Term
| What are two types of the Earth's crust? |
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Definition
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Term
Compare the two types of crust.: oceanic and continental |
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Definition
oceanic: - 5-10 km thick
- underneath oceans
- denser
continental: - 32-70 km thick
- continents rest on it
- thickest beneath mountains
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Term
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Definition
| Remains of traces of an ancient plants and animals |
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Term
| What type of rock are fossils typically found in? |
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Definition
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Term
| What is the name of the tool scientists use to describe the age of the Earth and all of it's life forms? |
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Definition
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Term
| Describe natural selection. how is it related to the geologic time scale? |
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Definition
natural selection= the process by which organisms with traits best suited an environment survive and reproduce, while others die out because they lack those traits. With the geologic time scale, you can tell which species died out and who couldn't survive |
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Term
What are the two methods for identifying the age of rocks? Describe each |
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Definition
Abosolute Dating=actual age of rock (ex. 1,2 13, 56) Relative Dating=comparing rock age by younger or older.(ex. rock 1 is younger than rock 2) |
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Term
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Definition
| principle that a sedimentary rock layer is older than the layers above it and younger than the layers below it. |
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Term
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Definition
| rocks are layed down in a horizontal fraction |
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Term
| Law of Cross-cutting relationships |
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Definition
| principle that a fault or intrusion is always younger than the rock layers it cuts through |
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Term
| Law of contact metamorphism (Baked contact) |
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Definition
| change in the structure and mineral composition of rock surrounding an igneous intrusion |
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Term
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Definition
| theory that geologic processes at work in the present were also at work in the past |
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Term
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Definition
| break in the geologic record |
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Term
| describe the three types of unconfomities |
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Definition
Disconformity= the boundary between the older surface and the younger is nearly horizontal. Angular unconformity=boundary between horizontal and tilted layers of rock. Nonconformity= stratified rock rests in unstratified rock. |
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Term
| compare the age of continental rocks to those along the mid-ocean ridges |
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Definition
the younger rocks are located along the ridges. The farther the rocks move from the ridge the older they are. |
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Term
| describe the term half-life |
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Definition
| time required for hald the mass of a radioactive element to decay into it's daughter element |
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Term
| what is continental drift? |
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Definition
| hypotheseis stating that the continents once formed a single landmass, broke up, and drifted to their present locations |
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Term
| what supported the theory of continental drift? |
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Definition
- matching fossil plant remains on two different continents
- matching animal remains on two different continents
- identical sedimentary rocks of the same age at widely spread location
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Term
| the continents are moving apart from one another due to magma rising out of the mid-ocean ridges is called... |
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Definition
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Term
| theory of plate tectonics |
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Definition
| theory that the lithosphere is made up of plates that float on the asthenosphere and that the plates possibly are moved by convection currents. |
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Term
| what are lithospheric plates? |
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Definition
| makes up the oceanic and continental crust. thin outer shell of the earth consisting of the crust and upper mantle. |
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Term
Describe the process of subduction of an oceanic plate beneath a continental plate. |
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Definition
| Th oceanic plate would subduct under the continental plate because the oceanic plate is denser. |
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Term
| what are the plate boundaries that form between two litospheric plates? |
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Definition
| divergent, convergent, transformfault |
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