Research Prospect on Tectonic Evolution and Coal-bearing Sedimentary Action in Qiongdongnan Basin

Qiongdongnan basin is located in the sea area of southeastern Hainan Island,it was a NE-direction extensional basin formed in Cenozoic Era.In this paper,the evolution processes of Qiongdongnan basin structures and the sedimentary incoalation in the basin were synthetically analyzed by using basin tectonic evolution,stratigraphic correlation and other analysis methods.The comprehensive analysis showed that tectonic evolution in Qiongdongnan basin was of the features of episodic rifting,coal formation occurred in the last rifting sediment strata(Yacheng formation and Lingshui formation).From analysis on the sedimentary environment,we concluded that Yacheng formation was marine-terrigenous facies filling stage and Lingshui formation was neritic environment filling stage.However,the analysis on the research results in the area found that there still were some problems,i.e.,the unclear stratigraphic distributions,unknown coal bed spatial distribution and the mechanism of basin evolution in various stages,etc.,and all of them become the main directions of in-depth study of Qiongdongnan basin.