莺歌海盆地东方X区浅海地震沉积相

第四纪全新世，研究区主要发育充填水道和深海平原。由于地震反射波同向轴连续整一，无上超、削截等现象，利用地震反射终止类型进行层序界面划分难度较大。文中基于沉积时间顺序确定目标层位，研究了层间地震相和沉积相在时间和空间的分布特征以及沉积相演化。研究区识别出6种地震沉积相类型，即丘状反射—盐(泥)丘体、充填状反射—“U”(V)型水道、透镜状反射—水道充填相、楔形反射—三角洲沉积、平(亚平)行席状反射—深海平原和杂乱反射地震相。Q104—Q10时期沉积相呈复杂的水道—三角洲体系到较简单的水道沉积体系发展趋势。

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.