Chapter 6 and 7
Chapter 6 and 7 80203 - GEOL 1010-003
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Popular in Geology
This 11 page Class Notes was uploaded by Alex Casale on Tuesday October 6, 2015. The Class Notes belongs to 80203 - GEOL 1010-003 at Clemson University taught by Mine Dogan in Summer 2015. Since its upload, it has received 54 views. For similar materials see Physical Geology in Geology at Clemson University.
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Date Created: 10/06/15
Sedimentary Rocks Continued 10415 423 PM iClicker Question 0 If you found the following sequence of rocks what does that tell you about their depositional environment Soil 9 Sandstone 9 Shale 9 Limestone o The environment changed from terrestrial to marine overtime Transgressive Sequence 0 Sea level rises and the shoreline advances inland Regressive Sequence 0 Sea level falls shoreline retreats seaward Sedimentary Resources 0 1 BTU British Thermal Unit 1055 Joules is the heat you need for 1lb of Water 1F 0 insert picture from page 25 0 Sources of Energy 0 insert picture Nonmetallic Resources 0 Stone Clays Salt Phosphate Rock Cement Sand and Gravel o Other nonmetals Metallic Resources 0 Iron Aluminum Copper Lead Zinc Manganese o Other metals 0 Energy Resources 0 Petroleum 0 Coal 0 Natural Gas OOOOO OOOOO 0 Building Materials 0 Natural aggregate crushed stone sand and gravel o Gypsum 0 Clay 0 Industrial Materials 0 Fertilizers Nitrate phosphate and potassium compounds are important to agriculture o Sulfur 0 Salt Sedimentary Resources Energy COAL o Formed mostly from plant material 0 Along with oil and natural gas coal is commonly called a fossil fuel 0 The major fuel used in power plants to generate electricity 0 Potential environmental problems from mining and air poHqun o The longer in the ground the better the quality OIL AND NATURAL GAS o Derived from the remains of marine plants and animals 0 Both are composed of various hydrocarbon compounds and found in similar environments 0 Oil Trap geologic environment that allows significant amounts of oil and gas to accumulate Basic Conditions for and Oil Trap n Porous permeable reservoir rock n Impermeable cap rock such as shale n Cap rock keeps the mobile oil and gas from escaping at the surface A MI I an I 65 DJIW gmm Carbon Cycle Carbon dioxide C02 is one of the most activate parts of the carbon cycle Stored in the plants and then changes into sedimentary rocks CARBON CYCLE Carbon dioxide C02 is one of the most active parts of die carbon Weathering Vaocfzgc Weathering of carbonate F of granite Photosynthesvs 390 3quot Burning and by vegetation Respiration decay oi biomass by and organisms Burning of fossil fuels Burial of V biomass Photosynthesis and respiration of marine d organisms Sediment and sedimentary rock CO entering the atmOSphere 0 leavung the C atmosphere Metamorphism and Metamorphic Rocks 10415 423 PM Rock Cycle The Rock Cycle Weathering Transportation t Degosltion max Uplift and Exposure gneous rocks Sediments extrusive Lithification Sedimentary rocks Metamorphic rocks Igneous rocks intrusive Metamorphism to change formquot The transition of one rock into another by temperatures or pressures unlike those in which it formed Changes in mineralogy and sometimes chemical composition 0 Every metamorphic rock has a parent rock the rock from which it formed Parent rocks can be igneous sedimentary or other metamorphic rocks During metamorphism the rock must remain essentially solid Metamorphic grade is the degree to which the parent rock changes during metamorphism Progresses from low grade low temperatures and pressures 0 Parent Rock shale 9 low grade metamorphism 9 metamorphic rock slate o to high grade high temperatures and pressures 0 Parent rock granodiorite 9 high grade metamorphism 9 metamorphic rock folded gneiss 0 Most rocks undergoing metamorphism will change into a form of clay Metamorphism as a Process 0 Driven by 0 Heat Confining pressure Differential stress Compressional stress Chemically active fluids Parent rock OOOOO HEAT 0 Most important agent Recrystallization the process of forming new stable minerals larger than the original 0 Two sources of heat Geothermal gradient an increase in temperature with depth about 25C per kilometer Contact metamorphism rising mantle plumes CONFINING PRESSURE Forces are applied equally in all directions 0 Similar to water pressure 0 Causes the spaces between mineral grains to close 0 Example a balloon under pressure will pop DIFFERENTIAL STRESS Forces are unequal in different directions 0 Stresses are greater in one direction COMPRESSIONAL STRESS Rocks are squeezed as if in a vice Shortened in one direction and elongated in the other direction CHEMICALLY ACTIVE FLUIDS Enhances migration of ions 0 Aids in recrystallization of existing materials o In some environments fluids can transport mineral matter over considerable distances PARENT ROCK 0 Most metamorphic rocks have the same overall chemical composition as the original parent rock 0 Mineral makeup determines the degree to which each metamorphic agent will cause change Metamorphic Textures Foliated 0 Texture describes the size shape and arrangement of mineral grains 0 Metamorphic rocks can display preferred orientation of minerals in which the platy mineral grains exhibit parallel to subparallel alignment 0 Foliation any planar arrangement of mineral grains of structural features within a rock 0 Examples of Foliations Parallel alignment of platy or elongated minerals Parallel alignment of flattened mineral grains or pebbles Compositional banding of dark and light minerals o Cleavage where rocks Foliation can form in various ways 0 Rotation of platy minerals o Recrystallization that produces new minerals perpendicular to the direction of maximum stress 0 Flattening spherically shaped grains 0 Look at pictures in book and PowerPoint Foliated Textures 0 Rock or slaty cleavage Rocks split into thin slabs Develops in beds of shale with lowgrade metamorphism o Schistosity Texture Platy minerals are discernible with the unaided ete n Mica and chlorite flakes begin to recrystallize into large muscovite and biotite crystals OOO Exhibit a planar or layered structure Rocks having this o Gneissic Texture During highgrade metamorphism ion migration results in the segregation of minerals into light and dark bands Metamorphic rocks with this texture are called gneiss Although foliated gneiss do not usually 0 Other metamorphic textures Nonfoliated metamorphic rocks are composed of minerals that exhibit equidimensional crystals and lack foliation n Develop in environments in which deformations is minimal Porphyroblastic textures n Unusually large grains called porphyroblasts are surrounded by a fine grained matrix of other minerals Common Metamorphic Rocks Metamorphic Rock Textme Comments P33 comm Of my chm and mica slabs called slat cleavage smoo39h dull surfaces mfng LIE I It vf 44 a a sheen breaks along wavy surfaces Phyllite f39 I Medium to cmmminwo dominate 3 M07quot 5ng SW compositional bandins due 0 W0 Of light and dark colomd mineraIs Medium to relative39y 5 3 oquot the Mons scale intedockins ca39ci e or dolomite grains Medium to coarseBrai39m39 my hard massive fused quartz grains Very negrained often exceedingw tough am dummo usually dark colored 10415 423 PM
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