| Literature DB >> 11539502 |
H Ohmoto1, T Kakegawa, D R Lowe.
Abstract
Laser ablation mass spectroscopy analyses of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (>>10(-13) of the present atmospheric level) of free oxygen.Entities:
Keywords: NASA Discipline Exobiology; Non-NASA Center
Mesh:
Substances:
Year: 1993 PMID: 11539502 DOI: 10.1126/science.11539502
Source DB: PubMed Journal: Science ISSN: 0036-8075 Impact factor: 47.728