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Relative Age
The age of an object in relation to the ages of other objects. -
Uniformation
A principle that geological processes that occurred in the past can be explained by current geological proccesses. -
Law Superstition
The principle that a sedimentary rock layer is older than the layers above it and younger than the layers below it if the layers are not disturbed. -
Unconformity
A break in the geological record created when sediment is not deposited for a long time. -
Law of Crosscutting Relationships
The principle that a fault or body of rock is younger than any other body of rock that it cuts through. -
Absolute Age
The numeric age of an object or event, often stated in years before the present, as established by an absolute dating process, such as radiometric dating. -
Varves
A pair of sedimentary layers that is deposited in an annual cycle, commonly in glacial lakes, and that can be used to determine the absolute age. -
Radiometric Dating
A method of determining the absolute age of an object by comparing the relative percentage of radioactive parent and stable daughter isotope. -
Half-Life
The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope.