This grant supports upgrade of an existing thermal ionization mass spectrometer (TIMS) in the Earth and Environmental Sciences Department at the University of Rochester. The instrument was installed in 1988 and later upgraded through EAR/IF support (EAR-0732679 ) to support detector electronics and a modern data acquisition system. This funding will allow for additional electronic component upgrades (magnet power supply, filament control) that are failing. The TIMS lab at Rochester supports research and research training in radiogenic isotope geochemistry as applied to problems in igneous petrology, geochronology and tectonics and environmental geochemistry including studies of the timing and petrogenesis of rift volcanics from the Afar basin, geochemical and tectonic studies of Franciscan complex subduction generated magmatic sequences from the California Coast Ranges, and studies of the magmagenesis of Rajmahal flood basalts from eastern India. The proposed upgrade will extend the life of a 22 year old instrument at a fraction of the cost of a new TIMS.
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The purpose of the upgrade of the instrument was to maintain the continuity of producing high quality analytical results for geochemical research that were used in the preparation and completion of one PhD, two Master’s and one undergraduate senior thesis during the tenure of the grant period. Also during the grant period, the mass spectrometer was transferred from the University of Rochester to the University of Texas at Arlington where the instrument is currently operational, and is being used by students and post-doctoral researchers. Two outstanding research papers were published during the tenure of this grant period, both dealing with the mass extinction event at the Permian- Triassic boundary some 252 million years ago when most living things from the land and the oceans became extinct. The study sites were in Vietnam and in the Indian Himalayas in Himachal Pradesh. The lead isotopic compositions of blackened marine micro fossils from this boundary in Vietnam (Nestell et. al. 2015) indicate presence of carbon in the seawater ,sourced from coal deposits. Our data indicate that the Siberian flood basalts must have erupted through coal deposits creating at least partially an environmental crisis. The second paper (Ghosh et. al. 2015) dealt with the geochemistry of sedimentary rocks from the Permian-Triassic boundary in the Himalayan section in Spiti in Himachal Pradesh. We discovered the effects of both a meteorite impact and Siberian volcanism in the geochemistry and sedimentology of these rocks from the Himalayas. References of the above two publications resulting from this grant: Galina P. Nestell, Merlynd K. Nestell, Brooks B. Ellwood, Bruce R. Wardlaw, Asish R. Basu, Nilotpal Ghosh, Luu Thi Phuong Lan, Harry D. Rowe, Andrew Hunt, Jonathan H. Tomkin & Kenneth T. Ratcliffe (2015): High influx of carbon in walls of agglutinated foraminifers during the Permian-Triassic transition in global oceans, International Geology Review, DOI:10.1080/00206814.2015.1010610 Nilotpal Ghosh, Asish R.Basu, O.N.Bhargava, U.K.Shukla, Arundhuti Ghatak, Carmala N.Garzione & Arun D.Ahluwalia (2015). Catastrophic environmental transition at the Permian-Triassic Neo-Tethyan margin of Gondwanaland: Geochemical, isotopic and sedimentological evidence in the Spiti Valley, India. Gondwana Research, DOI: 10.1016/j.gr.2015.04.006
