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当大洋板块向大陆板块下俯冲时，上覆板块的边缘可以以沟—弧—盆体制发育，也可以不发育弧后拉伸盆地．为什么同属上覆板块边缘但可以这二种完全不同的体制演化是现代地球科学研究的一个热点．本文在查阅大量最新文献的基础上认为造成这二种不同演化体制除了与俯冲作用的年代学特征有关外还可能主要与俯冲板片的形貌不同所导致局部地幔对流方式不一有关．由于俯冲的倾角，俯冲达到的最大深度以及俯冲板片在６７０ｋｍ上下地幔过渡带处保存的形态等因素不同，造成仰冲板块边缘之下软流圈对流方式不一．从而，造成弧体近陆一侧是否将发生岩石圈拉伸的动力学过程．
When the oceanic plate subducts beneath the continental plate, the margin of the overlying plate may develop with a ditch-arc-basin system, or it may stretch the basin without developing the arc. Why are both belong to the edge of overlying plate but can be two completely different system evolution is a hot spot in modern earth science research. Based on a large number of recent literatures, this paper argues that apart from the chronological characteristics of subduction, these two different evolutionary systems may also be related to the different local mantle convection modes due to the different topography of subducted slab. Due to the dip of subduction, the maximum depth of subduction and the shape of subducted slab preserved at the transition zone of upper and lower mantle of 670km, the convection way of asthenosphere beneath the edge of the upwelling plate is different. As a result, the kinetic process of lithospheric stretching will occur near the inland side of the arc.