Exam 11: Geologic Time

In the late 1800's various principles original horizontality, inclusions, cross cutting relations, etc. arête. were established and used to______ .

Strata above an______were deposited after older strata were deformed.

The half- life of carbon- 14 is about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15,000 years ago. How much of the original carbon- 14 would remain today?

About 88 percent of geologic time is represented by the time span called the______ era.

Unconformities that represent a break in the geologic record of deposition are geologically significant______.

Which of the following best characterizes an angular unconformity?

The term______ refers to life forms intermediate in complexity between early and much later, more modern- looking life forms.

The term______ describes the era of ancient life forms.

The era known as the "age of mammals" is the______ era.

Faunal succession recognized in the sequence of fossils in stratified sedimentary rocks was a key concept that led to______ .

Which of the following geologic observations would not bear directly on working out the sequence of geologic events in an area?

An unconformity is a buried______ .

Radiometric data was ______modern geology replacing catastrophism.

The principle of superposition which states that in undeformed rocks, the younger rocks will be on top of older rocks, is particularly important because ______ .

The era of "ancient life" is the______ era.

The basic concept of Uniformitarianism is ______ .

You go for a hike across an outcropping of sandstone and you see large footprints in the sandstone. You have just found______ .

We now live in the______ era.

When a beta particle is emitted, the mass number of the isotope______.

You pick up a piece of sandstone. In the rock sample you see an impression of a sea shell in the rock. This type of fossil is a ______ .