High-resolution multichannel seismic data enables the discovery of a previous, undocumented submarine canyon (Huaguang Canyon) in the Qiongdongnan Basin, northwest South China Sea. The Huaguang Canyon with a NW orientation is 140 km in length, and 2.5 km to 5 km in width in its upper reach and 4.6 km to 9.5 km in width in its lower reach. The head of the Huaguang Canyon is close to the Xisha carbonate platform and its tail is adjacent to the central canyon. This buried submarine canyon is formed by gravity flows from the Xisha carbonate platform when the sea level dropped in the early stage of the late Miocene (∼10.5 Ma). The internal architecture of the Huaguang Canyon is mainly characterized by high amplitude reflections, indicating that this ancient submarine canyon was filled with coarse-grained sediments. The sediment was principally scourced from the Xisha carbonate platform. In contrast to other buried large-scale submarine canyons (central canyon and Zhongjian Canyon) in the Qiongdongnan Basin, the Huaguang Canyon displays later formation time, smaller width and length, and single sediment supply. The coarse-grained deposits within Huaguang Canyon provide a good environment for reserving oil and gas, and the muddy fillings in Huaguang Canyon have been identified as regional caps. Therefore, Huaguang Canyon is potential area for future hydrocarbon exploration in the northwest South China Sea. Our results may contribute to a better understanding of the evolution of submarine canyons formed in carbonate environment.

高分辨率的多通道地震数据使您能够在南海西北部的琼东南盆地找到一个先前未记录的海底峡谷（华光峡谷）。西北方向的华光峡谷长140公里，上游河段宽度为2.5 km至5 km，下游河段宽度为4.6 km至9.5 km。华光峡谷的头部靠近西沙碳酸盐台地，其尾部与中央峡谷相邻。在中新世晚期（〜10.5 Ma）早期海平面下降时，潜入海底峡谷是由西沙碳酸盐台地的重力流形成的。华光峡谷的内部结构主要表现为高振幅反射，这表明这个古老的海底峡谷充满了粗颗粒的沉积物。沉积物主要是从西沙碳酸盐台地中冲刷出来的。与琼东南盆地其他埋藏的大型海底峡谷（中部峡谷和中建峡谷）不同，华光峡谷的形成时间较晚，宽度和长度较小，且泥沙供应单一。华光峡谷内的粗粒沉积物为油气的储藏提供了良好的环境，华光峡谷的泥质充填物已被确定为区域性盖层。因此，华光峡谷是南海西北部未来油气勘探的潜在地区。我们的结果可能有助于更好地了解碳酸盐岩环境中形成的海底峡谷的演变。与琼东南盆地其他埋藏的大型海底峡谷（中部峡谷和中建峡谷）不同，华光峡谷的形成时间较晚，宽度和长度较小，且泥沙供应单一。华光峡谷内的粗粒沉积物为油气的储藏提供了良好的环境，华光峡谷的泥质充填物已被确定为区域性盖层。因此，华光峡谷是南海西北部未来油气勘探的潜在地区。我们的结果可能有助于更好地了解碳酸盐岩环境中形成的海底峡谷的演变。与琼东南盆地其他埋藏的大型海底峡谷（中部峡谷和中建峡谷）不同，华光峡谷的形成时间较晚，宽度和长度较小，且泥沙供应单一。华光峡谷内的粗粒沉积物为油气的储藏提供了良好的环境，华光峡谷的泥质充填物已被确定为区域性盖层。因此，华光峡谷是南海西北部未来油气勘探的潜在地区。我们的结果可能有助于更好地了解碳酸盐岩环境中形成的海底峡谷的演变。华光峡谷内的粗粒沉积物为油气的储藏提供了良好的环境，华光峡谷的泥质充填物已被确定为区域性盖层。因此，华光峡谷是南海西北部未来油气勘探的潜在地区。我们的结果可能有助于更好地了解碳酸盐岩环境中形成的海底峡谷的演变。华光峡谷内的粗粒沉积物为油气的储藏提供了良好的环境，华光峡谷的泥质充填物已被确定为区域性盖层。因此，华光峡谷是南海西北部未来油气勘探的潜在地区。我们的结果可能有助于更好地了解碳酸盐岩环境中形成的海底峡谷的演变。