Geologic time scale
Geissman, John W. Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico.
Palmer, Allison R. Institute for Cambrian Studies, Boulder, Colorado.
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- Relative time scale
- Faunal succession
- Absolute time scale
- Links to Primary Literature
- Additional Readings
An ordered, internally consistent, internationally recognized sequence of time intervals, each distinct in its own history and record of life on Earth, including the assignment of absolute time in years to each geologic interval. The geologic time scale (see table) has two essential components: a relative scale, consisting of named intervals of geologic history arranged in chronologic sequence from oldest (bottom) to youngest (top); and a numerical (or absolute) time scale, providing estimates of absolute ages for the boundaries of these intervals.
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