Eskers are primarily ridges of glaciofluvial sediment deposited in subglacial, englacial and supraglacial conduits. They are typically straight to sinuous features, however, their planform morphology can be highly diverse. Esker enlargements are spatially confined ridge sections that are significantly wider than the trunk ridge (typically 250–400 m) and that reconverge downflow. The enlargements include complex ridge networks or coherent sediment bodies. We mapped >1400 esker enlargements across Fennoscandia and Keewatin, Canada, to investigate their distribution and morphological characteristics. Esker enlargements are less abundant below the marine limit, and tend to become more abundant in areas of faster ice retreat. They form local clusters along particular ridges, and can occasionally be traced laterally between adjacent esker systems. Based on morphological observations, we link their formation to roof collapses in subglacial conduits. The distribution of esker enlargements indicates that subglacial conduit collapse became an increasingly significant process during the final stages of deglaciation of both the Scandinavian and Laurentide ice sheets, and may have exerted a positive feedback on ice sheet retreat at land-terminating ice margins.

Eskers 主要是沉积在冰下、冰期和冰上管道中的冰河沉积物的脊。它们通常是直接弯曲的特征，然而，它们的平面形态可以高度多样化。Esker 扩大是空间受限的海脊部分，比主干海脊（通常 250-400 m）宽得多，并且会重新收敛下流。扩大包括复杂的山脊网络或连贯的沉积体。我们在加拿大 Fennoscandia 和 Keewatin 绘制了 1400 多个 esker 放大图，以研究它们的分布和形态特征。Esker 扩大在海洋极限以下不太丰富，并且往往在冰退速度较快的地区变得更加丰富。它们沿着特定的山脊形成局部集群，偶尔可以在相邻的 esker 系统之间横向追踪。根据形态观察，我们将它们的形成与冰下管道中的屋顶坍塌联系起来。esker 扩大的分布表明，在斯堪的纳维亚和劳伦特冰盖冰消的最后阶段，冰下管道坍塌变得越来越重要，并且可能对陆地终止冰缘的冰盖退缩产生了正反馈。