ISOTOPIC COMPOSITION AND CONCENTRATION OF SULFUR IN CARBONACEOUS CHONDRITES

New sulfur isotopic ratio measurements are reported for seven carbonac eous chondrites. Newly developed procedures permit measurement of delt a S-33, delta S-34, and delta S-36 at precisions significantly greater than previously reported. A search for S-36 nucleosynthetic anomalies coproduced with anomalies in, for example, Ti-50 and Ca-48 was negati ve. The high endemic sulfur concentration probably dilutes any S-36 an omaly, and separation of individual sulfur phases may be needed to ide ntify S-36 carrier phases. Large internal isotopic variations are obse rved, deriving from parent body and possibly nebular processes. Chondr ule separates from Allende demonstrate isotopic compositions which var y as a function of diameter. High-temperature gas-solid exchange and a two-component mixing model may account for the observations. High-res olution isotopic data and structural information are reported for orga nic sulfur compounds separated by chemical extractions. The insoluble organics appear to be of either aliphatic or alicyclic structure and a re dominant phases.