Term
| Scientific Method creates: |
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Definition
| a set consistent set of objective statements. This is because every scientific idea must be tested thoroughly, and can be accepted only when supported by documented observations. |
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Definition
| Recognizing the problem, collecting the data, proposing hypotheses and testing hypotheses. |
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| The present is the key to the past. Processes we see today have worked in the same way through out time. |
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| Sudden violent, short-lived geological events, were responsible for shaping the earth |
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| Which theory is more correct, Uniformitarianism or Catastrophism? |
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Definition
| They are both correct, a combination of long term processes and short-lived geological events have shaped and created the world that we see today. |
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| Early incorrect ideas about the universe: |
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Definition
Geocentric view- that the earth is the center of the solar system. Replaced my heliocentric view or the sun centered view.
Also the belief that the earth was flat, in reality the earth is oblate spheroid. |
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| The concept of geologic time |
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| The Expanding Universe Theory |
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Definition
| The Big Bang is estimated to have occurred about 13.7 Billion years ago. In the beginning everything was compressed into an infinitesimally small point which exploded and has been expanding every since. Since the Big Bang our universe has been constantly expanding and forming into what it is today. |
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| Cataclysmic Explosion 13.7 billion years ago. At first it was so small and hot and dense it was only energy. Then Hydrogen and eventually other light atoms. molecules slowed down and formed into dark patchy clouds of nebulae of mostly hydrogen and helium. Nebula became protostars > real stars start with nuclear fission about 800 millions years after the big bang. Then the process of death of starts and new stars and such began. |
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| Stellar Nucleosynthesis and supernova explosions created most o13.7 billion years ago. At first it was so small and hot and dense it was only energy. Then Hydrogen and eventually other light atoms. molecules slowed down and formed into dark patchy clouds of nebulae of mostly hydrogen and helium. Nebula became protostars > real stars start with nuclear fission about 800 millions years after the big bang. Then the process of death of starts and new stars and such began. f the elements in the world. Thus we are all made up of stardust. |
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Definition
| The sun and all other objects in the Solar System form from material that had been swirling around in a nebula. Nebula swirls into a disk, the inner portion collapses from gravity into a dense ball (protostar)that eventually becomes a sun. The outer portion (protoplanetary disk) eventually becomes all of the planets. Because of the hot sun the inner part of the disk has a higher concentration of dust (thus rocky planets) and the outer portion has a high concentration of ice (gas giants). Our Solar System is about 4.7 billion years old. |
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Definition
| An object that orbits a star, is spherical and has cleared it's neighbor of other objects. |
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| Inner small and dense rock planets. Mercury, Venus, Earth and Mars. |
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| Outer large and low-density gaseous planets. Jupiter, Saturn, Uranus, |
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| 4.6 Billion years old. Or 4.56 because for the first half billion years earth was too molten to have rocks! |
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| Level of Scientific understanding |
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Definition
| Hypothesis > Theory > Scientific Law |
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| When Earth was molten an asteroid hit it and ripped part of the earth off and it started orbiting the earth and it's part combined into our Moon. ( The moon too use to be molten with volcanoes and everything but it is now inert) |
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| Crust, Mantle, Liquid Outer Core, Inner Solid core (Because pressure is so intense) |
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| What's another name for earth's magnetic system. |
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Definition
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| Has oceanic and continental crust. Both are rigid and Solid. |
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| Technically solid though after 150 km it is hot enough to flow. Has three parts, upper mantle, transition and lower mantle. |
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| Outer core is liquid Iron alloy, the flow of which generates earth's magnetic field. Inner core is solid iron-nickel alloy. |
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| Rigid outer shell is the crust plus most of the upper mantle (100 to 150 km). Are what makes up the Tectonic Plates |
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Definition
| portion of the mantle that can flow. Is what moves the Tectonic Plates |
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| Oceanic vs Continental crust |
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Definition
| The continents are high because they are of mostly low density granite. The ocean basins are low because they are mostly higher density Basalt. Also continental crust is thicker than oceanic crust. |
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Term
| Continental Crust (density, thickness, composition) |
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Definition
35 to 40 km thick
Granite (or mostly silica and oxygen)
2.7 g/ cm^3 |
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| Oceanic crust (density, thickness, composition) |
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Definition
3.0 g/ cm^3
7 to 10 km thick
Basalt |
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| Lower boundary of the crust |
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Definition
| The idea was proposed by Alfred Wegener. He said that the continents once fit together like pieces of a giant jigsaw puzzle, making a vast super continent called Pangaea. And that this later separated into the continents we see today. |
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| Other ideas besides plate tectonics? |
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Definition
| Expanding and Shrinking Earth! |
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| Proof of continental drift? |
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Definition
| Continents Fit, fossil evidence, glacial evidence, matching geology (rock types and mountain belts). Yet he had no process for why it occurred. |
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Term
| Why was continental drift rejected? |
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Definition
| He wasn't an earth scientist and he couldn't explain why they were drifting. |
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| What helped prove Alfred right? |
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Definition
50s and 60s studies of undersea exploration and paleomagnetic studies.
specifically concentrated earthquake belts, sea floor spreading proof. |
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| What did paleomagnetism do? |
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Definition
| Helped to prove plate tectonics. Proved that the continents must move relative to a fixed pole. |
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| New crust moves up from ridge as old crust is subducted and recycled in places called trenches. Begin by noticing that think sediment layers might mean the oceanic crust is relatively young. Then he theorized that because the ridges have the least sediment that new crust might be forming here and be subducting somewhere else. Provided the mechanism to make continental drift work. |
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| the magnetic fields of ancient rocks indicated the origination of the magnetic field relative to the rock at the time the rock was formed. |
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| Using Bathymetry to show depth variations Bathymetric maps showed mid ocean ridges, abyssal plains, deep ocean trenches, sea mounts, fracture zones. |
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| What is powering plate tectonics? |
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Definition
| convention in the lower mantle or the asthenosphere movies the plates composed of lithosphere. |
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| Plates are moving together. Either ocean-ocean, continent-continent or ocean-continent ** LOOK IN NOTES ** |
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| Plates move apart. Has 2 realms- Ocean and Mid ocean ridges and Terrestrial and Continental Rifts. ** LOOK IN NOTES** |
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| Convection cells and hot spots form >combine into a ridge > basalt starts sinking and forms an ocean > ocean spreads |
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| Also called strike-slip faults they have no vertical motion. **look up in book** |
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| Caused by mantle plumes. Results in a chain or arc of volcano islands! |
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| What causes plate motion? |
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Definition
Ridge push force- gravity caused the elevated lithosphere at the ridge axis to push away on the lithosphere that lies farther from the axis, making it move away.
Slab-pull force- the lithosphere formed 10 million years ago is denser than the asthenosphere so it can sink! |
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Definition
| Subatomic Particles (Protons, Neutrons and Electrons) > Atoms > Elements > Minerals > Rocks |
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Definition
Transfer Electrons
Weak Bond |
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Share Electrons
Stronger Bond |
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Valence Electrons are free to migrate over the atoms.
Weakest and less common.
Good for mallability and conduction! |
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| Definition of a Mineral: (5 things you need to know) |
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Definition
1. Must Be Solid
2. Must be natural
3. Must be inorganic
4. Needs a specific and definable chemical composition
5. Needs a specific and ordered internal structure |
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| Color of a mineral in it's powdered form |
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| External expression of internal structure. (Needs space, time and fluid to occur) |
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| Tendency for minerals to break along planes of weakness |
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| Resistance of a mineral to being scratched. All minerals are compared in hardness on the Mohs Scale. |
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| Appearance of mineral in reflected light. |
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| Dana system of Mineralogy |
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Definition
Organization System Based on Chemical Groups.
Two main ones: Silicates-SiO2 and Non-Silicates-(Which are divided further based on anions) |
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Definition
| Two different minerals (such as diamond and graphite) that have the same composition but different crystal arrangement. |
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Definition
| Generally unreliable in mineral identification and often highly variable due to slight changes in mineral composition. |
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| What is an Igneous Rock? How do they From? |
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Definition
| They are the result of the cooling and crystallization of magma. |
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Definition
| Molten Rock beneath the surface vs Molten Rock on the surface. |
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| Rocks formed underground and cool slowly vs Rocks formed on the surface and cool quickly. |
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| How are Igneous Rocks Classified? |
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Definition
| By Texture which tells you how the rock cooled and where and by chemistry which is what you really need to know an igneous rock. |
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Definition
| a large, deep body of solidified magma. Called a Dike if vertical and a Sill if horizontal. |
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Definition
| Can occur in Passive Lava Flows or explosive pyroclastic phenomena. |
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| Liquid, Solid crystal seeds and volatiles or dissolved gas. |
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| Fine-grained texture- few crystals. (Extrusive Igneous) |
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| Coarse-grained Intrusive Igenous rock. |
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| Mixed Grain- large xtals in a sea of small xtals. can be intrusive or extrusive igneous. |
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Definition
| Igneous. Caused in Explosive eruptions. Magma is fragmented into gas, ash, glass and rock fragments. Transported by air currents and pyroclastic flows. Tuff- deposits of pyroclastic explosions, looks like sedimentary rock. |
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Term
| Composition of Igneous Rocks |
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Definition
| Mainly Silicate Minerals (SiO2). Rocks are thus defined as Felsic, Intermediate, Mafic, and Ultramafic based on decreasing Silicate Content. |
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Definition
| Less than 50% Silicate and are generally dark Minerals. |
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Definition
| 70 to 75% SiO2 and are generally light Minerals. |
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Definition
| Melting of rocks in mantle and crust. Temperature increases help melting, pressure increases can inhibit melting. Volatiles or more water in a rock can cause it to melt at a lower temperature. |
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Definition
| Partial Melting- parts of the rock melt because of the different minerals in it. Decomposition Melting- magma moves up from convection and this decrease in pressure causes melting. (happens at ocean ridges and subduction zones) Flux Melting- a catalyst like H20 lower melting temperature. (Important at Subduction Zones) |
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| Sedimentary rocks are composted of rock and mineral fragments, shells and mineral precipitates cemented into rocks. |
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Definition
| Many rocks have pre-existing fractures called joints. These weak areas can facilitate weathering. |
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| Large, flat curved sheets of rock fracture and are detached from an outcrop. aka rocks peeling like an onion. Commonly happens in igneous rocks. |
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| Cube rock weathered into a spheroid because corners have 3 exposed sides, edges two exposed sides and faces one exposed side. Thus weathering goes fastest at the corners, medium at the edges and slowest at the faces turning a cube into a spheroid. |
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Term
| Two main components of soil |
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Definition
| Regolith- weathered rocks and minerals and humus- organic component. |
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| Two processes of Lithification |
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Definition
| Compation and Cementation (Minerals invade pore spaces between sediments and solidify. |
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| 3 classes of Sedimentary Rocks |
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Definition
Chemical- comes from solution.
Clastic- small clasts or rock fragments.
Biochemical/Organic- fossils, shells, ect. |
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Definition
| The more angular and coarser they are the closer to the source they formed. |
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| Evaporation triggers deposition of chemical precipitates. In book it says that because salt deposits form as a consequence of evaporation geologists refer to them as evaporites. |
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| Depositional Environments |
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Definition
| Locations where sediments accumulate. Common in Terrestrial Environments and Marine Environments/Carbonate Environments. |
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Definition
| Parallel layers of sediments, each one is a bed. |
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| Beds at different angles, from changing winds and water currents. |
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| Small "ridges" formed on sand by water or wind currents. in and out current forms symmetrical ridges, one way currents do not. |
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| Similar to ripples expect much larger. |
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| polygonal patterns of cracks in mud from dessication or drying out. |
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| Burrow marks, tracks or trials left in sediments by animals. |
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Definition
| Usually Marine but can also occur in limstone settings. Reefs are carbonate environments. |
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Definition
| Rocks that change form as the result of increased pressure, temperature or the acquaintance of hot fluids. |
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| How are Metamorphic Rocks Classified |
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Definition
| Foliated (have pattern or geometry) or Non-foliated. |
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Term
| What condition of temperature and pressure can't occur for metamorphic rocks. |
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Definition
| High pressure and low temperature. |
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| Types of pressure for metamorphic rocks |
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Definition
| Directed pressure- unequal pressure that is greater from one particular direction (caused folliation) vs confining pressure which is a general pressure from all directions. (non folliation) |
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Definition
| crystals formed in folliation of metamorphic rocks. |
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| More intensity or a higher grade results in larger xtals or crystals than less intensity and a lower grade. |
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Definition
| Methamorphism over a broad area due to deep burial or tectonic forces. (usually associated with plate tectonics) |
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Definition
| Small scale, localized and low pressure hear from pluton meamorphoses existing rocks. These rocks are economically viable because they have lots of minerals. |
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Definition
| Hot water percolates through spaces in rocks and minerals crystallize. Has high T and low P, occurs at hot springs, geysers and mid-ocean ridges. |
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Definition
| rocks are metamorphosed by the weight of overlying rocks. The affected area can vary as can the amount of metamorphism depending on the depth of burial. |
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| Deformation (Fault) Metamorphism |
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Definition
| Rocks along fault planes are crushed, stressed and pulverized. occurs at low temperature and relatively low temperature and high pressure. |
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Definition
| Meteorite Impact or nuclear detonations. Has extremely height temperature and pressure. |
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| The parent material that the particles in a sedimentary rock came from! |
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