Subduction erosion, commonly occurring in convergent margins, serves as a key mechanism for effective recycling of materials into the deep subduction. Subduction of bathymetric highs is widely recognized as a critical factor of subduction erosion of the forearc. The Mariana margin is an often-cited example of a tectonically erosive zone, with numerous topographic features such as seamounts, ridges, horsts, and grabens. However, few studies have attempted to determine the regional subduction erosion regime. By combining high-resolution bathymetric data and multichannel seismic profiles, this study analyzed the seafloor roughness, forearc taper angle, accretionary prism, and forearc topography to reveal evidence of subduction erosion at the Mariana margin. The subduction of rough seafloor (seamounts, horsts, and grabens) has accelerated the erosion process of the sediment-starved (<1 km) Mariana margin. In addition to causing depressions and landslides on the inner trench slope, this erosive process resulted in a flat forearc topography, which in turn may have induced a steeper forearc slope and taper angle. The arc-trench distance also shows a strong negative correlation with subduction erosion along the Mariana margin. The involvement of fluid inhibits the erosive process by favoring the development of a smooth surface along the plate interface. Our results suggest that tectonic erosion at the Mariana margin is jointly due to three mechanisms: seamount subduction, horst and graben subduction, and hydrofracturing. This integrated erosive process corresponds to a long-term subduction erosion rate of the submerged forearc of 7–8 km/km/Myr, significantly lower than those calculated along the other global convergent margins.

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缺乏沉积物的马里亚纳辐合边缘的地貌和俯冲侵蚀机制

俯冲侵蚀通常发生在汇聚边缘，是有效回收深俯冲物质的关键机制。测深高点的俯冲被广泛认为是弧前俯冲侵蚀的关键因素。马里亚纳边缘是构造侵蚀带的一个经常被引用的例子，具有许多地形特征，例如海山、山脊、地垒和地堑。然而，很少有研究试图确定区域俯冲侵蚀机制。通过结合高分辨率测深数据和多道地震剖面，该研究分析了海底粗糙度、弧前锥角、增生棱柱和弧前地形，揭示了马里亚纳边缘俯冲侵蚀的证据。粗糙海底（海山、地垒和地堑）的俯冲加速了缺乏沉积物（<1公里）的马里亚纳边缘的侵蚀过程。除了在沟渠内坡上造成凹陷和山体滑坡外，这种侵蚀过程还导致弧前地形平坦，进而可能导致弧前坡度和锥角更陡。弧沟距离也显示出与马里亚纳边缘俯冲侵蚀的强烈负相关性。流体的参与有利于沿板界面形成光滑表面，从而抑制侵蚀过程。我们的研究结果表明，马里亚纳边缘的构造侵蚀是由三种机制共同造成的：海山俯冲、地垒和地堑俯冲以及水力压裂。这种综合侵蚀过程对应于淹没前弧的长期俯冲侵蚀速率为 7-8 km/km/Myr，显着低于沿其他全球汇聚边缘计算的速率。