Using the size and position of drumlins to understand how they grow, interact and evolve
Using the size and position of drumlins to understand how they grow, interact and evolve
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DOI：
10.1002/esp.4241
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发表时间：
2018-04
影响因子：
3.3
通讯作者：
J. Ely;C. Clark;M. Spagnolo;A. Hughes;C. Stokes
中科院分区：
文献类型：
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作者：
J. Ely;C. Clark;M. Spagnolo;A. Hughes;C. Stokes
鼓林是沿冰流方向流线型的冰下河床。它们在冰川消融的景观中很常见，已经被广泛研究，为它们的内部地质、大小、形状和间距提供了丰富的信息。与地貌学其他领域的地形调查（例如风成沙丘、河流沙丘和波纹）不同，大多数鼓林研究都是从遗留物中获得观察结果，因此是静态特征。这使得我们很难获得关于它们随时间演变的信息和见解，这可能会阻碍我们对鼓麟形成过程的理解。在这里，我们采取形态学的方法，研究鼓的大小和间距度量。与以往的研究不同，我们采用空间-时间替代方法，使用分布在空间中的单个鼓形流集作为不同开发时间/时期的代理。在风成和河流地貌学的框架和辅助下，我们使用我们的度量数据来探索鼓林生长、演化和相互作用的可能情景。我们研究了36222个鼓点的大小和间距的度量，分布在71个流动集中，由前英国-爱尔兰冰盖留下，并询问是否可以通过统计分析得出其他形式现象的共同行为。通过描述和分析每个流集的大小和间距度量的概率分布函数的形状，我们认为鼓点会随着它们的进化而增长，并可能迁移，从而导致模式粗化。此外，我们的研究结果进一步支持了鼓形尺寸不存在上限的观点，以及如果给予足够的时间，可能会发生永久粗化的观点。我们提出，通常应用于非冰川河床的过程和模式框架对于理解鼓状地层和破译冰川景观具有潜在的强大作用。©2017作者。地球表面过程和地形由约翰威利和儿子有限公司出版。
Drumlins are subglacial bedforms streamlined in the direction of ice flow. Common in deglaciated landscapes, they have been widely studied providing rich information on their internal geology, size, shape, and spacing. In contrast with bedform investigations elsewhere in geomorphology (aeolian and fluvial dunes and ripples for example) most drumlin studies derive observations from relict, and thus static features. This has made it difficult to gain information and insights about their evolution over time, which likely hampers our understanding of the process(es) of drumlin formation. Here we take a morphological approach, studying drumlin size and spacing metrics. Unlike previous studies which have focussed on databases derived from entire ice sheet beds, we adopt a space‐for‐time substitution approach using individual drumlin flow‐sets distributed in space as proxies for different development times/periods. Framed and assisted by insights from aeolian and fluvial geomorphology, we use our metric data to explore possible scenarios of drumlin growth, evolution and interaction. We study the metrics of the size and spacing of 36 222 drumlins, distributed amongst 71 flow‐sets, left behind by the former British‐Irish Ice Sheet, and ask whether behaviour common to other bedform phenomena can be derived through statistical analysis. Through characterizing and analysing the shape of the probability distribution functions of size and spacing metrics for each flow‐set we argue that drumlins grow, and potentially migrate, as they evolve leading to pattern coarsening. Furthermore, our findings add support to the notion that no upper limit to drumlin size exists, and to the idea that perpetual coarsening could occur if given sufficient time. We propose that the framework of process and patterning commonly applied to non‐glacial bedforms is potentially powerful for understanding drumlin formation and for deciphering glacial landscapes. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.