georefid:2007-088109georefid:2007-088081SEDIS 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.149.225.19961996-01-01publicationgeorefid:2007-088109doi:10.2973/odp.proc.sr.149.225.1996Feraud, GilbertUniversite de Nice Sophia-Antipolis, Institut de Geodynamique, Nice, FranceauthorBeslier, Marie-OdileRice University, United StatesauthorCornen, GuyOcean Drilling Program, United StatesauthorTexas A&M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentDigitalIn: Whitmarsh, Robert B., Sawyer, Dale S., Klaus, Adam, Beslier, Marie-Odile, Collins, Eric S., Comas, Maria Carmen, Cornen, Guy, de Kaenel, Eric, Pinheiro, Luis de Menezes, Gervais, Elisabeth, Gibson, Ian L., Harry, Dennis L., Hobart, Michael A., Kanamatsu, Toshiya, Krawcyzk, Charlotte M., Liu, Li, Lofts, Jeremy C., Marsaglia, Kathleen M., Meyers, Philip A., Milkert, Doris, Milliken, Kitty L., Morgan, Julia K., Ramirez, Pedro, Seifert, Karl E., Shaw, Timothy J., Wilson, Chris, Yin, Chuan, Zhao, Xixi, Proceedings of the Ocean Drilling Program; scientific results, Iberia abyssal plain; covering Leg 149 of the cruises of the Drilling Vessel JOIDES Resolution; Balboa Harbor, Panama, to Lisbon, Portugal; sites 897-901, 10 March-25 May 1993149489-495Ocean Drilling Program Hole 899B on the Iberia Abyssal Plain penetrated a thick serpentinite breccia flow underlain by smaller breccia flows, all separated by sediments containing weathered basalt and diabase (microgabbro) clasts. The basalt and diabase clasts, some with discolored weathering rinds, recovered with Early Cretaceous sediments below the thick upper serpentinite breccia, have the compositional characteristics of mid-ocean ridge basalt (MORB) modified by weathering on the seafloor. Seafloor weathering has added MgO and K (sub 2) O and removed CaO from the clasts, resulting in strongly modified major element compositions. However, the more immobile trace elements remain largely unaltered, and all basalt and diabase clasts have rare-earth element and spidergram patterns similar to transitional to enriched MORB (E-MORB). The E-MORB clasts are similar to the type of mid-ocean ridge volcanism that later produced the Atlantic Ocean floor in the region of the present Azores Plateau. The incompatible element enrichment necessary to produce E-MORB indicates a plume contribution and suggests that Early Cretaceous rifting on the Iberia Abyssal Plain was plume initiated despite the lack of extensive volcanism.completedGeochronologyabsolute ageAr/ArAtlantic Oceancontinental crustcontinental marginCretaceouscrustdatesemplacementEuropefeldspar groupframework silicatesgabbrosIberian abyssal plainIberian Peninsulaigneous rocksLeg 149Lower CretaceousmantleMesozoicNorth AtlanticNortheast AtlanticOcean Drilling Programoceanic crustODP Site 899plagioclaseplate tectonicsplutonic rocksriftingsilicatesSouthern Europeurn:org.iodp:exp:149urnlargerWorkCitationcampaignurn:org.iodp:exp:149:site:899urnlargerWorkCitationstudyurn:org.iodp:exp:149urnlargerWorkCitationcampaignEnglishgeoscientificInformation-12.1604-12.160440.462240.4622application/pdfunknownSEDIS Publication Catalogue

ana.macario@awi.de

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