Organic Geochemistry of Sedimentary Rock-hosted Disseminated Gold Deposits in Southwestern

Organic Geochemistry of Sedimentary Rock-hosted

Disseminated Gold Deposits in Southwestern

Guizhou Province,China

BAO Zhiwei;ZHAO Zhenhua;Jayanta GUHA

【期刊名称】《地质学报（英文版）》 【年(卷),期】2005(079)001

【摘要】Sedimentary rock-hosted disseminated gold (SRHDG) deposits in the Youjiang-Nanpanjiang Basin,southwestern Guizhou Province are commonly hosted by the same fold crests that commonly contain a remarkable amount of organic material. The total organic carbon (TOC) contents of the ores and host rocks are usually less than 1%. The reflectance of vitrinite and pyrobitumen in the ores and the host rocks ranges from 1.5% to 4.5%, often in the range of 2% to 3%. In the Lannigou deposit, the reflectance of vitrinite and pyrobitumen in the ores is usually somewhat higher than those within the host rocks, indicating a hydrothermal impact on the organic matter in the altered host rocks. On the contrary, the estimated maximum paleotemperatures of the Getang and Zimudang deposits are higher than the homogenization temperatures of the fluid inclusions in the ores, signifying that the organic matter maturation predated Au mineralization. No correlation between the organic matter contents and Au concentrations were recognized in the ores.However, the most