Relative Dating: Rock Layers

Front

What is the numerical age, in years, of any object?

Back

Absolute age

Front

What is a fault in geology?

Back

A fault is a fracture or zone of fractures between two blocks of rock.

Front

What is the youngest layer in a sequence of rock layers?

Back

The youngest layer is typically found at the top of the sequence.

Front

Which layer is considered the oldest in a sequence of rock layers?

Back

The oldest layer is typically found at the bottom of the sequence.

Front

What is an intrusion in geology?

Back

An intrusion is a body of igneous rock that has formed from magma that has cooled and solidified within the crust.

Front

What is relative dating?

Back

Relative dating is the science of determining the relative order of past events without necessarily determining their absolute age.

Front

What is an inclusion in geology?

Back

An inclusion is a piece of one rock unit that is contained within another.

Front

What is an unconformity?

Back

An unconformity is a surface that represents a break in the geological record, indicating that deposition stopped for a period of time.

Front

How do geologists determine the relative ages of rock layers?

Back

Geologists use principles such as superposition, original horizontality, and cross-cutting relationships.

Front

What does the principle of superposition state?

Back

In an undeformed sequence of sedimentary rocks, the oldest layers are at the bottom and the youngest are at the top.