Monday, January 25, 2016

Pondering the Precambrian #1

A study used diamonds to suggest the start of plate tectonics was approximately 3.5 billion years ago during the PaleoArchean.

Carbon deposited in the PaleoArchean Australia appears to be biological in origin.

Another study claims plate tectonics started 3 billion years ago during the MesoArchean through the examination of granites and magnesium.

The Helen Iron Formation in Canada was formed during the NeoArchean, 2.75 billion years ago, in moderately deep water when underwater volcanism ceased for a time.

There is evidence of NeoArchean plate tectonics in India

Oxygen levels during the PaleoProterozoic Great Oxygenation Event may have been higher than the following Proterozoic steady state.

Evidence of freshwater stromatolites have been found from the Stenian of Michigan in the Copper Harbor Conglomerate.

There is paleoclimatic evidence also from the Stenian of Michigan.  The paleosols appear to indicate it was a floodplain.

Evidence from China gives insight into marine plate subduction during the Tonian.

Evidence from the Doushantuo Formation in China suggest the Ediacaran there had a carbon anomaly and the phosphated embryos found predate the Gaskiers Glaciation.

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