南海北部深海甲烷冷泉自生碳酸盐岩显微结构特征与流体活动关系初探

现代地质 ›› 2008, Vol. 22 ›› Issue (3): 376-381.

南海北部深海甲烷冷泉自生碳酸盐岩显微结构特征与流体活动关系初探

苏新¹,陈芳²,陆红锋²,黄永样²

1中国地质大学海洋学院，北京 100083;2广州海洋地质调查局，广东广州 510760

收稿日期:2008-05-10 修回日期:2008-06-12 出版日期:2008-03-20 发布日期:2008-03-20
作者简介:苏新, 女, 教授，博士生导师,1957年出生, 地层古生物专业, 主要从事钙质超微化石、海洋地质和海洋气体水合物方面的研究。
基金资助:
国家自然科学基金项目（40672005）

Micro-textures of Methane Seep Carbonates from the Northern South China Sea in Correlation with Fluid Flow

SU Xin¹, CHEN Fang², LU Hong-feng², HUANG Yong-Yang²

1School of Marine Geosciences, China University of Geosciences, Beijing 100083,China;
2Guangzhou Marine Geological Survey, Guangzhou, Guangdong 510760，China

Received:2008-05-10 Revised:2008-06-12 Online:2008-03-20 Published:2008-03-20

摘要/Abstract

摘要：

对2002年“海洋四号”在南海北部深水冷泉活动区水深约3 000 m海底获得的1块自生碳酸盐岩展开了岩石学、地球化学和显微结构的分析研究。结果表明，该HD-83站位岩石样品为有多孔不规则块体，属于与扩散流有关的冷泉自生碳酸盐岩。其自生碳酸盐矿物成分为镁方解石或文石，含量达全岩的17%。全岩碳同位素值δ¹³C为-61.403‰，氧同位素值δ¹⁸ O为3.560 6‰，属于甲烷冷泉喷口成因自生碳酸盐岩，甲烷来源以微生物成因为主。该岩石显微结构有泡孔状、充填通道、不规则裂隙、虫孔边缘加厚4种主要类型。通过对比，推知这些显微结构可能与甲烷分解排气释放或流体逃逸通道有关。本研究注意到在岩石的裂隙或孔道中菌丝体普遍存在，可能属于菌席的组成份子，依靠通道内流体进行化能合成。

关键词: 甲烷冷泉自生碳酸盐岩, 显微结构, 流体, 菌丝, 南海

Abstract:

A small piece of carbonate concretion collected by research vessel “Haiyang 4” from about 3,000 m seafloor of northern South China Sea was analyzed. The piece of carbonates was identified as methane seep carbonate with 17% magnesium calcites andδ¹³C value of -61.403‰ and δ¹⁸O value of 3.560,6‰. The carbonate shows four micro-textures derived by methane degassing, fluid flow and organisms activities. Calcite rings occur commonly along the walls of vesicles. Inner walls of burrow(worm tubes)are also coated by carbonate rims. Bacterial filaments were found in the fractures or conduits of carbonate, which depended on the methane-rich fluid to survive. Fluid conduits and fractures were often filled by coarser sands, which resulted from fluid flow escaping along these conduits.

Key words: methane seep carbonate, micro-texture, fluid, bacterial filament, South China Sea

中图分类号:

苏新,陈芳,陆红锋,黄永样. 南海北部深海甲烷冷泉自生碳酸盐岩显微结构特征与流体活动关系初探[J]. 现代地质, 2008, 22(3): 376-381.

SU Xin, CHEN Fang, LU Hong-feng, HUANG Yong-Yang. Micro-textures of Methane Seep Carbonates from the Northern South China Sea in Correlation with Fluid Flow[J]. Geoscience, 2008, 22(3): 376-381.

参考文献

[1]Bohrmann G, Greinert J, Suess E, et al. Authigenic carbonates from the Cascadia subduction zone and their relation to gas hydrate stability[J]. Geology, 1998, 26〖BF〗(7): 647-650.

[2]DiazDelRio V, Somoza L, MartinezFrias J, et al. Vast fields of hydrocarbonderived carbonate chimneys related to the accretionary wedge / olistostrome of the gulf of Cadiz[J]. Marine Geology, 2003, 195: 177-200.

[3]Stakes D S, Orange D, Paduan J B, et al. Coldseeps and authigenic carbonate formation in Monterey Bay, California[J]. Marine Geology, 1999, 159: 93-109.

[4]Roger Luff, Klaus Wallmann. Fluid flow, methane fluxes, carbonate precipitation and biogeochemical turnover in gas hydratebearing sediments at Hydrate Ridge, Cascadia Margin: Numerical modeling and mass balances[J]. Geochimica et Cosmochimica Acta, 2003,67(18): 3403-3421.

[5]Simona Cavagna, Pierangelo Clari, Luca Martire.The role of bacteria in the formation of cold seep carbonates: geological evidence from Monferrato(Tertiary, NW Italy)[J]. Sedimentary Geology,1999, 126: 253-270.

[6]陈多福，陈先沛，陈光谦. 冷泉流体沉积碳酸盐岩的地质地球化学特征[J]. 沉积学报，2002， 20（1）：34-40.

[7]陈多福, 苏正, 冯东, 等. 海底天然气渗漏系统水合物成藏过程及控制因素[J]. 热带海洋学报, 2005, 24(3): 1-9.

[8]张光学,黄永样,祝有海,等.南海天然气水合物的成矿远景[J]. 海洋地质与第四纪地质，2002，22（1）:75-81.

[9]苏新, 陈芳,于兴河,等. 南海陆坡中新世以来沉积物特性与气体水合物分布初探[J].现代地质，2005， 19（1）：1-13.

[10]彭勇. 南海首次发现冷泉，证实可燃冰存在[EB/OL].2003-12-29. http://gd.sina.com.cn.htm.

[11]Suess E. RV SONNE cruise report SO 177, SinoGerman cooperative project, South China Sea Continental Margin: geological methane budget and environmental effects of methane emissions and gas hydrates. IFMGEOMAR Reports. http://store.pangaea.de/documentation/Reports/SO177.pdf.2005.

[12]Zhang H,Yang S,Wu N, et al. GMGS-1 Science Team. China’s first gas hydrate expedition successful. Fire in the Ice: Methane Hydrate Newsletter[R].National Energy Technology Laboratory, US Department of Energy, 2007,Spring/Summer Issue,1.

[13]陈多福，黄永样，冯东，等. 南海北部冷泉碳酸盐岩和石化微生物细菌及其地质意义[J].矿物岩石地球化学通报，2005，24（3）：185-189.

[14]陆红锋，陈芳，刘坚，等. 南海北部神狐海区的自生碳酸盐岩烟囱——海底富烃流体活动的记录[J]. 地质论评，2006,52（3）：352-357.

[15]Chen Duofu, Huang Yongyang, Yuan Xunlai, et al. Seep carbonates and preserved methane oxidizing archaea and sulfate reducing bacteria fossils suggest recent gas venting on the seafloor in the Northeastern South China Sea[J].Marine and Petroleum Geology, 2005,22: 613-621.

[16]陈忠, 颜文, 陈木宏, 等. 南海北部大陆坡冷泉碳酸盐结核的发现: 海底天然气渗漏活动的新证据[J]. 科学通报, 2006, 51(9): 1065-1072.

[17]Han Xiqiu,Suess Erwin,Huang Yongyang, et al.Jiulong methane reef: Microbial mediation of seep carbonates in the South China Sea[J]. Marine Geology, 2008, 249: 243-256.

[18]Greinert J, Bohrmann G, Suess E.Gas hydrateassociated carbonates and methaneventing at Hydrate Ridge: classification, distribution and origin of authigenic lithologies[M]//Paull C K, Dillon W P. Natural Gas Hydrates: Occurrence, Distribution and Detection. Washington D C: Geophys Monogr American Geophysical Union, 2001: 99-113.

[19]Roberto Barbieri, Barbara Cavalazzi. Microbial fabrics from Neogene cold seep carbonates,

Northern Apennine, Italy[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2005, 227: 143-155.

[20]Mazzini A, Jonk R, Duranti D,et al. Fluid escape from reservoirs: implications from cold seeps, fractures and injected sands: Part I. The fluid flow system[J].Journal of Geochemical Exploration,2003,(78-79): 293-296.

[21]Han X, Suess E, Sahling H, et al. Fluid venting activity on the Costa Rica Margin: new results from authigenic carbonates[J].International Journal of Earth Sciences(Geol Rundschau),2004, 93: 596-611.

[22]Greinert Jens,Bohrmann Gerhard,Elvert Marcus. Stromatolitic fabric of authigenic carbonate crusts: result of anaerobic methane oxidation at cold seeps in 4,850 m water depth[J].International Journal of Earth Sciences(Geol Rundschau),2002, 91:698-711.