Evolution of the Kerguelen Plume: Constraints from Geochemical Studies of Lava Sequences in the Kerguelen Archipelago

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9614532 Frey The long-term goal of this research is to understand the origin and evolution of the ~115 Ma record of volcanism related to the Kerguelen mantle plume. The Kerguelen plume is particularly important because:1) it is long-lived; 2) all aspects of plume-related volcanism are accessible for study; 3) lavas have a distinctive geochemical signature that may reflect recycling of crust into the deep mantle; and d) formation of the large igneous province (Kerguelen Plateau) in the newly formed Indian Ocean may have enabled dispersal of these plume geochemical characteristics into the Indian Ocean asthenosphere. This proposal seeks to extend the current project to include the recent (40 Ma) volcanic history of this plume that is recorded in a thick sequence of flood basalts which are the major volumetric unit of the Kerguelen archipelago. The chemical composition (major and trace element abundances) and isotopic (He, Sr, Nd, Pb, and Os) characteristics of these lavas will be determined to show how the lava compositions have changed with time (both on a relative and absolute basis with control by 40Ar-39Ar dating) and location in the archipelago.