G.R. Tripathy

G.R. Tripathy

Department of Earth & Climate Sci.,
Indian Institute of Science Education & Research, Pashan, Pune 411 008
Email: grtripathy@gmail.com, grtripathy@iiserpune.ac.in

G R Tripathy, IISER, Pune, selected to Associateship in 2015. Tripathy’s research interests includes isotope geochemistry, tectonics-climate-weathering link, Paleo-erosion pattern and Re-Os geochronology. He has received the INSA Young Scientist Award (2015) and the DST-INSPIRE Faculty Award, Earth and Atmospheric Sciences (2013).

Session 3B - Inaugural Lectures

Re-Os geochronology: Clues for past marine and atmospheric conditions

Changes in the seawater chemistry have influenced the biosphere greatly in the past. These important variations in past oceanic conditions and their precise timing can be constrained using Re-Os isotopic compositions of organic-rich marine sedimentary rocks (e.g. black shale). Re and Os present in black shales are mostly hydrogenous in nature and abundances of these elements, owing to their redox-sensitive nature, serve as a good measure for past ocean redox state. The 187Re-187Os radioactive decay scheme in black shale yields its depositional age and the initial 187Os/188Os ratio (Osi) of the sedimentary basin during the shale deposition period. Compilation of Osi ratios for marine shales of Proterozoic age shows a coarse synchrony with the atmospheric oxygen level, pointing to dominant role of oxidative weathering on past ocean 187Os/188Os ratio. The presentation will highlight some of these important research outcomes, based on Re-Os isotopic studies, on paleo-ocean and atmospheric conditions.

© 2016 Indian Academy of Sciences, Bengaluru.