伊朗Kashan地区古近系库姆组层序地层及盆地演化特征

库姆组沉积时期伊朗Kashan地区为中伊朗盆地库姆盆地东南方向的弧后边缘海盆地,以浅海相的碳酸盐岩和碎屑岩沉积为主.受构造运动与全球海平面旋回变化控制,大部分地区的库姆组形成了5个三级层序S1～S5,上覆上红组底部蒸发岩层,在这5个三级层序之下,盆地沉降中心位置还可见S0a和S0b层序.对格架中层序地层特征的动态演化分析后认为,Kashan地区在库姆组及其上、下地层沉积时期经历了7次重要的地层演化阶段:低水位充填期、初次海侵期、沉降充填期、孤立泻湖期、再次海侵期、构造抬升期、完全孤立期.

Sequence Stratigraphy and Stratigraphic Evolution of Qum Formation in Kashan, Iran

Kashan area is located in southeastern part of Qum Basin in the central Iran Basin.During Late Oligocene to Early Miocene,Qum Formatiom was formed,a mixed carbonate,evaprites and clastics succession deposited in a back-arc basin resulted from the collision of the Arabian Plate with continental Eurasian.Based on the integrated study on the sufficient outcrops,wells and seismic profiles obtained recently,five third-order sequences have been found in Qum Formation,underlain by S0_a and S0_b only distinguished in the depositional center from the seismic interpretation and overlain by the evaprites unit of Upper Red Formation.The chrono-,litho-,sequence stratigraphy of Qum Formation indicates that depositional evolution of the subbasin in Kashan area had undergone seven important events from Late Oligocene to Early Miocene: basin filling,initial transgression,successive subsiding and filling,interval isolation,secondly great transgression,tectonic uplifting and regressive depositing,and completely isolation.