Abstract:
Shallow lacustrine deposits are widely distributed in the Enping Formation of the Huizhou depression of the Pearl River Mouth Basin,and has long been considered as a kind of infilling of a faulted basin.Through the study of lithology,geophysical responses,paleontology,geochemical proxies,and grain size distribution,this paper confirms that a special delta,shallow braided river delta,was developed in the Enping Formation of the Huizhou depression in a broad shallow flat lake,with sufficient terrigenous deposits.And this system is characterized by a well-developed delta plain,an undeveloped coarsening-upwards sequence of a mouth bar,and a well-developed braided stream.Depositional features of shallow braided delta are widely observed,such as the lacustrine deposits formed in the fault-sag transition stage,wide-spread thin coal seam,high sedimentation rate,widely distributed sand body,and coarse deposits in the research area,totally different with the depositional features of the infilling deposits in a faulted lake.The new model may help exploration in the Eogene of the Huizhou depression.