Geology Test 1 Notes
Geology Test 1 Notes Geol 201
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Popular in Geology
This 12 page Study Guide was uploaded by Hailey-Rae Rose on Thursday April 21, 2016. The Study Guide belongs to Geol 201 at California Polytechnic State University San Luis Obispo taught by Professor Hughes in Spring 2016. Since its upload, it has received 15 views. For similar materials see Physical Geology in Geology at California Polytechnic State University San Luis Obispo.
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Date Created: 04/21/16
SANDSTONE Sedimentary GNEISS Clastic Metamorphic Meta-Sediments LIMESTONE SHALE Sedimentary Sedimentary Biogenic Clastic GABBRO GRANITE Igneous Igneous Intrusive Intrusive 1-Distilled 2-Distilled TUFF POTASSIUM FELDSPAR Igneous Mineral Extrusive 2-Distilled PYROXENE CHERT Mineral Sedimentary Biogenic/Chemical Precipitates BASALT Igneous CONGLOMERATE Extrusive Sedimentary Clastic 1-Distilled QUARTZ AMPHIBOLE Mineral Mineral Peridotite SODIUM FELDSPAR Igneous Mineral Intrusive 0-Distilled SERPENTINITE SCHIST Metamorphic Metamorphic Metamorphosed Igneous Meta-Sediments SLATE MARBLE Metamorphic Metamorphic Meta-Sediments Meta-Sediments CALCITE BIOTITE Mineral Mineral COAL Sedimentary Biogenic NOTES I. Formation of the Solar System and Early Earth A. Telescopic Observation and Seismic Probing are the primaries tools used to explain the formation of the Earth and Solar System B. Solar System Formation 1. Stars are made of mostly hydrogen and as the density of the gas increases fusion occurs in the core and hydrogen atoms fuse together to form helium atoms and heat 2. Eventually, the hydrogen will be exhausted 3. Once a star runs out of hydrogen fuel, the helium atoms will begin to fuse into higher elements called stellar nuclear synthesis, helium through iron are created in the core a) Gravity is not strong enough to fuse iron 4. When fusion materials run out, the star will expand and turn into a red giants and die through a supernova, after a supernova there are a few things a star can turn into: a) Small stars turn into White Dwarfs and eventually Black Dwarfs b) Medium stars turn into Neutron Stars c) Large stars turn into Blackholes d) The debris (gas and dust) from a supernova form a nebula which contains a certain number off all of the elements (1)The heavier elements not created in the star are created during the supernova by fusion due to the massive amounts of energy of a supernova 5. The vast clouds of gas and dust swirl around a center with more mass and thus gravity called Eddies and will eventually form a disk 6. A star is formed at the center of the disk and is balanced by fusion pushing out and gravity pulling in a) Solar wind ejected from the star push out gases that are near the star but the heavier dust stays closer to the star (that is why the rocky planets are closer to the sun and the gas planets are father away) C. Formation of the Proto-Earth 1. Particles start to clump together, causing them to have more gravity pulling more particles in called Gravity Accretion and this cycle continues for planet formation 2. The Proto-Earth was formed by gravity accretion and early Earth faced heavy bombardment making it a very violent place a) These bombardments made the proto-earth very hot and it was mostly molten b) Since the rocks were liquid the heavier/denser rocks sank and the lighter rocks rose to the surface during a process called planetary differentiation (1) The rocks that sank became the core (completely molten) and the rocks that ﬂoated became the mantel (mostly molten) (2) Since the core was completely liquid, the earth had no magnetic ﬁeld 3. Bombardment tapers off the the Earth begins to cool through radiation through the surface D. Sources of Heat from Earth’s Interior 1. Latent Heat - the heat that must be added to convert solid to liquid without changing temperature a) In the Earth, there is a release of latent heat when the liquid in the outer core cools into a solid b) The magnetic ﬁeld is created because the liquid core and the solid core spin at different speeds 2. Radioactive Decay 3. Gravitational Warping - The gravitation pull of the moon as it orbits around the Earth create a “solid Earth tide” 4. Radioactive Decay and Gravitational Warping are non-primordial, meaning they are not heat that was generated during accretion E. Seismic Probing 1. Seismic waves travel through the Earth’s interior, and Seismometers sense the arrival of seismic energy 2. Seismic wave propagation is used to infer the interior structure of the Earth a) P-Waves: compressional motions, can travel through solids and liquids and are typically faster than s-waves b) S-Waves: Wave-like motion, travel ONLY through solids and are slower than p-waves 3. Waves travel faster in denser material, the movement and turning of waves through different materials is referred to as refraction II. The Earth’s Heat A. Thermal Radiation: 1. Heat is released when the liquid outer-core cools and becomes solid (increasing the size of the solid inner-core) B. The solidifying liquid core acts as a source of heat for the layers above the core 1. The increased heat leads to Fractional Melting, when minerals with the lowest melting point melt while minerals with higher melting points stay solid 2. The minerals that melt become buoyant and rise, the solid materials sink and become the bottom of the magma chamber 3. The buoyant force of the molten rock and the force of gravity act together to split the lithosphere apart a) This is why the crust is made out of lower-melting temperature (besalt and gabbros) minerals compared to the mantle C. Layers of the Earth 1. Crust: uppermost layer made of besalt and gabbros (respectively) a) Lithosphere: made of the crust and upper mantle 2. Moho: boundary between the crust and mantle (located in the lithosphere) 3. Mantle: made up of peridotite and is mostly primordial a) Asthenosphere: very weak and not rigid (‘astheno’ means no strength in Latin) 4. Outer-Core: liquid iron 5. Inner-Core: solid iron III.Plate Techtonics A. Mid Ocean Ridges (Fractional Melting I) 1. The force of the buoyant magma chambers pushing up through the layers of the Earth and the downward force of gravity splits the oceanic crust causing ocean ridges a) The molten rock that cools rapidly once it comes in contact with the ocean water turns into pillow besalt b) The continual process of the rising magma pushing open the ridge pushes away the pillow besalt, creating sheeted dikes, thus the further away the rock is from the ridge the older it is (while rock close to or at the ridge can range from days to weeks old) B. Subduction Zones (Fractional Melting II) 1. As the fractional melting and ocean ridges push apart the crust, on the other side of Earth the crust is getting pushed together 2. Where crust is getting pushed together, one plate tectonic is pushed under the other and this is called the Subduction zone a) The crust that is pushed under the other undergoes a lot of heat as it gets closer to the core b) As the crust is heated up again it goes through fractional melting again (1) This second round of fractional melting turns besalt into granite and tuff C. Ophiolite sequence (Ancient seaﬂoor crust - sequence described in III-A) 1. Oceanic sediments -> pillow besalt -> sheeted dikes -> besalt -> grade to gabbros -> Moho -> peridotite IV. Minerals and Rocks A. Minerals: naturally occurring, crystalline solids with a constant chemical composition 1. Naturally occurring: forms as a result of ‘natural’ bio-geo-chemical processes, solidiﬁcation from a ‘melt’, precipitation from an aqueous solution or gas, biologically-aided reactions 2. Crystalline solids: discernible crystal form - internal crystal structure is manifested in the outward appearance of a mineral, leads to a classiﬁcation system, more time allows crystals to grow larger since they grow atom by atom B. Igneous Rocks: Undergo Bowen’s reaction series 1. 0-Distilled- ultra maﬁc 2. 1-Distilled- maﬁc 3. 2-DIstilled- felsic 4. Intrusive- Phaneritic, course grained 5. Extrusive- Aphaneritic, ﬁne grained C. Sedimentary Rocks 1. Clastic: small piece of bigger rocks with continental origin, accumulation of class + lithiﬁcation = clastic sedimentary rocks a) Classiﬁed by sizes (‘clasts’=grains) 2. Biogenic: formed from biology a) ex. Coal is made from broken down plants that have died and underwent high pressure and heat b) Oxygen, nitrogen, argon, and carbon dioxide are all gases that make up the air, and get dissolved in the ocean c) Dissolved carbon dioxide and water mix to make bicarbonate acid d) Calcium + bicarbonate ion = calcium carbonate + a hydrogen ion 3. Chemical Precipitates: form from chemical precipitation a) ex. rock formation inside of caves D. Metamorphism: form from pre-existing rocks (protolith) that are altered by heat and/or pressure and/or ﬂuids into a new form a) Serpentinite = serpentine and magnetite, often peridotite or olivine bearing besalt get transformed into serpentinite with low pressure and low temperature in the presence of ﬂuids E. Ocean sedimentary rates are affected by the amount of calcium carbonate that falls to the ocean ﬂoor 1. Sediments build up on the ocean ﬂoor when creatures die and their shells ﬂoat down to the ocean ﬂoor 2. These sediments are high in calcium carbonate and calcium carbonate in mineral form is calcite 3. The shells that sink and turn into sediments eventually turn into limestone and metamorphosis through lithiﬁcation, and after some more time they turn into marble 4. Sediments are measured in mm/1000years (high sediment F. Most of the carbon on Earth is in rocks 1. Limestone and Marble = 79.95% 2. Kerogen = 19.99% 3. Total = 99.94% of carbon (in both the crust and atmosphere) MATCHING/LABELING 6 7 1 2 3 4 5 8 9 10 16 17 15 11 13 18 14 12 Image from: http://sbaran.net/8science/8sciweeks/index8020909.html ANSWERS 1.Crust 2. Upper Mantle 3.Mantle 4. Outer Core 5.Inner Core 6. Lithosphere 7.Moho 8.Trench 9. Trust Fault 10.Volcano 11.Magma Chamber 12.Subduction Zone 13.Transitional Crust 14.Lithosphere 15.Crust 16.Besalt 17.Gabbros 18.Moho
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