Earth History

All are types of fossils EXCEPT

• Mineral Replacement
• Bone neutralization
• Carbon Film
• Cast and Mold

The half-life Carbon-14 is 5,730 years. How much parent material is left after 5,730 years?

• 75%
• 50%

The absolute age of an igneous rock can best be determined by ...

• comparing radioactive isotopes
• comparing crystal sizes

The bottom layer of rock is

• the oldest
• has fossils

Index fossils are useful for determining the relative age by ...

• a narrow time range and a wide geographic range
• a narrow time range and a narrow geographic range

In what way are index fossils and layers of of ash found in ice cores?

• both are used for relative dating
• both only occur in igneous rocks

Which time period on the chart was the longest?

• Permian
• Cambrian

Trilobite fossils are found in Cambrian rocks but not in Triassic rocks. This is best explained because ...

• Trilobites went extinct before the Triassic rocks
• fossils did not form during the Triasssic

Ice cores are most useful for determining 

• the atmospheric composition of the past
• the number of species alive in the pas

Which layer of rock is most likely the youngest?

• A
• D