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本文把南海分为五个海底地貌区:(1)陆架区;(2)淹没的亚洲大陆边缘;(3)台湾岛、吕宋岛、巴拉望和加里曼丹岛等被淹没的岛屿边缘;(4)“危险地带”所在的海台区;(5)中央海盆。西部和南部的陆架区宽阔,东部岛屿附近的陆架狭窄。珊瑚礁几乎是整个陆架的共同特点。陆架通过深度分别为30米和70米(相当于17(口寻)和38(口寻))的海槛与印度洋和东海进行水交换。穿越陆架的水道把南海与苏禄海及太平洋连接起来,水道深度分别为450米和100米(相当于246(口寻)和55(口寻))。淹没的大陆边缘和淹没的岛屿边缘包括若干阶地、珊瑚礁和海谷。珊瑚礁主要出现在阶地上。因为阶地深达1800米(1000(口寻)),它们上面出现珊瑚礁是不寻常的。据设想,阶地是下沉陆块,而且珊瑚的生长与陆块下沉保持着相应的速度。“危险地带”区包括一个很大的发育着许多珊瑚礁的海台,并为许多海谷所切割。因为在水深1500米(800(口寻))和2000米(1100(口寻))之间凹凸不平的海台表面发现有珊瑚礁,说明这一地块也是下沉的。中央海盆基本上是一块海底平原,大体上从水深3400米(1850(口寻))向南递降至4200米(2300(口寻))。海盆中心附近有许多海山。这些海山可能是火山成因的,最高者也未能到达海平面。最近海军海洋局把南海的测深成果编绘成海底水深地势图。这幅图用概略形式表明地形特点和地貌分区,而不是用全等深线绘制的水深图。勾画特征的等深线并不受固定等深线间距的限制,而且能够表示变化较大的坡度和起伏较小的地形。
This paper divides the South China Sea into five submarine topography areas: (1) shelf areas; (2) inundated Asian Continent edges; (3) submerged island margins such as Taiwan Island, Luzon Island, Palawan and Kalimantan ; (4) Haitai District where “dangerous zone” is located; and (5) central basin. The shelf areas are broad in the west and south, and the shelves in the east are narrow. Coral reefs are a common feature of almost the entire shelf. Shelfs exchange water with the Indian Ocean and the East China Sea through sills at depths of 30 and 70 meters (equivalent to 17 (mouth-seeking) and 38 (mouth-seeking) respectively). Waterways across the shelf connect the South China Sea to the Sulu Sea and the Pacific Ocean at depths of 450 meters and 100 meters (equivalent to 246 (mouth-seeking) and 55 (mouth-seeking) respectively). Inundated continental and inundated island margins include several terraces, coral reefs and sea valleys. Coral reefs mainly appear on the terrace. Because the terraces are as deep as 1,800 meters (1000 (mouths)), it is unusual for coral reefs to appear on top of them. It is envisaged that the terraces are subsidence patches, and the growth of the corals and the subsidence of the patches maintain their corresponding velocities. The “Dangerous Zone” area includes a large sea-bed with many coral reefs cut and cut by many sea valleys. Because coral reefs were found on the surface of rugged platforms between 1,500 meters (800 (mouth) and 2000 meters (1100)), indicating that the site is also subsided. The central basin is basically a submarine plain, descending to a depth of 4,200 meters (2300 (mouth)) southward from a depth of 3400 meters (1850 (mouth)). There are many seamounts near the basin center. These seamounts may be volcanogenic and the highest ones fail to reach sea level. Recently, the Naval Oceanic Administration compiled sounding results of the South China Sea into seabed depth maps. This picture shows, in a rough form, topographical features and geomorphological zonations, rather than water depth maps, drawn in full depth. The isobaths of the sketching features are not constrained by the constant isobath spacing, but can also represent greatly varying slopes and undulations.