Precambrian Period
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The Precambrian Period is a time period spans from the formation of Earth (about 4600 million years ago )to the beginning of the Cambrian Period.
- Context:
- It was preceded by the Earth Formation Period.
- It was succeeded by the Paleozoic era (which began with the Cambrian).
- It included the Organic Life Initiation Period.
- It included the Great Oxygenation Extinction Period.
- …
- Counter-Example(s):
- See: Phanerozoic, Eon (Geology), Geologic Time Scale, Earth, Geologic Period.
References
2014
- (Wikipedia, 2014) ⇒ http://en.wikipedia.org/wiki/precambrian Retrieved:2014-2-22.
- The Precambrian (or Pre-Cambrian) is the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale. It spans from the formation of Earth about 4600 million years ago (Ma) to the beginning of the Cambrian Period, about Ma, when macroscopic hard-shelled animals first appeared in abundance. The Precambrian is so named because it precedes the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the classical name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of geologic time.