辽宁省寒武-奥陶系沉积环境与层序地层划分

Sedimentary Environment and Sequence Subdivision of Cambrian and Ordovician Sysems in Liaoning Province

辽宁省寒武系、奥陶系主要分布于复州-大连、太子河及辽西三个小区，三者地层系统一致，岩相、岩性雷同，同处于"华北型"沉积环境，可进行层序对比。其中辽西小区共发育 8个层序，复州-大连小区发育 16个层序，太子河流域划分 15个层序，除层位缺失因素，三者层序划分基本相同，层序界面一致，其中Ⅱ级界面可以追索。通过对比，发现层序的发育与环境演化关系密切。总体而言，在环境开阔，水体能量较高区域，层序之海侵体系域较发育，而高水位体系域相对较少，而在环境相对闭塞、水体循环不畅的条件下，层序组成主要以高水位体系域为主，同时，在深水陆棚碳酸盐岩沉积中，往往发育淹没不整合事件，层序结构为 SB3＋ CS＋ HST。

Cambrian and Ordovician systems in Liaoning province mainly distribute in Fuzhou Dalian,Taizi River Basin and West Liaoning.In the 3 typical areas,stratigraphic systems are concordant,lithofacies and lithologic character istus are same,and all lie in the same craton environment of North China type' sedimentary. So the sequences in the 3 typical areas can be contrasted.In West Liaoning,there are 8 sequences,in Fuzhou－ Dalian,16 sequences and in Taizi River Basin,15 sequences.Except some position absence, the subdivision of sequences in the 3 typical areas are basically identical with consistent sequence boundaries. By correlation, the development of sequences has a close relationship with environmental evolution. In general,in a broad environment with a high water energy,transgressive system domains of sequences are developed well,but high water system domains relatively little;in a relatively closed environment with an unfree circulation of water body,sequences are mainly consisted of high water system domains.And in deep shelf carbonate sedimentary,unconformity events usually were drowned,the texture of sequences is SB3＋ CS＋ HST.