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2307101 Earth Dynamics Department of Geology, Faculty of Science, Chulalongkorn University ROCK Igneous, Sedimentary and Metamorphic Rocks ผูชวยศาสตราจารย ดร.วิชัย จูฑะโกสิทธิ์กานนท ภาควิชาธรณีวิทยา คณะวิทยาศาสตร จุฬาลงกรณมหาวิทยาลัย [email protected] ลําดับขั้นของการนําเสนอ แร และหิน วัฎจักรของหิน การจําแนกประเภทของหิน หินอัคนี หินตะกอน หินแปร สรุป แร (mineral) ธาตุหรือสารประกอบอนินทรียที่เปนของแข็งที่เกิดขึ้นตามธรรมชาติ มีโครงสรางภายในที่เปนระเบียบ มีสูตรเคมี และมีสมบัติทางเคมีและทางกายภาพที่แนนอน หรือเปลี่ยนแปลงไดในวงจํากัด เพชร ทอง ควอรตซ แคลไซต แอลไบต (Diamond) (Gold) (Quartz) (Calcite) (Albite) C Au SiO2 CaCO3 NaAlSi3O8 ควอรตซ หิน (rock) มวลของแข็งที่ประกอบดวยแรชนิดเดียวหรือหลายชนิดรวมตัวกัน อยูต ามธรรมชาติ หรือประกอบดวยแกวธรรมชาติ หรือสสารจากสิ่งมีชีวิต หินแกรนิต หินทราย หินปูน หินควอรตไซต หินออบซิเดียน ลิกไนต (Granite) (Sandstone) (Limestone) (Quartzite) (Obsidian) (Lignite) quartz, K-feldspar, biotite quartz, feldspar, rock fragments calcite quartz volcanic glass C-H-O-N หินแกรนิต Rock Cycle การจําแนกประเภทของหิน Rock classification Igneous rock (หินอัคนี) Plutonic rock (หินอัคนีระดับลึก) Volcanic rock (หินภูเขาไฟ) Sedimentary rock (หินตะกอน) Clastic rock (หินเนือ้ ประสม) Non-clastic rock (หินเนือ้ ประสาน) Metamorphic rock (หินแปร) Foliated rock (หินเนือ้ ริ้วขนาน) Non-foliated rock (หินเนือ้ ไรริ้วขนาน) Rock classification Igneous rock Plutonic rock Volcanic rock Sedimentary rock Clastic rock Non-clastic rock Metamorphic rock Foliated rock Non-foliated rock หินอัคนี Molten rock/materials (1) Magma = molten materials below the earth’s surface (2) Lava = molten materials above the earth’s surface Igneous rock a rock that forms when hot molten rock (magma or lava) cools and freezes solid Types of molten materials Magma = molten materials below the earth’s surface Lava = molten materials above the earth’s surface Geothermal Gradient 15 °C /km Crystallization of magma N. L. Bowen Artificial magma, O, Si, Al, Fe, Mg, Ca, Na, K Crystallization path Continuous reaction series of plagioclase Discontinuous reaction series of olivine, pyroxene, amphibole, biotite Bowen’s reaction series Norman Levi Bowen (in 1909) Bowen’s Reaction Series Crystallization path O, Si, Al, Fe, Mg, Ca, Na, K Classification & types of igneous rocks Mode of occurrence (รูปแบบการเกิด) Plutonic or Intrusive rocks Volcanic or Extrusive rocks Chemical & mineralogical classification (องคประกอบทางเคมีและแร) Felsic rocks Intermediate rocks Mafic rocks Ultramafic rock Mode of occurrence Plutonic (Intrusive) rock – เย็นและแข็งตัวใตพนื้ ผิวโลก ความแตกตางของอุณหภูมิ = แตกตางเพียงเล็กนอย อัตราของการเย็นตัวเปนไปอยางชาๆ ---> large crystals (phaneritic texture) Volcanic (Extrusive) rock – เย็นและแข็งตัวบนพื้นผิวโลก ความแตกตางของอุณหภูมิ = แตกตางมาก อัตราของการเย็นตัวเปนไปอยางรวดเร็ว ---> small crystals or glasses (aphanitic texture & glassy texture) The specimen shown is about two inches (five centimeters) across. Chemical & mineralogical classification Felsic rocks ---> feldspar + silica Intermediate rocks Mafic rocks ---> magnesium + ferric Ultramafic rock felsic = quartz, K-feldspar mafic = olivine, pyroxene, amphibole SiO2 = < 45, 45-52, 52-65, > 65 % mafic felsic The specimen shown is about two inches (five centimeters) across. increasing Fe and Mg increasing Silica content SiO2 = > 65% Pluto nic ro cks Igneous Rock Classification Plutonic (magma) (coarse grained) Intrusive Aphanitic Volcanic (lava) (fine grained) Extrusive Glassy Volcanic (lava) (no crystals) Extrusive Volca nic rocks Phaneritic Grain Size < 0.05 mm SiO2 = 45-52% Felsic/Silicic Intermediate Mafic Ultramafic light colored dark colored very dark colored high in SiO2 low in SiO2 very low in SiO2 Granite Diorite Gabbro Peridotite Dunite & Pyroxenite Rhyolite Andesite Basalt Scoria Obsidian Pumice Rock-forming minerals in igneous rocks Quartz K-feldspar Plagioclase Muscovite Biotite Magnetite Chlorite Granite แรประกอบหิน (rock-forming minerals) แรปฐมภูมิ (primary minerals) แรหลัก (essential minerals) ----------- Rock Name แรรอง (accessory minerals) แรทุติยภูมิ (secondary minerals) Rhyolite Rock-forming minerals in igneous rocks Olivine Pyroxene Plagioclase Spinel Magnetite Chlorite Olivine basalt แรประกอบหิน (rock-forming minerals) แรปฐมภูมิ (primary minerals) แรหลัก (essential minerals) ----------- Rock Name แรรอง (accessory minerals) แรทุติยภูมิ (secondary minerals) Felsic Chemical Composition Phaneritic Texture – slow cooling large crystals Granite Aphanitic Texture – rapid cooling small crystals Rhyolite Intermediate Chemical Composition Phaneritic Texture – slow cooling large crystals Diorite Aphanitic Texture – rapid cooling small crystals Andesite Mafic Chemical Composition Phaneritic Texture – slow cooling large crystals Gabbro Aphanitic Texture – rapid cooling small crystals Basalt Obsidian Glassy texture – very rapid cooling, no crystal structures conchoidal fracture Pumice Glassy texture & Vesicular texture no crystal structures & bubble capture Scoria Volcanic bomb Aphanitic texture & Vesicular texture Vesicular basalt Amygdaloidal basalt Aphanitic texture Vesicular texture & Amygdaloidal texture Classification of plutons Subjacent mass Batholith ---- geographically area > 100 km2 Stock ---- geographically area < 100 km2 Injected mass country rock injected mass Dike / Dyke Sill Laccolith Lopolith Other subjacent mass injected mass subjacent mass PLUTON Subjacent mass Batholith > 100 km2 Stock < 100 km2 Injected mass Dike / Dyke Sill Laccolith Lopolith VOLCANO Shield volcano Cinder cone volcano Stratovolcano / Composite volcano FISSURE ERUPTION S M L fine-to medium-grained hypabyssal rock (หินอัคนีระดับตื้น) = intrusive rock + phaneritic plutonic texture aphanitic volcanic texture S M 2 mm-the IUGS recommendation Microgabbro/Diabase L S S L fine-to medium-grained hypabyssal rock (หินอัคนีระดับตื้น) = intrusive rock + phaneritic plutonic texture aphanitic volcanic texture Classification of volcanoes Geographical sense Extinct volcanoes, Sleeping volcanoes, Active volcanoes Geological sense Shield volcanoes --- formed by lava flows of low viscosity — lava that flows easily Cinder cone volcanoes --- built almost entirely of loose volcanic fragments called cinders (pumice, pyroclastics, or tephra) Stratovolcanoes / Composite volcanoes FISSURE ERUPTION --- formed by lava flows of low viscosity along the fissure (not formed as “volcano”) country rock Stratovolcanoes / Composite volcanoes PLUTON Subjacent mass Batholith > 100 km2 Stock < 100 km2 Injected mass Dike / Dyke Sill Laccolith Lopolith VOLCANO Shield volcano Cinder cone volcano Stratovolcano / Composite volcano FISSURE ERUPTION Caldera A caldera is a large, usually circular depression at the summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir. The removal of large volumes of magma may result in loss of structural support for the overlying rock, thereby leading to collapse of the ground and formation of a large depression. Volcanic by-products Lava mafic felsic SiO2 = < 45, 45-52, 52-65, > 65 % Chemical Classification – basaltic, andesitic, rhyolitic Physical Classification – pahoehoe, aa, pillow lava pa-ho’-e-ho’-e Volcanic gas – H2O, CO2, N2, SO2, SO3, S2 Pyroclastic debris Tephra SIZE = 2-64 mm, > 64 mm Debris -- volcanic dust, ash, lapilli/cinder, block, bomb Pyroclastic rocks -- volcanic tuff, volcanic breccia aa pillow lava pahoehoe columnar joint lava flow pyroclastic flow Pompeii Rock classification หินตะกอน Sediments (1) Material (broken rock fragments such as gravel, sand, silt, mud, lime, and clay) that is weathered, eroded and transported by wind, water, ice, or gravity; (2) Material that is precipitated from solution; (3) Deposits of organic origin (such as peat, shell fragments, coral reefs, and diatoms) Igneous rock Plutonic rock Volcanic rock Sedimentary rock Clastic rock Non-clastic rock Metamorphic rock rock formed by accumulation Foliated rock and consolidation of sediments Non-foliated rock Sedimentary rock No n-c last ic r ock s Cla stic ro cks Classification & types of sedimentary rocks Clastic rocks • • • • • Sandstones Conglomerates Breccias Shales/Mudstones Siltstone These rocks are formed due to evaporation of saline water (sea water) e.g. Gypsum, Halite (rock salt) Evaporitic rocks Non-clastic rocks Chemical & Organic rocks Form basically from CaCO3 – both (1) by chemical leaching and (2) by organic source (biochemical) e.g. Limestone; Dolomite Form due to decomposition of organic remains under temperature and pressure e.g. Coal/Lignite etc. Carbonate rocks Organic rocks Clastic rocks • formed from broken rock fragments weathered, eroded and transported by river, glacier, wind and sea waves. These clastic sediments are found deposited on floodplains/beaches, in deserts, and on the sea floors. solidified/lithified Clastic rocks •Clastic rocks are classified on the basis of the grain size: conglomerate, sandstone, siltstone, shale, mudstone, claystone, etc. Grain size Gravel >256-2 mm Sand 2- 0.062 mm Boulder: >256 mm Very coarse sand: 1-2 mm Cobble: 64-256 mm Coarse sand: 0.5-1 mm Pebble: 4-64 mm Medium sand: 0.25-0.5 mm Granule: 2-4 mm (Fine gravel) Fine sand: 0.125-0.25 mm Udden-Wentworth grade scale Silt 0.062-0.004 mm Very fine sand: 0.0625-0.125 mm Clay <0.004 mm MATRIX Matrix: is the finer grains or materials that surrounds the larger clasts. It consists of either clay, silt and sand. CEMENT Cement: dissolved substance that bounds the grains or sediments. 1. Calcareous 2. Siliceous 3. Ferruginous +/- Argillaceous GRAIN Clast/Grain & Any rock fragments (in this case, size is > 4 mm=Pebble) Fine-gravel/Granule (size <4 mm) Roundness Degree of roundness helps in knowing the distance of transportation • Angular clasts :- short distance transport from the source • Rounded clasts :- long distance transport Sorting Sorting of the sediments also suggests the mode of deposition and transportation Long distance transport = well-rounded and well-sorted sediments Short distance transport = poorly sorted angular grains Size Rounding Roundness Sphericity Sorting Conglomerate & Sedimentary breccia When rounded clastic fragments are cemented or undergo consolidation, they are called… CONGLOMERATES Similarly when angular clasts undergo consolidation, they are called… SEDIMENTARY BRECCIA ANSWER 1 = A60, B20, C20 2 = A25, B40, C35 3 = A10, B70, C20 4 = A00, B25, C75 ternary diagram http://www.waterproofpaper.com/graph-paper/triangular-grid-graph-paper.pdf http://www.waterproofpaper.com/graph-paper/triangular-graph-paper.pdf ternary diagram Sandstone • Sandstones are clastic rocks, made up mainly sands • Different types of sandstones (based on their compositions :- quartz, feldspar and rock fragments) such as the names, orthoquartzite, protoquartzite, arkose, graywacke • Sometimes contain fossils • Deposition takes place under high fluvial regime or under strong water current. Graywacke Orthoquartzite Arkose (Feldspar) Sandstone Protoquartzite Orthoquartzite Arkose (Feldspar) ternary diagram Graywacke Different types of Sandstones (based on their compositions) Shale • Shales are clastic rocks, made up mainly fine silt/clay • Shales are most abundant sedimentary rocks, accounts for about 80% of them • Often contain fossils • Mostly the hydrous aluminum silicates in composition = from weathered feldspars • Deposition takes place under low fluvial regime or under weak water current. e.g. Offshore or in Lagoon fissility Classification & types of sedimentary rocks Clastic rocks • • • • • Chemical & Organic rocks Sandstones Conglomerates Breccias Shales/mudstones Siltstone These rocks are formed due to evaporation of saline water (sea water) e.g. Gypsum, Halite (rock salt) Evaporitic rocks Form basically from CaCO3 – both (1) by chemical leaching and (2) by organic source (biochemical) e.g. Limestone; Dolomite Form due to decomposition of organic remains under temperature and pressure e.g. Coal/Lignite etc. Carbonate rocks Organic rocks Evaporitic rocks These rocks are formed within the a depositional basin from chemical substances dissolved in the seawater or lake water. Gypsum CaSO4.2H20 Halite NaCl Gypsum Rock salt Classification & types of sedimentary rocks Clastic rocks • • • • • Chemical & Organic rocks Sandstones Conglomerates Breccias Shales/mudstones Siltstone These rocks are formed due to evaporation of saline water (sea water) e.g. Gypsum, Halite (rock salt) Evaporitic rocks Form basically from CaCO3 – both (1) by chemical leaching and (2) by organic source (biochemical) e.g. Limestone; Dolomite Form due to decomposition of organic remains under temperature and pressure e.g. Coal/Lignite etc. Carbonate rocks Organic rocks Carbonate rocks • Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. • The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3) and dolostone/dolomite, which is composed of the mineral dolomite (CaMg(CO3)2). • The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock. Limestone • Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). • Limestone makes up about 10% of the total volume of all sedimentary rocks. • (1) limestones formed by chemical precipitation are usually fine grained, whereas, in case of (2) organic limestones the grain size vary depending upon the types of organisms responsible for the formation. • Most limestone is composed of skeletal fragments of marine organisms (such as coral or foraminifera). chert nodules travertine • Limestone often contains variable amounts of silica in the form of chert (sometimes = chalcedony, flint, jasper, etc.) • Travertine is a form of limestone deposited by mineral springs, especially hot springs. Travertine often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and even rusty varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. • Similar (but softer and extremely porous) deposits formed from ambient-temperature water are known as tufa. Limestone Limestone Corals Crinoids Brachiopods Limestone Fusulinids Dolomite • Dolostone is also known as dolomite, although that name is confusing due to the mineral dolomite which it consists of. • It looks much like limestone, however it does not react with HCl unless finely powdered. It is also darker, has less fossils, and has got more crystalline material. • Apart from the mineral dolomite, it contains quartz, feldspars and mica, and secondary silicates. Classification & types of sedimentary rocks Clastic rocks • • • • • Chemical & Organic rocks Sandstones Conglomerates Breccias Shales/mudstones Siltstone These rocks are formed due to evaporation of saline water (sea water) e.g. Gypsum, Halite (rock salt) Evaporitic rocks Form basically from CaCO3 – both (1) by chemical leaching and (2) by organic source (biochemical) e.g. Limestone; Dolomite Form due to decomposition of organic remains under temperature and pressure e.g. Coal/Lignite etc. Carbonate rocks Organic rocks Radiolarians Diatoms Organic rocks Plant debris Mollusks Chert / Radiolarian chert Radiolarians An electron microscope image of a radiolarian fossil. Radiolarians are tiny plankton that form intricate "skeletons" of silica. These "skeletons" accumulate at the bottom of the deep ocean into layers of silica ooze that can solidify into chert. Diatomite Diatoms Diatomites are the result of accumulations of billions of diatom skeletons in either a lake or marine setting. Diatoms are very small, unicellular, photosynthetic organisms. Diatom Diatomite, or diatomaceous earth, is a very distinctive sedimentary rock. It is whitish, powdery, and very lightweight. It seems quite soft, but the individual particles making up the rock are siliceous (opaline silica), having a hardness around 6 on the Mohs Scale. This makes diatomaceous earth a wonderful mild abrasive. It is mined for use in a wide variety of products. Most people encounter diatomites everyday as one of the ingredients in toothpaste (the opaline silica scrapes away foreign material from tooth surfaces). Diatomites are the result of accumulations of billions of diatom skeletons in either a lake or marine setting. Diatoms are very small, unicellular, photosynthetic organisms. Some call them "algae", but they're not. Some call them "plants", but they're not. They're probably best placed in Kingdom Protista. Diatoms make a hard, two-part skeleton composed of opal (opaline silica, SiO2·nH2O). The diatom skeleton is called a frustule (see example photo). Diatom frustules are either rounded or elongated, and the two parts of the skeleton nest into each other, kinda like a large petri dish over a slightly smaller petri dish. Careful examination of fossil diatoms typically requires use of a scanning electron microscope (SEM). Diatomites such as the sample shown below contain immense numbers of many different species of fossil diatoms. The appearance of diatomite very closely resembles chalk. Chalk is calcareous, and will bubble in acid - diatomite won't do that. Chalk is also noticeably heavier than diaomite. Diatomite and chalk also closely resemble kaolinite, a clay mineral. First of all, kaolinite will not bubble in acid. Kaolinite is also distinctive in having an earthy feel and an earthy smell, especially when wet. Kaolinite becomes noticeably sticky when wet. Chalk Foraminifers /Forams Coquina Shell fragments Lignite |<- - COAL - ->| Peat Rock classification Igneous rock Plutonic rock Volcanic rock Sedimentary rock Clastic rock Non-clastic rock Metamorphic rock Foliated rock Non-foliated rock หินแปร • Metamorphism – mineralogical, chemical, and physical changes that occur in solid rocks. • Occurs at depths greater than that of lithification (Diagenesis). Metamorphic rock rock formed by metamorphism of preexisting rocks Factors controlling the metamorphism Temperature Pressure Fluids Others :- texture, duration Temperature Catalyst in reactions (metamorphism) Important factors in the recrystallization, chemical recombination, chemical replacement Help to change rocks to plastics and flows Start at temp 100-300 C / depth 10-20 km Generally metamorphic temp 200-800 C Geothermal Gradient 15 °C /km & 250-300bar/km Pressure Confining pressure (load pressure, lithostatic pressure) σ1 = σ2 = σ3 Metamorphic pressure 1-10 kbar (depth 15 km) Stress pressure (dynamic pressure, directed pressure) σ1 ≥ σ2 ≥ σ3 Foliation S tre ss & P re s sure Stress & Pressure horizontal slaty cleavage vertical slaty cleavage foliation Relationship among P° T° & Metamorphic rocks prograde metamorphism retrograde metamorphism Fluids water, solution, gas (out residual /in) out = residual fluid in pore spaces in = hydrothermal solution metasomatism การแปรสภาพคงองคประกอบ isochemical metamorphism / treptomorphism การแปรสภาพองคประกอบ allochemical metamorphism = metasomatism Types of metamorphisms Thermal metamorphism (Contact meta.) Dynamic metamorphism (Mechanical meta.) Dynamothermal meta’ism (Regional meta.) Contact metamorphism Recrystallization (a = A) calcitelimestone = calcitemarble Chemical recombination (a+b = c) quartz + calcite = wollastonite + CO2 Chemical replacement (a+dmagma = e) Regional metamorphism No n-f olia ted ro cks Fol iate d ro cks Orthogneiss cks No n-f olia ted ro Paragneiss Hornfels cks Fol iate d ro Mudstone Claystone Mudstone, Chert Dolomite Slate slaty cleavage Phyllite Schist schistosity Gneiss banding Orthogneiss designates a gneiss derived from an igneous rock, and Paragneiss is one from a sedimentary rock. Quartzite Marble Hornfels Antracite Metamorphic Facies Very Low Grade: Low Grade: Medium Grade: High Grade: Zeolite, prehnite-pumpellyite, and blueschist facies Greenschist, Ep-Ab hornfels facies Amphibolite, hornblende hornfels facies Granulite, pyroxene hornfels, sanidinite facies Cla stic r No roc n-clas ks tic ks roc ed d ro cks Fol iat No n-f olia te Igneous rock Plutonic rock Volcanic rock Sedimentary rock Clastic rock Non-clastic rock Metamorphic rock Foliated rock Non-foliated rock ock s สรุป THANK YOU hypabyssal rock (หินอัคนีระดับตื้น) = intrusive rock + volcanic texture
