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以往研究认为琼东南盆地陆架坡折形成于中新世末期,而在中新世早中期盆地北部为古斜坡地形。通过对琼东南盆地中新统坡折带、区域海平面、三角洲与重力流海底扇沉积的关系分析,结合钻井、地震等资料确定了琼东南盆地中中新世海底扇沉积特征及控制因素。结果表明,在中新世早中期盆地北部发育沉积、断裂和挠曲3种类型坡折,海底扇的沉积分布主要是受到沉积坡折控制,尤其是10.5Ma区域海平面下降时期,陵水凹陷、乐东凹陷发育早、晚2期大型富砂海底扇,早期海底扇沉积在陵水凹陷,浊积水道迁移快,数量多但下切作用不强;晚期海底扇沉积在乐东凹陷,浊积水道稳定分布,数量少,下切明显,朵叶体平面呈扇形分布,海底扇水道和朵叶体是有利的沉积单元。
Previous studies suggest that the continental shelf slope of Qiongdongnan Basin was formed in the late Miocene, whereas the northern part of Mid-Miocene basin is ancient slope topography. Based on the analysis of the relationship between Miocene slope break, regional sea level, delta and gravity flow subsea fan in the Qiongdongnan Basin, the sedimentary characteristics and controlling factors of the Miocene submarine fan in the Qiongdongnan Basin have been determined based on drilling and seismic data. The results show that there are three types of slope subsidence in the early and middle Miocene basin sedimentation, fracture and flexure. The sedimentary distribution of the submarine fan is mainly controlled by the sedimentary slope, especially in the period of sea level decline of 10.5 Ma, In the Ludong depression, large-scale sand-rich seafloor fan developed in the early and late stages. The early submarine fan deposited in the Lingshui sag and the hydrotrope migrated rapidly but the quantity was low but the undercutting effect was not strong. The late submarine fan was deposited in the Ledong Sag, The watercourse has a stable distribution, a small number, a clear undercut, and a flat fan-shaped body with fan-shaped distribution. The submarine fan channel and the duotone are favorable depositional units.