SEDIMENTARY AND SEISMIC FACIES OF SHALLOW SEA IN THE DONGFANG X AREA OF YINGGEHAI BASIN

Holocene filling channels and deep sea plains are well developed in the research area. Since the seismic reflection waves along the same axis shows no discontinuous phenomena such as overlapping and truncation, it is difficult to define sequence boundaries. Target intervals are thus calibrated by deposition time in this paper. Six types of seismic sedimentary facies are identified, including the mound-like reflection from salt or mud deposits, filling reflection from "U" (V) type channels, lenticular reflection from channel filling deposits, wedge-like reflection from deltaic deposits, flat and sheet-like reflection from deep sea plain and disordered reflection seismic facies. Upon the basis, the spatio-temporal distribution pattern of seismic facies and sedimentary facies as well as facies evolution are studied. Our results suggest that during the period Q₁₀₄—Q₁₀, there is a evolutional trend of sedimentary facies from a rather complex deltaic system to a simpler one.