COLLABORATIVE RESEARCH: Relief Evolution at the Fluvial-Glacial Transition

9980419格兰杰大多数中纬度和高纬度的山脉都是由冰川侵蚀雕刻而成的。孤立的尖顶，狭窄的山脊，长长的裸露的岩石山坡，以及高山地形的宽阔山谷立即给人一种水生的印象，即冰川是高效的侵蚀剂，冰川侵蚀产生了相当大的缓解。 然而，人们对冰川侵蚀的速率和模式、控制它们的因素以及从河流（非冰川）侵蚀到冰川侵蚀的形态后果知之甚少。 我们建议利用自然实验室在南部的冰川作用的限制，在邻近的，部分的，和非冰川作用，但在其他方面类似，盆地可以beststudied。 我们确定了两个领域的设置在东部山脉内华达州，加州，和北方桑格雷德克里斯托范围，科罗拉多，其中一个可以定量估计的数量和模式的地形变化归因于冰川侵蚀单独作为一个函数的强度ofglaciation。 我们提出了一个在这两个野外环境中结合野外制图、DEM分析和宇宙成因同位素测年的研究方案，以定量地检验在冰川地貌和侵蚀的初步调查中提出的5个假设

9980419GrangerMost mid- and high-latitude mountain ranges have been sculpted dramaticallyby glacial erosion. The isolated spires, narrow ridges, long bare-rockhillslopes, and broad valleys of alpine terrain immediately give aqualitative impression that glaciers are highly efficient erosive agentsand that glacial erosion produces considerable relief. However, little isknown quantitatively about the rates and patterns of glacial erosion, thefactors that control them, nor even the morphological consequences of ashift from fluvial (non-glacial) to glacial erosion. We propose to exploitnatural laboratories at the southern limit of glaciation where adjacentfully-, partially-, and un-glaciated, but otherwise similar, basins can bestudied. We identify two field settings in the eastern Sierra Nevada,California, and the northern Sangre de Cristo range, Colorado, where onemay estimate quantitatively the amount and pattern of topographic changeattributable to glacial erosion alone as a function of the intensity ofglaciation. We propose a research program in these two field settingscombining field mapping, DEM analysis, and cosmogenic isotope dating totest quantitatively 5 hypotheses developed during a preliminaryinvestigation of glacial landforms and erosion