8 Rock Record Practice

Front

When scientists compare things to determine which geological artifacts are older or younger, this is called ____________.

Back

Relative aging

Front

Scientific study of rock layers

Back

Stratigraphy

Front

What scientific law tells us that in rock strata, the oldest layer is at the bottom and the youngest layer is at top?

Back

Superposition

Front

Fossils such as footprints, burrows or droppings.

Back

Trace fossils

Front

A gap in the sequence of sedimentary rock layers caused by erosion.

Back

Unconformity

Front

Fossils made from organisms that were fairly common and existed only during a certain span of time, used to determine the age of rock layers.

Back

Index Fossils

Front

What scientific law tells us that if one rock layer contains pieces or fragments of another rock layer, then the fragments will be older than the rock layer that surrounds it?

Back

Inclusions

Front

Term used for the time it takes for half of the atoms in a sample of a radioactive element to decay.

Back

Half-life

Front

When scientists use half-life, radiometric dating, or carbon dating, what are they trying to determine about a geological artifact?

Back

Absolute age

Front

What scientific law tells us that if one rock layer crosses over other layers, then that layer of rock will be younger than any rock layers that it crosses?

Back

Cross-cutting