Geological Stage

Stage, Geological


a subdivision of the general stratigraphic scale, subordinate to a geological series. A stage is subdivided into stratigraphic zones. It includes the stratum of rocks that formed in one geological age and corresponds to a definite phase in the geological development of the earth. The chief criterion for the establishment of the size and boundaries of a stage is the findings of biostratigraphic analysis. Most stages identified on the basis of open marine basins correspond to terrestrial subdivisions.

References in periodicals archive ?
We have sedimentary basins in the different geological stages.
Extinction rates vary widely between geological stages, he notes.
If he is right, Mars evolved in several distinct geological stages.
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