Do subglacial bedforms comprise a size and shape continuum?
Do subglacial bedforms comprise a size and shape continuum?
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冰下地床形态是否包含尺寸和形状连续体？
DOI：
10.1016/j.geomorph.2016.01.001
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发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
Ely J
中科院分区：
文献类型：
--
作者：
Ely J
了解冰床界面的演化对于深入了解冰块的动力学和冰下地貌是如何形成的至关重要。然而，在这条边界上形成的一套地貌--冰下床--的形成是一个有争议的问题，尚未完全解决。在风沙、河流和海洋环境中形成的床型要么属于不同的形态种群，要么被认为代表了由相同的控制过程产生的一系列形态。对于冰下河床，已经假设了一个大小和形状的连续体，但它还没有得到充分的检验。在这里，我们分析了有史以来整理的最大的冰下床形大小和形状测量数据集(96,900个床形)。我们的结果表明，笛子形成了一个不同的狭窄床型种群。然而，在形成冰下连续体的鼓状冰纹和大尺度冰川纹线(MSGL)之间没有明显的区别。冰下肋骨的连续体也存在，没有明显的大小或形状差异表明不同的种群。此外，一类与冰流没有明确方位的未被报道的床型(准圆形床型)与肋状和线理连续体重叠，通常出现在两者之间的空间过渡带中，有可能将这三种床型合并为一个更大的连续体。
Understanding the evolution of the ice-bed interface is fundamentally important for gaining insight into the dynamics of ice masses and how subglacial landforms are created. However, the formation of the suite of landforms generated at this boundary — subglacial bedforms — is a contentious issue that is yet to be fully resolved. Bedforms formed in aeolian, fluvial, and marine environments either belong to separate morphological populations or are thought to represent a continuum of forms generated by the same governing processes. For subglacial bedforms, a size and shape continuum has been hypothesised, yet it has not been fully tested. Here we analyse the largest data set of subglacial bedform size and shape measurements ever collated (96,900 bedforms). Our results show that flutes form a distinct population of narrow bedforms. However, no clear distinction was found between drumlins and megascale glacial lineations (MSGLs), which form a continuum of subglacial lineations. A continuum of subglacial ribs also exists, with no clear size or shape distinctions indicating separate populations. Furthermore, an underreported class of bedform with no clear orientation to ice flow (quasi-circular bedforms) overlaps with the ribbed and lineation continua and typically occurs in spatial transition zones between the two, potentially merging these three bedform types into a larger continuum.