The Almahata Sitta (AhS) meteorite is a unique polymict ureilite. Recently, carbonaceous chondritic lithologies were identified in AhS. Organic matter (OM) is ubiquitously found in primitive carbonaceous chondrites. The molecular and isotopic characteristics of this OM reflect its origin and parent body processes, and are particularly sensitive to heating. The C1 lithologies AhS 671 and AhS 91A were investigated, focusing mainly on the OM. We found that the OM in these lithologies is unique and contains primitive isotopic signatures, but experienced slight heating possibly by short-term heating event(s). These characteristics support the idea that one or more carbonaceous chondritic bodies were incorporated into the ureilitic parent body. The uniqueness of the OM in the AhS samples implies that there were large variations in primitive carbonaceous chondritic materials in the solar system other than known primitive carbonaceous chondrite groups such as CI, CM, and CR chondrites.

中文翻译：

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Almahata Sitta 碳质球粒陨石岩性中的有机质：将先前未取样的碳质球粒陨石岩性合并到尿素岩风化层中

Almahata Sitta (AhS) 陨石是一种独特的多晶硅陨石。最近，在 AhS 中发现了碳质球粒陨石岩性。有机质 (OM) 普遍存在于原始碳质球粒陨石中。这种 OM 的分子和同位素特征反映了它的起源和母体过程，并且对加热特别敏感。研究了 C1 岩性 AhS 671 和 AhS 91A，主要关注 OM。我们发现这些岩性中的 OM 是独一无二的，包含原始同位素特征，但可能因短期加热事件而经历了轻微加热。这些特征支持一个或多个碳质球粒陨石小体并入尿结石母体的观点。