Archean Eon

The oldest ascertained life form of fossilized bacteria in microbial mats, 3,480 million years old, found in Western Australia, is from this era

The Isua Greenstone Belt is an Archean greenstone belt in southwestern Greenland. The belt is aged between 3.7 and 3.8 Ga, making it among the oldest rock in the world. The belt contains variably metamorphosed mafic volcanic and sedimentary rocks. The occurrence of Boninitic geochemical signatures offers evidence that plate tectonic processes may be responsible for the creation of the belt. Pillowed basalts indicate that liquid water existed on the surface at this time.- Wikipedia (includes (as of edit of 15 June 2011 ) comprehensive list of references)

The oldest ascertained life form of fossilized bacteria in microbial mats, 3,480 million years old, found in Western Australia, is from this era

The oldest ascertained life form of fossilized bacteria in microbial mats, 3,480 million years old, found in Western Australia, is from this era

Thw split between bacteria and archaea occurs.

Diversification and expansion of acritarchs.

Diversification and expansion of acritarchs.

Photosynthesizing cyanobacteria evolved; they used water as a reducing agent, thereby producing oxygen as a waste product.

The Pongola glaciation occurred around 2,900 million years ago.

Oldest evidence for microbial life on land in the form of organic matter-rich paleosols, ephemeral ponds and alluvial sequences, some of them bearing microfossils.

The oldest ascertained life form of fossilized bacteria in microbial mats, 3,480 million years old, found in Western Australia, is from this era

Oldest evidence for microbial life on land in the form of organic matter-rich paleosols, ephemeral ponds and alluvial sequences, some of them bearing microfossils.

The oldest ascertained life form of fossilized bacteria in microbial mats, 3,480 million years old, found in Western Australia, is from this era

The supercontinent Kenorland formed during this period, about 2.7 billion years ago.