Eskers are useful for reconstructing meltwater drainage systems of glaciers and ice sheets. However, our process understanding of eskers suffers from a disconnect between sporadic detailed morpho‐sedimentary investigations of abundant large‐scale ancient esker systems, and a small number of modern analogues where esker formation has been observed. This paper presents the results of detailed field and high‐resolution remote sensing studies into two esker systems that have recently emerged at Horbyebreen, Svalbard, and one at Breiðamerkurjokull, Iceland. Despite the different glaciological settings (polythermal valley glacier vs. active temperate piedmont lobe), in all cases a distinctive planform morphology has developed, where ridges are orientated in two dominant directions corresponding to the direction of ice flow and the shape of the ice margin. These two orientations in combination form a cross‐cutting and locally rectilinear pattern. One set of ridges at Horbyebreen is a hybrid of eskers and geometric ridges formed during a surge and/or jokulhlaup event. The other sets of ridges are eskers formed time‐transgressively at a retreating ice margin. The similar morphology of esker complexes formed in different ways on both glacier forelands implies equifinality, meaning that care should be taken when interpreting Quaternary esker patterns. The eskers at Horbyebreen contain substantial ice‐cores with a high ice:sediment ratio, suggesting that they would be unlikely to survive after ice melt. The Breiðamerkurjokull eskers emerged from terrain characterized by buried ice that has melted out. Our observations lead us to conclude that eskers may reflect a wide range of processes at dynamic ice margins, including significant paraglacial adjustments. This work, as well as previous studies, confirms that constraints on esker morphology include: topographic setting (e.g. confined valley or broad plain); sediment and meltwater availability (including surges and jokulhlaups); position of formation (supraglacial, englacial or subglacial); and ice‐marginal dynamics such as channel abandonment, the formation of outwash heads or the burial and/or exhumation of dead ice.

中文翻译：

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复杂 eskers 的等价性和保存潜力

Eskers 可用于重建冰川和冰盖的融水排水系统。然而，我们对 eskers 的过程理解受到对丰富的大规模古代 esker 系统的零星详细形态沉积研究与观察到 esker 形成的少数现代类似物之间的脱节。本文介绍了最近在斯瓦尔巴群岛 Horbyebreen 和冰岛 Breiðamerkurjokull 出现的两个 esker 系统的详细实地和高分辨率遥感研究结果。尽管有不同的冰川环境（多热谷冰川与活跃的温带山麓裂片），但在所有情况下都形成了独特的平面形态，其中山脊朝向两个主要方向，分别对应于冰流的方向和冰缘的形状。这两个方向组合形成了横切和局部直线图案。Horbyebreen 的一组山脊是在浪涌和/或 jokulhlaup 事件期间形成的 eskers 和几何山脊的混合体。其他几组山脊是在退缩的冰缘上随时间推移形成的 eskers。两个冰川前陆上以不同方式形成的 esker 复合体的相似形态意味着等值性，这意味着在解释第四纪 esker 模式时应该小心。Horbyebreen 的 eskers 包含大量冰核，冰：沉积物比很高，这表明它们在冰融化后不太可能存活。Breiðamerkurjokull eskers 出现在以融化的掩埋冰为特征的地形中。我们的观察使我们得出结论，eskers 可能反映了动态冰缘的广泛过程，包括显着的冰缘调整。这项工作以及之前的研究证实了对 esker 形态的限制包括： 地形设置（例如封闭的山谷或广阔的平原）；沉积物和融水可用性（包括浪涌和 jokulhlaups）；形成位置（冰上、冰期或冰下）；和冰边缘动态，例如通道废弃、冲洗头的形成或死冰的掩埋和/或挖掘。包括重大的冰河边缘调整。这项工作以及之前的研究证实了对 esker 形态的限制包括： 地形设置（例如封闭的山谷或广阔的平原）；沉积物和融水可用性（包括浪涌和 jokulhlaups）；形成位置（冰上、冰期或冰下）；和冰边缘动态，例如通道废弃、冲洗头的形成或死冰的掩埋和/或挖掘。包括重大的冰河边缘调整。这项工作以及之前的研究证实了对 esker 形态的限制包括： 地形设置（例如封闭的山谷或广阔的平原）；沉积物和融水可用性（包括浪涌和 jokulhlaups）；形成位置（冰上、冰期或冰下）；和冰边缘动态，例如通道废弃、冲洗头的形成或死冰的掩埋和/或挖掘。