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28 Cards in this Set
- Front
- Back
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Four units of time from biggest to smallest
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Eon, era, period, epoch
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Last three era's and first Eon
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Cenozoic, mesozoic, paleozoic, Precambrian
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Age of earth, percent of time in past three eras
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4.6 bil, 1.4% cenozoic, 4 mesozoic, 6.3 paelozoic, 88.3 precambrian
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Dating
two types |
Relative – sequence, leads to stratigraphy, based on fossils
Absolute – number of years, based on radiometric dating |
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Fundamental principle in geologic time scale is:
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uniformitarianism
“the same physical processes active in the environment today have been operating throughout geologic time |
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in cooling, elements sorted by
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density, iron to middle, silica to top
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Layers going in
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lithosphere, asthenosphere, upper mantle, lower mantle, outer core, inner core
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make up of upper and lower mantle, outer and inner core
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olivine, silicate minerals
olivine iron magnesium silicates liquid molten iron solid iron |
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lithosphere is?
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Crust and uppermost mantle
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two discontinuities?
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Mohorovicic crust/mantle
gutenbert mantle/core |
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two types of crust and props
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continental: lighter thicker
oceanic denser thinner |
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isostasy?
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buoyancy and balance of crust on liquid inner earth
More weight above pushes crust into uppermost mantle and it into |
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sedimentary are what % of crust and surface, igneous are what %
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sedimentary are 5% of crust and 75% of surface, igneous are 95% of crust and 25% of surface
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classification of intrusive
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I. pluton: any intrusive
A. batholith: largest B. magma conduits 1. sills: parallel to sedimentary a. laccolith: lens shaped sill 2. dikes: form across sed layer |
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one type of extrusive, intrusive
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basalt, granite
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two types of igneous by composition
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felsic: feldspar and silica, lighter less dense
mafic: mg and ferric, darker and denser |
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four kinds of sedimentary rock and root material
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sandstone, shale: mud, limestone: little animals, coal: plants
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lithification
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process of compaction, cementation, and hardening of sediments, also chemical prepitation
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two types of sedimentary and formation
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clastic: transported rock fragments
chemical: precipitates of minerals: limestone |
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foliated:
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metamorphic rock that shows patterns or lines from particular alignment of minerals
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5 metamorphic transformations
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shale ->slate
granite/shale/slate -> gneiss basalt/shale/peridotite->schist limestone/dolomite->marble sandstone->quartzite |
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Alfred Wegner came up with: 2
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continental drift
pangea scientific evidence of both |
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plate tectonics make
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volcanic activity
upwelling of magma crustal plate movement crustal changes earthquakes subduction of crust sea floor spreading |
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seafloor spreading dated by?
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magnetic orientation of new crust
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which goes under when ocean hits continent crust?
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ocean bc its denser
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two parts of geologic cycle
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exogenic: tearding down powered by solar energy
endogenic: building up, internal heat powered |
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at least how many plates
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14
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fracture zone
fracture fault |
moving in same direction
different directions |
