vocabulary

Question 1

uniformitarianism

Answer 1

a principle that states that geologic processes that occurred in the past can be explained by current geologic processes

Question 2

relative dating

Answer 2

any method of determining whether an event or object or older id older or younger than other events or objects

Question 3

superposition

Answer 3

a principle that states that younger rocks lie above older rocks if the layers have not been disturbed

Question 4

absolute dating

Answer 4

any method of measuring the age of an events or object in years

Question 5

isotope

Answer 5

an atom that has the same number of protons (or the same atomic numbers) as other of atoms of the same element do but that has a different numbers of neutrons (and thus a different atomic mass)

Question 6

half-life

Answer 6

the time needed for half of a sample of radioactive substance to undergo radioactive decay

Question 7

unconformity

Answer 7

a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time

Question 8

Mass extinction

Answer 8

A mass extinction is usually defined as a loss of about three quarters of all species in existence across the entire Earth over a “short” geological period of time. Given the vast amount of time since life first evolved on the planet, “short” is defined as anything less than 2.8 million years.

Question 9

jurrasic period

Answer 9

The Jurassic is a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago (Mya) to the beginning of …

Question 10

cretaceous period

Answer 10

Cretaceous Period, in geologic time, the last of the three periods of the Mesozoic Era. The Cretaceous began 145.0 million years ago and ended 66 million years ago; it followed the Jurassic Period and was succeeded by the Paleogene Period (the first of the two periods into which the Tertiary Period was divided).