摘要
天然气水合物沉积环境出现的岩石矿物主要为碳酸盐岩、黄铁矿、石膏等。自生碳酸盐岩的典型特点为极负的δ^(13)C_(PDB)值(最低可达-70.0‰)、正的δ^(18)O_(PDB)值(+2.5‰～+6.5‰),碳酸盐矿物主要为镁方解石、文石、白云石和菱铁矿。黄铁矿以霉球状、条状为主。石膏则主要为自形晶体,透明。此类自生岩石矿物与甲烷厌氧氧化过程或水合物的形成效应有关。南海沉积物中出现的自生碳酸盐岩、黄铁矿和石膏,其特点与水合物沉积环境中的十分类似,预示了南海可能存在有利于水合物成藏的地球化学过程。
Authigenic carbonate, pyrite and gypsum were the main minerals associated with cold seeps or gas hydrate deposit. Authigenie carbonate is eharaeterozed by exceptionally negative δ13CPDB （ up to - 70‰） and positive δ18 OPDB （ ＋ 2. 5‰- ＋ 6. 5‰） , the main carbonate phase of Mg-calcite, aragonite, dolomite and siderite. The morphology of authigenic pyrite is framboids and rods. Gypsum shows a transparent regarded as the indirect products of anaerobic and euhedral crystal shape. These minerals were methane oxidation or gas hydrate precipitating effect. From the sediments of South China Sea, we got large amounts of authigenic carbonates and pyrite, some gypsums. The authigenic minerals found in South China Sea are identical to the ones retrieved at cold seeps or gas hydrate sites, indicating a possible geochemical process of gas hydrate forming at South China Sea.
出处
《南海地质研究》
2006年第1期93-104,共12页
Gresearch of Eological South China Sea
