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Geologic Timescale (table)

(Encyclopedia)Geologic Timescale 1 Not an era but the time preceding the Cambrian. ...

geologic timescale

(Encyclopedia)CE5 geologic timescale, a chronological scale of earth's history used to measure the relative or absolute age of any part of geologic time. Of the numerous timescales, the most common is based on g...

epoch

(Encyclopedia)epoch, unit of geologic time that is a subdivision of a period. The Pleistocene and Holocene epochs, for example, are divisions of the Quaternary period. Epoch is also used to describe a short length ...

period, in geologic time

(Encyclopedia)period, unit of time on the geologic timescale. Periods are shorter than an era and longer than an epoch. Periods are of variable length, generally lasting tens of millions of years, with characterist...

Quaternary period

(Encyclopedia)Quaternary period kwətûrˈnərē [key], younger of the two geologic periods of the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table) from 2 millon years ago to t...

Mesozoic era

(Encyclopedia)Mesozoic era mĕzˌəzōˈĭk [key] [Gr.,=middle life], major division of geologic time (see Geologic Timescale, tablegeologic timescale, table) from 65 to 225 million years ago. Great crustal disturb...

Holocene epoch

(Encyclopedia)Holocene epoch hŏlˈəsēn [key] or Recent epoch, most recent of all subdivisions of geologic time, ranging from the present back to the time (c.11,000 years ago) of almost complete withdrawal of the...

Cambrian period

(Encyclopedia)Cambrian period [Lat. Cambria=Wales], first period of the Paleozoic geologic era (see Geologic Timescale, tablegeologic timescale, table) extending from approximately 570 to 505 million years ago. It ...

Devonian period

(Encyclopedia)Devonian period dĭvōˈnēən [key], fourth period of the Paleozoic era of geologic time between 408 and 360 million years ago (see Geologic Timescale, tablegeologic timescale, table). It was named (...

Pliocene epoch

(Encyclopedia)Pliocene epoch plīˈəsēn [key], fifth epoch of the Cenozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), from 5.1 to 2 million years ago. By the beginning of the P...