Chronostratigraphic division and sedimentary rate characteristics in the south alluvial plain of Yongding River

Based on magnetostratigraphy and ¹⁴C dating, combined with stratification characteristics of strata, the stratigraphy of Quaternary in the southern alluvial plain of Yongding River was classified, and its sedimentary rate was discussed based on the stratigraphic classification results from boreholes QGJ01 and QHJ01.The chronostratigraphy of borehole QYJ01 is divided into Upper Pliocene, Lower Pleistocene, Middle Pleistocene, Upper Pleistocene and Holocene, the corresponding depth is 198.1~450.9 m, 111.5~198.1 m, 88.65~111.5 m, 23.7~88.65 m and 0~23.7 m, respectively.The sedimentary rate of Quaternary strata revealed by boreholes QYJ01, QGJ01 and QHJ01 were analyzed comprehensively.It is indicated that the sedimentary center of the late Cenozoic in the south alluvial plain of Yongding River experienced two migrations: the first was the migration of the sedimentary center from the east to the south in the Early Pleistocene and the second was the migration from the south to the east in the Holocene.This study provides some reference for the study of neotectonic activity intensity and time limit in Yoagding River alluvial plain and the division and correlation of Quaternary stratigraphy in deep covered area.