fossil record Flashcards
uniformitarianism
the theory that changes in the earth’s crust
catastrophism
a principle that states that geologic change occurs suddenly
paleontology
the scientific study of fossils
relative dating
any method of determining when an event or object is older or younger than other events or objects
absolute dating
any method of measuring the age of an event or object in years
superposition
a principle that states that younger Rock lie above older rocks if the layers have not been Disturbed
isotope
an atom that has the same number of protons as other atoms of the same element doing but that has a different number of neutrons
radioactive decay
the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element
half-life
the time it takes for one-half of a radioactive element to decay into a daughter isotope.
fossil
The Remains are physical evidence of an organism preserved by geological process
trace fossil
a fossilized mark that is formed in soft sediment by the movement of an animal
mold
a Mark or cavity made in a sedimentary Surface by a show or another body
cast
the type of fossil that forms from sediments fill in the cavity left by a decomposed organism
unconformity
a break in the geologic record created when Rock layers are eroded or when sediment is not deposited for a long period Of time
mass extinction
when lots of things go extinct at once
Jurassic period
geologic period and system that spanned 56 million years
Cretaceous period
The Cretaceous is defined as the period between 145.5 and 65.5 million years ago
Devonian period
The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years
Quaternary period
Quaternary is current and most recent of the three periods of the Cenozoic Era in the geologic time scale
Permian period
geologic period and system which spans 47 million years
