Organic Composition of Sulphide Ores in the Okinawa Trough and Its Implications

作     者：张绮玲 侯增谦 唐邵华 ZHANG Qiling;HOU Zengqian;Tang Shaohua

作者机构：Institute of Mineral Deposits Chinese Academy of Geological Sciences 26 Baiwanzhuang Road 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2001年第75卷第2期

页      面：196-203页

核心收录：

学科分类：0709[理学-地质学] 081803[工学-地质工程] 07[理学] 08[工学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 

基　　金：This work was supported by the National Natural Science Foundation of China Grant 49773177 

主　　题：Okinawa Trough sulphide ores organic matter biomarker 

摘      要：A preliminary organic geochemical study shows that the sulphide ores from the hydrothermal deposit of the Okinawa Trough are generally low in the total organic carbon and extremely low in the soluble organic matter. In the aliphatic hydrocarbon fraction, the n-alkanes range from C15 to C35, with usual maxima in the middle n-C20 region and strong odd-carbon number predominance when n C25 (CPI = 1.2). The dominant analog in the aromatic fraction is phenanthrene, a polynuclear aromatic hydrocarbon, which provides evidence for hydrothermal activity. The organic matter derived mainly from marine planktonic and terrigenous vascular plants is entrapped in a high-temperature regime such as an active chimney and cooled quickly in the sulphide ores on the seafloor. Organic matter and sulphides are definitely products of a high-temperature alteration. The biomarker compounds indicate that the ores are formed under low Eh and pH conditions—a reducing to anoxic environment, which is favourable for sulphates to be reduced into sulphides by biogenic (bacterial) or abiogenic activity.