江苏白垩纪陆相层序地层研究

系统的探讨了区内白垩纪地层的划分与沉积相特征，深入研究了陆相地层的层序发育特征。指出，无论冲积扇、河流、三角洲或湖泊沉积的陆相地层层序均受地层基准面控制。地层基准面穿越旋回控制着陆相环境重大层序分布。根据不同时间间隔的基准面穿越旋回序次，将陆相层序划分为盆地充填层序、构造层序、层序、亚层序及小层序五个级别。每个层序根据基准面波动可划分为基准面上升沉积体系域和基准面下降沉积体系域，并可根据亚层序组的叠置特征进一步细分。根据上述陆相地层层序划分原理，作者将研究区白垩纪陆相地层划分为三个构造层序，并初步将葛村组划分为五个、浦口组四个、赤山组三个和泰州组三个沉积层序。

STUDY ON CRETACEOUS STRATIGRAPHIC SEQUENCE OF CONTINENTAL BASIN IN JIANGSU

The paper is the results of study on the basic principle of continental sequence division, characteristics and pattern of continental depositional sequence including sequence classfication and identification of sequence bounding surface. The authors put forward that base level is a unifying concept in continental stratigraphic sequence and the base level trasit cycle is control of the change of accommodation space as well as sedimentation and stratigraptiic preservation or sediment bypass and erosion. The base level transit cycle fluctuate dominantly in response to tectonism and climate and is the critical factor in determining the stratigraphy of continental stata. The concept of the base level transit cycle has been applied sequence genesis analysis and sequence division for the depositional succession including alluvial, desert and lacustrine strata of Cretaceous System in Jiangsu. The Cretaceous lithostratigraphic subdivision in Jiangsu shown in table 1. According to developing charactenstics of the terrigenous depositional succession, tile continental sequence can be divided into five ranks of the basin -- fill sequences tectonic senquence, sequence, subsequence and microsequence and are interpreted to be formed during the base level transit cycle of the differential rank with time -- intervals of 60-- 120Ma. 20 - 40Ma. 0. 5 -- 5Ma. 0. 1 -- 0. 5Ma and < 0. 1Ma respectively. On the basis of general characteristics of continental depositional sequence, which internal architecture is controled of rise -- fall cycle of the base level, two systems tracts can be easy to idenfy, i. e. the systems tract of base level up and systems tract of base level down. In the report, the Cretaceous system in Jiangsu can be subdivided into three tectonic sequences and pointed out the Cretaceous continental basin compose of three kinds of prototype basin which are piled up. i. e. early -- middle Cretaceous pull -- apart basin, middle -- late Cretaceous fault basin and late Cretaceous -- Paleogene rift -- basin. The three kinds of prototype basin formed three tectonic sequence reflecting the long -- term base level cycles. Based on the mid -- term base level cycles, could be divided into the corresponding five, four, five, three stratigraphic depositional sequences respectively in Cecun. Pukou, Chishan and Taizhou Formations.