Sequence stratigraphy of the Devonian-Triassic strata in Southwest Anhui,China

This paper studies the stratigraphic sections of the Devonian-Triassic stratigraphic outcrops and their sedimentary environments and facies in the Susong-Dongzhi zone of Anhui by using the theory and research approach of sequence stratigraphy on the basis of the 1∶250 000 regional geological survey.It also divides the depositional sequences and system tracts and discusses the nature of the boundary,type,and characteristics sequences.The Devonian-Triassic strata can be divided into one first-order sequence,five second-order sequences and twenty-nine third-order sequence sets.The former two show a general trend of change in facies succession from shallow to deep and back to shallow up-section,coincident with the curve of sea-level fluctuation.The sea-level fluctuation of the last one is commonly controlled by tectonism,sea-level change and glaciation.