Saturday, December 23, 2017

Pondering the Precambrian #7



The Tarim Craton may have been connected to the North India Block rather than Australia within the supercontinent of Rodinia during the Tonian.

Has evidence of mountain building during the Tonian been found in Scotland?

The Tonian/Cryogenian transition seems to have been located in Svalbard.

How complete is the evidence of glaciations during the Cryogenian in Scotland?

How oxygenated was the ocean between the Snowball Earth episodes?

Caution with carbon-13 shifts are urged in Cryogenian deposits as they are deposit dependent.

Evidence of hydrothermal modification of a dolostone during the Marinoan Glaciations.

Was there a delayed oxygenation of the oceans from the Cryogenian to the Ediacaran?

Evidence from Mongolia's 540 million year old Khesen formation documents the rise of animals.

Evidence that Ediacaran Parvancorina was motile and could sense benthic currents.

Were there constant anoxic bottom waters during the Ediacaran?

Cyanobacterial-algal crusts have been found from Ediacaran paleosols.


Cyanobacterial microfossils are examined from Calymmian China.

Were tellurium and selenium weathered from sandstones into the Mesoproterozoic oceans?


Biosignatures have been found for eukaryotes from Statherian China.

There is evidence of an impact in India during the Siderian.

Was there a subduction cessation during the Siderian in China?

More evidence of warm subduction during the Orosirian from Cameroon.

Was the Great Oxygenation Event really an abiotic process?!

There appears to have been gradual oxygenation in the oceans (in some cases) just prior to the GOE.

A large igneous province is detected from India from the Rhyacian.

Was the early biosphere nutrient limited?


Evidence from China, specifically the North China Craton, about the composition of NeoArchean sea water.

Inland lakes appear to have fostered the diversification of microbial life during the MesoArchean.

The oldest known paleosols (fossil soil) date from the PaleoArchean (3.46 billion years ago) and originate in Australia and may have formed from sulfuric acid weathering.

Could there be a problem with the cherts being used from the PaleoArchean to claim microbial life?

Or is there a definitive example of fossil life from the PaleoArchean?  Does that mean life is common in the universe?

Is some of Earth's magma ocean preserved in PaleoArchean rock?


Exploring the Precambrian lithosphere of Zambia and Malawi.

The effect of paleoseawater chemistry on hydrothermal ridges.

Origin of Life:

The origin and diversification of the endosymbiont known as the mitochondria.

A new lineage of eukaryotes has given information on mitochondrial genome reduction.

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