Saturday, April 14, 2018

Pondering the Precambrian #8

Proterozoic:

NeoProterozoic:

Some paleosols found in the Baltic were formed during the NeoProterozoic during an extended weathering event.

What came first?  High levels oxygen in the atmosphere or animals?  Animals.

Evidence encrusting became an ability of Metazoans during the Ediacaran.

Were the Beltanelliformis fossils of the Ediacaran just cyanobacteria colonies?

There is evidence of carbon isotopic excursions from the Ediacaran Bilara Group in India.

The Ediacaran carbon isotopic excursions in South China are associated with phosphite upwellings.

There is evidence of the Ediacaran glaciations from Morocco.

Evidence of the transition from anoxic oceanic conditions during the Cryogenian to the oxic in the Ediacaran as well as the great meltwater from the Cryogenian snowball has been found.

Evidence of the mixing of glacial waters with the anoxic ocean has been found in California from during the Cryogenian.

There appears to have been an oxygen spike during the early Tonian.

There are banded iron formations in early NeoProterozoic Hainan, China.

Can Nanosims be useful in examining organic walled microfossils from the NeoProterozoic?

It appears something was burrowing in the late Ediacaran of Mongolia, much earlier than previously thought.


Exploring the effect of oxygen on the formation of haze in the NeoProterozoic atmosphere.

MesoProterozoic:

The Upper Vindhyans formation in India dates from the Late MesoProterozoic.

Evidence from China suggests the oceans of the Ectasian were anoxic to suboxic.

There is also evidence of Ectasian/Calymmian boundary oceans having banded iron formations.

Evidence from China also suggests active hydrothermal systems put a lot of iron into the shallow seas during the break up of the Columbia supercontinent.

Does photosynthesis in modern plants date to the Stenian?

PaleoProterozoic:

It appears the oceans of the Siderian become oxygenated 250 million years BEFORE the atmosphere did.

There is evidence a snowball earth scenario unfolded during the Siderian as well.

It looks like there is evidence of a tsunami or a storm from the PaleoProterozoic.

Organic remains in granular iron formations suggest they might be biological in origin.

Paleoproterozoic stromatolites from South Africa were formed in a restricted basin.

Evidence of the Great Oxygenation Event comes from rock salt from Russia.

Archean:

The Late Heavy Bombardment is being questioned.

By the end of the NeoArchean, the first modern continents had formed.

There may be volcanogenic pseudofossils in the PaleoArchean formation at Pilbara.

There's evidence of an oceanic plateau from the Archean in Nunavut, Canada.

University of Tuebingen in Germany and the Chinese Academy of Sciences in Beijing experimentally attempted to recreate the ocean of the Archean to explain its banded iron formations.

When did life originate?  At the dawn of the Archean?  Or later?

Hadean:

What the nitrogen cycle of a prebiotic Earth might have been like.

META:

Chromium isotopes can give false data for oxygen levels.

Chemists have found a plausible formula for the origin of life in Prebiotic earth.

Argnine might have played an important role in the origin of life.

A new origin of life hypothesis has been forwarded.

Did volcanic eruptions spew enough sulfur dioxide to kick off the origin of life?

Manganese oxides can produce pseudofossils.

Constraining the Early Earth's climate and oceanic acidity.

When was the earliest life could have originated?

Did ice in the earliest Earth's ocean help facilitate the origin of life?

Oceanic tides may greatly decrease when supercontinents form.

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