Whiffs of Oxygen in Archean Atmosphere

In a significant contribution in the field of Earth Sciences, researchers from the Department of Geology traced back the first evidence of appearance of oxygen in the early atmosphere from rock record of some 300 crore years before present. Faculty members of the Geology Department, Prof. Joydip Mukhopadhyay, Dr. Gautam Ghosh, Dr. Sankar Bose, postdoctoral scientist Dr. Sampa Ghosh and two PhD scholars along with their collaborators from the Trinity College Dublin, Prof. Q. Crowley and K. Heron published their findings in ‘Geology’, the prestigious high-impact journal of the Geological Society of America. The little rise in oxygen content in the air of that time is in all probability because of the emergence of photosynthetic microbiota, that now act as the factory for the supply of oxygen in air. Previously it was believed that such events took place only during 240 crore year before present, but this research and finding pushed back this date to 60 crore year further! It all came from their discovery of a partly preserved lateritic ancient soil profile (paleosol) in between older and younger rock units in some open cast clay mines from the town of Keonjhar, Odisha. The 'Keonjhar Paleosol' as they name this ancient soil preserved in very old rock succession, bears evidences in its chemical composition to suggest the presence of oxygen in the early atmosphere. There are only two such records from ancient soils (paleosols) so far established worldwide from other continents, which are at least 60 to 250 million years younger than this Keonjhar Paleosol.

For Reading: http://geology.gsapubs.org/content/early/recent:
Oxygenation of the Archean atmosphere: New paleosol constraints from eastern India, Geology,doi:10.1130/G36091.1, Joydip Mukhopadhyay, Quentin G. Crowley, Sampa Ghosh, Gautam Ghosh, Kalyan Chakrabarti, Brundaban Misra, Kyle Heron, and Sankar Bose"