Pondering the Precambrian #40

Proterozoic:

NeoProterozoic:

Palaeopascichnus jiumenensis can be used to determine the Ediacaran/Cambrian boundary.

There's a new way to determine oxygen levels during paleo time periods.  It seems to check out in the Neoproterozoic-Cambrian transition based on comparison to other methods.

A bilateralan metazoan (animal) fossil and trackway was found in China dating from the Ediacaran.

The rise of siliceous sponges helped shift the Ediacaran ecosystems to the modern Cambrian. 

The differences between the Weng'an and Kuanchuanpu biotas is largely due to how they were preserved.

Acritarchs from the Ediacaran Doushantuo Formation allow for biostratigraphic correlation with the Tanarium conoideum–Cavaspina basiconica Assemblage Zone.

There appears to have been long term denudation of the continents from the middle Ediarcaran based on Nd isotope traces in carbonates.

A new formation has been found dating from the Cryogenian with evidence of bacterial and algae life in South China.

How much hydrothermal activity was there during the Marinoan Glaciation (snowball earth episode) during the Cryogenian?

There is evidence of a large igneous province in the Tonian.

MesoProterozoic:

Horodyski moniliformis, regarded by some as a eukaryote fossil from the Calymmian, has been declared a pseudofossil.

PaleoProterozoic:

Plate tectonics have evolved over the last 2.5 billion years.

Is there evidence for the oxygen overshoot hypothesis from the Orosirian?

There was a paleocontinent named 'Atlantica' proposed.  Recent research suggests it was configured rather differently than proposed.

Evidence has arisen supporting a snowball earth scenario during the Huronian glaciation.

An asteroid impact has been IDed from the Rhyacian in Australia.

Did the supercontinental cycle begin in the PaleoProterozoic?

Archean:

There is evidence of a PaleoArchean continent.

Origin of Life:

Prebiotic amino acids can bind to lipid membranes and stabilize them.

When did eukaryotes originate?  Do we have a way to understand that?

Did the lack of nitrogenase limit early life?