Collaborative Research: Geochemical Transect from Oceanic Adare Basin to Adjacent Continental Adare Peninsula: Implications for the Origin of Intraplate (HIMU-like) Alkaline Magmas

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ntellectual Merit: This proposal is for a combined geochronologic, petrographic, geochemical, and Sr-Nd-Pb-Os-O isotopic investigation of existing lava samples from the seamounts in the Adare Basin and from the adjacent continental Hallett Volcanic Province in Northern Victoria Land. A comparative study of contemporaneous intraplate oceanic and continental alkaline volcanism will be used to evaluate sources and processes responsible for magma production and differentiation. The seamount lavas will provide an opportunity to better characterize the composition of their underlying mantle source whereas the continental lavas will provide information on any effects of contamination by continental crust on their source signatures. The cause of Cenozoic magmatism in West Antarctica has been explained by a variety of models based primarily on geochemical evidence from continental volcanism. The proposed investigation will for the first time provide detailed geochronologic and geochemical data for both continental lavas and adjacent oceanic seamount lavas, thus offering a means by which to critically assess whether Cenozoic alkaline volcanism is due to plume or plume-related activities or magmatism unrelated to mantle plumes. The classic element of this controversy is whether the geochemistry of the magmas represents melting of mantle asthenosphere or subcontinental lithosphere and whether there is a degree of contamination as they rise through relatively thick and chemically heterogeneous continental crust. Broader impacts: This project will support a PhD and MSc student. Undergraduate students will also be involved in sample preparation, analytical work and interpretation via honors/senior theses. A post-doctoral associate will be involved in the oxygen isotopic analysis of the samples. The students will be involved in a multi-institutional and international collaboration. The geochemical database generated will be made available to other researchers in the region and the results will be published in peer-reviewed journals.