Division And Contrast Of Paleozoic Cambrian Sequence Stratigraphic In Fuzhou Area,Dalian,Liaoning Province

The Fuzhou area is located in the southern of the Liaodong Peninsula,It is a typical development area of the Cambrian System in Liaoning and even the whole country.To solve the problem of the level of research is relatively backward,Sequencing disorder,Parasequence application blur in Fuzhou area.The thesis is based on the project of the Liaoning Bureau of Geology and Mineral Resources Exploration “Sequence stratigraphic division ratio study of the Neoproterozoic-Paleozoic in Liaoning,C hina”,use part of its scientific research achievements,learn from the latest international research methods,and then use the classical outcrop sequence stratigraphic theory to complete this article.Through the survey of 42 strata profiles in the study area,get a lots of informations about rock composition features,sedimentary facies,paleontology,and sequence boundary.By indoor comprehensive analy,5 types of sedimentary facies have been identified,such as shallow sea basin,edge of the platform,platform,gentle slope and shore bank,and has been divided into subphases and microfacies.After the identification o f the sequence interface,18 third sequences(?S1-?S18)are identified.And ?S1 belongs to the I-type sequence,?S2,?S14,?S15,?S16,?S18 belong to the II-type sequence,?S3-?S13,?S7 sequences belongs to the type III sequence.Then,the system tract,parasequece sets,parasequece in the sequence are discussed in detail.By comparing with the predecessors' division scheme in this area and the North C hina area and the Yishui area of Shandong,It is proved that the partition scheme has relative accuracy,and the third-order sequence is globally comparative on the stable platform.According to the above contents,it is summarized basin evolution process of the Cambrian in Fuzhou area.It is suggested that there are 5 large-scale transgression-regression(T-R)events in the study area.Therefore,there are 5 super sequences(Xietun supersequence,Fuzhouwan supersequence,Paotai supersequence,Yuantai supersequence and Changxingdao supersequence).And also computed for second sequence average formation time in the study area is 8.8 Ma,and the third sequence is 2.4 Ma.Analysis of the control factors of sequence formation of the Cambrian sequence in the area,that the five large-scale T-R events in the study area caused by tectonic subsidence,sequence cycle is controlled by global sea level rise and tectonic subsidence together,depositional thickness and extensibility of the sequence are influenced by supply rate of deposits,and the main factors affecting the deposition of the evaporite is the paleoclimate.