Mesoarchean
Encyclopedia
The Mesoarchean is a geologic
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 era within the Archean
Archean
The Archean , also spelled Archeozoic or Archæozoic) is a geologic eon before the Paleoproterozoic Era of the Proterozoic Eon, before 2.5 Ga ago. Instead of being based on stratigraphy, this date is defined chronometrically...

, spanning 3200 Ma to 2800 Ma (million years ago). The period is defined chronometrically and is not referenced to a specific level in a rock section on Earth. Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s from Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 show that stromatolite
Stromatolite
Stromatolites or stromatoliths are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria ....

s have lived on Earth since the Mesoarchean. The Pongola glaciation occcured at 2.9 Ga. The first supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...

 Vaalbara
Vaalbara
Vaalbara is theorized to be Earth's first supercontinent, beginning its formation about , completing its formation by about and breaking up by . The name Vaalbara is derived from the South African Kaapvaal craton and the West Australian Pilbara craton...

broke up during this time around 2.8 Ga.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK