Over the past 115 My a significant fraction of the eastern Indian Ocean seafloor was formed by magmas derived from the Kerguelen mantle plume. The overall goal of this research is to use this volcanic record to understand the origin and evolution of the Kerguelen mantle plume. This is an important objective because magmas derived from mantle plumes provide information about physical and chemical processes occurring in the earth's mantle that cannot be obtained from study of volcanism associated with diverging and converging plates. Specifically, mantle plumes provide information about convection processes in the mantle, and the effects of long-term recycling of crust into the mantle. The Kerguelen Plume is particularly important because: (a) it is long-lived; (b) all aspects of plume-related volcanism are accessible for study; i.e., a very large igneous province (Kerguelen Plateau) which is commonly associated with plume initiation, a long hotspot track of volcanoes (Ninetyeast Ridge) which formed as the Indian plate migrated rapidly northwards over the plume, and a large, recently active oceanic island (Kerguelen Archipelago) located on the Antarctic Plate; (c) lavas associated with this plume have a distinctive geochemical signature which reflect recycling of crust into the deep mantle; (d) formation of the large igneous province in the newly formed relatively small Indian Ocean may have enabled dispersal of these plume geochemical characteristics into the Indian Ocean asthenosphere, thereby creating the distinctive geochemical characteristics of basalts erupted at currently active seafloor spreading centers in the Indian Ocean; and (e) the high magma flux reflected by the mid-Cretaceous formation of the Southern Kerguelen Plateau may have significantly affected the earth's hydrosphere/atmosphere system. Geochemical and age data for igneous rocks from the Kerguelen Archipelago and submarine Northern Kerguelen Plateau will be obtained in order to understand the source and evolution of the <40 My volcanism related to the Kerguelen Plume.
