• 责任者：Chen Fang (Guangzhou Marine Geological Survey ; Guangzhou 510075 ; China) ; Su Xin
• 刊名：Earth Science
• 出版年：2013
• 卷期：38(5)
• 关键词：有孔虫类 ; foraminiferas ; 天然气水合物 ; gas hydrates ; 南海 ; South China Sea
• 页码：p.907-915
• 图表：9 illus., 1 table, 22 refs.
• 分类号：1003
• issnNo：ISSN1000-2383
• isbnNo：CN42-1233/P

     Based on studies of sedimentary features in the sediment interval containing high-saturation gas hydrate（HS-GHZ）in the Shenhu area,this paper presents results of Shenhu gas hydrates drilling site SH7B,at which HS-GHZ is observed at two major sediment intervals：between 155and 166m,and between 172and 177m.Our results suggest that the fine-grained sediments are foraminifera-contained clayey silt and silt;with very few siliceous microfossils.Two sediment intervals with high abundance of foraminifera coincide with two intervals of HS-GHZs,with high correlation coefficient up to 72%.Scanning electron microscope analysis on microstructure of sediments shows that existing of abundant sand-sized foramineral shells makes obvious contribution to the increase of sand fraction in these sediment intervals and shell-room space of foraminifers（intraframe pore space）are significantly larger than pore space between silt-sized grains（inter-particle pore space）.Only a few numbers of foraminiferal shell-rooms are filled with fine silt-or clay-sized grains or pyrites,suggesting slight influence of post-sedimentary diagenesis on foraminifera shells.In addition,shell-room spaces of foraminifers are generally in round-form with smooth pore-walls,which surely increases volume-containing capability in comparison with irregular and same diameter-sized inter-particle pore space.These evidences suggested that abundant foraminifers do not only increase in porosity of fine-grained sediments,but also provide high volume-containing capability of pore spaces for accumulating of gas hydrate in those two HSGHZs at site SH7B.Furthermore,HS-GHZs are also well correlated to abundant foraminiferal intervals at two adjacent gas hydrates obtained sites,e.g.sites SH2Band SH3B,in the Shenhu area.All of these results lead to the assumption and explanation that a large portion of gas hydrates should be stored in shell-room spaces of abundant foraminifers in fine-grained sediment layers in Shenhu area,which are different from the results obtained by ODP gas hydrate drillings;and existence of abundant foraminifers is an important sedimentary factor for controlling accumulation and storage of high saturation of gas hydrates in Shenhu area.