摘要
岩相古地理研究是重建地质历史中海陆分布、构造背景、盆地发育和沉积演化的重要途径和手段,高分辨率层序地层学理论在岩相古地理研究中的应用则有效地提高了岩相古地理图的精度。按照高分辨率层序地层学理论,将四川盆地晚三叠世须家河组划分为2个超长期、4个长期、14个中期及数十个短期基准面旋回层序。在此基础上,分别以长期的上升和下降半旋回为单元,分析了须家河组不同时期的岩相古地理特征及演化,认为:(1)四川盆地须家河期沉积主要由从周边山系向盆内和从川中隆起向盆地中心逐渐推进的,以发育(冲积扇)辫状河-辫状河三角洲-浅湖沉积为主的沉积体系组成,致使四川盆地浅湖区域为向南西倾斜的"∩"形,浅湖内零星发育有小型浅湖砂坝沉积;(2)沉积相带的展布格局严格受构造控制,以盆地边缘最为特征;(3)晚三叠世须家河期,以龙门山构造带逆冲推覆活动为主,米仓山-大巴山活动相对较弱。
Under the guidance of the high resolution sequence stratigraphic theory, the Upper Triassic Xujiahe Formation in Sichuan Basin was divided into 2 super-long-term, 5 long-term, 18 medium-term and 10 short-term base level cyclical sequences. Based on this and taking long-term asending and descending half-cycle as a unit, this paper analzes the lithofacies paleogeographic characteristics and the evolution of the Xujiahe Formation at different periods. The result is that： （1） the Xujiahe deposition in Sichuan Basin has been gradually advanced from the peripheral mountain system to intrabasins and from the central Sichuan uplift to the centre of the basin, which mainly consists of developed （alluvial fan） braided river-braided delta-shallow lake deposits, resulting in shallow lake areas inclining to the southwest in ＂∩＂ shape, with a scatter and sparse distribution of small type shallow lake sandbars; （2） the distribution of the sedimentary facies belts is strictly controlled by the structure, especially on the basin margin; （3） the late Triassic Xujiahe stage is dominated by the thrusting in the Longmen structural belt, and the Micang-Daba activity is relatively weak.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2008年第6期630-638,共9页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
中国石油天然气总公司攻关项目(06-01A-02-01)
关键词
长期旋回
层序
岩相古地理
须家河组
四川盆地
long term cycle
sequence
lithofacies paleogeography
Xujiahe Formation
Sichuan Basin
