Analyzing the Rock and Fossil Records

Front

What is lateral continuity?

Back

Sediments are deposited in large, continuous sheets in all lateral directions.

Front

What is relative age?

Back

The age of rocks and geologic features compared with other rocks and features nearby.

Front

Who are geologists?

Back

Scientists who study Earth and the processes that have shaped Earth.

Front

What are cross-cutting relationships?

Back

If one geologic feature cuts across another, the feature that it cuts across is older.

Front

What are mass extinctions?

Back

Times when many species on Earth died or became extinct within a relatively short period of time.

Front

What are sedimentary rocks?

Back

Rocks formed by the accumulation of sediments, often layered.

Front

What is the principle of superposition?

Back

In undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest are at the top.

Front

What is a fossil?

Back

The remains or traces of ancient living things.

Front

What is the significance of index fossils?

Back

Index fossils are used to identify and date the layers of rock in which they are found.

Front

What is radiometric dating?

Back

A method used to determine the age of rocks and fossils by measuring the decay of radioactive isotopes.