Sato, Hiroshi (2004): Mineral compositions of MORB from the Australian Antarctic discordance (AAD); implications for mantle source characteristics. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Pedersen, Rolf B., Christie, David M., Miller, D. Jay, Balzer, Vaughn G., Einaudi, Florence, Gee, M. A. Mary, Hauff, Folkmar, Kempton, Pamela D., Liang, Wen-Tzong, Lysnes, Kristine, Meyzen, Christine M., Pyle, Douglas G., Russo, Christopher J., Sato, Hiroshi, Thorseth, Ingunn H., Proceedings of the Ocean Drilling Program; scientific results; mantle reservoirs and migration associated with Australian Antarctic rifting; covering Leg 187 of the cruises of the drilling vessel JOIDES Resolution; Fremantle, Australia, to Fremantle, Australia, Sites 1152-1164; 16 November 1999-10 January 2000, 187, georefid:2005-011566

Abstract:
The chemical compositions of olivine, plagioclase, pyroxene, and spinel in lavas collected during Ocean Drilling Program Leg 187 in the Australian Antarctic Discordance, Southeast Indian Ridge (41 degrees -46 degrees S, 126 degrees -135 degrees E) were analyzed, and modeling of the theoretical equilibrium petrogenetic conditions between olivine and melt was conducted. The cores of larger olivine phenocrysts, particularly in the isotopic Indian-type mid-ocean-ridge basalt (MORB), are not equilibrated with melt compositions and are considered to be xenocrystic. Larger plagioclase phenocrysts with compositionally reversed zonation are also xenocrystic. The compositions of primary magma were calculated using a "maximum olivine fractionation" model for primitive MORB that should fractionate only olivine. Olivine compositions equilibrated with calculated primary magma and compositions of calculated primary magma suggest that (1) isotopic Pacific-type MORB is more fractionated than Indian-type MORB, (2) Pacific-type MORB was produced by higher degrees of partial melting than Indian-type MORB, and (3) primary magma for Indian-type MORB was segregated from mantle at 10 kbar ( approximately 30 km depth), whereas that for Pacific-type MORB was segregated at 15 kbar ( approximately 45 km depth).
Coverage:
West: 126.0000 East: 135.0000 North: -41.1500 South: -46.0000
Relations:
Expedition: 187
Supplemental Information:
Available only on CD-ROM in PDF format and on the Web in PDF or HTML
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.187.202.2004 (c.f. for more detailed metadata)
Data download: application/pdf
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