相对海平面变化对烃源岩发育的影响——以鄂尔多斯盆地为例  

INFLUENCE OF RELATIVE SEA LEVEL VARIATION ON HYDROCARBON SOURCE ROCK DE VELOPMENT ——TAKING E’ERDUOSI BASIN AS AN EXAMPLE

作　　者：腾格尔[1] 刘文汇[2] 徐永昌[3] 陈践发[4] 

机构地区：[1]南京大学地球科学系 [2]中国石化石油勘探开发研究院 [3]中国科学院兰州地质所 [4]石油大学

出　　处：《天然气工业》2005年第5期9-13,共5页Natural Gas Industry

基　　金：国家重点基础研究发展规划(973)项目(编号:2001CB209102;G1999043306)资助。~~

摘　　要：以鄂尔多斯盆地西南缘奥陶系马家沟组为例,应用碳酸盐岩碳氧同位素、有机碳含量及其同位素组成,结合地层、古生物特征,探讨相对海平面变化对海相碳酸盐岩有机质富集及烃源岩发育的影响。研究表明,桌子山地区受贺兰裂谷的强烈沉降,克里摩里期相对海平面上升幅度较大,引起一系列利于有机质富集和烃源岩发育的结果:①静水、缺氧环境;②有机质埋藏量增加和质量优化;③碳酸盐碳、氧同位素值偏重,而有机碳同位素值偏轻。在岐山地区,相对海平面波动较小,为浅水、氧化环境,不利于有机质保存。对一个地区或盆地而言,相对海平面变化是全球性海平面升降和区域性构造活动的综合效应,它通过改变古环境控制了有机质富集及烃源岩发育。因此,相对海平面变化的研究对海相烃源岩的发育程度及其分布预测具有重要意义。By taking Majiagou Formation of Ordovician in the southwest fringe of E' erduosi Basin as an example, according to the data on carbon isotope, oxygen isotope, organic carbon content and its isotopic composition, the influence of relative sea level variation on the organic matter enrichment and hydrocarbon source rock development in marine carbonate rocks, is discussed in the paper in combination with the stratigraphic and palaeontologic characteristics. The research results indicated that the relative sea level at Zhuozishan region had greatly risen because of the strong subsidence of Helan Rift in Kelimoli period, thus causing a series of results beneficial to the organic matter enrichment and hydrocarbon source rock development: 1 An euxinic and anoxic environment; 2 The quantitative increase and qualitative optimization of buried organic materials; and 3 The positive excursion of carbonate's carbon and oxygen isotopic ratios and the negative excursion of organic carbon isotopic ratio. The fluctuation of the relative sea level at Qishan region was small, which was unfavorable for the organic matters being preserved because of the shallow and oxic environment. In regard to a region or a basin, the relative sea level variation was a comprehensive effect of global sea level change and regional tectonic activity. The organic matter enrichment and hydrocarbon source rock development could be controlled by the change in palaeoenvironment.

关 键 词：相对海平面变化 鄂尔多斯盆地 相对海平面上升 海相碳酸盐岩 有机碳同位素 碳氧同位素 同位素组成 有机碳含量 古生物特征 有机质 海平面波动 海平面升降 海相烃源岩 马家沟组 缺氧环境 质量优化 碳酸盐碳 氧化环境 综合效应 

分 类 号：P618.13[天文地球—矿床学]