Geologic History of the Yosemite Valley
Geologic History of the Yosemite Valley
复制标题
优胜美地山谷的地质历史
DOI：
10.1007/978-1-349-15480-7_6
复制
发表时间：
2002
影响因子：
1.2
通讯作者：
F. Matthes
中科院分区：
文献类型：
--
作者：
F. Matthes
在内华达山脉的任何地方，冰川活动的证据都没有在约塞米蒂地区得到更详细的研究。约翰·缪尔是第一个从事这项工作的人。在约塞米蒂山谷居住的几年里，他花了很大一部分空闲时间来追踪古代冰川所遵循的路径，不仅在山谷附近，而且在上面的高山山脉。30年后，美国地质调查局的亨利·W·特纳(Henry W.Turner)承诺在一张小比例地图上定位更大的冰川沉积物，但他没有完成这项任务。直到1913年，才开始进行系统和详细的冰川调查--本报告所依据的调查--并将获得的数据汇编成一张大比例尺地图。在接下来的几年里，这项调查扩展到了高塞拉山脉以及约塞米蒂地区以下的国家，直到最终覆盖了曾经位于约塞米蒂冰川及其支流和邻居统治下的整个地区。因此，这些冰川在其最大伸展时所达到的长度、宽度和深度现在都是明确的。更重要的是，对它们因气候变化而前进和衰退的历史有了一些洞察，因此现在可以合理地确定，约塞米蒂山谷曾三次受到冰川的入侵。
In no part of the Sierra Nevada have the evidences of glacial action been studied in greater detail than in the Yosemite region. John Muir was the first to engage in this work. During the years of his residence in the Yosemite Valley he devoted a large part of his leisure time to tracing the pathways followed by the ancient glaciers, not only in the immediate vicinity of the valley but also in the High Sierra above. Thirty years later Henry W. Turner, of the United States Geological Survey, undertook to locate the larger glacial deposits on a small-scale map, but he did not finish the task. It was not until 1913 that a systematic and detailed glacial survey — the survey on which the present account is based — was instituted and that the data obtained were assembled on a large-scale map. In subsequent years this survey was extended to the High Sierra as well as to the country below the Yosemite region, until at length the entire area that once lay under the dominion of the Yosemite Glacier, with its tributaries and neighbors, was covered. As a result, the length, breadth and depth attained by each of these glaciers at the time of their greatest extension are now definitely known. What is more, some insight has been gained into the history of their advances and recessions in response to climatic changes, so that it is now reasonably certain that the Yosemite Valley was invaded by a glacier three times.