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Arabian Journal of Geosciences

, Volume 6, Issue 9, pp 3175–3184 | Cite as

A mineralogical and geochemical study of polymict eucrite discovered in Sahara of southwest Algeria

  • Abdelmadjid Seddiki
  • Bertrand Moine
  • Jean Yves Cottin
  • Jérôme Bascou
  • Marguerite Godard
  • François Faure
  • Michèle Bourot-Denise
  • Nacera Remaci
Original Paper

Abstract

NWA2268 is a polymict eucrite discovered in the Sahara, at southwest Algeria, close to the region of Tindouf. This meteorite weighs 65 g and presents a thin black fusion crust. The rock is fine- to medium-grained breccia and contains mineral fragments of plagioclases, pyroxenes, spinel, olivine and silica. The rock contains some basaltic fragments with sub-ophitic or cumulative textures, constituted by plagioclases and exsolved pigeonite. Pyroxferroite grains are present and locally destabilised in an association of hedenbergite, fayalite and silica. It also presents unequilibrated eucritic clast with heterogeneous pyroxenes and plagioclases compositions. Pyroxenes in the all of the other clasts have equilibrated composition, with exolved pigeonites with augite lamellaes. This polymict eucrite contains also partially devitrified glass that represents impact melts linked to impact event. None recrystallization of this glass confirms a lack of post-brecciation metamorphism. Diogenitic fragments are less abundant than 10 %. The oxygen isotopic composition of NWA2268 is Δ17O (−0.43). This meteorite is interpreted as belonging to the HED group attributed to the 4-Vesta asteroid.

Keywords

Algeria Meteorite Basaltic achondrite Polymict eucrite 4-Vesta NWA2268 

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Copyright information

© Saudi Society for Geosciences 2012

Authors and Affiliations

  • Abdelmadjid Seddiki
    • 1
  • Bertrand Moine
    • 2
  • Jean Yves Cottin
    • 2
  • Jérôme Bascou
    • 2
  • Marguerite Godard
    • 3
  • François Faure
    • 4
  • Michèle Bourot-Denise
    • 5
  • Nacera Remaci
    • 1
  1. 1.Laboratoire de Géoressources et Risques NaturelsUniversité d’OranOranAlgeria
  2. 2.Laboratoire de Pétrologie-GéochimieUniversité Jean MonnetSaint-Etienne cedex2France
  3. 3.Géosciences MontpellierUniversité Montpellier IIMontpellier cedex5France
  4. 4.CRPG, Université Henri Poincaré de NancyVandoeuvre-lès-NancyFrance
  5. 5.Laboratoire de MinéralogieMuséum National d’Histoire NaturelleParisFrance

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