羌塘盆地胜利河油页岩有机地球化学特征及意义  

Geochemical Characteristics and Geological Significance of Shengli River Oil Shale in Qiangtang Basin,Northern Tibet,China

作　　者：何江林[1,2] 王剑[2] 付修根[2] 孙涛[3] 申家年[4] 

机构地区：[1]中国地质科学院研究院,北京100037 [2]中国地质调查局成都地质矿产研究所,成都610081 [3]中国科学院油气资源研究重点实验室,兰州730000 [4]大庆石油学院地球科学学院,黑龙江大庆163318

出　　处：《沉积学报》2010年第3期626-634,共9页Acta Sedimentologica Sinica

基　　金：国家自然科学基金(批准号:40972807,40702020);国家油气专项“青藏高原油气资源战略选区调查与评价”项目(XQ2004-06)资助

摘　　要：通过对藏北羌塘盆地胜利河地区2008年新发现的油页岩剖面进行系统采样和GC—MS分析,结果显示该地区油页岩具有较高C29ααα20Sα/αα（20S＋20R）（0.38～0.44）、C29αββ/（ααα＋αββ）（0.37～0.47）和C3122S/（22S＋22R）（0.52～0.59）比值,表明其有机质已进入生油阶段。分析的油页岩样品具有较高的C27甾烷含量（32.82%～43.6%）和较高4甲-基甾烷/规则甾烷（0.04～0.22）、甾/藿（0.80～1.04）比值,显示浮游植物为主的生物母源对油页岩的贡献。此外,油页岩具有较高的γ-蜡烷指数（0.34～0.50）、C35升藿烷指数（0.076～0.102）和较低的Pr/Ph比值（0.32～0.49）,表明胜利河地区油页岩沉积期水体处于相对闭塞还原和盐度较高的沉积环境。Marine oil shale from the Shengli River oil shale section discovered in 2008 in the Qiangtang basin,northern Tibet,China,was collected systematically and analyzed by means of GC-MS.The results indicate that the oil shales from Shengli River area exhibit relatively high values of C31-steranes 22S/（22S＋22R） [0.38～0.44],C29-steranes αββ/（ααα＋αββ） [0.37～0.47] and C31-steranes 22S/（22S＋22R） [0.52～0.59] ratios.These results indicate that the thermal evolutionary phase of organic matter in oil shale has reached oil-generating window.The relatively high concentrations of C27-steranes[32.82%～43.6%] and relatively high values of 4-methyl sterane to regular sterane ratios[0.04～0.22],sterane to hopane ratios[0.80～1.04] unanimously indicate that the biological sources of organic matter in oil shale are phytoplankton and bacteria,especially with an important contribution of phytoplankton.The relatively high values of gammacerane index[0.34～0.50],homohopane index [0.076～0.102] and low pristine to phytane ratios[0.32-0.49]indicate the occlusive water environments are anoxic and relatively hypersaline in the Shengli River area during oil shale deposition.

关 键 词：羌塘盆地 生物标志化合物 泻湖 油页岩 

分 类 号：P593[天文地球—地球化学]