Saturday, June 30, 2018

Pondering the Precambrian #9


There is evidence from the Proterozoic that Earth's day was 18 hours long.



The evolution of biological productivity and primary producers across the Ediacaran/Cambrian boundary

The Hüttenberg Anomaly appears to have been evidence of the Ediacaran oxygenation event.

Oxygenation variations in the atmosphere and shallow waters in the Yangzte platform.

Did anoxia kill off the Ediacaran benthic communities?

The Doushantuo fossils from China get examined closer.

Bilateral animal trackways and metazoan burrows have been discovered in the Ediacaran Dengying formation.

Two new disc critters from the Ediacaran have been found.  One was named for Sir David Attenborough.  The other for Barrack Obama.

Why did rangeomorphs grew so large during the Ediacaran?

What caused the mass extinction of the Ediacaran Biota?


Argonite fans were present in the bottom sediments during the Marinoan Glaciation.


India and Suixian sedimentary group were connected and either were on the margin of the supercontinent of Rodinia or were on a separate plate.


Evidence of an island arc from the Calymmian has been found.


Australia was not connected to Laurentia from 1.8 gya to 1.65 gya during the Nuna/Columbia supercontinet.

During a continent breakup, there appears to have been enhanced terrestrial input into Chinese carbonates.

There is evidence of oceanic crust subduction from China.

During the Siderian, continental microbes and their 'crusts' on rocks might have helped seed the oceans with nitrogen.



Continents rising above the ocean changed the climate and environment, permanently, on earth.  

Did the dawn of plate tectonics trigger a NeoArchean Snowball Earth episode?

The interplay between crustal arcs and mantle plumes was important in the Archean.

There is no support of wide spread increases in oxygen in shallow waters from South Africa leading up to the Great Oxygenation Event.


There might be evidence of two separate turns of the Wilson Cycles in Chinese deposits during the Archean.

Yet, it seems crustal production was periodic prior to 2.7 gya.


Evidence of microbial mats was found from the PaleoArchean.


The Earth might have been able to form a high silica crust during the Hadean, less than 350 million years after its formation.

Origin of Life:

How primordial life might have replicated itself.

Experimental Paleontology:

Fish eggs were used to test how precambrian embryos might have been silicified.  

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