Ramparted depressions (doughnut-shaped debris-cored ridges with peat- and/or sediment-filled central basins) are commonly perceived to represent the relict collapsed forms of permafrost ground-ice mounds (i.e. pingos or lithalsas). In Wales, UK, ramparted depressions of Late Pleistocene age have been widely attributed to permafrost-related processes. However, a variety of alternative glacial origins for these enigmatic landforms are also consistent with the available geological and geomorphological evidence, although previous studies have barely considered such alternative processes of formation. From detailed geophysical, sedimentological and remote-sensing studies at two field sites, we demonstrate that: (i) the wastage of stagnating glacier ice is a viable alternative explanation for the formation of ramparted depressions in Wales; (ii) the glacial geomorphology and geology of these landforms is analogous to supraglacial and subglacial landforms from the last Laurentide and Fennoscandian ice sheets; (iii) these landforms have significant potential for characterising the nature of deglaciation around the margins of the Irish Sea during the last glacial cycle, and may record evidence for the overextension and stagnation of the south-eastern margin of the Irish Sea Ice Stream; and (iv) investigations of ramparted depressions within formerly glaciated terrains must consider both glacial and periglacial mechanisms of formation.

中文翻译：

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残骸“pingos”的冰川起源，威尔士，英国

壁垒洼地（带有泥炭和/或沉积物填充的中央盆地的甜甜圈状碎屑岩心脊）通常被认为代表了永久冻土地面冰丘（即 pingos 或 lithalsas）的残余坍塌形式。在英国威尔士，晚更新世时代的壁垒洼地已被广泛归因于与永久冻土相关的过程。然而，这些神秘地貌的各种替代冰川起源也与可用的地质和地貌证据一致，尽管以前的研究几乎没有考虑过这种替代形成过程。通过在两个野外地点进行详细的地球物理、沉积学和遥感研究，我们证明：（i）停滞的冰川冰的浪费是威尔士形成壁垒洼地的一种可行的替代解释；(ii) 这些地貌的冰川地貌和地质类似于最后的劳伦泰德和芬诺斯坎第冰盖的冰上和冰下地貌；(iii) 这些地貌在表征上一次冰期循环期间爱尔兰海边缘周围的冰川消退的性质方面具有重要潜力，并可能记录爱尔兰海冰流东南边缘过度扩张和停滞的证据；(iv) 对以前的冰川地形内的壁垒洼地的调查必须考虑冰川和冰缘的形成机制。(iii) 这些地貌在表征上一次冰期循环期间爱尔兰海边缘周围的冰川消退的性质方面具有重要潜力，并可能记录爱尔兰海冰流东南边缘过度扩张和停滞的证据；(iv) 对以前的冰川地形内的壁垒洼地的调查必须考虑冰川和冰缘的形成机制。(iii) 这些地貌在表征上一次冰期循环期间爱尔兰海边缘周围的冰川消退的性质方面具有重要潜力，并可能记录爱尔兰海冰流东南边缘过度扩张和停滞的证据；(iv) 对以前的冰川地形内的壁垒洼地的调查必须考虑冰川和冰缘的形成机制。