Electron microprobe investigation of primary minerals in basalts from the West Philippine Sea basin (Ocean Drilling Program Leg 195, Site 1201)

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doi: 10.2973/odp.proc.sr.195.108.2005
Author(s): D'Antonio, Massimo; Kristensen, Mette B.
Ocean Drilling Program, Leg 195, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
Universita degli Studi di Napoli "Federico II", Dipartimento di Scienze della Terra, Naples, Italy
Other:
Geological Survey of Canada, Canada
Ocean Drilling Program, United States
Japan Agency for Marine-Earth Science and Technology, Japan
University of Leicester, United Kingdom
Universita di Napoli "Federico II", Italy
University of Southampton, United Kingdom
Alfred Wegener Institute for Polar and Marine Research, Federal Republic of Germany
Rosenstiel School of Marine and Atmospheric Science, United States
University of Hawaii at Manoa, United States
ISTEEM, Laboratoire de Tectonophysique, France
University of Texas at Dallas, United States
University of Wisconsin at Madison, United States
University of Toronto at Scarborough, Canada
U. S. Geological Survey, United States
University of Aarhus, Denmark
Western Washington University, United States
University of South Florida, United States
China University of Geosciences, China
National Taiwan University, Taiwan
Volume Title: Proceedings of the Ocean Drilling Program; scientific results; seafloor observatories and the Kuroshio Current; covering Leg 195 of the cruises of the drilling vessel JOIDES Resolution; Apra Harbor, Guam, to Keelung, Taiwan; Sites 1200-1202; 2 March-2 May 2001
Volume Author(s): Shinohara, Masanao, editor; Salisbury, Matthew H.; Richter, Carl; Araki, Eiichiro; Barr, Samantha R.; D'Antonio, Massimo; Dean, Simon M.; Diekmann, Bernhard; Edwards, K. Michelle; Fryer, Patricia B.; Gaillot, Philippe J.; Hammon, William S., III; Hart, David; Januszczak, Nicole; Komor, Stephen C.; Kristensen, Mette B.; Lockwood, John P.; Mottl, Michael J.; Moyer, Craig L.; Nakahigashi, Kazuo; Savov, Ivan P.; Su Xin; Wei, Kuo-Yen; Yamada, Tomoaki
Source: Proceedings of the Ocean Drilling Program; scientific results; seafloor observatories and the Kuroshio Current; covering Leg 195 of the cruises of the drilling vessel JOIDES Resolution; Apra Harbor, Guam, to Keelung, Taiwan; Sites 1200-1202; 2 March-2 May 2001, Masanao Shinohara, Matthew H. Salisbury, Carl Richter, Eiichiro Araki, Samantha R. Barr, Massimo D'Antonio, Simon M. Dean, Bernhard Diekmann, K. Michelle Edwards, Patricia B. Fryer, Philippe J. Gaillot, William S. Hammon, III, David Hart, Nicole Januszczak, Stephen C. Komor, Mette B. Kristensen, John P. Lockwood, Michael J. Mottl, Craig L. Moyer, Kazuo Nakahigashi, Ivan P. Savov, Su Xin, Kuo-Yen Wei and Tomoaki Yamada; Ocean Drilling Program, Leg 195, Shipboard Scientific Party, College Station, TX. Proceedings of the Ocean Drilling Program, Scientific Results (CD ROM), Vol.195, 24p. Publisher: Texas A&M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 1096-2514
Note: In English. Data report; available only on CD-ROM in PDF format and on the Web in PDF or HTML. 26 refs.CD-ROM, ISSN 1096-2514; WWW, ISSN 1096-7451; illus., incl. 3 tables
Summary: The basement cored at Site 1201 (west Philippine Basin) during Ocean Drilling Program Leg 195 consists of a 91-m-thick sequence of basalts, mostly pillow lavas and perhaps one sheet lava flow, with a few intercalations of hyaloclastite and interpillow sedimentary material. Hydrothermal alteration pervasively affected the basalt sequence, giving rise to a variety of secondary minerals such as K-Fe-Mg-clay minerals, oxyhydroxides and clay minerals mixtures, natrolite group zeolites, analcite, alkali feldspar, and carbonate. The primary minerals of pillow and sheet basalts that survived the intense hydrothermal alteration were investigated by electron microprobe with the aim of characterizing their chemical composition and variability. The primary minerals are mostly plagioclase, ranging in composition from bytownite through labradorite to andesine, chromian-magnesian-diopside, and spinels, both Ti magnetite (partially maghemitized) and chromian spinel. Overall, the chemical features of the primary minerals of Site 1201 basalts correspond to the primitive character of the bulk rocks, suggesting that the parent magma of these basalts was a mafic tholeiitic magma that most likely only suffered limited fractional crystallization and crystallized at high temperatures (slightly below 1200°C) and under increasing fO2 conditions. The major element composition of clinopyroxene suggests a backarc affinity of the mantle source of Site 1201 basement.
Year of Publication: 2006
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; Basalts; Chemical composition; Concentration; Electron probe data; Geochemistry; Hydrothermal alteration; Igneous rocks; Lava flows; Leg 195; Metasomatism; Mineral composition; North Pacific; Northwest Pacific; ODP Site 1201; Ocean Drilling Program; Pacific Ocean; Philippine Sea; Volcanic rocks; West Pacific; West Philippine Basin
Coordinates: N191700 N191800 E1350600 E1350500
Record ID: 2006066608
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