Exam 24: Geologic Time

The term Cambrian explosion refers to

Rubidium-______________ dating is an important radiometric dating tool.

The Phanerozoic eon and the Paleozoic era began about ______________ million years ago.

When rocks and geologic events are placed in chronological order without regard to actual dates, ______________ geologic time is obtained.

The Oligocene is a(n)

Amber is fossilized

Relative and absolute geologic times are combined to give the ______________ scale.

The Pleistocene epoch is also referred to as the ______________.

Geologists have principally used which class of rocks to establish the relative time scale?

Which of the following is the era sometimes called the age of reptiles?

The K-T impact is thought to have occurred at what site?

The fundamental concept of geology that was developed by James Hutton is

Wood from an ancient stump has a ratio of carbon-14 to carbon-12 that is one-eighth that of new wood. About how old is the stump? (Carbon-14's half-life is 5730 years.)

Archaeopteryx fossils are those of a prehistoric

The Eocene is a(n)

The ______________ states that an igneous rock is younger than the rock layers it has disturbed.

An important radiometric dating process is the decay of potassium-40 to ______________-40.

The Phanerozoic is a(n)

The Holocene epoch began when

The earliest evidence of prehistoric life is the single-celled organisms called ______________.