Rai Vinai K, Jackson Teresa L, Thiemens Mark H
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093-0356, USA.
Science. 2005 Aug 12;309(5737):1062-5. doi: 10.1126/science.1112954.
Sulfides from four achondrite meteorite groups are enriched in 33S (up to 0.040 per mil) as compared with primitive chondrites and terrestrial standards. Stellar nucleosynthesis and cosmic ray spallation are ruled out as causes of the anomaly, but photochemical reactions in the early solar nebula could produce the isotopic composition. The large 33S excess present in oldhamite from the Norton County aubrite (0.161 per mil) suggests that refractory sulfide minerals condensed from a nebular gas with an enhanced carbon-oxygen ratio, but otherwise solar composition is the carrier. The presence of a mass-independent sulfur effect in meteorites argues for a similar process that could account for oxygen isotopic anomalies observed in refractory inclusions in primitive chondrites.
与原始球粒陨石和地球标准相比，来自四个无球粒陨石群的硫化物富含33S（高达千分之0.040）。恒星核合成和宇宙射线散裂被排除为异常的原因，但早期太阳星云的光化学反应可能产生这种同位素组成。诺顿县紫苏辉石无球粒陨石中的硫镁矿中存在的大量33S过剩（千分之0.161）表明，难熔硫化物矿物是从具有增强碳氧比的星云气体中凝聚而成的，但除此之外，太阳成分是载体。陨石中质量无关的硫效应的存在表明存在一个类似的过程，该过程可以解释在原始球粒陨石的难熔包体中观察到的氧同位素异常。
