Saturday, June 10, 2017

Pondering the Precambrian #4



From Brazil, Ediacaran vase shaped fossils have been found.  is this the earliest known protist fossils yet?

How did the Ediacaran critter Dickinsonia grow?

A mixed Cloudinia-Corumbella-Namacalathus assemblage shows increasing ecological complexity over the course of the Ediacaran.


Did a freshwater layer exist on the world's oceans and persist after the Snowball Earth episodes like the one in the Cryogenian?

As the Snowball Earth ended, how much oxygen weathering took place and what were the biotic impacts?


There was a huge Andes-like mountain range on the northwest of Rodinia that may have lasted for 100 million years during the Tonian 800 million years ago.


Wind patterns have been inferred from dunes from Calymmian Brazil.

The diversity of Eukaryote microfossils of Calymmian China is impressive.


In Statherian China, there is evidence of a sillicified microbiota from the Dahongyu Formation.

The Sudbury Impact appears to have caused long lived volcanic eruptions during the Orosirian PaleoProterozoic.  Since it was one of 150 impacts within a relatively short period, combined with this above volcanism, it should be no surprise life didn't recover to take a second stab at complexity for a billion years.

The Sudbury Basin continued to have geothermal heat during the Huronian snowball earth.

Can the Rhyacian/Siderian Glaciations (huronian snowball earth) be dated based on subglacial hydrothermal activity?

Beginning in the Siderian, ancient carbon was subsumed into the Earth's mantle.

Did anaerobic oxygenic photosynthesis (read the paper) come about in cyanobacteria prior to modern aerobic photosynthesis?

During the Siderian, Earth had a hazy, methane filled atmosphere.

Did eukaryotes arise during the Siderian?


Lenticular organisms from South Africa are related to the Pilbara forms.

Did life arise during the EoArchean WITHOUT using phosphate?

Fossils were found from the Eoarchean 3.77 billion years ago in Quebec, Canada.

How did the crust form?


The Earth probably began with a solid shell for a crust, like Mars.


New branches have been found in Archaea.

Iron eating, methanogen organisms probably kept the Earth warm for its first 2 billion years.

Mineral self assembly was common in the early years of the Earth.

No comments: