Exam 8: Geologic Time

Since the Moenkopi Formation was deposited at the end of the Permian period and the very beginning of the Triassic, and the Navajo Sandstone was deposited at the end of the Triassic and into the Jurassic, what is the age of the Chinle Formation?

The principle of ________ is the concept that ancient life forms evolved in a definite order and therefore their fossils can help determine the geologic ages of strata.

The earliest 88 percent of geologic time is represented by the time span informally called the ________.

If numerical dating of rock unit A gave a crystallization age of 1.2 billion years, and numerical dating of rock unit F gave a crystallization age of 500 million years, then how old is rock unit E?

The Phanerozoic, Proterozoic, and Archean are all eons.

A worm would stand a poor chance of being fossilized because ________.

The process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas is ________.

Who first formulated the principle of uniformitarianism?

All of geologic time prior to the beginning of the Paleozoic era is commonly referred to as the ________.

Catastrophism and uniformitarianism differed in which way?

Which of the following is an essential characteristic of an index fossil?

After three half-lives, ________ of an original, radioactive, parent isotope remains and the rest has decayed into the daughter isotope.

We now live in the ________ era.

According to the figure, the age of the Dakota Sandstone must be less than 160 million years, and greater than 66 million years old.

Use the geological cross-section to determine the age of rock layer D as precisely as possible.

Why do the eras of the Pharnerozoic eon all end with "zoic"?

"John is older than Susan" is an example of a relative date.

The amount of time it takes for half of the remaining radioactive isotopes to decay is the ________ of a isotope system.

The four basic units that make up the geologic time scale are the eon, the aria, the episode, and the period.

Assuming that this is an undisturbed sedimentary sequence (that is, superposition is valid), and that unit G is Cambrian in age, unit F could be Ordovician.