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36 Cards in this Set
- Front
- Back
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geology
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study of the earth's layers
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how are rocks classified?
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by origin (how they are formed)
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igneous
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fire made, rock so hot it flows
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extrusive
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lava
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intrusive
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magma
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types of granite and uses of it
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mica, feldspar, quartz;countertops, tombstones
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pumice
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lava soap
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obsidian
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igneous
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sedimentary rocks
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made of sediments cemented together, carried by water to oceans and wind
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chemical sedimentary
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dissolved by water and come out of solution
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examples of sedimentary rocks
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rock salt, limestone, gypsum
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clastic
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made of fragments of preexisiting rock
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metamorphic
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rocks that have changed from igneous or sedimentary and packed until they become more dense.
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how are metamorphic rocks formed?
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high pressure and high heat
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quarry
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rocks are cut from the ground
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fossil
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used to be a living thing, a trace of an ancient organism
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types of fossils
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imprint, mold and cast, petrified
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what is petrified?
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once living matter changing to a rock
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amber
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Ancient tree sap
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for fossils to form there must be:
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no bacteria or fungus (dry, cold, buried) and no scavengers
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(hard/soft) parts are easiest to preserve
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hard
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eras
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separate periods of worldwide change
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periods
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divided by montain building in a particular part of the earth
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epuch
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separated by major climatic change
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pre-cambrian
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not much fossil record
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paleozoic
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invertebrates dominate (old life) 295 million years
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messozoic
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reptiles dominated "middle life" 130 million years
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cenozoic
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mammals dominated, "modern life" 65 million years
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index fossil
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used to pinpoint particular time
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standard geological column
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all sedimentary layers and fossils ever found on earth, organized by relative age
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radioactive decay
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determines absolute time
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half life
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decay rate at radioactive material
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law of superposition
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if a rock layers on top it is probably younger
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magma
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inside earth's crust
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lava
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oozed out on surface
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absolute time
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the time in years each event is known
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