The northern unit is a slope of the continental slope, mainly formd by accumulation and extending to NE, and its topography is simple, the slope surface is smooth and its geomorphic type is single.

• 其中陆坡斜坡位于北部，呈北东向延伸，地形较为简单，斜坡面单一平整，地貌类型单一，主要为堆积型斜坡；