摘要
南海东北部沉积物顶空气甲烷含量较高,海底存在明显的甲烷渗溢现象。该海域6个沉积物岩心的孔隙水硫酸盐浓度和顶空气甲烷含量随深度变化而变化,出现明显的硫酸盐-甲烷互相消耗区域,硫酸盐和甲烷浓度均急剧下降。HD109、HD170、HD196A、HD200、HD319和GC10等6个岩心的硫酸盐还原-甲烷厌氧氧化界面(SMI)分别位于704、911、728、636、888、792cm处,完全落入全球水合物区富甲烷环境的SMI深度范围之内。强烈的甲烷渗溢过程使得硫酸盐-甲烷互相消耗作用加剧,并形成浅的SMI。浅的SMI显示了东北部存在强烈的甲烷渗溢活动以及强烈的甲烷厌氧氧化作用,具有天然气水合物成藏的典型特征。
Abstract： The Northeastern part of the South China Sea （SCS） is rich in methane and there is methane seepage on the seafloor. Six sediment cores recovered from the northeastern SCS show that both sulfate and methane contents decrease with depth in the consuming zone of sulfate and methane. Headspaee meth- ane of these cores increases with depth and reaches an anomalous high at the bottom of cores. By extrapo- lation, the depth of sulfate-methane interface （SMI） in the cores of HD109, HD170, HD196A, HD200, HD319 and GC10 are located at 704cmbsf, 911cmbsf, 728cmbsf, 636cmbsf, 888cmbsf, 792cmbsf, respec- tively, indicating very shallow SMI depths. Strong methane seepage will intensify the co-consumption of sulfate and methane, leading to the shift of SMI depths towards the seafloor. The shallow SMIs, which of ten occur in gas hydrate localities worldwide, imply that the northeastern SCS is a good gas hydrate-prone setting.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2012年第1期93-98,共6页
Marine Geology & Quaternary Geology
基金
国家自然科学基金项目(40730844)
"973"项目(2009CB219502)
中国地质调查局"天然气水合物资源评价及勘探开发战略研究"下属课题(GZH200200203-04-01)
