Basin Evolution and Distribution of Lacustrine Systems in Middle and Upper Eocene,Dongying Basin
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摘要: 东营盆地中，上始新统沉积旋回可划分出五个亚层序（ＤＳ１－ＤＳ５），六种沉积体系和十一种相带，从下向上按三个发育阶段演化。盐湖期（ＤＳ１）广泛发育碳酸盐岩体系；咸水深湖期（ＤＳ２－ＤＳ３）是各类沉积体系发育的鼎盛时期，但以湖相体系和重力流体系发育最佳；淡水浅湖期（ＤＳ４－ＤＳ５）发育三角洲体系和河流体系。平面上，缓坡带沉积厚度薄，由碳酸盐署向滨－浅湖相和河流相砂岩演化；陡坡带沉积物厚度大，由冲积扇相砂砾岩向扇三角洲相和辫状河三角洲相砂岩演化，反映了半地堑盆地充填演化的不对称性。三角洲体系沿凹陷轴向发育，向盆地进积，造成沉积中心自东向西迁移，构成了盆地沉积充填的主体。Abstract: The sedimentary cycle in the middle and upper Eocene of Dongying basin is distinguished into five subsequences (DSI -DS5), six types of depositional systems and eleven factes, and divided into three evolution periods from bottom to top.Carbonatite system is extensively developed in the salt lake period (DS1) ; All types of sedimentary systems in the salt and deep lake period (DS2-DS3), however, lacustrine and gravity flow systems is mainly developed ; Delta and fluvial systems in fresh and shallow lake period (DS4-DS5).Sediments in gentle slope is thin, evolving from carbonatite to littoral-shallow lacustrine and fluvial factes sandstones. Sediments in steep slope is thick, evolving from pluvial fan factes sandy conglomerate to delta factes and braided delta factes sandstones. It represent asymmetry of the filling and evolution of the halfgraben basin. The delta system developed along the axis of the basin and prograded basinwards,resulting in the migration of the depocentre from east to west and forming main basin filling.
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Key words:
- Subsequence /
- depositional /
- systems distribution /
- basin evolution
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[1] 1.Van Wagoner J. C. et al.，1990, Siliciclastic sequence stratigraphy in well logs, cores, and outcrops: concepts for high 一resolution correlation of time and facies, AAPG methous in exploration servies, No. 7.
2.Hamblin A. P.，1992, Half-graben lacustrine sedimentary rocks of the lower carboniferous strathlorne formation, Hor- ton Group, Cape Breton Island, Nova Scotia, Canada. Sedimentology, V. 39, p. 263一284. -
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