Sedimentary model of K-Successions Sandstones in H21 Area of Huizhou Depression, Pearl River Mouth Basin, South China Sea

Abstract

The nearshore sand bar-sheet sedimentary system of the K-Successions sandstones of the Zhujiang Formation (23.8-16.5 Ma) in H21 Area of Huizhou Depression, Pearl River Mouth Basin has been identified in this research according to lithological characteristics, lithofacies, sedimentary sequence and seismic attributes. Seven lithofacies were recognized: fine-grained massive sandstone (Sm), fine-grained trough cross-bedded sandstone (St), fine-grained planar-bedded sandstone (Sp), fine-grained ripple cross-bedded sandstone (Sr), fine grained horizontally-bedded sandstone (Sh), laminated claystone with interbedded siltstone (Fl) and massive mudstone (Fm). Three sedimentary microfacies were further divided: sand bar, sand sheet and interbar. With the progradation and retrogradation process influenced by sea level changing, delta evolution of K-Successions sandstones in H21 area of Huizhou Depression can be divided into four stages: the early stage of the transgressive systems tract, A/S>1; the medium stage of the transgressive systems tract, A/S>1; the end stage of transgressive systems tract; the stage of the highstand systems tract, A/S<1. Different evolution stages controlled the sandstones distribution.

Keywords

• k-successions sandstones
• lithofacies
• delta evolution
• huizhou depression
• china