The northwestern South China Sea (NW-SCS) presents a spatial-temporal evolution of its source-to-sink (S2S) system, that recorded the movement of the Indochina block and the collision between the Indian and Eurasian plates. However, complex tectonic movements and topographic evolution have led to controversial studies about the spatial-temporal distribution of allogenic materials and autogenic sediments. In this study, we integrated a number of multiscale data to review the S2S system evolution of the northwestern area of the South China Sea from the Eocene to the Miocene. The series include the initial synrift, postrift and thermal subsidence stages. First, we identified the major sediment pathways using seismic profile interpretation. We reconstructed the sediment distribution and lithofacies association within the dispersal sink area based on seismic data, core samples and grain-size analysis. We quantitatively studied the sediment flux and catchment area based on mass balance calculation modeling. Following this, we acquired rare-earth element (REE) data and zircon U–Pb age data from the bedrocks of the continental blocks and the South China Sea Cenozoic basement and rivers in the NW-SCS area to restore the provenance area and evaluate the migration distance by inspecting the heavy mineral assemblages. According to the above studies, three phases of S2S dynamics were identified. 1) The initial rifting stage occurred during the Eocene, and active rifting in the South China Sea induced a major topographic change. A large amount of autogenic slump sediments and a smaller amount of paleo-Red River sediments were injected into the Beibu Gulf Basin (BBGB) and the Yinggehai-Song Hong Basin (YGHB). 2) The postrift stage occurred during the Oligocene. Regional uplift and tectonic inversion probably linked to the clockwise rotation of the Indochina Block, broke the connection between the Beibu Gulf Basin and the Red River catchments. The paleo-Qin River and the paleo-Lian (Nanliu) River brought a large amount of clastic material into the Beibu Gulf Basin from the Cathaysia Block. 3) The thermal subsidence stage occurred during the Miocene: the eastward topographic tilt was enhanced, and the drainage basin entered postrift stage. The development of the Paleo-Red River and its branches, the Lam River and the Ma River, brought distal sediment into the YGHB, while the rivers in the west Cathaysia Block transported sediment into the BBGB. Statistical analysis of the S2S system parameters suggests that the average terrain altitude played a dominant role in determining the S2S system volume during the Eocene, while the dominant role transferred to the sediment supply during the Oligocene and Miocene.

南海西北部（NW-SCS）呈现其源到汇（S2S）系统的时空演变，记录了印度支那板块的运动以及印度和欧亚板块之间的碰撞。然而，复杂的构造运动和地形演化导致了关于异源物质和自生沉积物的时空分布的有争议的研究。在本研究中，我们整合了大量多尺度数据，回顾了南海西北部从始新世到中新世的 S2S 系统演化。该系列包括初始同裂谷、后裂谷和热沉降阶段。首先，我们使用地震剖面解释确定了主要的沉积物路径。基于地震资料、岩心样品和粒度分析，我们重建了分散汇区内的沉积物分布和岩相组合。我们基于质量平衡计算模型对泥沙通量和流域面积进行了定量研究。此后，我们从陆块基岩和南海新生代基底以及西北-南海地区河流中获取了稀土元素（REE）数据和锆石U-Pb年龄数据，以恢复物源区并评估通过检查重矿物组合的迁移距离。根据上述研究，确定了 S2S 动力学的三个阶段。1) 初始裂谷阶段发生在始新世，南海活动的裂谷活动引发了重大的地形变化。北部湾盆地（BBGB）和莺歌海-松洪盆地（YGHB）注入了大量自生滑塌沉积物和少量古红河沉积物。2）后裂阶段发生在渐新世。区域隆升和构造反转可能与印度支那地块的顺时针旋转有关，打破了北部湾盆地与红河流域之间的联系。古秦河和古廉（南流）河将华夏地块带入北部湾盆地的大量碎屑物质。3）中新世发生热沉降阶段：地形向东倾斜增强，流域进入后裂陷阶段。古红河及其支流林河和马河的发展将远端沉积物带入了YGHB，而华夏地块西部的河流则将沉积物输送到BBGB。S2S系统参数的统计分析表明，平均地形高度在始新世S2S系统体积中起主导作用，而主导作用转移到渐新世和中新世的沉积物供应。