#neoarchean

[goodrichthyseskdalensis]

Here's a little sketch thingy I did of the paleoenvironment of the Archean (specifically Neoarchean) Rietgat Formation, which is part of the Ventersdorp Supergroup of South Africa. The sediments of the Rietgat Formation are believed to represent an ancient lake which preserves stromatolites as well as fragments of microbial mats. Over time, the lake level fluctuated, resulting in periodically desiccated mudflats (evidenced by preserved mud cracks found in certain parts of the formation) as it lowered and stromatolites as it rose. The lack of evidence for the influence of currents or waves on the formation of the stromatolites suggests they may have formed below wave base, the point at which the influence of waves ends. It has also been suggested that this lake may have represented an oxygen oasis

The drawings are pretty messy but I think they're ok considering they took probably somewhere between 10 and 30 minutes.

References/Further reading:

Neoarchean (2.7 Ga) lacustrine stromatolite deposits in the Hartbeesfontein Basin, Ventersdorp Supergroup, South Africa: Implications for oxygen oases

Evidence for benthic oxygen production in Neoarchean lacustrine stromatolites

[katborg82]

The Neoarchean era began 2.8 billion years ago and lasted until 2.5 billion years ago. The cyanobacteria empire continued to evolve and diversify, even adapting to life on land. It is thought at this time that the land would actually start to turn green, not from plants yet, but rather the massive microbial ecosystems pumping oxygen into the atmosphere. During this era we would also see the planet's first supercontinent, named Kenorland

[goodrichthyseskdalensis]

Here's a little pixel art gif I made of Thuchomyces lichenoides, a bizarre fossil organism known from roughly 2.8 billion year old (around the Meso/Neoarchean boundary) rocks in Witwatersrand, South Africa. They have been suggested to be fungi, but they are older than most commonly accepted dates for the origin of fungi, and are about 400 million years older than the next oldest suggested fungi.

The environment they were found in apparently has evidence of being a sand-blasted desert with occasional streams, which is what I have shown here. I've also included mountains because I'm think there were some mountains near Witwatersrand around this time.

[eternallycoilingserpent-blog]

The Ocean - "Neoarchean"