Forensically tracking the origin and evolution of life and earliest earth

Earth's earliest atmosphere will be one of the topics at a seminar day on 'Geochemistry and Photochemistry' at the Hebrew University of Jerusalem today at the Fredy and Nadine Hermann Institute of Earth Sciences at the Edmond J. Safra campus. One of the speakers is Prof. Mark Thiemens of the University of California, San Diego, who will talk about atmospheric photochemistry and Mass Independent Fractionation (MIF) in the geological record.

Thiemens and colleagues have discovered and developed a forensic isotopic tracer based upon a new quantum mechanical process that can read the history of the atmosphere from the makeup of the oldest rocks on earth. Its observation in nature has lead to a new tool to unravel processes in nature that range from the origin of the solar system, to the source and transport of greenhouse gases, and the definition of ancient atmospheric processes on Mars.

Recent measurements in the Earth's atmosphere have led to a better understanding of the carbon-oxygen reservoir, of importance in understanding the issues in global warming, but also in interpreting key changes in the atmosphere, especially some 700 million years ago during the snowball Earth period when it is apparent the earth was frozen. It was after the thawing of the earth that life on earth exploded from simple organisms to the great variety and complexity observed today. What the driving force was for this is unknown and is of profound importance. From the isotopic record and the latest observations we are now able to understand at a significantly more refined level what the atmosphere was like and how it changed.

Some of the other presentations include: Prof. Menachem Luria of the Hebrew University on 'Photochemistry in the Dead Sea'; Dr. Yeala Shaked of the Hebrew University on 'Photochemical cycling of iron and oxygen radicals in the Gulf of Aqaba'; and Prof. S.K. Bhattacharya of the Physical Research Laboratory in Ahamedebad on 'Investigation of the isotopic anomaly in stratospheric carbon dioxide'.

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