records

Question 1

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

Answer 1

uniformitarianism

Question 2

a principle that states that geologic change occurs suddenly

Answer 2

catastrophism

Question 3

the scientific study of fossils

Answer 3

paleontology

Question 4

a method of determining whether an event or object, such as a fossil, is older or younger than other events or objects without referring to the object’s age in years

Answer 4

relative dating

Question 5

any method that measures the age of an object or event in years rather than measuring the age relative to another object or event; one such method is radiometric dating

Answer 5

absolute dating

Question 6

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

Answer 6

superposition

Question 7

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

Answer 7

isotope

Question 8

the disintegration of an unstable atomic nucleus into one or more different nuclides, accompanied by the emission of radiation, the nuclear capture or ejection of electrons, or fission

Answer 8

radioactive decay

Question 9

the time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope

Answer 9

half-life

Question 10

the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock

Answer 10

fossil

Question 11

a fossilized mark that formed in sedimentary rock by the movement of an animal on or within soft sediment

Answer 11

trace fossil

Question 12

in geology, a mark or cavity made in a sedimentary surface by a shell or other body

Answer 12

mold

Question 13

a type of fossil that forms when sediments fill in the cavity left by a decomposed organism

Answer 13

cast

Question 14

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

Answer 14

unconformity

Question 15

an episode during which large numbers of species become extinct

Answer 15

mass extinction

Question 16

a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period

Answer 16

Jurassic period

Question 17

s a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 mya. It is the last period

Answer 17

Cretaceous period

Question 18

is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago, to the beginning of the Carboniferous

Answer 18

Devonian period

Question 19

is the name for the time in which we live

Answer 19

Quaternary period

Question 20

is a geologic period and system which spans 46.7 million years from the end of the Carboniferous Period 298.9 million years age

Answer 20

Permian period