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Earth's History
Term | Definition |
---|---|
Index fossils | A fossil that is useful for dating and correlating the strata in which it is found. |
lithosphere | the rigid outer part of the earth, consisting of the crust and upper mantle |
extinction | the state or process of a species, family, or larger group being or becoming extinct. |
law of superposition | sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom |
unconformities | a surface of contact between two groups of unconformable strata |
divergent | boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth's surface between the two plates |
convergent | boundary where two plates are moving towards each other causes a change in the Earth's surface |
transform | boundary where two plates slide rubbing against each other creating new crust |
faults | break in the rocks on the Earth's surface |
plate tectonics | theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates that move slowly over the underlying mantle |
continental drift | gradual movement of the continents across the earth's surface through time |
absolute age | true age of a rock or fossil |
relative age | age of a fossil organism, rock, or geologic feature or event defined relative to other organisms, rocks, or features or events rather than in terms of years |
half-life | time taken for the radioactivity of a specified isotope to fall to half its original value |