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现代俯冲带内的沉积类型是复杂多变的,並不一定都符合海底扇的沉积模式。重建古代俯冲复合体环境时,应尽可能使之符合现代类似的俯冲带环境,並必须考虑诸如浊积岩相组合、垂向沉积旋回、区域古水流型式等因素,在很多情况下还要考虑构造的形态和砂岩的岩石特征。海沟沉积作用主要的易变因素包括注入海沟的沉积物的体积和结构,以及主要的沉积物源区(特别是大海底峡谷)的分布。尽管在局部地区,例如,在海底峡谷的谷口,水流与大陆边缘可能成高角,但沉积物在海沟内通常是纵向搬运的。海沟沟坡的沉积物类型在很大程度上取决于沟坡的地形。一般来说,粗粒沉积物不是被捕集在构造脊之后(沟坡盆地之内),就是取道海底峡谷绕过沟坡。背景沉积作用则以半远洋沉积为主。水流方向通常与大陆边缘成高角,但在大而长的沟坡盆地内,亦可能出现纵向流。主要的相组合包括海底峡谷、沟坡、成熟的沟坡盆地和不成熟的沟坡盆地。
Sediment types in modern subduction zones are complex and variable, and do not always correspond to the sedimentary pattern of the submarine fan. When reconstructing the ancient subduction complex environment, it should be as far as possible to conform to the modern similar subduction zone environment, and must take into account such factors as turbidite assemblage, vertical sedimentary cycle and regional paleocurrent pattern, and in many cases, it should also consider Tectonic Morphology and Sandstone Rock Features. The major variable factors in trench ditch deposition include the volume and structure of the sediment injected into the trench and the distribution of the major sedimentary source areas, especially the large seabed canyon. Although in some areas, such as the valley mouth of a submarine canyon, the water flow may be at a high angle to the continental margin, the sediment is usually transported longitudinally within the trench. The type of sediment in the trench ditch depends to a large extent on the topography of the ditch. In general, coarse-grained sediments are not trapped behind the structural ridges (within the slope-slope basin), but bypasses the trench along the seabed canyons. Sedimentary background is dominated by semi-ocean sediments. The flow direction is usually at a high angle to the continental margin, but longitudinal flow may also occur in large and long ditch basins. The major combinations include the seabed canyon, the ditch slope, the mature ditch slope basin and the immature ditch slope basin.