Mesozoic history of the Hawaiian hotspot and Pacific magmatism preserved in Kamchatka

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The Hawaiian hotspot, representing the strongest mantle plume on Earth, has been active for at least 85 Ma as recorded in the 5800 km long Hawaiian-Emperor Seamount Chain. The earlier history of the hotspot however has been subducted beneath what now belongs to eastern Kamchatka. Preliminary investigations suggest that the Mesozoic Kamchatsky Mys ophiolites in northeastern Kamchatka are accreted fragments of the older hotspot track and therefore may preserve the missing earlier history of the Hawaiian hotspot. The major goals of the proposed project are 1) to determine the absolute ages of the accreted ophiolitic terranes in northeastern Kamchatka using Ar/Ar step-heating and single-crystal techniques, and 2) to characterize their origin and mantle sources using major and trace elements, Sr-Nd-Pb-Hf isotope systematics and the composition of melt inclusions in a variety of minerals. We anticipate that this study could have broad implications for the long-term evolution of mantle plumes, the longevity of hotspots, the evolution of Mesozoic Pacific ocean floor, the geologic evolution of the eastern Asian active margin, and the composition of the input into the Kamchatkan subduction system.