PAART | PROTEROZOIC EON | NEOPROTEROZOIC ERA

NEOPROTEROZOIC ERA

PALEOPYRGIAN PERIOD

By the end of the Ectasian at 3690Myo, Paart had its first eukaryotes, a couple hundred species of rhizopods, diatoms, cilliates, and by the start of the Paleopyrgian, true algae.

By this time, land was dominated by a couple dozen species of fungi and bacteria that fed on the biologic material thrown upon land by storms and waves, those locations would often bear small towers of few centimeters tall, built with leftover material and minerals on the soil and decaying matter. Hence the name, "Ancient Towers".

Ice sheets covering the southern continental shelf would often break up and shed icebergs into the sea

The tightening of the gap between continents slowly decreased the amount of space available for stromatolite formation, though algae were still doing well - isolated ponds, insular regions and lakes that formed trapping algae, gave rise to variants that could thrive with less water (as the boreal continent started to trap megatons of ice, lowering the sea-level each year), some early moss-like plants were already starting to thrive on land by the start of a new ice age, the Mesofrigian.

NEOPYRGIAN PERIOD

The start of the Neopyrgian is marked by the appearance of fungi building over plant matter, with several taller structures being able to be constructed as the plants and previous generations of fungi broke up the rock and sand into soil, depositing nutrients.

It is also marked by the extinction of the stromatolite population due the ice age of the Mesofrigian Epoch.

Mesofrigian Epoch

The Mesofrigian was the time by which the continents united into the super-continent Sthalika, and fully closed it's insular regions, the mountain ranges by the southern regions deviated all warm wind into the north pole, bringing water vapour further north and increasing the planet's albedo with a polar icecap that extended over 26th parallel, this event lasted for almost 45 million years, reaching it's apex by 3740Myo.

Though this event killed the stromatolite population, the production of oxygen was able to continue far after this, but still with less efficiency - by the early plant life.

The southern ocean would cast several hypercanes and tsunamis over the equatorial part of the supercontinent

The dragging of the continental crust created large portions of shallow seas, in which the developing animal life could flourish, giving rise to the first marine invertebrates and arthropods.

- M.O. Valent, 14/02/2020

PAART | PROTEROZOIC EON | MESOPROTEROZOIC ERA

MESOPROTEROZOIC ERA

STATHERIAN PERIOD

The continents migrated to tropical latitudes, as the ice melted away, and the cloudy atmosphere dissipated, paartian soil could start to come back to it's original color

Stathera is greek for Constant

Paart's oldest exposed continental lithosphere formed during the late Paleoproteroic, ie, pieces of crust that will not subduct (at least, not so soon in it's habitability lifespan).

The Early Statherian is marked by the appearance of the first great microbial structures in the fossil record, stromatolites, which lived in the shallow seas in between the approaching continents...

Spoiler Alert: these guys ain't gonna make it very far D:

Although stromatolites produced large quantities of oxygen in this period, those levels weren't able to go beyond the ~5% mark, having a couple peaks in between volcanic activities...

ECTASIAN PERIOD

From the greek for Area, Éktasi, comes the name of the period that bears large areas of subducting continents which shelfs now are home to billions upon billions of stromatolites

The Ectasian period occupies most of the Mesoproterozoic (~73%), and it is marked by several breakthroughs in life.

The Early Ectasian (3270 ~ 3410Myo), harbors the peak of stromatolite population, covering ares the size of Australia on several occasions.

The Mid Ectasian (3340 ~ 3590Myo), is when the stromatolite formations cause the Second Little Oxygenation Event, when the oxygen levels reached a peak of 14%, also creating a thin layer of oxides upon land.

The Late Ectasian (3590 ~ 3690Myo), earliest Eukaryotes (protozoans) appear followed by sexual reproduction, global temperatures also tended to drop over time as a great portion of the continents concentrated around the south pole...

- M.O. Valent, 05/03/2020

PAART | PROTEROZOIC EON | PALEOPROTEROZOIC ERA

Welcome to the
PALEOPROTEROZOIC ERA

Last time time we saw Paart, the oceans where starting to turn purple because of photosynthetic bacteria, plus the soil on dry land started to oxidize, making the landmasses whiter.

~*Taste the SUN*~

Side effect: now there's oxygen everywhere and the sky is blue - then the Earth might have been a snowball for a while, maybe a couple of times...

Fun Fact 

I didn't actually wanted to "mimic" Earth's history, by no means, I'm just using the continental drift maps and ocean currents to point out the climatic events, and it happens so that we may have a couple more ice ages and desertification along the way...

 Paart's purple oceans slowly turned more foggy as the dissolved metals also oxidized, mainly on shallow seas

In the following millions of years, the planet's index of carbon dioxide had already decreased considerably, plus the increase in overall albedo of the planet, plus the continents drifting closer to the newly formed polar streams where able to capture more water vapor on their surfaces - and the presence of ice decreased the temperatures even more, this period was named Oxygenian, due to the large portions of oxygen released into the atmosphere, still most of it was absorbed by the faster crust cycle (2,15x that of the Earth).

Paart's solar irradiation is on the 64% mark, which means the oxygenic photosynthesis already happens on a steady slow rhythm, plus the faster rate of crust recycling will bring those atmospheric oxygen levels from potentially ~15% - as on Earth at the time - down to between 4,46% and 6,97%.

Hence why I resolved to call this period after the greek fire and volcanoes (among other stuff) god - Hephaestos

The collision of plates that formed the center-left continents opened up a volcanic mountain range, that brought the carbon levels up, but also spilled billions of tons of metals to be oxidized, and the gas reactions created acid clouds and acid rains all over the world, increasing the albedo and also dissolving more rock into the oceans.

From the greek lefkó - meaning white,, here comes the lower part of the Lefíkian period, the Cryogenian (cryo for obvious reasons should I say)

However, as the metals dissolved in the ocean oxidized preventing the oceans from oxygenating properly for a while, that lead to the return of methanogens and rise of cryophile archea and bacteria, many of those traits such as cold resistance would be later inherited by complex life. Once the metals were starting to be not enough to hold the oxygen production, it went to the atmosphere, the reaction between the methane and atmospheric oxygen leads to the formation of carbon dioxide and water, although carbon dioxide is a greenhouse gas, it's still only 3,5% as effective as methane, and thus, the already cooling planet lost it's thermostat control.
As the extra water vapour could easily follow the inland wind and fall as snow - the central range of volcanic mountains diverged equatorial wind both north and south, the northern hemisphere had a large ocean, which didn't help much with the formation of ice, on the flip-side, the south pole had much land and fewer geographical barriers to the formation of large and thick ice sheets - starting the Cryogenian Epoch.

Relative high absorption of green and blue light by early photosynthesis, sulfur and iron compounds, plus the high volcanic smog content in the atmosphere filtering most of the blue light, later lead to Paart's characteristic cyan photosynthetic life
(Personally, one of the most interesting phases of Paart)

Paart was a very smoggy and cold world, the vapors of volcanic pools carried corrosive compounds and the low temperatures meant that smoke would tend to clump in dense runny clouds... For a long period of early photosynthetic life, blue was an absent color in the sky, for the exception of the days that clouds opened a breach letting out the damaging UV rays burn the bacteria and algae, as a mechanism of defense they turned blue - later that would be inherited as then main characteristic of Paartian plant life, bearing a cyan sometimes bluish pigment, as millions of years later, the planet would still lack a dense ozone layer.

Later, by the end of the Lefíkian, volcanic activity intensified, but it eventually came to a stop at 3120Myo, Paart's oldest exposed continental lithosphere formed during the end of this period.

Early Proterozoic paartian sunset

Notice how Vol is highly distorted due atmospheric refraction

- M.O. Valent, 05/03/2020
- M.O. Valent, updated in 19/04/2020