Sea-level fluctuations exert a major influence on deep-water depositional processes through changing sediment supply and oceanographic processes. By utilizing the bathymetric map and six piston cores (P1 and P5–P9) from the two major canyon systems (i.e., Pearl River Canyon (PRC) and Shenhu Submarine Canyon Group (SSCG)) within the Baiyun Sag, northern South China Sea (SCS), this study investigated the deep-water depositional responses to the sea-level fluctuations in the past 30 kyr, during which the last glacial maximum (LGM) shelf edge remained farther (>60 km) seawards of the contemporary shoreline and had water depths greater than 120 m. In the past 30 kyr, the Baiyun Sag was dominated by mixed sedimentary processes involving in both turbidity and bottom currents. Coarse-grained turbidites were mostly deposited at the upper-middle segments of the slope channel within the PRC and the canyon heads of the SSCG from the LGM to the middle deglacial stage (ca. 11.5 ka); while the fine-grained contourites were continuously and widely deposited within the Baiyun Sag. It is noted that the contourites show fining- and coarsening-upwards trends before and after 6.7 ka, respectively.

The turbidity currents in the past 30 kyr were mainly triggered by oceanographic processes (i.e., contour currents and internal waves) within the Baiyun Sag. Internal waves exerted greater effects on the occurrences of turbidity currents flowing within the canyons of the SSCG. The near-seafloor intensities of contour currents and internal waves around the shelf edge weakened with sea level rising. Internal waves were responsible for triggering high-frequency turbidity currents to deposit the multiple thin-bedded turbidites at the slope canyon heads of the SSCG. The fining-upwards trend of the contourites during the period of 29.5–6.7 ka was mainly attributed to the decreasing sediment supply from the Pearl River with sea level rising, whereas the coarsening-upwards trend in the past 6.7 kyr was resulted from the circulation intensification, in response to the reopening of all straits around the SCS. This study provides a new insight into the significance of varying oceanographic processes for deep-water deposition in response to sea-level fluctuations on sediment-starved continental margin with wide shelf.

海平面波动通过改变沉积物供应和海洋学过程，对深水沉积过程产生重大影响。利用南海白云凹陷海域的测深图和来自两个主要峡谷系统（即珠江峡谷（PRC）和神湖海底峡谷群（SSCG））的六个活塞核（P1和P5-P9）（ SCS），这项研究调查了过去30年来对海平面波动的深水沉积响应，在此期间，最后的冰川最大值（LGM）陆架边缘仍保持着当代海岸线向海（> 60 km）的更远且有水深度大于120 m。在过去的30年中，白云凹陷以混浊和底流两个沉积过程为主。从LGM到中冰期（约11.5 ka），粗粒浊积物主要沉积在中华人民共和国境内斜坡通道的中上段和SSCG的峡谷首部。而细粒的等长岩则连续而广泛地沉积在白云凹陷内。值得注意的是，等高线岩分别在6.7 ka之前和之后显示出细化和粗化的上升趋势。

过去30年的浊流主要是由白云凹陷内的海洋过程（即等高线流和内波）触发的。内波对在SSCG峡谷内流动的浊流的影响更大。随着海平面的上升，等高线电流和架子边缘附近的内部波浪的近海强度减弱。内部波负责触发高频浑浊电流，以在SSCG的斜坡峡谷顶部沉积多个薄层浊积岩。29.5–6.7 ka期间等高线的细化上升趋势主要是由于珠江的沉积物供应减少，海平面上升所致，而过去6.7年的粗化上升趋势是由于环流加剧引起的。 ，为应对南海周围所有海峡的重新开放。这项研究提供了新的见解，说明了深海沉积变化的海洋学过程的重要性，以应对沉积物匮乏的大范围陆架边缘海平面的波动。