Return to Geology Index PagePrecambrian Era
The Precambrian Era is Earth's first era of time. It began with the creation of the Earth around 4.6 billion years ago and lasted until 570 million years ago. The Precambrian saw many drastic changes during this time. The five major events of the Precambrian are:
1. The formation of the Sun and light.
2. The creation of the Earth.
3. The creation of the atmosphere through volcanic out-gassing.
4. The creation of the oceans. After rainfall, the Earth's surface was cooled down and the rainwater collected into low areas which formed oceans and seas. The ocean became stable around 1 bya when no more salt from rocks could be dissolved into the water.
5. The creation of life. This actual process remains open to debate as to how it all took place.
The Precambrian Era is divided into three periods: the Azoic, Archeozoic and the Vendian. The Azoic period was the formation of the Earth and the atmosphere and oceans. The Archeozoic is the period when first simple life forms such as bacteria and simple algae formed. The Vendian, the last period of time in the Precambrian, witnessed the rise of simple organisms such as jellyfish and sea worms.
All Precambrian life forms were usually simple one-cell to simple multi-cell creatures. These life forms were blind, brainless and soft bodied creatures, in that they had no hard skeleton.