The earliest geological period is known as the Precambrian. This is a very long period of time which begins about four and a half billion years ago, with the formation of the Earth, ending at the beginning of the Cambrian Era which is about 541 million years ago. So the Precambrian is about four billion years long, longer than all other eras combined.
The Precambrian or, to be even more precise, the Archean Eon, which began about 4 billion years ago with the formation of the Earth's crust and extended to the start of the Proterozoic Eon (which is the second division of Precambrian time) 2.5 billion years ago, .
The longest "Period" was the Cretaceous period. It lasted about 80 million years.
The longest period in the Phanerozoic Eon is the Cretaceous, which lasted for 81 million years.
The Cryptic era, Precambrian.
holocene
The pangae was formed
An era, in geologic terms, is a geological time period encompassing two or more geologic periods.
It must have lived for a short geologic period of time.
Statistical analysis of the fossil records indicates that somewhere around 35% of all species disappeared at the end of the Cretaceous Era (there is considerable margin for error in that figure).
Precambrian time - The period in the geologic time scale from the formation of the Earth to the beginning of the Palezonoic era, from about 4.6 billion to 543 million years ago.
Gitchie Manitou State Park Sioux Quarzite
The oldest eon of geologic time is the Archaean Eon of the Precambrian period. The oldest rocks and fossils date from this time, about 3.8 to 2.5 billion years ago. (Prior to that, the Hadean Eon began with the formation of the Earth. No geologic record exists from the Hadean, during which the Earth cooled from its molten state.)
The oldest are located at the bottom of an undisturbed column.
They will normally be located at the bottom, unless otherwise upset through geologic activity.
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The oldest period is the Triassic period.
the Jurassic Period
Cenezoic
Period.
before the dinosuars
A period.
On the geologic time scale, an era is longer than a period. There are 12 geologic eras in total and they are composed of geologic periods. For instance, the Mesozoic era is composed of the Triassic, Jurassic and Cretaceous periods.