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The Precambrian is divided into three eons: the Hadean (4567–4031 Ma), Archean (4031-2500 Ma) and Proterozoic (2500-538.8 Ma). See Timetable of the Precambrian. Proterozoic: this eon refers to the time from the lower Cambrian boundary, 538.8 Ma, back through 2500 Ma. As originally used, it was a synonym for "Precambrian" and hence included ...
An eon is the largest geochronologic time unit and is equivalent to a ... the time before the Cambrian is often referred to as the Precambrian or pre ...
The Precambrian includes approximately 90% of geologic time. It extends from 4.6 billion years ago to the beginning of the Cambrian Period (about 539 Ma).It includes the first three of the four eons of Earth's prehistory (the Hadean, Archean and Proterozoic) and precedes the Phanerozoic eon.
c. 4,533 Ma – Hadean Eon, Precambrian Supereon and unofficial Cryptic era start as the Earth–Moon system forms, possibly as a result of a glancing collision between proto-Earth and the hypothetical protoplanet Theia (the Earth was considerably smaller than now, before this impact). This impact vaporized a large amount of the crust, and sent ...
It is the eon during which abundant animal and plant life has proliferated, ... the first period of this eon, due to the lack of Precambrian fossil record back then.
The Precambrian dates from the beginning of Earth's formation (4.6 billion years ago) to the beginning of the Cambrian Period, 539 million years ago. [1] [2] The Precambrian consists of the Hadean, Archaean and Proterozoic eons. [1]
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth itself.
The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, the most recent period is expanded in the fourth timeline, and the most ...