Sedimentary development of the Pearl River Estuary based on seismic stratigraphy

The Pearl River Estuary in the Southern China was studied both by applying concepts of seismic stratigraphy to the interpretation of high resolution seismic profiles and by correlating with borehole records. The correlation between seismic facies and borehole stratigraphy of the estuary enables to propose a seismic stratigraphy model of the estuarine infill. The stratigraphy and evolution of the Holocene succession of the estuary were reconstructed. The history of estuarine sedimentary development consists of five stages represented by 5 seismic units bounded by laterally sub-continuous seismic interfaces and being consistent with the 5 borehole subdivisions: (i) The basal stage deposits, represented by BU and the borehole section P, might represent the paleo Pearl River alluvial deposits in the Late Quaternary. (ii) The stage I deposits, represented by SU1 and the borehole section A, might be late glacial prodeltaic deposits that occurred during Marine Isotope Stage 3 highstand. (iii) The stage II deposits, represented by SU2 and the borehole section B, consist of relatively coarse-grained sediments deposited during the post glacial transgression about 20–10 ka BP. (iv) The stage III deposits (SU3 and the borehole section C) were generated when the rate of sea level rise decreased in ∼ 20–10 kz BP, which forced sediments to be deposited inside the estuary, where a tidal ravinement surface was characterized by strong erosions and channel formations in the outer zone of the estuary. (v) The stage IV deposits (SU4 and the borehole section D) are the infillings of the estuarine highstand progradation during the last 6000 yrs when the sea surface almost reached the present level.