湖北秭归晚寒武世末期至早奥陶世早期层序地层格架

The Sequence_Stratigraphy Framework at the End of Late Cambrian Early Stage of Early Ordovician, Zigui County,Hubei

湖北秭归地区晚寒武世末期至早奥陶世早期总体上表现为一个大的海侵沉积序列。本文通过详细的露头层序地层学研究及１∶５万区域地质填图，将该区娄山关组顶部至红花园组划分为２个三级层序，总结了各层序的层序界面性质及体系域发育特征，并建立了区域地层格架，从而进一步指出：块状白云岩的形成和分布明显受海平面下降事件的控制。

The mega cycle sequence is dominated by transgression sedimention during the late stage of Late Cambrian the early stage of Early Ordovician in Zigui County, Hubei. On the basis of the study of the out crop sequence stratigraphy and 1∶50000 scale regional geological surveys, Two third order sequences are distinguished from top of the Loushanguan Formation to top of the Honghuayuan Formation. The nature of sequence boundaries and the character of system sracts of the two sequence are summed up and the regional stratigraphic framework is established. Furthermore, the authors conside that the formation and distribution of the massive dolostones were controlled by the sea_level descending events.