Presolar grains in the CM 2 chondrite Sutter's Mill

• Published in: Meteoritics & planetary science Vol. 49; no. 11; pp. 2038 - 2046
• Main Authors: Zhao, Xuchao, Lin, Yangting, Yin, Qing‐Zhu, Zhang, Jianchao, Hao, Jialong, Zolensky, Michael, Jenniskens, Peter
• Format: Journal Article
• Language: English
• Published: 01.11.2014
• ISSN: 1086-9379; 1945-5100
• DOI: 10.1111/maps.12289

Abstract The Sutter's Mill ( SM ) carbonaceous chondrite is a regolith breccia, composed predominantly of CM 2 clasts with varying degrees of aqueous alteration and thermal metamorphism. An investigation of presolar grains in four Sutter's Mill sections, SM 43, SM 51, SM 2‐4, and SM 18, was carried out using Nano SIMS ion mapping technique. A total of 37 C‐anomalous grains and one O‐anomalous grain have been identified, indicating an abundance of 63 ppm for presolar C‐anomalous grains and 2 ppm for presolar oxides. Thirty‐one silicon carbide (SiC), five carbonaceous grains, and one Al‐oxide (Al 2 O 3 ) were confirmed based on their elemental compositions determined by C‐N‐Si and O‐Si‐Mg‐Al isotopic measurements. The overall abundance of SiC grains in Sutter's Mill (55 ppm) is consistent with those in other CM chondrites. The absence of presolar silicates in Sutter's Mill suggests that they were destroyed by aqueous alteration on the parent asteroid. Furthermore, SM 2‐4 shows heterogeneous distributions of presolar SiC grains (12–54 ppm) in different matrix areas, indicating that the fine‐grained matrix clasts come from different sources, with various thermal histories, in the solar nebula.