Terms in this set (24)
The actual geologic age of a fossil, or geologic event
a comparative age
a theory that says all phenomena existing today have been present in the past
principle of superposition
rock layers on the bottom are older and decrease in a ge as you move up
sediments settling out from water are deposited horizontally on layers that lie parallel to the earth surface
igneous rock formed on the surface of the earth
when magma intrudes on preexisting rock layers
principle of crosscutting relationships
a geologic feature that cuts across rock layers must be younger than any rock it cuts across.
a buried erosional surface. It represents a gap in the rock history
a raise in the water level on land either from a sinking of the land or rising of the seas
like uplift. a lowering of the water level on land from a rising land
geologic time scale
the order of geologic time periods
a major division of geologic time composed of a number of periods
a unit of time, longer than an epoch and shorter than an era
the fossil of a creature that existed for a short time, ut lived over a wide era.
radioactive isotope of carbon used to determining the absolute age of organic materials
matching one layer of rock with another layer of rock with layer of rock in a distant location.
a mountain building event
the gradual change of species and development of new tones
the transformation of an unstable parent element into a more stable daughter product.
the amount of time that it takes for 50% of a radioactive parent element to decay into its daughter product.
a variety of an element with different numbers of neutrons
the extinction of a larger number of species in a short amount of time.
the release of juvenile gases and water to the surface from magma source.