重晶石沉积类型及成因评述--兼论扬子地区下寒武统重晶石的富集机制

重晶石沉积类型丰富，具有多种成因过程。通常，沉积型重晶石可分为生物、热液、成岩和冷泉重晶石四种类型。富钡与富硫酸盐的流体（海水、早成岩孔隙水或热液流体）及其相互作用过程（水柱、热液系统、沉积柱、沉积物-水界面附近）决定了重晶石的沉积环境、宏微观产出方式、同位素组成及相应的地质意义。另外，根据扬子地区下寒武统富重晶石沉积的地质特征，简述了其各种富集机制的适用性及争论。据此建议，结合埃迪卡拉纪-寒武纪转折时期的古海洋背景，对其进行详细的沉积学及地球化学分析，有助于深化成因认识，弥合分歧。

Genetic Classification of Sedimentary Barites and Discussion on the Origin of the Lower Cambrian Barite-rich Deposits in the Yangtze Block,South China

Barites are widely distributed in sedimentary records with various geological characteristics and formation processes. In general, sedimentary barites can be subdivided into marine (or biogenic), hydrothermal, diagenetic and cold seeps barites. The sedimentary environments, macro- and micro-occurrences, geochemical features (especially Sr and S isotopes) and corresponding geological implications of these four barite subtypes are controlled by the origin of barium- and sulfate-fluids (seawater, diagenetic porewater or hydrothermal fluids) and related interaction process (in seawater column, sediment column, sediment-water interface or hydrothermal system). In addition, this study further introduces the geological features of the Lower Cambrian barite-rich sediments in the Yangtze Block, South China, and summarizes the enrichment mechanisms having been proposed for these barite deposits and argues on their reconciliation and biases with geological features and processes. Based on the paleo-oceanic context during the Ediacaran-Cambrian transitional period, integrated sedimentological and geochemical researches together would provide better constrains on the origins of the Lower Cambrian barium-rich deposits in the Yangtze Block.