Planet Earth - The Orosirian Period

The Orosirian Period ran from 2,050 to 1,800 million years ago. It is named after the Greek word for "mountain range".

So it stands to reason that there would be a great deal of mountain development within these 250 million years as well as some impacts from small (a meteor is the visible tail of the meteoroid [a sand to boulder sized particle] and if it lands then it becomes classed as a meteorite) to larger extraterrestrial material. Some of these larger impacts have been recorded within the geology of the newly formed super continents.

One example was an asteroid of 5 to 10 kilometres in diameter (that is 3.1 to 6.2 miles in imperial units) that hit the earth's surface in an area close to the town of Vredefort in what is now South Africa. It left an impact crater of 250 to 300 miles in diameter (160 to 190 miles) but with this type of impact there other effects left. The nearby structures of the Bushveld Igneous Complex and the Witwatersrand Basin were also formed around the same geological period and it is thought that the kinectic movement from the impact may have caused the regional vulcanism (volcanic activity). So why are the geological structures so important, the Bushveld Igenous Complex holds a great proportion of the world's platinum group metals and Witwatersrand holds gold reserves. 

By 2,000 million years ago, it is thought that the luminosity of the sun had reached eighty-five percent of its present luminosity and more free oxygen started to accumulate in the atmosphere.

In 1,850 million years ago, the planet was rocked by another impact from a fireball of between 10 to 15 kilometres in diameter. Sudbury Basin, in Ontario, is about 62 kilometres long (39 miles), 30 kilometres (19 miles) wide and 15 kilometres (9.3 miles) deep and it scattered debris over an area of 1.6 million square kilometres (620,000 square miles). The crater then filled with magma and solidified over time with such economic minerals as copper, gold, palladium and platinum to name but a few. 

Next time - The Statherian Period