Exam 11: Geologic Time

Oysters are an invertebrate the lives today in brackish waters along coastal zones. When a geologist working in stratified rocks observes a limestone bed with oyster fossils overlain by beds with clam and echinoderm fossils indicative of marine conditions, the safest conclusion to gather from the fossils is that ______.

The principle of horizontality which states that sediments are usually deposited in relatively flat layers is important because______ .

The geologic time scale was devised based on ______.

Which of the following organisms would be most likely to be preserved in the geologic record?

One of the primary goals of geology is to ______.

Visualize five horizontal undeformed sedimentary strata exposed in a cliff or canyon wall identified by consecutive numbers, with 1 representing the lowest of the five beds and 5 representing the highest of the 5 beds. Which of the following statements concerning the strata is true?

What fundamental concept states that in a horizontal sequence of conformable sedimentary strata, each higher bed is younger than the bed below it?

Different periods of the geologic time scale are different in length. Why?

What process involves identifying and matching rocks of similar ages in different areas?

A geologist observes abundant fossils of a distinctive trilobite species in a shale, but this trilobite disappears as she walks through the shale. In younger rocks, just above the horizon where the fossil disappears another species of trilobite becomes the prominent fossil in similar shales. Which conclusion is most logical for this observation?

As it relates to the names of the eras in the geologic time scale, what is meant by "zoic"?

Examine the words and/or phrases below and determine the relationship among the majority of words/phrases. Choose the option that does not fit the pattern.

After three half- lives,______ of an original radioactive parent isotope remains.

The ratio of parent to daughter isotopes in a radioactive decay process is 0.40. How many half- lives have elapsed since the material was 100% parent atoms?

What is the age of Earth accepted by most scientists today?

All of geologic time prior to the beginning of the Paleozoic era is termed the______ eon.

Compare and contrast relative age dating with radiometric age dating. What is a limitation if any. of each?

An unconformity in which the strata on either side are essentially parallel is termed an______.

Which of the following is not a fossil?

In the mid- 1600s, James Ussher determined that Earth was created in 4004 BC based on______ .