpg ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks http://www.globalsecurity.org/military/library/policy/army/fm/5-484/fig2-26.gif Lithification thru Compaction Lithifaction thru Cementation Diagnostic Features Texture Composition rounded clasts contains pebbles, clasts >2 mm variable angular clasts pink, reddish-brown, buff color, angular grains buff, white, brown color, scratches glass medium sand clasts 2-1/16 mm K-feldspar quartz Rock Name Conglomerate Breccia Arkosic Sandstone Quartz Sandstone Graywacke Sandstone Siltstone poorly sorted (mix of grain sizes), dark to gray color medium to fine sand mixed rock and mineral clasts feels gritty, but clasts look like powder fine (clasts barely visible) 1/15-1/256 mm fine to very fine (clasts not visible) very fine (clasts not visible) < 1/256 mm small spherical pellets (ooids) coarse crystalline (visible interlocking crystals) very fine (crystals too small to see) very fine to coarse crystalline very fine to coarse crystalline very fine to coarse crystalline variable (light to dark color) variable (light to dark color) variable (light to dark color) calcite calcite Oolitic Limestone Crystalline Limestone calcite Micritic Limestone dolomite silica halite Dolostone Chert Rock Salt very fine to coarse crystalline gypsum spherical to irregular shaped nodules coarse to very coarse bioclasts (biologically-derived particles), porous fine to very fine bioclasts phosphate minerals (apatite) Rock Gypsum Phosphate Nodules calcareous shells Coquina laminated (thin layering) smooth, powder often rubs off on hands, not laminated effervesces in HCl effervesces in HCl effervesces in HCl powder weakly effervesces in HCl scratches glass, color variable same hardness as fingernail, tastes salty softer than fingernail dark gray to black color effervesces in HCl, shell fragments effervesces in HCl, white powder effervesces in HCl, fossils coarse to very coarse bioclasts mixed with mud dull to shiny black, often contains plant impressions very fine grained Shale Origin Clastic (comprised of lithified grains derived from the weathering and erosion of pre-existing rocks) Claystone Chemical (precipitated inorganically at, or just below, the earth surface) both Biogenic calcareous microfossils too small to see calcareous shells and mud carbon Chalk Fossiliferous Limestone Coal (includes the insoluble remains of once living organisms) ROCK CYCLE magma metamorphic rocks igneousr ocks (clastic) sediments transportation, deposition, & lithification sedimentary rocks ROCK CYCLE magma metamorphic rocks igneousr ocks sediments transportation, deposition, & lithification ions in solution sedimentary rocks Diagnostic Features Texture Composition rounded clasts contains pebbles, clasts >2 mm variable angular clasts pink, reddish-brown, buff color, angular grains buff, white, brown color, scratches glass medium sand clasts 2-1/16 mm K-feldspar quartz Rock Name Conglomerate Breccia Arkosic Sandstone Quartz Sandstone Graywacke Sandstone Siltstone poorly sorted (mix of grain sizes), dark to gray color medium to fine sand mixed rock and mineral clasts feels gritty, but clasts look like powder fine (clasts barely visible) 1/15-1/256 mm fine to very fine (clasts not visible) very fine (clasts not visible) < 1/256 mm small spherical pellets (ooids) coarse crystalline (visible interlocking crystals) very fine (crystals too small to see) very fine to coarse crystalline very fine to coarse crystalline very fine to coarse crystalline variable (light to dark color) variable (light to dark color) variable (light to dark color) calcite calcite Oolitic Limestone Crystalline Limestone calcite Micritic Limestone dolomite silica halite Dolostone Chert Rock Salt very fine to coarse crystalline gypsum spherical to irregular shaped nodules coarse to very coarse bioclasts (biologically-derived particles), porous fine to very fine bioclasts phosphate minerals (apatite) Rock Gypsum Phosphate Nodules calcareous shells Coquina laminated (thin layering) smooth, powder often rubs off on hands, not laminated effervesces in HCl effervesces in HCl effervesces in HCl powder weakly effervesces in HCl scratches glass, color variable same hardness as fingernail, tastes salty softer than fingernail dark gray to black color effervesces in HCl, shell fragments effervesces in HCl, white powder effervesces in HCl, fossils coarse to very coarse bioclasts mixed with mud dull to shiny black, often contains plant impressions very fine grained Shale Origin Clastic (comprised of lithified grains derived from the weathering and erosion of pre-existing rocks) Claystone Chemical (precipitated inorganically at, or just below, the earth surface) both Biogenic calcareous microfossils too small to see calcareous shells and mud carbon Chalk Fossiliferous Limestone Coal (includes the insoluble remains of once living organisms)
