Relative Age and Geologic Time

Front

What is the process that geologists use to identify the number of years that have passed since the rock has formed?

Back

Radioactive dating is the process used by geologists to determine the absolute age of rocks by measuring the decay of radioactive isotopes.

Front

What is a surface where the rock has eroded away, producing a break, or gap, in the rock record?

Back

An unconformity is a surface that represents a gap in the geological record due to erosion.

Front

What do we call the process when sediment is moved around by wind or water?

Back

Erosion is the process of moving sediment from one location to another by wind, water, or ice.

Front

What are gaps in rock layers caused by erosion called?

Back

Unconformities are gaps in the geological record caused by erosion.

Front

What can fossils tell us about the Earth's history?

Back

Fossils provide information about the types of organisms that existed in the past.

Front

What is the term for the age of a rock in relation to other rocks?

Back

Relative age is the age of a rock compared to the ages of other rocks.

Front

What principle states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom?

Back

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

Front

What is the process of breaking down rocks into smaller pieces called?

Back

Weathering is the process that breaks down rocks into smaller pieces.

Front

What is the term for the study of rock layers and layering?

Back

Stratigraphy is the study of rock layers and layering.

Front

What do we call the preserved remains or traces of ancient organisms?

Back

Fossils are the preserved remains or traces of ancient organisms.