The oxygen content increased when the Earth was covered in ice

In the beginning, planet Earth was a very inhospitable place with no oxygen and only single-celled bacteria as inhabitants. According to a new study, the oxygen content in the air began to increase about 2.4 billion years ago, at the same time as the global glaciation and when all continents were gathered in a single huge landmass, or supercontinent. How to explain the exact connection between these events, however, is a question that baffles the researchers. 'Our results also show that oxidation coincided in time with an event of global glaciation of the Earth and extensive volcanism', says Ulf Söderlund, Professor of Geology at the Faculty of Science at Lund University in Sweden. In the recent international study, researchers from Lund University, among others, have pinpointed the timing of this so-called Great Oxidation Event - a crucial starting point in the development of life. The results come from age dating of volcanic rocks in southern Africa, and they show that the global glaciation occurred 200 million years prior to what was previously believed. The global glaciation meant that most of the planet was covered in ice.