Sequence stratigraphy of the Late Quaternary in Liaodong Bay

High-resolution seismic reflection data are studied in details together with core data in order to determine the stratigraphic sequence of Liaodong Bay since the MIS5 of Late Quaternary. The high-resolution seismic profiles selected from the study area may be subdivided into six seismic units, i.e. SU₅, SU₄, SU₃, SU₂, SU₁², SU₁¹ in descending order, which could be clearly correlated with the six depositional units, DU₅, DU₄, DU₃, DU₂, DU₁², DU₁¹ respectively based on lithology, microfossil assemblages and geochronology of the cores. These units may be grouped into three distinctive sequences, SQ3, SQ2, SQ1 in descending order by two sequence boundaries of R5 and R3 with obvious hiatus, which correspond to the low sea-levels of MIS4 and MIS2, respectively. The SQ3 is the remained upper part of transgressive systems tract (TST) and highstand systems tract (HST), corresponding to DU₅, the littoral and neritic facies of MIS5. SQ2 is composed of lowstand systems tract (LST), fluvial deposits and incised-channel filling facies (DU₄₎ formed in MIS4 plus the TST littoral facies (DU ₃) deposited during Early-Middle MIS3. And the SQ1 is comprised of the LST, DU₂ fluvial deposits to incised-channel filling facies formed in MIS2, TST, DU₁² deposits of littoral facies formed during Early-Middle Holocene, and the HST, DU₁¹ deposits of neritic facies since the highstand sea-level of Holocene. The TSTs is relatively continuous and widely distributed, while LSTs vary considerably in thickness and lateral distribution since MIS5 in Liaodong Bay.