Presolar grains in the CM2 chondrite Sutter's Mill |
| |
| Authors: | Xuchao Zhao Yangting Lin Qing‐Zhu Yin Jianchao Zhang Jialong Hao Michael Zolensky Peter Jenniskens |
| |
| Institution: | 1. Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, , Beijing, 100029 China;2. Department of Earth and Planetary Sciences, University of California at Davis, , Davis, California, 95616 USA;3. ARES, NASA Johnson Space Center, , Houston, Texas, 77058 USA;4. SETI Institute, , Mountain View, California, 94043 USA;5. NASA Ames Research Center, , Moffett Field, California, 94035 USA |
| |
| Abstract: | The Sutter's Mill (SM) carbonaceous chondrite is a regolith breccia, composed predominantly of CM2 clasts with varying degrees of aqueous alteration and thermal metamorphism. An investigation of presolar grains in four Sutter's Mill sections, SM43, SM51, SM2‐4, and SM18, was carried out using NanoSIMS 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 (Al2O3) 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, SM2‐4 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. |
| |
| Keywords: | |
|
|
