Name: ________________
Date: ________________
Period: _________
Index Fossils
Index Fossil
 A __________________ that can be used to provide information about the __________ of rock layers.

Not all fossils are __________________ fossils.
Characteristics of an Index Fossil
1. The organisms lived only during a _____________ period of Earth’s history.
2. _____________ fossils of the organism can be found in the rock ________________.
3. The organism is ______________________.
Which would make a better index fossil?
A. A fern that live on Earth since the Pennsylvanian Period (300 mya)
B. A trilobite that lived many areas for a few million years during the Cambrian period.
Which fossil is the BEST index fossil?
The __________________ is the best index fossil because it is
only found in ___________ layer in all ___________
outcrops/sites.
Law of Superposition
Place the following fossils in order
from YOUGEST to OLDEST.
In your own words, describe the Law of
Superposition.
Relative Dating
 Used to arrange geological events to determine a _______________________.

Does ____________ provide the ________________ age.
Using the index fossil determine
which layer is the OLDEST.
Using the index fossil determine
which layer is the YOUNGEST.
Absolute Dating
 Used to determine the ________________________ of rocks.

Scientists use __________________________ dating to determine the actual age of rocks.
Unconformities
 A ______________ in the ____________________________ that occurs when rock is ______________
exposing older rock and then new rock forms on the much older exposed rock.

Shows ______________________ of the geological record.
Layer _______ was likely eroded away at location 1.
Weathering vs. Erosion
 Weathering is the __________________________ of rocks, soil, and minerals through contact with
the Earth’s atmosphere, water, and biological organisms.

Erosion is the __________________ of processes such as wind or water that _______________ soil,
rock, or dissolved material from one location on earth and __________________ it to another.
Determine whether the following describes weathering or erosion.
1. Plants break up soil with as their roots grow.
2. A glacier causes a landslide of rock.
3. Heavy rain causes small pieces of rock to break off the side of a mountain.
4. Wind carries loose pieces of rock away from the mountain.
Name 5 facts that can be made from the picture
1.
2.
3.
4.
5.