Report Title: The Origin and removal of the lithospheric mantle beneath the Canadian Cordillera            

Report Time：PM 3: 00 – 4: 30, Aug 4, 2018

Report Place：TGRC building Room 103

Introduction of the reporter

Professor Polat is a professor of Earth and Environmental Sciences, University of Windsor, Lecture Professor of Yangtze River Scholars, China University of Geosciences, is currently editor-in-chief of Canadian Journal of Earth Sciences and a member of the Lithos Editorial Board (2008-present), and former editor-in-chief of Geology (2013-2015) and associate editor of Geoscience Frontiers (2012-2015). His research interests include trace and isotope geochemistry, geodynamics, Archean greenstone belts, ophiolites, mantle traps, and paleosols. Professor Polat, provides key evidence for the initiation time limit of plate tectonic movement mechanism by demonstrating the typical rock assemblages of the oldest known Archean subduction zones in the world, which greatly challenges the traditional geosciences' understanding of the origin of plate tectonics. He has more than 100 research papers have been published in mainstream Geosciences journals such as Earth-Science Reviews, Geology, EPSL, GCA, Chemical Geology, PR, GR, Lithos and so on. His papers have been cited more than 6000 times and his H index is 46.

Abstract:
The lithospheric spinel lherzolite xenoliths in the Quaternary alkaline basalts, southeastern British Columbia, contain abundant feldspar veins, interconnected melt pockets, and spongy clinopyroxene, recording partial melting and alkaline mantle metasomatism. Generation of the melt pockets may have reduced the strength of the lithosphere beneath the Cordillera, facilitating its recycling to the asthenosphere. The xenoliths display Cretaceous to Paleoarchean Nd model ages (66–3380 Ma) and depleted to enriched epsilon-Nd (-8.2 to +9.6) values, recording multiple melt extraction events. Data from the Tasse mantle xenoliths suggest that convergent plate margins are not only sites of lithospheric formation, but also locations of lithospheric destruction and recycling.