Saturday, August 03, 2019

Pondering the Precambrian #39

Proterozoic:

NeoProterozoic:

Global microfossil changes across the Ediacaran/Cambrian are characterized.

A new method of characterizing oxygen availability across the Ediacaran/Cambrian boundary has been found.

The lack of attention to taphonomy can mislead about the late Ediacaran fossils.

Data from Argentina covers the Ediacaran's oxygenation event.

Simulations of Ernettia suggest it was a filter feeder and fed better in groups.

Has there been a case of lateral gene transfer detected in bilaterians?

Ancient paralogies suggest jellyfish are a sister group to all other metazoans.

Green algae transitioned to macroscopic growth multiple times, but only as recently as the NeoProterozoic.

There is evidence of strange magmatism in the Sahara from the Ediacaran 580 million years ago.

An astronomical time scale for the middle/upper Doushantuo Formation has been established.

Braided rivers were not the rule prior to the evolution of plant life despite previous thought.

The Paleo Hunan Ocean was completely closed by 830 million years ago during the Tonian.

Evidence of two carbon excursions are detected in Tonian deposits in Namibia.

MesoProterozoic:

A new model suggests a sluggish, tepid mesoproterozoic ecosystem.

A very large igneous magmatic province has been found in South Africa from Stenian of South Africa.  These provinces are associated with mass extinctions like the Permian and Triassic/Jurassic.

An impact has been found in Scotland dating from the Mesoproterozoic.

Was anaerobic photosynthesis the reason for the delayed rise in oxygen in Earth's atmosphere?

PaleoProterozoic:

Iron stones were laid down by iron oxidizing bacteria during the Statherian.

There is evidence of deep subduction from North China from the Paleoproterozoic.

There is also evidence of a significant back arc continental collision during the Orosirian in the North China Craton.

There is evidence, according to Retallack, of macroscopic terrestrial life from the Orosirian.

The shape of the Dhala Crater in India from the Rhyacian is reconstructed.

Paleoproterozoic dolomites shed some light on the evolution of marine chemistry.

Archean:

The early Earth's oceans may not have been as hot as originally thought.

Compared to later granites, Archean granites had relatively unstable compositions.

Archean sulfur isotopes from Australia's Fraser Zone have unexplained ratios and amounts.

Did the subduction of the oceanic basins take place during the mesoarchean?

Could continents have existed from the dawn of the Archean, during the Eoarchean?

Eoarchean hydrothermal vent boron deposits give some insight to the origin of life.

Origin of Life:

Peptides can form without amino acids.

Could microscopic bubbles (interfaces) have helped kickstart life?

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