南海北部烟囱状碳酸盐岩记录的冷泉流体活动演化特征研究
发布时间：2019-05-09 15:11
【摘要】：冷泉碳酸盐岩是冷泉渗漏活动的重要产物之一,它记录了冷泉流体的来源、其活动演化特征和沉积环境等。通过对南海北部东沙海域Site3站位采集的三个烟囱状冷泉碳酸盐岩的矿物成分、碳氧同位素及碳酸盐岩中黄铁矿硫同位素的研究,确定了冷泉渗漏可能的流体来源,结合烟囱状碳酸盐岩独特的形貌特征,探讨了研究区冷泉流体的活动演化特征。烟囱A为环状,外环直径16 cm,中央流体通道直径5 cm;烟囱B呈底部直径8 cm的实心锥形;烟囱C也为环状,外环直径20 cm,中央流体通道直径12 cm。三个烟囱都具有较负的碳同位素组成(δ~(13)CVPDB值低至 55.7‰)和较正的氧同位素组成(δ~(18)OVPDB值高达5.4‰)特征。研究认为,甲烷是该海域冷泉渗漏流体的主要烃类来源,其中沉淀烟囱C的冷泉流体中很可能存在水合物分解释放流体的加入。三个烟囱状碳酸盐岩的外层相比于内层,普遍具有δ~(13)C值高、δ~(18)O值低、δ~(34)S值高的特征,认为这是由于烟囱状碳酸盐岩从外至内形成过程中沉积空间逐渐受到限制导致流体渗漏强度增强而造成的。综上所述,烟囱状冷泉碳酸盐岩因其独特的形态结构,是冷泉流体渗漏特征在时间和空间上变化的优良记录者。
[Abstract]:Cold spring carbonate rock is one of the important products of cold spring leakage. It records the source of cold spring fluid, its activity evolution characteristics and sedimentary environment. Based on the study of mineral composition, carbon and oxygen isotopes and pyrite sulfur isotopes in three chimneys cold spring carbonate rocks collected at Site3 station in Dongsha sea area, northern South China Sea, the possible fluid sources of cold spring leakage have been determined. Based on the unique morphologies of chimney-shaped carbonate rocks, the active evolution characteristics of cold spring fluids in the study area are discussed. Chimney A is annular, outer ring diameter 16 cm, central fluid channel diameter 5 cm; chimney B is solid cone with bottom diameter 8 cm, chimney C is also annular, outer ring diameter 20 cm, central fluid channel diameter 12 cm. All three chimneys have negative carbon isotopic composition (未 ~ (13) CVPDB value as low as 鈮，
本文编号：2472862
[Abstract]:Cold spring carbonate rock is one of the important products of cold spring leakage. It records the source of cold spring fluid, its activity evolution characteristics and sedimentary environment. Based on the study of mineral composition, carbon and oxygen isotopes and pyrite sulfur isotopes in three chimneys cold spring carbonate rocks collected at Site3 station in Dongsha sea area, northern South China Sea, the possible fluid sources of cold spring leakage have been determined. Based on the unique morphologies of chimney-shaped carbonate rocks, the active evolution characteristics of cold spring fluids in the study area are discussed. Chimney A is annular, outer ring diameter 16 cm, central fluid channel diameter 5 cm; chimney B is solid cone with bottom diameter 8 cm, chimney C is also annular, outer ring diameter 20 cm, central fluid channel diameter 12 cm. All three chimneys have negative carbon isotopic composition (未 ~ (13) CVPDB value as low as 鈮，
本文编号：2472862
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