DEPOSITIONAL SEQUENCES OF YITONG GRABEN (EASTERN CHINA) AND ITS RESPONSE TO TRANSFORM-EXTENSIONAL PROCESSES
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摘要: 伊通地堑处于中国东部第三纪裂谷系向东北延伸的分支,其东侧盆缘断裂为正断层,西侧为高角度走滑断层,其旁侧为扇-扇三角洲楔状体,表明这些断裂控制着沉积充填。第三系在断陷中厚达6000m,油气勘探中已识别出一系列不同级别的间断面及构造反转事件,根据大的区域性间断面划分出3个构造层序,并进一步划分了三级和四级层序,在构造层序界面处识别出了深切谷充填。在层序地层格架的基础上重建了沉积体系域。结合各阶段同生构造的配置揭示了总体伸展背景下构造体制由右旋张剪向左旋压剪的转化,盆地属于转换伸展性质。伸展及走滑两种机制共同控制了盆地的演化及各阶段的充填样式-沉积体系的三维配置。这一研究成果已作为预测储层和烃源岩分布及地层岩性圈闭的基础。Abstract: The Yitong Graben is located in the north eastern segment of the Tertiary rift system in East China.The graben is bounded by a steep dipping transform fault on the northwestern side and subparallel normal faults on the southeastern side, with very thick marginal fan complexes indicating syntectonic sedimentation. The graben is infilled with Tertiary sediments up to 6000 m thick, in which a series of different scaled hiatuses and tectonic inversion events have been discerned during hydrocarbon exploration. According to regional and local conformities, the basin infill may be divided into three tectonic sequences, among which the major sequence TS2 is further subdivided into three sequences sets and fourteen subsequences. Based on the sequence stratigraphic framework, depositional system tracts are reconstructed. Integrative analysis of the depositional structural features showed that the regional tectonic stress system experienced a transformation from dextral transfersional-shear through thermal subsidence to sinistral compressional-shear with a general extensional setting. Extension and wrenching dominated the graben evolution and affected the depositional style in different evolutionary stages and the spatial configuration of depositional system. The conclusions have been applied with some success to prospection of reservoir and hydrocarbon source-rock distribution and lithologic-stratigraphic traps in this basin.
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[1] Van Wagoner J C, Mitchum R M, Campion K M, et al.Silliciclastic sequence stratigraphy in well logs, cores and outcrops: concepts for high-resolution correlation of time and facies[M].AAPG Methods in Exploration Series.1990, 7: 1~12. [2] 解习农.伊通地堑层序构成及层序地层格架样式[J].现代地质,1994,8 (3). [3] Xie Xinong, et al.Depositional model and tectonic evolution of tertiary transform extensional basins in northest China : case study on Yitong and Damintun Grabens [J].Journal of China University of Geosciences, 1997, 36 (8): 771~784. [4] 李思田.论沉积盆地分析系统[J].地球科学,1992,17(增刊):31~39. [5] 解习农, 任建业, 焦养泉.断陷盆地构造作用与层序样式[J]. 地质论评, 1996, 42 (3). [6] 李思田,杨士恭,等.中国东北部晚中生代裂陷作用和东北亚断陷盆地系[J].中国科学(B辑),1997,(2):185~195. [7] Li Sitian, Yang Shigong, Xie Xinong.Tectonic evolution of Tertiany basin in circum-Pacific Belt of China and their geodynamic setting[J].Journal of China University of Geosciences.1997, 8 (1): 4~10. [8] Li Sitian, Mo Xianxue, Yang Shigong.Evolution of Circum-Pacific Belts in East China and their geodynamic [J].Journal of China University of Geosciences.1995, 6 (6): 48~58. [9] 焦养泉,周海民,刘少峰,等.断陷盆地多层次幕式裂陷作用与沉积响应——以南堡老第三纪断陷盆地为例[J],地球科学, 1996, 21(6): 633~636. -
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