Provenance Transformation and Sedimentary Evolution of Enping Formation, Baiyun Sag, Pearl River Mouth Basin

Zeng Zhiwei; Zhu Hongtao; Yang Xianghua; Xia Chenchen; Chen Ying; Han Yinxue

doi:10.3799/dqkx.2017.123

Abstract：In order to clarify the sediment supply and sedimentary filling evolution,seismic attributes and seismic facies,the sediment supply and infilling evolution are studied by analyzing the changes in sedimentary environment,morphology,the shape and chronology of the detrital zircons,and the characteristics of sand-bodies,based on the main measuring method of the paleogeomorphology,paleontology,LA-ICPMS zircon U-Pb dating.The results indicate that the sediment supply and sedimentary filling have greatly changed during different sequences of the Enping Formation.During the SQ1 and SQ2 of the Enping Formation,the sedimentary environment was characterized by lacustrine rift basins with relatively small sedimentary-range.The sediments around the paleo-uplift were composed of Mesozoic igneous rocks and interpreted to have sourced via relatively short-distance transportation.The southern steep slope zone mainly developed a series of medium-small scale proximal fan deltas.The northern slope zone mainly formed a series of braided deltas with typical channel-filling and beach-bar sand-bodies,and the sediments were mainly derived from the Panyu lower uplift and Dongsha uplift.During the SQ3 of the Enping Formation,the sedimentary environment was characterized by semi-closed bay with relatively large sedimentary-range.The sediments mainly derived from the South China Folded Belt which were composed of Precambrian-Paleozoic metamorphic rocks.The activity of the syn-depositional faults in the southern steep slope zone gradually weakened and mainly formed a series of small scale proximal fan deltas with the sediments provided by the southern uplift.The northern slope zone was interpreted to havesourced via relatively long-distance transportation and deposited along the northwesksoutheast-trending,forming three stages large-scale prograding braided deltas.