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78 Cards in this Set
- Front
- Back
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Four Main Divisions of Geologic Time |
Cenozoic - current era
Mesozoic Paleozoic Precambrian - oldest -separated by mass extinctions- |
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seismic velocity |
speed of seismic waves -S-waves can't travel through core -when waves move from slower to faster they get refracted upwards |
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continental crust/oceanic crust/mantle/core composition |
continental - granite; least dense oceanic - basalt mantle - olivine core - iron alloy |
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istostacy |
relationship between crustal thinning and elevation -Airy Istostacy: topographic changes accommodated by thickness changes -Pratt Istostacy: elevation accommodated by density differences |
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Curie Temperature |
temp at which a material's permanent magnetism changes to induced magnetism |
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Convergent Boundary Features |
1. volcanoes 2. earthquakes 3. trench ocean to continent: ocean subducts bc continent is less dense |
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Divergent Boundary Features |
1. volcanoes 2. shallow earthquakes 3. symmetrical geochronology |
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Transform Features |
not much, some shallow earthquakes |
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Qualifications of a Mineral |
1. Solid 2. Natural 3. Inorganic 4. Specific Chemical Composition 5. Ordered Internal Structure |
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Major rock forming minerals |
Silicates (i.e. silicon atom bonded w/ four oxygen atoms), carbonates, oxides, halides, sulfides/sulfates |
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Rock Textures |
Pegmatite: v large crystals Coarse Grained Medium Grained Fine Grained Glassy Porphyritic: large crystals in fine grained ground mass vesicular: gasses trapped in erupted material |
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Felsic |
Si, Al |
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Mafic |
Mg, Fe |
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Physical Weathering |
Thermal Expansion, Frost Wedging, Salt/Mineral Wedging, Root Wedging, Animal Attack |
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Chemical weathering |
Dissolution, Hydrolysis, Oxidation can result in saprolite which is a layer of rotten rock |
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Flexure Basins |
bending of lithosphere - mountain belt weighs down and fills w/ sediment where ocean is lower so it floats on continent, sediment piles up |
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Rift Basins |
splitting of lithosphere - crustal thinning - deposition of sediment into areas of lower topography |
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Causes of Metamorphism |
1. Heating and Recrystallization 2. Reaction with Hot fluids 3. Pressure 4. Differential Stress |
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Shale metamorphizes.... |
shale - slate - phyllitie |
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sandstone metamorphizes.... |
quartzite |
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limestone metamorphs.... |
marble |
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coals... |
lignite - bituminous coal - antracite
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Magma chamber |
underground body of molten rock |
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pluton |
solidified magma chamber |
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batholith |
connected plutons |
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dike |
vertical |
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sill |
horizontal |
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laccolith |
dome shaped magma chamber that sits above main pluton |
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Types of Volcanoes |
scoria cone - v small, basaltic sheild - huge, basaltic composite: andesitic dome: felsic |
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Orogenesis |
mountain building by way of rocks undergoing deformation |
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deformation |
change in the configuration of a body from its original configuration into a new configuration (caused by stress) |
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stress |
force applied to a surface per unit area -force = mass x acceleration |
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types of stress |
compression, tension, shear stress |
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strain |
change in shape of a material (caused by stress, not the same thing) |
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types of strain |
stretching, shortening, shear strain |
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strike |
line formed from intersection of plane and the horizon |
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dip |
steepest angle of descent between plane and horizon (always 90 degrees from strike) |
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continental accretion |
process through which material is added to continents (occurs thru orogenesis during subduction and collision, also when erosion causes deposition of new sediments into plate margins) |
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rifts |
caused by lithospheric stretching - mantle upwells due to thinning NOT THE SAME AS A HOTSPOT |
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local elevation causes |
1.folding 2. erosion resistant layers stay and form hills |
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passive margins |
occurs when a continental plate sits next to an oceanic plate and as sediment piles up near boundary, plates flex allowing for more room |
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surface waves |
shears material up and down or back and forth, slowest |
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s-waves |
shears material, faster, can't move through liquid |
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p-waves |
compresses material, fastest |
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unconformities |
gap in the rock record |
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angular unconformity |
deposition/folding or erosion/more deposition (can visually see angular difference) |
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nonconformity |
igneous/metamorphic rock uplifted and eroded, then deposition of sediment (so sandstone on top of granite or something similar) |
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disconformity |
deposition, weathering, deposition |
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discharge |
length x width x speed |
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meanders |
erosion on outer bend, deposition on inner bend |
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talweg |
fastest section of a stream - around a meander its at the outside |
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levees |
built up during floods, coarse grins in suspension are deposited when banks are overtopped |
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formation of terraces |
1. early river level with floodplain 2. downcutting forms new, lower floodplain, stranding terrace 3. high terrace is oldest, downcutting leaves a series of terraces |
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tides |
caused by ocean being pulled by the gravitational force of the sun and moon (mostly moon) |
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spring tide |
extra big tide once a month due to the sun and moon being aligned |
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neap tide |
extra small tide bc sun and moon pulling in diff directions |
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waves |
caused by wind -wave base = (1/2)wave length -waves break where wave base is greater than or equal to water depth -waves bend and refract if they get to shore at an angle |
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when do waves erode? |
1.steep or absent beach face 2. little avail sediment 3. rising sea level causes sea cliffs, sea arches, pinnacles and sea stacks, wave cut platforms |
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when do waves deposit? |
1. gentle gradient 2. lots of available sediment 3. falling sea level causes sand bars, spits, barrier islands |
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porosity |
volume of void/volume of total determined by sorting, grain shape and grain packing |
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permeability |
ability of a material to allow fluids to pass through an interconnected network of pores determined by # of conduits for fluid flow, size of conduits for fluid flow, straightness of conduits |
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DARCY'S LAW |
Q=-KAI or -KA(delta h/L) Q=discharge A=area of pipe L=length of pipe delta h = change in hydraulic head K=intrinsic permeability I=hydraulic gradient (always negative) |
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what happens when a river is lower than the water table |
gain water and vice versa |
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karst topography |
due to groundwater dissolving minerals - creates caves, surfaces w sinkholes, limestone pillars, disappearing streams |
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Mass Wasting |
coherent masses or loose materials are mobilized and transported down slope: two main types: slope failures and sediment flow |
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slope stability is determined by... |
1. nature of materials (sediment vs rock) 2. slope angle 3. water content |
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what can trigger slope failure? |
1. precipitation 2. overgrazing 3. overloading/undercutting slope 4. earthquakes/volcanic eruption |
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creep |
slow |
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debris slide |
very little water, larger sediment, somewhat coherent |
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earth flow |
mostly smaller sediment, some water |
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debris flow |
lots of water and mud |
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rock and debris avalanches |
complete collapse of a slope |
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glaciers |
moving mass of ice w rocks and sediments requires cold temperatures and abundant snow |
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valley/alpine glaciers |
glaciers that flow down valleys, tend to be v narrow |
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piedmont glaciers |
valley glaciers that flow out of the mountains and start to spread out when they encounter flatter topography |
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albedo |
the ratio of reflected sunlight to incident sunlight.....high albedo means lots of reflection |
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ekman transport |
direction of water flow will be 90 degrees to the right of the wind in the NH and to the left in the SH |
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gyre |
system of large rotating ocean currents |
