THE OPENING OF QIONGZHOU STRAIT: EVIDENCE FROM SUB-BOTTOM PROFILES

The interpretation and analysis of the high-resolution sub-bottom profiles and ¹⁴C dating data reveal that:1) The R1 reflector on the sub-bottom profile represents the opening of the Qiongzhou Strait. The strata underlying the R1 surface is a set of low-energy marine deposits which is homogeneous without bedding, while the overlying strata is a tidal delta which is a prograding depositional unit with bedding well developed. When the strait was completely open, bottom current strengthened sharply and led to the clearly different structure between the overlying and underlying depositional unit of the R1 surface. 2) The Qiongzhou Strait ended opening about 8000a ago, when Holocene transgression happened in this area.