Exam 23: Geologic Timereading the Rock Record

The Cenozoic era represents a period of

Why is it believed that large parts of the United States were once covered by shallow seas?

The first time period for which abundant fossils have been found is the

At the end of the Paleozoic era, all

Conditions for the preservation of fossils are best achieved

When comparing geologic time to a calendar year, the time of the dinosaurs is in the

The "Cambrian explosion" refers to the

Similar reptiles were present on all continents during the Mesozoic era, but mammals of the Cenozoic era are often different on the different continents. Explain.

The Carboniferous period is well noted for the

Ancient coal beds can be found in Antarctica because

Granitic pebbles with a radiometric age of 300 million years are embedded in a sedimentary rock. A dike, dated at 200 million years, intrudes into the sedimentary rock. With all this information we can estimate the age of the sedimentary rock to be

Large deposits of gypsum and other evaporite minerals are evidence of

What are the limitations in obtaining radiometric dates?

The breakup of Pangaea resulted in

What was the one most important event in the Precambrian?

The isotope most useful for dating rocks from the late Pleistocene is

Most coal deposits were formed in the

The most important highlight of Precambrian Time was the

Paleozoic sedimentary rocks derived from marine deposits are widely distributed in all of the continents. What does this indicate about the height of the continents relative to sea level during the Paleozoic?

All continental landmasses joined together as Pangaea resulted in