Northwest Africa 5958: A weakly altered CM‐related ungrouped chondrite, not a CI3. (9th March 2016)

• Record Type: Journal Article
• Authors: Jacquet, Emmanuel; Barrat, Jean‐Alix; Beck, Pierre; Caste, Florent; Gattacceca, Jérôme; Sonzogni, Corinne; Gounelle, Matthieu
• Is Part Of: Meteoritics & planetary science. Volume 51:Number 5(2016:May)
• Page Start: 851
• Page End: 869
• Publication Date: 2016-03-09
• Subjects: Meteorites -- Periodicals; Planetology -- Periodicals; 523.4
• DOI: 10.1111/maps.12628
• Languages: English
• ISSNs: 1086-9379

Abstract

Abstract: Northwest Africa (NWA) 5958 is a carbonaceous chondrite found in Morocco in 2009. Preliminary chemical and isotopic data leading to its initial classification as C3.0 ungrouped have prompted us to conduct a multitechnique study of this meteorite and present a general description here. The petrography and chemistry of NWA 5958 is most similar to a CM chondrite, with a low degree of aqueous alteration, apparently under oxidizing conditions, and evidence of a second, limited alteration episode manifested by alteration fronts. The oxygen isotopic composition, with ∆' 17 O = −4.3‰, is more 16 O‐rich than all CM chondrites, indicating, along with other compositional arguments, a separate parent body of origin. We suggest that NWA 5958 be reclassified as an ungrouped carbonaceous chondrite related to the CM group.