Page 115 - Science Course 3 (Book 2)

Mo11-L2b: How to Determine the Relative Ages of Rocks?

Correlation
Nonconformity
Matching rocks and fossils from separate locations
Younger sedimentary layers are deposited on
older igneous or metamorphic rock layers that is called correlation.
been eroded.
Geologists use correlation to f ll in gaps in the rock
record.
Younger
sedimentary rock

Sometimes it is
Older possible to connect
igneous rock rock layers simply by
walking along rock
formations and
looking for similarities.
Key Concept
How to Determine the Relative Ages of Rocks? Geologists use correlation to established a historical
record.
How does an unconformity represent a gap in
time?

Navajo
Navajo
sandstone
sandstone
Moenkopi
Moenkopi
Formation Carmel Formation
Formation

Kaibab Limestone national park

Bryce Canyon
Grand canyon
national park
Zion national park

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