D'Antonio, Massimo; Kristensen, Mette B. (2006): Electron microprobe investigation of primary minerals in basalts from the West Philippine Sea basin (Ocean Drilling Program Leg 195, Site 1201). Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Shinohara, Masanao (editor), Salisbury, Matthew H. (editor), Richter, Carl (editor), 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, 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, 195, georefid:2006-066608

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 degrees C) and under increasing fO (sub 2) conditions. The major element composition of clinopyroxene suggests a backarc affinity of the mantle source of Site 1201 basement.
West: 135.0500 East: 135.0600 North: 19.1800 South: 19.1700
Expedition: 195
Site: 195-1201
Supplemental Information:
Data report; available only on CD-ROM in PDF format and on the Web in PDF or HTML
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Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.195.108.2005 (c.f. for more detailed metadata)
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