Exam 17: Geologic Time: Concepts and Principles

To correlate rock units over a large area or to correlate age-equivalent units of different composition, fossils and the principle of fossil succession must be used.

Which statement about methods of determining Earth's age is false?

A hiatus between igneous or metamorphic rocks and sedimentary rocks is represented in the rock record by a(n)____.

A rock sample containing an isotope with a half-life of 12 million years has an initial mass of 72 grams. How much of the daughter isotope will be present after three half-lives?

Stratigraphy is the study of the composition, origin, areal distribution and age relationships of layered rocks.

The principle of ____________________ states that rock layers extend laterally in all directions unless or until they terminate in one of a number of natural means.

Index, or guide, fossils are most useful because they ____.

To determine the age of sedimentary rocks containing fossils, ____________________ zones are established, plotting the overlapping geologic ranges of different species of fossils.

Different varieties of an atom that have a different number of neutrons in their nuclei are ____________________.

Why don't the sources of uncertainty in radiometric dating invalidate or lend suspicion to the results obtained?

Why was Lord Kelvin's argument for the age of Earth fundamentally in error?

Radiocarbon dating is possible primarily because ____.

Which principle states that fossil assemblages succeed one another through time in a regular and predictable order?

What is the general term for a gap in the geologic rock record that represents a period of non-deposition, erosion, or both?

The longest divisions of geologic time are called ____.

Radiocarbon dating is only useful for organic material.

Divisions in geologic time represent ____.

The geologic time scale was initially developed by using ____________________ dating and subsequently refined by using ____________________ dating.