Exam 16: Geologic Time: Concepts and Principles

James Hutton concluded that Earth must be very old and wrote that "we find no vestige of a beginning,and no prospect of an end."

Why do igneous rocks yield the most accurate radiometric ages,and what is the calculated date the actual age of?

The best dating method for a frozen mammoth carcass is rubidium 87-strontium 87.

How do geologists do correlation using rocks and fossils?

Which of the major rock types were most important originally in developing the geologic time scale,and why?

What are the three types of unconformities,and what is each missing?

How does the sequence of events differ between an angular unconformity and a disconformity?

If you start with an element with 1,000,000 parent atoms,how many parents and how many daughters will there be after 6 half-lives?

Uraniun 234 to thorium 230 dating of layers of stalagmites is reliable back to about 1,000,000 years.

What is the principle of original horizontality?

Long-lived radioactive isotope pairs used in radiometric dating have half-lives of the magnitude of ____________________ or ____________________ of years.

A surface of erosion on metamorphic or igneous rocks below sedimentary rocks is a(n):

A fossil that is particularly useful for correlation is an evolutionary fossil.

Carbon 14 has a half life of 5,730 years.

A clast of granite taken from a conglomerate is determined by radiometric dating to be one hundred million years old.What,if anything,does this tell you about the age of the conglomerate?

The placement of events into a sequential order based upon their position in the rock record is referred to as ____________________ dating.

What is relative dating,and what can it tell us?

What is the principle of lateral continuity?

Prior to the discovery of radioactivity in the late ____________________ century,geologists were able to develop a(n)____________________ geologic time scale.

Whose work was the basis for the principle of uniformitarianism and the unavoidable necessity of a great age for Earth?