FN Archimer Export Format PT J TI The Amsterdam-St. Paul Plateau: A complex hot spot/DUPAL-flavored MORB interaction BT AF JANIN, M. HEMOND, Christophe MAIA, Marcia NONNOTTE, Philippe PONZEVERA, Emmanuel JOHNSON, K. T. M. AS 1:;2:;3:;4:;5:;6:; FF 1:;2:;3:;4:;5:PDG-REM-GM-LGM;6:; C1 Univ Brest, CNRS, Inst Univ Europeen Mer, FR-29280 Plouzane, France. Univ Europeenne Bretagne, FR-29200 Brest, France. IFREMER, Dept Geosci Marines, FR-29280 Plouzane, France. Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. C2 UBO, FRANCE UEB, FRANCE IFREMER, FRANCE UNIV HAWAII MANOA, USA SI BREST SE IUEM PDG-REM-GM-LGM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-univ-france copubli-int-hors-europe IF 2.94 TC 7 UR https://archimer.ifremer.fr/doc/00102/21368/19008.pdf LA English DT Article CR MD 171 / GEISEIR-1 MD 175 / GEISEIR-2 MD157 PLURIEL/EXTRAPLAC/DEFLO-HY BO Marion Dufresne DE ;DUPAL anomaly;Indian Ocean;Sr-Nd-Pb-Hf isotopes;ridge-hot spot interaction AB The Amsterdam-St Paul (ASP) oceanic plateau results from the interaction between the ASP hot spot and the Southeast Indian ridge. A volcanic chain, named the Chain of the Dead Poets (CDP), lies to its northward tip and is related to the hot spot intraplate activity. The ASP plateau and CDP study reveals that ASP plume composition is inherited from oceanic crust and pelagic sediments recycled in the mantle through a 1.5 Ga subduction process. The ASP plateau lavas have a composition (major and trace elements and Sr-Nd-Pb-Hf isotopes) reflecting the interaction between ASP plume and the Indian MORB mantle, including some clear DUPAL input. The Indian upper mantle below ASP plateau is heterogeneous and made of a depleted mantle with lower continental crust (LCC) fragments probably delaminated during the Gondwana break-up. The lower continental crust is one of the possible reservoirs for the DUPAL anomaly origin that our data support. The range of magnitude of each end-member required in ASP plateau samples is (1) 45% to 75% of ASP plume and (2) 25% to 55% of Indian DM within 0% to a maximum of 6% of LCC layers included within. The three end-members involved (plume, upper mantle and lower continental crust) and their mixing in different proportions enhances the geochemical variability in the plateau lavas. Consequently, the apparent composition homogeneity of Amsterdam Island, an aerial summit of the plateau, may result from the presence of intermediate magmatic chambers into the plateau structure. PY 2012 PD SEP SO Geochemistry Geophysics Geosystems SN 1525-2027 PU Amer Geophysical Union VL 13 IS 9 UT 000309417200002 BP 1 EP 26 DI 10.1029/2012GC004165 ID 21368 ER EF