The idea that geologic phenomena are brought about by sudden dramatic changes rather than ongoing and long-term processes, as inuniformitarianism. Although it was once used to promote the idea of a very young Earth, catastrophism today is accepted, in a very modified form, by many earth scientists.
The study of Earth's age and the dating of specific formations in terms of geologic time.
The study of the solid earth, in particular, its rocks, minerals, fossils, and land formations.
Folklore inspired by geologic phenomena.
The study of Earth's physical history. Historical geology is one of two principal branches of geology, the other being physical geology.
Involving a comparison between qualities that are not definedprecisely, such as "fast" and "slow" or "warm" and "cold."
Involving a comparison between precise quantities—for instance, 10 lb. versus 100 lb. or 50 mi. per hour versus 120 mi. per hour.
A set of principles and procedures for systematic study that includes observation; the formation of hypotheses, theories, and laws; and continual testing and reexamination.
Material deposited at or near Earth's surface from a number of sources, most notably preexisting rock.
The study of rock layers, or strata, beneath Earth's surface.
An apparent gap in the geologic record, as revealed by observing rock layers, or strata.
The idea that the geologic processes at work today provide a key to understanding the geologicpast. The speed and intensity of those processes, however, may not always be the same at any juncture in geologic history. Uniformitarianism usually is contrasted with catastrophism.
The breakdown of rocks and minerals at or near the surface of Earth due to physical or chemical processes or both.
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