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
Article first published online: 6 DEC 2013
© The Meteoritical Society, 2013.
Meteoritics & Planetary Science
Volume 48, Issue 12, pages 2451–2468, December 2013
How to Cite
Fazio, A., D'Orazio, M., Folco, L., Gattacceca, J. and Sonzogni, C. (2013), 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. Meteoritics & Planetary Science, 48: 2451–2468. doi: 10.1111/maps.12231
- Issue published online: 23 DEC 2013
- Article first published online: 6 DEC 2013
- Manuscript Accepted: 7 OCT 2013
- Manuscript Received: 17 APR 2013
- Italian Ministry of Education, University and Research. Grant Number: 008222KBS_005
- Italian Programma Nazionale delle Ricerche in Antartide
- Italian Ministero degli Affari Esteri Progetti di Grande Rilevanza
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.