Abstract A number of unidirectionally migrating channels have been interpreted as the result of the interaction between turbidity flows and bottom currents. Based on the analysis of the morphology and internal architecture of channels, different conceptual models of unidirectionally migrating channels were built to reveal the flow process of the interaction between turbidity flows and bottom currents. Most previous studies mainly focused on the straight section of channels, however, the relevant models did not elucidate the flow process in sinuous sections, limiting the knowledge on the formation mechanism and evolution of the whole unidirectionally migrating channels. By using 3D seismic data, the current study not only depicted the geomorphology and internal architecture of a sinuous unidirectionally migrating channels in the Rovuma Basin, offshore Mozambique, but also quantitatively analyzed the flow processes in the straight and bend sections of the channels. The results show that the interaction between turbidity flows and the northward-flowing Antarctic Bottom Water (AABW) led to the unidirectional migration of the turbidite channels. In the straight section of channels, fine-grained material from the upper parts of turbidity flows was deflected northward via flow stripping induced by the AABW, and this material was finally deposited as sandy lateral accretion packages and muddy drifts. The lateral deposits steepened northern channel banks and forced the southward migration of channel axes. However, in the bend section of channels, the upper parts of turbidity flows were forced towards the inner (southern) bank due to the helical flow induced by centrifugal forces, which probably offset the effect of the AABW, and therefore no lateral drifts developed. The effect of bottom currents on turbidity flows is related to the relative direction of turbidity flow and bottom currents. The lateral deposition and corresponding erosion induced by bottom currents influence the formation of the unidirectionally migrating channels, and the channels migrate towards the erosional side but away from the lateral deposition. Our results can help reveal the complete flow processes and sedimentation in the unidirectionally migrating channels in deep water basins around the world.

中文翻译：

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蜿蜒单向迁移河道中浊流与底流相互作用的流动过程：以莫桑比克近海鲁伍马盆地渐新世河道为例

摘要 许多单向迁移通道被解释为浊流和底流相互作用的结果。在分析河道形态和内部结构的基础上，建立了单向迁移河道的不同概念模型，揭示了浊流与底流相互作用的流动过程。以往的研究主要集中在河道的直线段，但相关模型并未阐明弯曲段的流动过程，限制了对整个单向迁移通道的形成机制和演化的认识。通过使用 3D 地震数据，目前的研究不仅描绘了鲁伍马盆地蜿蜒的单向迁移通道的地貌和内部结构，莫桑比克近海，但也定量分析了通道直段和弯段的流动过程。结果表明，浊流与向北流动的南极底水（AABW）之间的相互作用导致浊流通道的单向迁移。在河道的直线段，来自浊流上部的细粒物质通过AABW引起的流剥离向北偏转，这些物质最终沉积为砂质横向吸积包和泥质漂移。侧向沉积使北部河道岸陡峭并迫使河道轴线向南迁移。然而，在通道的弯曲段，由于离心力引起的螺旋流，浊流的上部被迫流向内（南）岸，这可能抵消了 AABW 的影响，因此没有产生横向漂移。底流对浊流的影响与浊流和底流的相对方向有关。底流引起的侧向沉积和相应的侵蚀作用影响单向迁移通道的形成，通道向侵蚀侧迁移但远离侧向沉积。我们的研究结果有助于揭示世界各地深水盆地单向迁移通道的完整流动过程和沉积。底流引起的侧向沉积和相应的侵蚀作用影响单向迁移通道的形成，通道向侵蚀侧迁移但远离侧向沉积。我们的研究结果有助于揭示世界各地深水盆地单向迁移通道的完整流动过程和沉积。底流引起的侧向沉积和相应的侵蚀作用影响单向迁移通道的形成，通道向侵蚀侧迁移但远离侧向沉积。我们的研究结果有助于揭示世界各地深水盆地单向迁移通道的完整流动过程和沉积。