Time: 14:00-15:30, October 11 (Thursday)
Venue: Lecture Hall 221, Institute of Surface-Earth System Science (Building No. 16), Tianjin University
Speaker: Katz SUZUKI（JAMSTEC）Researcher
Abstract：
The Re-Os isotope system utilizing the beta decay of 187Os to 187Os with the half life of 4.16 X 1010 yrs has been more and more widely applied to investigate the chemical evolution of the Earth. As it is the radiometric decay system, it is also used as a chronometer. Especially, as the Re and Os are chalcho- and sidero-phile elements, and are enriched in sulfide minerals, it is the most useful method to dating of sulfide ore deposits.
Marine 187Os/188Os values reflect the relative influx of continental crust with high 187Os/188Os (> 1.0), and of mantle and of extraterrestrial components (~0.13) to the global ocean. The relatively short residence time of marine Os (a few tens ky) leads to application of this isotope as a high-resolution tool to detect the global geological events such as massive volcanism and its linkage to oceanic anoxic events and the meteorite impact followed by mass extinction.
I will talk about the following topics as examples of application of the marine Os isotope based on our results.
1. Detailed processes of the snowball Earth and great oxidation events at approximately 2.3 Ga based on the Os isotope record in the Huronian Supergroup sedimentary rocks.
2. Oceanic anoxic events caused by massive volcanism in late Jurassic and Cretaceous.
3. Meteorite impact recorded in Os isotopic compositions of Triassic sedimentary sequence.
