Geological Time- Proterozoic Eon

- lasted from 2.5 billion years ago, until 541 million years ago.

Protozerozoic eon

World condition

Interesting Facts

Major Events

By- Edwin Romero

World condition

Oceans Were Full of iron which are believed to have made the ocean green due to rust. Green rust occurs when there is no oxygen present in the reaction. Irons instead chemically changed by hydroxides and elements like sulfur/chlorine. Atmosphere was mostly nitrogen, with water vapor, carbon dioxide, & methane; Since very little oxygen was present in this atmosphere, anaerobic microbes were the main living organisms in this environment.

Early Environment

Interesting Facts

Interesting Facts

Major Events

Around 2.3 billion years ago, photosynthesizers appeared as bacteria like the blue-green Cyanobacteria or purple microbes known as Halo-bacteria. They used the suns energy to convert CO2 and water into food which released oxygen. Within about 200 million yrs, Oxygen became abundant and photosynthetic life continued to spread. The created oxygen began reacting with iron in the oceans that turned the world from green to red-brown.

New world forming

Protozerozoic Eon

Photosynthetic life

Cyanobacteria

Halobacteria

Major Events

Effects of A New Atmosphere

As photosynthetic life continued to rise, Oxygen became an abundant resource for the first time in History. This new rise in Oxygen began spreading out of the ocean and into the atmosphere. The Oxygen in these new conditions began poisoning anaerobic microbes who had previously been the main source of life. Oxygen reacted with methane in atmosphere removing it from atmosphere while also using up most of the carbon dioxide through the process of photosynthesis.

World condition

Interesting Facts

The absence of greenhouse gasses in the atmosphere caused the first major ice age and became known as the Huronian Glaciation that would last for 300 million years. These huge changes in climate and earths chemistry made most life go to the brink of extinction. This included the photosynthetic bacteria as they drowned in the oxygen they secreted. By the time the Huronian Glacial period ended, the surviving life inherited a new hospitable planet with a oxygen abundant atmosphere and oceans, now with a newly formed ozone layer. This ozone layer would allow life forms to become more complex by blocking ultraviolet radiation from the sun though coated layers of molecular oxygen.

Protozerozoic Eon

Protozerozoic Eon

Interesting Facts

Interesting facts about this section of time

• The word 'Proterozoic' is of greek origin and can be translated as "former/earlier life."
• The Proterozoic eon is the longest eon in all of Earth's history lasting 2 billion years.

• Only 2/3% of Earth's surface was dry land.
• This Eon is the first time life became larger than a cell. One of the earliest photosynthetic plants is red algae which has been found as far as 1.6 billion years ago.
• The extinction event of this eon became known as the Oxygen Catstrophe and is one of the biggest most deadly events in history.

World condition

Major Events