The Longtang Pb-Zn deposit occurs in the Upper Sinian Guanyinyan Formation. The host rocks include sandy shale, cherty limestone and dolomitic limestone.The deposit is a typical one of thallogen origin.The mineral ass...The Longtang Pb-Zn deposit occurs in the Upper Sinian Guanyinyan Formation. The host rocks include sandy shale, cherty limestone and dolomitic limestone.The deposit is a typical one of thallogen origin.The mineral assemblage in the ore is made up of sphalerite, galena, pyrite, enargite,tennantite, seligmannite, asphalt, etc. The ore-forming process is possessed of multiepisode and multi-stage characters. Generally sphalerites exhibit algal stromatolitic, bacterial and algal colloidal textures, providing evidence for the direct involvement of algaeand bacteria in mineralization of ore-forming elements during sedimentary diagenesis.This is the first transmingration of ore-forming elements. However, pyrite embracing bacteria and galena replacing/filling trichomes are typical organic textures, which are relatedto organic carbon and bitumen that can adsorb or reduce ore-forming elements. This is anindirect process of organic mineralization, i.e., the second transmigration of ore-formingelements. δ34S values are all greater than 5%o, indicating the dominance of the heavysulfur isotopes. The ore-forming temperature deduced from fluid inclusions ranges from100℃ to 150℃±. All this goes to show that the Longtang Pb-Zn deposit is of thallogenorlgin.展开更多
文摘The Longtang Pb-Zn deposit occurs in the Upper Sinian Guanyinyan Formation. The host rocks include sandy shale, cherty limestone and dolomitic limestone.The deposit is a typical one of thallogen origin.The mineral assemblage in the ore is made up of sphalerite, galena, pyrite, enargite,tennantite, seligmannite, asphalt, etc. The ore-forming process is possessed of multiepisode and multi-stage characters. Generally sphalerites exhibit algal stromatolitic, bacterial and algal colloidal textures, providing evidence for the direct involvement of algaeand bacteria in mineralization of ore-forming elements during sedimentary diagenesis.This is the first transmingration of ore-forming elements. However, pyrite embracing bacteria and galena replacing/filling trichomes are typical organic textures, which are relatedto organic carbon and bitumen that can adsorb or reduce ore-forming elements. This is anindirect process of organic mineralization, i.e., the second transmigration of ore-formingelements. δ34S values are all greater than 5%o, indicating the dominance of the heavysulfur isotopes. The ore-forming temperature deduced from fluid inclusions ranges from100℃ to 150℃±. All this goes to show that the Longtang Pb-Zn deposit is of thallogenorlgin.
