Exam 4: Geologic Time: a Story in the Rocks

Relative age measurement refers to:

When a parent isotope decomposes, the quantity of daughter isotopes in a sample decreases with time.

In order to determine the absolute ages of rocks, __________ __________ relies on measuring the relative amounts of parent and daughter isotopes.

The principle of faunal succession states that:

__________ __________ come from organisms that are abundantly preserved in rocks and are useful for dating.

According to the principle of __________, a rock must first exist before anything can happen to it.

The thin, sooty iridium-rich layer found at the end of the Permian is an example of a __________ __________.

Measurement of __________ age refers only to the order in which events occurred.

The half-life of a radioactive isotope is:

The Permian extinction occurred at the end of the:

The largest time units in the geologic column are periods.

The __________ encompasses approximately the first 4 billion years of Earth's history.

To be useful, an index fossil is produced by an organism that:

Matching rocks of similar ages from different localities is __________.

The fact that sedimentary rocks usually become younger from bottom to top is the principle of __________.

Younger layers of sediment always accumulate on top of older layers.

In a disconformity, older sedimentary beds were tilted and eroded before younger layers were deposited.

__________ __________ refers to the order in which geologic events occurred.

The principle of superposition assures us that sedimentary rocks formed continuously from 2 billion to 200 million years ago.

Humans evolved and lived wholly during the Mesozoic Era.