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    济阳、临清坳陷及鲁西地区中新生代构造演化对比分析

    Comparative analysis of Meso-Cenozoic tectonic evolutions of the Jiyang and Linqing depressions and Luxi area

    • 摘要: 提要:通过对横跨济阳、临清坳陷及鲁西地区的6条地震平衡剖面或正演构造模型的分析表明:该区古近纪伸展速率大大快于中生代,尤其表现在古近纪早期(E1-2k+E2-3s4),济阳坳陷大于临清坳陷,鲁西地区最小。济阳坳陷的东营与惠民凹陷原型盆地的发育可大致分为5个阶段,中生代时期东部伸展量明显大于西部,东部在白垩纪末期有过强烈的剥蚀,推测这与中生代沿郯庐断裂裂谷较发育有关,东部裂陷剧烈,白垩纪末构造反转亦强烈。沙河街组四段—孔店组时期东营与惠民凹陷伸展量相近,属于走滑拉分的沉积盆地,沙河街组三段以后,东西部再次差异发展,西部伸展明显大于东部。整个中新生代垂向上表现为裂陷强,反转亦强;平面上表现为类似翘翘板运动。临清凹陷由于处在强裂陷的过度部位而使其变换构造发育,断陷湖盆不能持续稳定的发育,因此成烃条件较差。

       

      Abstract: Abstract:Analyses of six balanced seismic sections or forward tectonic models across the Jiyang and Linqing depressions and Luxi area show that the extension rate in the region in the Paleocene, especially in the early Paleocene, was greatly higher than that in the Mesozoic, the extension rate for the Jiyang depression being higher than that for the Linqing depression and the extension rate for the Luxi area lowest. The development of the proto basin of the Dongying and Huimin subbasins in the Jiyang depression broadly went through five phases. In the Mesozoic the amount of extension in the east was markedly large than that in the west, and strong erosion occurred in the east during the Late Cretaceous. From the above, it is inferred that: this was related to the rifting along the Tanlu fault in the Mesozoic, and rifting was intense in the east and tectonic inversion was also strong at the end of the Cretaceous. The amounts of extension of the Dongying and Huimin subbasins were close during the deposition of the Four Member of the Shahejie Formation and Kongdian Formation. They belong to strike-slip pull-apart sedimentary subbasins. After the deposition of the Third Member of the Shahejie Formation, differential development again occurred in the east and west parts: the amount of extension in the east was noticeably larger than that in the west. The whole of Meso-Cenozoic witnessed strong vertical rifting and inversion, and in a plan view movement similar to a seesawing movement was manifest. Located in the transitional place of strong rifting, the Linqing subbasin had well-developed transitional structure and thus a downfaulted lake basin was unable to develop steadily; so the hydrocarbon-forming conditions were poor.

       

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