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82 Cards in this Set
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Declination |
Difference between geographic north and magnetic north |
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Inclination |
Compass needle points down toward core |
Dip |
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Magnetosphere |
The region of space surrounding an astronomical object in which charged particles are controlled by that object's magnetic field |
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Bathymetry |
Sea floor topography |
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Sea floor features |
Coast line ➡️ continental shelf ➡️ continental slope ➡️ abyssal plain ➡️ (mid)ocean ridges ➡️ trenches |
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Sea floor spreading |
Plates move apart |
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Subduction |
Crust is "destroyed" and sinks back into the mantle; continental crust always on top of oceanic crust |
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Oceanic-continental convergence |
Subduction zones; Ocean always subducts |
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Continental-continental convergence |
Mountain range; ex: Himalayas, the Alps |
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Rifting |
Crust is being ripped apart (spreading) |
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Atmospheric composition |
78% N, 20% O, .9% Ar, .03% CO2 |
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Exosphere |
Space shuttle, basically no pressure |
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Thermosphere |
100-300km above surface; northern lights; extremely low pressure; temp increases |
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Mesosphere |
50-100km above surface; very low pressure; meteor showers; coldest |
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Stratosphere |
17-48km above surface; ozone layer; temp increases slightly |
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Troposphere |
Lowest layer; weather; thinner at poles; temp decreases with altitude; 80% of atmospheric mass |
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Chondrites |
Carbonaceous meteorites |
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Stony meteorites |
Meteorites similar to Earth's mantle and crust |
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Iron meteorites |
Similar to the core |
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Pallasites |
Meteorites of rock and metal, similar to core/mantle boundary |
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Crust |
Thin, outermost "skin"; continental is thicker than oceanic, but oceanic is denser; base is called the MOHO |
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Lithosphere |
Crust and uppermost mantle; rigid, brittle; broken |
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Athenosphere |
Upper mantle below lithosphere; plastic/ductile; flows as a soft solid |
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Mantle |
Solid rock; 82% of Earth's volume; upper mantle/lower mantle; plate tectonics |
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Core |
Outer- liquid; inner- solid; magnetic field |
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Mineral |
Naturally occuring, formed by geologic processes, solid, crystalline structure, definable chemical composition, inorganic |
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Crystal |
A single piece of a crystalline solid typically bounded by flat surfaces known as crystal faces |
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Ionic bond |
Type of chemical bond that involves the electrostatic attraction between oppositely charged atoms |
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Covalent bond |
Chemical bond that involves the sharing of electron pairs between atoms |
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Polymorphs |
2 or more different minerals that have the same chemical composition but different crystal structures |
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Mineral formation |
Melt, solution, solid state diffusion, biomineralization, gas |
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Anhedral |
Crystals grown in a tight space |
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Euhedral |
Crystals grown in an open cavity |
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Mineral destruction |
Melting, dissolving, chemical reaction |
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Mineral classes |
Sulfides, carbonates, silicates |
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Igneous rock |
Forms when magma or lava cools and solidifes |
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Extrusive rock |
Forms from lava |
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Intrusive rock |
Forms from magma |
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Heat-transfer melting |
Occurs when heat is transported into the shallow crust via melt migration |
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Flux melting |
Occurs due to the addition of volatiles, such as water, to rock; subduction |
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Decompression melting |
Occurs when the pressure on the rock is reduced; mid-ocean ridge, mantle plume, rifts |
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Felsic |
66-76% silica; low temp; light color |
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Intermediate |
52-66% silica; medium color |
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Mafic |
45-52% silica; darker color |
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Ultramafic |
38-45% silica; high temp; dark color |
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Composition of Magma |
Partial melting (felsic); assimliation (surrounding wall rock); magma mixing; fractional crystallization |
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Cooling |
Rate determines crystal size; rate depends on depth (deeper is hotter, shallower is cooler), shape (spherical bodies cool slowly), ground water |
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Pegmatitic texture |
A crystalline igneous texture where the crystals are very coarse, larger than 2.5cm for the most part; slow cooling of magma at depth |
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Pyroclastic texture |
Rocks resulting from explosive volcanic eruptions, consisting of intermingled volcanic rock fragments, crystal fragments, & volcanic ash; ash fall & ash flow |
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Aphanitic texture |
A crystalline igneous texture characterized by crystals that are generally too small to be easily identified with the naked eye; rapid cooling of lava at the surface |
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Porphyritic texture |
Characterized by 2 distinctly different sizes of crystals: coarse-grained phenocrysts w/in a fine-grained groundmass; initial slow cooling at depth followed by eruption of the magma with rapid cooling |
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Phaneritic texture |
A crystalline igneous texture where the crystals are close to uniform in size & are easily visible to the naked eye w/o magnification; slow cooling at depth |
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Glassy texture |
Contain few crystalline minerals and may or may not contain small, trapped bubble; rapid quenching of lava as it erupts or rapid cooling viscous, very silica-rich (felsic) lava flows |
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Magma chambers |
Large underground pools of liquid rock |
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Vents |
Where magma erupts to the surface of the Earth; fissure, crater |
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Calderas |
Large circular depressions up to thousands of meters across & hundreds of meters deep that form via collapse of a volcanic edifice |
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Shield volcanoes |
Broad volcanic edifices with gentle slopes that form from low viscosity lava |
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Stratovolcanoes |
Steep sided volcanoes consisting of interlaying lava, tephra, & volcaniclastic debris |
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Cinder cones |
Cone shaped piles of basaltic lapilli and blocks |
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Explosive eruptions |
Violent; release pressure catastrophically; high gas pressure is from more viscous SiO2-rich magma; create pyroclastic flows and cover land with tephra; mostly andesitic and rhyolitic compositions |
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Effusive eruptions |
Gradual; produce a vast outpowering of lava; lava flows stream away from vents; lava lakes can form from near, or inside, the vent; can produce huge lava fountains 500m high; common with mafic magma (basalt) |
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Magma viscosity |
Depends on: silica content (lower SiO2 content = lower viscosity); temp (hotter temp = lower viscosity); volatile content (higher content = lower viscosity) |
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Strombolian eruptions |
Regular burps of magma |
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Vulcanian eruptions |
Moderately sized eruptions; occur when a build up of gas and magma explodes |
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Plinian eruptions |
Huge explosive eruptions; shoot huge column of pyroclastic debris up to 50km into the atmosphere; ex: Mt St Helens |
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Surtseyan eruptions |
Vent erupts in shallow sea water |
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Hawaiian |
Fountain explosions caused by escaping gas |
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Geologic settings of volcanism |
Mid-ocean ridge, convergent boundaries (ex: Cascades), continental rifts (ex: East African rift valley), oceanic hot spot (ex: Hawaii), continental hot spot (ex: Yellowstone), flood basalt (ex: Columbia River basalt |
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Volcanic threats |
Lava flows, threat of blast, landslides, lahars, earthquakes, tsunamis, dangerous gases, volcanic ash |
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Eruption warning signs |
Earthquakes, changes in heat flow, changes in shape, increases, in gas, steam emissions |
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Clastic Sedimentary rock |
Consists of clasts that are cemented together |
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Weathering |
Combination of processes that break up & corrode solid rock; root wedging, frost action & salt damage, chemical, biological |
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Erosion |
Separation of detritus from their original substrate; wind, water, ice, gravity |
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Transportation |
Carries eroded clasts away from their original locations; a medium's ability to transport clasts depends on its velocity and viscosity |
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Deposition |
Occurs when the detritus settles out of the transporting medium |
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Lithification |
Transformation of loose detritus into solid rock; occurs in 2-step process involving compaction & cementation |
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Clast/grain size |
Larger grains = closer to source |
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Angularity |
Well-rounded sediments = longer distance |
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Sorting |
Well-sorted grains = longer distance |
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Organic Sedimentary rock |
Made of carbon rich relicts of plants and other organisms; amorphous texture; crude conchoidal fracture; crystalline texture |
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Chemical Sedimentary rock |
Precipitated from surface water solutions; consisting of only a single mineral and possessing a Sedimentary crystalline texture; oolites |
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Biochemical Sedimentary rock |
Made of shells grown by organisms |
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