In the geologic record the Eoarchean erathem (pronEng|ˌiːoʊɑrˈkiːən, also spelled Eoarchaean) and the Eoarchean era in the geologic timescale correspond to one another in the dual system of classification of rock strata laid down beginning 4000 Ma to 3600 Ma (million years ago).

It was formerly officially unnamed and usually referred to as the first part of the Early Archean (now an obsolescent name) together with the later Paleoarchean era. It is the first part of the Archaean Eon, preceded by the "informal" Hadean eon, during which the Earth was considered to be essentially molten.

The International Commission on Stratigraphy currently does not recognize the lower boundary of the era which they've provisionally placed at 4000 MA [ [http://www.stratigraphy.org/cheu.pdf Recent ICS provisional chart] ] nor that of the preceding Hadean Eon.

The Eoarchean was followed by the Paleoarchean era.

The name comes from two Greek words: "eos" (dawn) and "archios" (ancient). The first supercontinent Vaalbara appeared around the end of this period around 3600 ma.

Prokaryote forms may have evolved from protobionts late in this era.

Also the oldest rock formation on earth the Isua greenstone belt also appeared during the Eoarchean around 3.8 Billion years ago.

ee also

Notes, links and references

External links

* [http://database.stratigraphy.net/zone_info.php?zone_id=109&zone_type_id=1&zone_theme_id=100&PHPSESSID=b96bd4624e49ce9804f5bbb370a1e4f1 A short fact sheet]



Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Eoarchean — 1. adjective of a geologic era within the Archaean eon from about 4600 to 3600 million years ago; the first single celled life began at this time 2. noun the Eoarchean era …   Wiktionary

  • Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… …   Wikipedia

  • Graphical timeline of our universe — This more than twenty billion years timeline of our universe shows the best scientific estimates of the occurrence of events since its beginning, up until anticipated events in the near future. Zero of the scale is the present day. A large step… …   Wikipedia

  • Mesoarchean — The Mesoarchean (  /ˌmiːz …   Wikipedia

  • Neoarchean — The Neoarchean (  /ˌniː …   Wikipedia

  • Evolutionary history of life — Although evidence of early life is scarce and often difficult to interpret, it appears that life appeared on Earth relatively soon (on the geologic time scale) after the planet had cooled enough for liquid water to be present. The dominant theory …   Wikipedia

  • Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… …   Universalium

  • Geology of the North Sea — Contents 1 Tectonic structure 2 Precambrian 3 Finnmarkian, Athollian, Caledonian Orogenies …   Wikipedia

  • Cambrian — For other uses, see Cambrian (disambiguation). Cambrian Period 542–488.3 million years ago …   Wikipedia

  • Carboniferous — For the album by Zu see Carboniferous (album). Carboniferous Period 359.2–299 million years ago …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.