Relative Age Dating

Front

What is an index fossil?

Back

An index fossil is a fossil that is used to define and identify a particular time period in the geological time scale. It is typically widespread, abundant, and existed for a relatively short duration.

Front

What does the Law of Superposition state?

Back

The Law of Superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the younger layers are at the top.

Front

Which is older: an intrusion or the surrounding rock layers?

Back

The surrounding rock layers are older than the intrusion, as intrusions are formed after the existing rock layers.

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 beneath the Earth's surface.

Front

How do sedimentary rocks typically form?

Back

Sedimentary rocks usually form horizontally from the accumulation and compaction of sediment over time.

Front

What is relative dating?

Back

Relative dating is a method used to determine the age of rocks and fossils in relation to one another, without determining their exact age.

Front

What is an unconformity?

Back

An unconformity is a surface that represents a gap in the geological record, where rock layers have been eroded or not deposited for a period of time.

Front

What is the significance of index fossils in relative dating?

Back

Index fossils help geologists correlate the age of rock layers across different locations, as they indicate the same time period.

Front

What is the difference between an inclusion and an extrusion?

Back

An inclusion is a piece of older rock that is enclosed within a younger rock, while an extrusion is lava that has erupted onto the Earth's surface and solidified.

Front

What is the principle of cross-cutting relationships?

Back

The principle of cross-cutting relationships states that a geological feature (like a fault or intrusion) that cuts through another feature is younger than the feature it cuts.