Geologic_Time

Geologic_Time - Geologic Time A major difference between...

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1 Geologic Time Geologic Time A major difference between geologists and most other scientists is their concept of time. A "long" time may not be important unless it is greater than 1 million years Fig. 10.1 Two Ways to Date Two Ways to Date Geologic Events Geologic Events 1) relative dating (fossils, structure, cross- cutting relationships): how old a rock is compared to surrounding rocks 2) absolute dating (isotopic, tree rings, etc.): actual number of years since the rock was formed Fig. 10.2 Fig. 10.3 Relative Dating
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2 Fig. 10.3 Steno's Laws Steno's Laws Nicholas Steno (1669) Principle of Superposition Principle of Original Horizontality These laws apply to both sedimentary and volcanic rocks. Principle of Superposition Principle of Superposition In a sequence of undisturbed layered rocks, the oldest rocks are on the bottom. Principle of Original Horizontality Principle of Original Horizontality Layered strata are deposited horizontal or nearly horizontal or nearly parallel to the
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This note was uploaded on 11/20/2010 for the course LIR 30 taught by Professor Thornley,k during the Spring '08 term at Santa Rosa.

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Geologic_Time - Geologic Time A major difference between...

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