The extremely reduced silicate‐bearing iron meteorite Northwest Africa 6583: Implications on the variety of the impact melt rocks of the IAB‐complex parent body |
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| Authors: | Agnese Fazio Massimo D'Orazio Luigi Folco Jérôme Gattacceca Corinne Sonzogni |
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| Institution: | 1. Dipartimento di Scienze della Terra, Università di Pisa, , 56126 Pisa, Italy;2. CNRS‐IRD 3. Aix‐Marseille Université, Centre Européen de Recherche et d'Enseignement de Géosciences de l'Environnement (CEREGE), UM34, , Aix‐en‐Provence, 13545 France |
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| Abstract: | Northwest Africa (NWA) 6583 is a silicate‐bearing iron meteorite with Ni = 18 wt%. The oxygen isotope composition of the silicates (?′17O = ?0.439 ‰) indicates a genetic link with the IAB‐complex. Other chemical, mineralogical, and textural features of NWA 6583 are consistent with classification as a new member of the IAB‐complex. However, some unique features, e.g., the low Au content (1.13 μg g?1) and the extremely reducing conditions of formation (approximately ?3.5 ?IW), distinguish NWA 6583 from the known IAB‐complex irons and extend the properties of this group of meteorites. The chemical and textural features of NWA 6583 can be ascribed to a genesis by impact melting on a parent body of chondritic composition. This model is also consistent with one of the most recent models for the genesis of the IAB‐complex. Northwest Africa 6583 provides a further example of the wide lithological and mineralogical variety that impact melting could produce on the surface of a single asteroid, especially if characterized by an important compositional heterogeneity in space and time like a regolith. |
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