By Sid Perkins
Analyses of ancient sulfide minerals and the modern organisms that create sulfides are giving scientists a better idea of what Earth’s atmosphere and oceans may have been like billions of years ago. The findings may also explain a paradox that has long puzzled solar astronomers.
In one of the new studies, scientists looked at the ratio of isotopes in sulfide particles trapped in diamonds unearthed from a mine in Botswana. Radioactive dating shows that those gems formed about 2.9 billion years ago, says Mark H. Thiemens, a chemist at the University of California, San Diego.