Dating Rocks - Study Guide

 

Geologic time scale - Precambrian (>543 my), Paleozoic (>248 my), Mesozoic (>65 my), Cenozoic

 Relative dating: layer sequence, superposition, original horizontality, lateral continuity, cross-cutting relationships, unconformities,  fossils

Absolute dating - radiometric dating: radioactive decay

Fossils - fossil succession:  Invertebrates (beginning of Paleozoic), fish (middle Paleozoic), amphibians (late-middle Paleozoic), reptiles (late Paleozoic, but dominant in Mesozoic), Mammals (Mesozoic  but dominant in Cenozoic)

 


Explain the difference between relative and absolute dating. Describe the ways by which relative ages are determined.  How is absolute age most commonly measured?

Be able to determine the sequence of events from a block diagram.

Explain how fossil succession can be used to determine the approximate age of a rock.  Know the times at which each major group of animals appeared on the planet.


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