北京西郊下苇甸剖面张夏组强迫型海退记录  

FORCED REGRESSIVE SEDIMENTS IN THE CHANGHSIA FORMATION AT THE XIAWEIDIAN SECTION IN THE WESTERN SUBURB OF BEIJING

作　　者：倪胜利[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《地层学杂志》2017年第1期103-109,共7页Journal of Stratigraphy

基　　金：国家自然基金项目(No.41472090;40472065)资助

摘　　要：强迫型海退是海平面(或基准面)下降产生的海退过程,从而区别于正常海退。在克拉通盆地中,强迫型海退常产生沉积基底的暴露并且产生沉积间断,在特定背景下,也会留下相应的沉积记录,北京西郊下苇甸剖面张夏组就是一个典型实例。在该张夏组由一个三级层序构成,进一步可划分为3个四级层序。有序的沉积相序列形成的张夏组,快速加深事件不但产生淹没不整合型层序界面,而且形成了张夏组中下部更多的陆棚相泥岩和泥灰岩沉积;但是,在其顶部,鲕粒滩灰岩的发育就成为对强迫型海退进程的响应。因此,上述现象为研究张夏组鲕粒滩的发育特征提供了重要线索,也为大范围的研究提供了一个概念性模型。A forced regression refers to the regressive process caused by a sea-level （or base level） fall and is distinguished from a normal regression. In cratonic basins, a forced regression often exposes sedimentary base and produces a depositional break. In certain depositional settings, the regressive process can leave a sedimentary record. The Changhsia （Zhangxia） Formation at the Xiaweidian section in the western suburb of Beijing provides such an example. The Changhsia Formation consists of one third-order sequence, which can be further subdivided into three forth-order sequences. Both the third- and forth-order sequences are marked by the regularly stacking pattern of sedimentary facies, and rapid flooding not only produced sequence boundaries of the drowning unconformity type, and also formed more shelf facies mudstone and muddy limestone deposits in the lower-middle Changhsia Formation. But oolitic banks which formed at the top Changhsia Formation represent the response to a forced regression. This study provides important insights into the development of oolitic banks in the Changhsia Formation.

关 键 词：层序地层 岩石地层 鲕粒滩 沉积相序 强迫型海退 张夏组 寒武纪 北京 华北 

分 类 号：P534.41[天文地球—古生物学与地层学] P539.2[天文地球—地质学]