Eoarchean

In the geologic record the Eoarchean (/ˌiːoʊ.ɑːrˈkiːən/; also spelled Eoarchaean) Era or erathem is the earliest time following the solidification of Earth's crust. It follows the Hadean Eon and precedes the Paleoarchean Era of the geologic timescale. The approximate abiotic origins of life have been dated to a time window from 4,000 to 3,600 million years ago when atmospheric pressure values ranged from 10 to 100 bar (10 to 100 atmospheres).

Chronology

It was formerly officially unnamed and usually referred to as the first part of the Early Archean (now an obsolete name) together with the later Paleoarchean Era.

The International Commission on Stratigraphy now officially recognizes the Eoarchean Era as the first part of the Archaean Eon, preceded by the Hadean Eon, during which the Earth is believed to have been essentially molten.

The International Commission on Stratigraphy currently does not recognize the lower boundary of the era which has been provisionally placed at 4,000 million years ago nor that of the preceding Hadean Eon.