Transcript Correlation and Fossils Powerpoint

Correlation and Fossils
WOOHOO!
Applying Principles of Relative Dating to
Determine Geologic History of an Area
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The process of matching rocks or geologic
events occurring at different locations of the
same age is called
CORRELATION
Correlation of rock layers often
relies upon fossils
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William Smith (late l700’s) noted that rock layers in
widely separated areas could be identified and
correlated by their distinctive fossil content
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This led to the "principle of fossil succession“
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Fossils succeed one another in a definite and
determinable order, and therefore any time period can
be recognized by its fossil content
Index Fossils
Index fossils - any animal or plant that is characteristic
of a particular span of geologic time or environment.
2 criteria must be met


Life form lived over a wide geographic area –
horizontal distribution
Life form existed for a short period of time – short
vertical distribution
NYS Index Fossil
Again….Corellation…
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Correlation- or CO-RELATION (two or more
things related) is a critical tool in the
reconstruction of Earth’s history.
Geologists look for a sequence of rocks (an
“order”) that is the same in two or more areas,
and can therefore say they are the same age!
Let’s check it out!!