欧洲二叠纪含铜页岩中含硫多环芳烃的成因探讨

Formation and distribution of polycyclic aromatic sulfur compounds in Permian kupferschiefer from europe

由于反应机制的不同,欧洲二叠纪含铜页岩中的含硫多环芳烃可能形成于不同的成岩阶段。一部分形成于成岩早期,而另一部分则形成于成岩晚期。含硫多环芳烃的含量不仅受沉积环境和有机质成熟度的影响,而且还受贱金属含量的影响。Oberkatz剖面中高成熟度样品的Ro达到了1.3%,而它的含硫多环芳烃的含量低于50μg/gCorg。实验证明,取自Sieroszowice-1,Si-eroszowice-2,Polkowice-1和Konrad地区的样品中的含硫多环芳烃含量较高(450μg/gCorg^850μg/gCorg),它们的成熟度介于0.7%~0.9%Ro,贱金属含量低于5%。形成于静海相环境下的高矿化度样品的贱金属含量达到23.1%,而含硫多环芳烃的含量仅为52μg/gCorg,这是因为在沉积的过程中,硫优先与贱金属反应,只有当金属被消耗完时,硫才会与有机质反应形成含硫的多环芳烃。所以沉积环境、干酪根类型和含硫多环芳烃在地层中的迁移不是含铜页岩中含硫多环芳烃形成的主要因素。

Polycyche aromatic sulfur compounds （PASCs） in Permian Kupferschiefer might form in different diagenetic stages by different mechanisms. A part of them might form in earlier diagenetic stage, and another part might form in later diagenetic stage. The contents of PASCs are influenced not only by depositional environment and the maturity of the organic matter, but also by base metal content. Ro of highly mature samples from the Oberkatz lithologic section reaches 1.3 %, the PASC contents are lower than 50 （ug/g Corg. Higher PASC contents （450 - 850 （ug/g Corg） are observed in the samples of SC1, SC2, PK1 and the samples from Konrad section. Their Ro values are between 0.7 and 0.9%, and their base metal contents are lower than 5 %. In a highly mineralized sample with base metal content of 23.1%, the PASC content is only 52 （ug/g Corg. This phenomenon may be explained by the preferential reaction of sulfur with base metals during the depositional process. Only after metals are used up, sulfur would react with organic matter and form PASCs. The depositional environment, kerogen type and the migration of PASCs from other strata are apparently not the predominant factors for the formation of PASCs in the Kupferschiefer.