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 order of units of geologic time from longest to shortest is: eon, era, period, epoch.
The longest subdivision in geologic time is the eon, which is further divided into eras. Eons represent the largest interval of time in the geologic time scale, such as the Phanerozoic eon which encompasses the last 541 million years.
eon>era>period
The longest segments of geologic time are eons, which are divided into eras, which are further divided into periods, epochs, and ages. The current eon, the Phanerozoic Eon, has been ongoing for approximately the last 542 million years.
The Phanerozoic Eon is the longest division of geological time, spanning approximately the last 541 million years and continuing to the present day. It is further divided into three eras: the Paleozoic, Mesozoic, and Cenozoic eras.
The longest in geological time is an Eon eg. Archeozoic Eon . Edit: there is also the supereon, which is usually composed of 2-3 eons.
About 50 to 100 million years.
The order of units of geologic time from longest to shortest is: eon, era, period, epoch.
The longest subdivision in geologic time is the eon, which is further divided into eras. Eons represent the largest interval of time in the geologic time scale, such as the Phanerozoic eon which encompasses the last 541 million years.
eon>era>period
The longest segments of geologic time are eons, which are divided into eras, which are further divided into periods, epochs, and ages. The current eon, the Phanerozoic Eon, has been ongoing for approximately the last 542 million years.
The Phanerozoic Eon is the longest division of geological time, spanning approximately the last 541 million years and continuing to the present day. It is further divided into three eras: the Paleozoic, Mesozoic, and Cenozoic eras.
The oldest division of geologic time is the Precambrian, specifically the Archaean Eon from which the oldest rocks and fossils date. (The Hadean Eon preceded the Archaean, but no geologic records date from this time because the Earth was cooling from a molten state.)
The geologic time intervals from longest to shortest are eon, era, period, epoch, and age. This hierarchical sequence represents the largest divisions (eons) to the smallest subdivisions (ages) of Earth's history.
Eon is the broadest division on the geologic time scale, representing the longest time span. Eons are further divided into eras, which are then subdivided into periods, epochs, and ages.
Supereon is the longest classification of time in geology. The Precambrian period is a supereon comprised of the Hadean, Archean, and Proterazoic eons.
An eon is the longest geologic time period, typically lasting billions of years. It is subdivided into eras, which are further divided into periods, epochs, and ages.