Earth's oldest Banded Iron Formations originally comprised of alternating layers of silica and Fe-hydroxides showed life forms 3.8 billion years ago.

‘Earth's marine chemical sediments retain information on the composition and presence of oxygenation/reduction processes in ambient seawater.’

Researchers led by Professor Robert Frei released a study indicating evidence for the presence of small concentrations of oxygen on Earth already 3.8 billion years ago. The researchers analysed Earth's oldest Banded Iron Formations (BIFs) from Western Greenland. BIFs are marine chemical sediments originally comprised of alternating layers of silica and Fe-hydroxides and are widely used as geochemical archives. 




The reason for this is that they retain information on the composition and presence of oxygenation/reduction processes in ambient seawater and on the interaction of the atmosphere with Earth's surface.
The fact that the analyses of the BIF layers from Western Greenland show elements that require presence of oxygen in the atmosphere opens up for the possibility of evolution of the earliest primitive photosynthetic life forms as early as 3.8 billion years ago. The research is published in the Journal Scientific Reports.
Source-ANI