Dorasterrolithic Period

The Dorasterolithic Period is the first and oldest period of the Plutolithic Era. It lasted from roughly 3.0 to 2.4 Ga (billion years), making it one of the longest geologic periods lasting a total of about 600 million years. Its name is a pun on Dorasterrock, a city in Bardonia where rocks of this age were first classified by geologists.

The period itself experienced a rise in the abundance (and likely biodiversity) of photosynthetic prokaryotes, as indicated by large reefs of stromatolites preserved in shallow marine strata of the time. A rapid increase of oxygen during this period occurred at about 2.75 Ga from a worldwide bloom of cyanobacteria that lasted for millions of years.

Some paleontologists have suggested that this 'Great Oxygenation Event' caused the first mass extinction in history, as the relatively high levels of oxygen (still only about 40% of modern oxygen levels) could have been too toxic for most anaerobic bacteria and other microbes to handle; others have indicated a lack of evidence for this hypothesis, and remain doubtful.