Shungite, a unique carbon-rich sedimentary rock from Russia deposited 2 billion years ago, holds clues about oxygen concentrations on Earth’s surface at that time. Led by Professor Kurt Konhauser at the University of Alberta and Professor Kalle Kirsimäe at the University of Tartu, an international research team involving other colleagues from France, Norway, Russia, and USA, have found strikingly high molybdenum, uranium, and rhenium concentrations, as well as elevated uranium isotope ratios in drill cores that dissect the shungite rocks. These trace metals are only thought to be common in Earth’s oceans and sediments when there is abundant oxygen around. The researchers found that such trace metal concentrations are unrivaled in early Earth’s history, suggesting elevated levels of oxygen at the time when the shungite was deposited.
Click here for original story, Study challenges common view of oxygen scarcity on Earth 2 billion years ago
Source: Phys.org