The Storm Squencies Characteristics And Significance From The Zhangxia Formation Of Cambrian In Yanshi Area, Western Henan

The storm sedimentation is special event deposit and is formed by the storm waves. Recently, many studies is focused on storm deposit, and storm deposit research has became one important branch in sedimentology field. Outcrop of Zhangxia formation was found in Yanshi region, Henan Province. This outcrop is well exposed and the strata is well kept completely. Typical storm sedimentary phenomenon was recorded in the strata.This dissertation focus on the cambrian Zhangxia Formation in Jimaoyao village, Yanshi region. Through field geological section measurements and petrography observations,conclusion has been draw as follows:1.The Zhangxia Formation of Cambrian has 13 storm sedimentation sequence combinations in Yanshi area of Henan and found 4 kinds of combinations of the storm sedimentary succession in zhangxia group. Including four types of rocks which are bioclastic limestone,oolitic limestone, calcirudite and argillaceous zebra limestone,and developping sedimentary structures which conclude the bottom erosion structure,tear, chip gravel radial structure, ring structure.2. Base on the lithologic characteristics,sedimentary structures,fossil feature, sedimentary sequence etc,and summarize the sequence of type I is characterized by bottom erosion,wavy bedding, limestone layer in construction and turbulent characteristics of sedimentary environment, sedimentation in fine weather wave base level above the upper are restricted platform environment. Sequence type II and type IV are characterized by bottom erosion structure, lag, ring structure, limestone layer and contains a small amount of wrist and a lot of characteristics of trilobite fossils, sedimentation in wave base level above the upper shoal in the platform environment. Sequence type III is characterized by bottom erosion structure,argillaceous the radial structure of limestone, gravel dust and the characteristics of limestone layer and deposit under the plane wave and storm wave base near water relatively deep open platform sedimentary environment.3.Through the above analysis,and indicate that the storm deposit found in Yanshi area of Henan for the study of tectonics,paleoclimate and paleoenvironment recovery work has important significance.