南海北部莺-琼盆地典型重力流沉积特征与物源体系

简述了莺-琼盆地横向沉积分布、纵向沉积序列、动态沉积过程，以及浅海重力流的沉积特征与形成机制。南海北部莺歌海盆地黄流组发育了浅海背景下的大型重力流沉积，琼东南盆地发育了半深海沉积环境下的陵水组、三亚组、梅山组海底扇。其中浅海重力流沉积的主要特征体现在:①沉积规模大小不等，且展布形态存在较大差异; ②海平面变化造成沉积特征的复杂性和多变性; ③浅海重力流沉积通常不具备扇体亚相分异; ④浅海重力流的水道沉积砂体迁移快、堆积厚，表现为水道富集且多期次叠加。莺-琼盆地物源演化与对比揭示了源-汇过程及不同物源输入的动态时空变化，主控因素包括物源供给、相对海平面变化、差异沉降、古地貌(古坡折及坡度)等。 

Typical gravity flow sedimentary features and provenance system in Yinggehai-Qiongdongnan Basin,northern South China Sea

This study reviewed the sedimentary characteristics and formation mechanism of the Yinggehai-Qiongdongnan Basin based on the lateral sedimentary distribution, vertical sedimentary sequence, and dynamic sedimentary process. Large-scale shallow-water gravity flow deposits developed against a shallow marine background in the Huangliu Formation of the Yinggehai Basin in the northern South China Sea. The submarine fan developed in a semideep marine depositional environment in the Lingshui, Sanya, and Meishan formations of the Qiongdongnan Basin.The main features of shallow marine gravity flow deposits are as follows: ① the scale and distribution patterns of deposits are quite different. ② The sea level changes causes the complexity and variability of sedimentary characteristics. ③ Shallow marine gravity flow deposits usually do not have fan subfacies differentiation of fan subfacies. ④ The channel sandbody of shallow gravity flow is distinguished by rapid migration and thick accumulation, which is reflected by enrichment and multistage stacking of channels.Moreover, the source to sink process and dynamic spatiotemporal changes in different source inputs are revealed through the provenance evolution and comparison of the Yinggehai-Qiongdongnan Basin. The main controlling factors of shallow marine gravity flow development and their coupling relationships are discussed from the aspects of sediment supply, relative sea level change, differential subsidence, and ancient geomorphology (ancient topography break and slope).