Northwest Africa 1232-a CO3 carbonaceous chondrite with two lithologies

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Author(s)

    • KIRIISHI Miho
    • Department of Earth and Planetary Sciences, Faculty of Science, Kobe University
    • TOMEOKA Kazushige
    • Department of Earth and Planetary Sciences, Faculty of Science, Kobe University

Abstract

Northwest Africa 1232 (NWA 1232) is a carbonaceous chondrite consisting of two lithologies (A and B) that are separated by a sharp boundary. A petrographic and mineralogical study indicates that both lithologies can be classified as type CO3. However, olivine in lithology B chondrules is more enriched in Fe than in lithology A, whereas olivine in lithology B matrix is more depleted in Fe than in lithology A. Chondrules and Ca-Al-rich inclusions (CAIs) in lithology B show a higher degree of nephelinization than those in lithology A. These differences can be explained by that lithology B has gone through a higher degree of thermal metamorphism than lithology A. These two lithologies probably represent rocks that have been thermally metamorphosed at different locations within a single CO parent body and later mixed to form the present combined rock during a brecciation process.

Journal

  • Journal of Mineralogical and Petrological Sciences

    Journal of Mineralogical and Petrological Sciences 103(2), 161-165, 2008-04-01

    Japan Association of Mineralogical Sciences

References:  9

Cited by:  1

Codes

  • NII Article ID (NAID)
    10020737275
  • NII NACSIS-CAT ID (NCID)
    AA11460926
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    13456296
  • Data Source
    CJP  CJPref  J-STAGE 
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