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

*Corresponding author for this work

Research output: Contribution to journalArticle

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.

Original languageEnglish
Pages (from-to)3175-3184
Number of pages10
JournalArabian Journal of Geosciences
Volume6
Issue number9
DOIs
Publication statusPublished - 2013
Externally publishedYes

Keywords

  • 4-Vesta
  • Algeria
  • Basaltic achondrite
  • Meteorite
  • NWA2268
  • Polymict eucrite

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