georefid:2000-063790georefid:2000-063779SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.163.121.19991999-01-01publicationgeorefid:2000-063790doi:10.2973/odp.proc.sr.163.121.1999Allan, James F.Texas A&M University, Department of Geology and Geophysics, College Station, TX, United StatesauthorForsythe, LanceOregon State University, United StatesauthorNatland, James H.Ocean Drilling Program, United StatesauthorTexas A & M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentHardcopyIn: Larsen, Hans-Christian, Duncan, Robert A., Allan, James F., Aita, Yoshiaki, Arndt, Nicholas T., Buecker, Christian J., Cambray, Herve, Cashman, Katharine V., Cerney, Brian P., Clift, Peter D., Fitton, J. Godfrey, Le Gall, Bernard, Hooper, Peter R., Hurst, Stephen D., Krissek, Lawrence A., Kudless, Kristen E., Larsen, Lotte Melchior, Lesher, Charles E., Nakasa, Yukari, Niu, Yaoling, Philipp, Harald, Planke, Sverre, Rehacek, Jakub, Saunders, Andrew D., Teagle, Damon A. H., Tegner, Christian, Scroggs, John (editor), Proceedings of the Ocean Drilling Program; scientific results, Southeast Greenland margin; covering Leg 163 of the cruises of the drilling vessel JOIDES Resolution, Reykjavik, Iceland, to Halifax, Nova Scotia, sites 988-990, 3 September-7 October 1995163119-134Coring during Ocean Drilling Program and Deep Sea Drilling Project Legs 163, 152, 104, 81, and 38 recovered sequences of altered basalt from North Atlantic seaward-dipping reflector sequences (SDRS) erupted during the initial rifting of Greenland from northern Europe and likely associated with excessive mantle temperatures caused by an impacting mantle plume head. Cr-rich spinel is found abundantly as inclusions and groundmass crystals within the olivine-rich lavas of Hole 917A (Leg 152) cored into the Southeast Greenland SDRS, but only rarely as inclusions within plagioclase in the lavas of the Voring Plateau SDRS, and it is absent from other cored SDRS lavas from the Rockall Plateau and Southeast Greenland. Eruptive melt compositions determined from inferred, thermodynamically-defined, spinel-melt exchange equilibria indicate that the most primitive melts represented by Hole 917A basalts have Mg/(Mg+Fe (super 2+) ) at least as high as 0.70 and approach near-primary mantle melt compositions. In contrast, Cr-rich spinels from Hole 338 (Leg 38) lavas on the Voring Plateau SDRS give evidence for melt with Mg/(Mg+Fe (super 2+) ) only as high as 0.64. This study underlines that primitive melts similar to those from Hole 917A comprise only a small fraction of the eruptive North Atlantic SDRS melts, and that most SDRS basalts were, in fact, too evolved to have precipitated Cr-rich spinel, with true melt Mg/(Mg+Fe (super 2+) ) likely below 0.60. The evolved nature of the SDRS basalts implies large amounts of fractionation at the base of the crust or deep within it, consistent with seismic results that indicate an abnormally thick Layer 3 underlying the SDRS.completedGeochemistry of rocks, soils, and sedimentsIgneous and metamorphic petrologyalkaline earth metalsArctic regionAtlantic Oceanbasaltschemical compositionchrome spinelchromiumconcentrationcontinental margincoresDeep Sea Drilling ProjectDSDP Site 338East GreenlandgenesisGreenlandigneous rocksIPODLeg 104Leg 152Leg 163Leg 38Leg 81magnesiummeltsmetalsNorth AtlanticOcean Drilling Programocean floorsODP Site 917oxidesSouth Greenlandspinelvolcanic rocksurn:org.iodp:exp:104urnlargerWorkCitationcampaignurn:org.iodp:exp:152urnlargerWorkCitationcampaignurn:org.iodp:exp:163urnlargerWorkCitationcampaignurn:org.iodp:exp:38urnlargerWorkCitationcampaignurn:org.iodp:exp:81urnlargerWorkCitationcampaignurn:org.iodp:exp:38:site:338urnlargerWorkCitationstudyurn:org.iodp:exp:38urnlargerWorkCitationcampaignurn:org.iodp:exp:152:site:917urnlargerWorkCitationstudyurn:org.iodp:exp:152urnlargerWorkCitationcampaignEnglishgeoscientificInformation-80.000020.00000.000084.0000GreenlandNorth AtlanticIncludes appendix