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Compare fossils found in
sedimentary rock to
determine their relative age.
Compare fossils found in sedimentary
rock to determine their relative age.
Compare fossils found in sedimentary
rock to determine their relative age.
Compare fossils found in sedimentary
rock to determine their relative age.
I. Fossils
A.Fossils – the preserved remains or traces of once
living organisms
1.Remains – any part of the organism is a fossil
a. example; bones, teeth, horns, even soft tissue
2. Traces - any imprint, footprint, tooth mark, tail
mark, scratch mark
a. not part of the actual animal but evidence the
animal has been there
Compare fossils found in sedimentary
rock to determine their relative age.
II. Dating fossils
A.Absolute dating – the exact age in years that a fossil has
existed
1.Example; 25,000 years or 65 million years
B.Relative dating – a comparison of the ages of different
fossils
1.only tells which is older or younger not a specific
number of years
Compare fossils found in sedimentary
rock to determine their relative age.
III. Fossil formation
A.Steps of fossil formation
1.The organism dies
2.the remains are rapidly buried in sediment
3.over time the sediment that covers the organism is
compacted and cemented to become sedimentary
rock
4.The layers of sedimentary rock above the remains
eventually erode and the fossil is exposed
Compare fossils found in sedimentary
rock to determine their relative age.
IV. Superposition
A.Superposition – the rock layers nearer to the surface
are younger than deeper rock layers
1.“younger over older”
2.Since the more shallow layers of rock are younger
than deeper layers of rock, then the fossils found in
more shallow rock layers are younger than the fossils
found in the deeper layers of rock.
3.This allows you and scientists to tell which fossils
and thus which animals lived first, next, and so on.
Compare fossils found in sedimentary
rock to determine their relative age.
Compare fossils found in sedimentary
rock to determine their relative age.
Compare fossils found in sedimentary
rock to determine their relative age.