Abstract Recent investigations have revealed several sets of linear ridges and grooves located in the seafloor of the submarine Dover Strait. The formation of these features is associated with the occurrence of megaflood flows during Middle–Late Pleistocene glacial stages. These megaflood events are also linked to the formation of a prominent inner channel within the Lobourg Channel and the incision of streamlined islands and longitudinal scours into its bed. However, the erosional origin of the linear ridges and grooves and their possible relationship to megaflood erosion have never been demonstrated. In the present study, high-resolution geophysical data were combined with geological data and direct observations to better understand the mechanisms that caused the formation of linear ridges and grooves in the Dover Strait. The combined interpretation of these datasets corroborates that those features are carved into a hard substratum. However, the linear ridges and grooves are truncated by scours, the formation of which is associated with the last episodes of megaflood erosion that imprinted the seafloor of the Dover Strait. Therefore, the linear ridges and grooves were carved by erosional/weathering processes that took place before the incision of those scours. Based on their morphology and regional palaeogeographic reconstructions, it is proposed that the incision of the linear ridges and grooves was caused by fluvial and high-magnitude (not necessarily mega) flood erosion. The linearity of these features and their location in carbonate rocks might also indicate some control of the erosion by permafrost processes, chemical weathering and/or the rock’s fabric.

中文翻译：

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横跨多佛海峡切割的中-晚更新世沟脊地貌特征

摘要 最近的调查揭示了位于多佛海峡海底的几组线状海脊和凹槽。这些特征的形成与中-晚更新世冰川期特大洪水的发生有关。这些特大洪水事件还与 Lobourg 海峡内一个突出的内河道的形成以及流线型岛屿的切口和纵向冲刷到其河床中有关。然而，线性山脊和凹槽的侵蚀起源及其与特大洪水侵蚀的可能关系从未得到证实。在本研究中，高分辨率地球物理数据与地质数据和直接观测相结合，以更好地了解导致多佛海峡线性脊和凹槽形成的机制。这些数据集的组合解释证实了这些特征被刻入了一个坚硬的底层。然而，线性山脊和凹槽被冲刷截断，冲刷的形成与在多佛海峡海底留下印记的最后一次大洪水侵蚀有关。因此，线性脊和凹槽是通过在这些冲刷切开之前发生的侵蚀/风化过程雕刻而成的。根据它们的形态和区域古地理重建，提出线状山脊和凹槽的切口是由河流和高强度（不一定是大型）洪水侵蚀造成的。这些特征的线性及其在碳酸盐岩中的位置也可能表明永久冻土过程、化学风化和/或岩石结构对侵蚀的某种控制。