Kerguelen mantle plume influence on magmatism of the east Antarctica and Indian Ocean

 ¹Sushchevskaya N.M., ²Belyatsky B.V., ³Dubinin E.P.

¹Vernadsky Institute of Geochemistry RAS, Moscow, Russia (nadyas@geokhi.ru); ²IPGG RAS, St. Petersburg, Russia (bbelyatsky@mail.ru); ³Lomonosov State University, MES, Moscow, Russia (dubinin@mes.msu.ru)

 

It has been widely accepted the Kerguelen plume begins to form 130-110 Ma ago. It involved the eastern Indian and the western Australian margins and even the eastern coast of Antarctica in the Lambert Glacier fracture region. Geochemical similarity of the Kerguelen plateau early enriched basalts and those from highs of the Indian Ocean as well as alkaline-ultrabasic magmas of Lambert Glacier points to continental lithosphere input in their formation. Rift magmatism at the early stages of the Indian Ocean opening, within the eastern part, directly connected with the Kerguelen-plume activity and preserved continental lithosphere fragments has been marked by wide isotope heterogeneity, which does not typical for modern tholeiites of this region. Close position of Kerguelen-plume to the ancient spreading zone (Wharton Ridge) substantially impacted on magmatism and gave rise to a number of deep-sea highs formation with hotspot involvement (ESIR and Broken Ridge, Af.Nikitin and Konrad Rises). Kerguelen Plateau generation, the southern and central parts of which have been resulted of interaction between continental crust remnants and Kerguelen-plume, has been lasted during 60 m.y. under subaerial environments [Bénard et al., 2010]. According to the isotopic data it has been revealed that the enriched components of the basalt melt source were represented by continental substances – low or upper crustal. Upwelling plume melts had signatures typical for depleted asthenosphere or enriched lithospheric matter which was formed by a remelting of ancient continental material buried in the upper mantle. These continental remnants could have been stripped off the Gondwana supercontinent basement due to the continental breakup that started 150 million years ago.