DEPOSITIONAL MICROFACTES, RHYTHMS, CYCLES AND SEQUENCE STRATIGRAPHY OF QIXIA FORMATION IN ZHEJIANG PROVINCE, CHINA

Based on the sedimentary microfacies and bioecologic analysis for the Qixia Formation of three sections in studied area, this paper summaried the depositional rhythms, cycles and sedimentary environment of Qixia Formation, and further analysed the characteristics of sequence boundary and depositional system tract. The results suggest that Qixia Formation in the study area was on the whole formed in a depositional setting of carbonate gradual slope that was subtidal, low-energied, open and non-barrier; and moreover two kinds of sequence boundaries and four sequences are recognized in Qixia Formation. According to the characteristics of sequence boundary and the stacking type of parasequences, it is divided into a transgressive system tract (TST) and a highstand system tract (HST).