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Geology 112
1.2 Dating methods used by geology
Question | Answer |
---|---|
Stensens 5 principals? | Superposition, horizontality, lateral continuity, intrusive relationships, included fragments |
Smiths Principal? | faunal succession |
Def. superposition | Younger layers of sed. rocks are depositited at the top. |
Def horizontality | If rock layers are inclined they have titled afterwards |
def lateral continuity | sedimentary rocks form extensive sheets |
def intrusive relationships | When igneous rocks cut through layers of sedimentary rocks, the sed rocks must have been present |
def included fragments | If fragments of a rock are found in a a larger rock, it is said that the fragmented rock was formed first |
def faunal succession | sed. rocks of a particular age have different fossils to sed. rocks of a different age, due to the changing biosphere |
3 Major Eons? | Phanerozoic 0 - 0.5 Ba, Proterozoic .5 - 2.5 Ba, Archaoezoic 2.5 - 4 Ba |
3 Eras of the Phanerozic? | Cenozoic Mesozoic Palaeozoic |
P C D S O C | Permian, Carboniferous, Devonian, Silurian, Ordovician, Cambrian |
Who named P C D S O C? | Sedgewick and Murchison |