NWA10758: A New CV3 Chondrite Bearing a Giant CAI with Hibonite-Rich Wark-Lovering RimNorthwest Africa (NWA) 10758 is a newly identified carbonaceous chondrite that is a Bali-like oxidized CV3. The large Ca-Al rich inclusion (CAI) in this sample is approx. 2.4 x 1.4 cm. The CAI is transitional in composition between type A and type B, with interior mineralogy dominated by melilite, plus less abundant spinel and Al-Ti rich diopside, and only very minor anorthite (Fig. 1A). This CAI is largely free of secondary alteration in the exposed section we examined, with almost no nepheline, sodalite or Ca-Fe silicates. The Wark-Lovering (WL) rim on this CAI is dominated by hibonite, with lower abundances of spinel and perovskite, and with hibonite locally overlain by melilite plus perovskite (as in Fig. 1B). Note that the example shown in 1B is exceptional. Around most of the CAI, hibonite + spinel + perovskite form the WL rim, without overlying melilite. The WL rim can be unusually thick, ranging from approx. 20 microns up to approx. 150 microns. A well-developed, stratified accretionary rim infills embayments of the CAI, and thins over protuberances in the convoluted CAI surface.
Document ID
20170005741
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Ross, D. K. (Jacobs Technologies Engineering Science Contract Group Houston, TX, United States)
Simon, J. I. (NASA Johnson Space Center Houston, TX, United States)
Zolensky, M. (NASA Johnson Space Center Houston, TX, United States)
Date Acquired
June 23, 2017
Publication Date
July 23, 2017
Subject Category
Lunar And Planetary Science And ExplorationGeophysics
Report/Patent Number
JSC-CN-39701
Meeting Information
Meeting: Annual Meeting of The Meteoritical Society