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