| 翻訳と辞書 |
| Crow Creek (Alaska) ： ウィキペディア英語版 |
Crow Creek (Alaska)
Crow Creek is a waterway in the Chugach Mountain Range, Alaska, US. It is the only notable tributary of Glacier Creek, which enters Turnagain Arm from the north, from its eastern end. The stream is notable as the site of ongoing gold mining since the late 19th century.
==Geography==
Crow Creek is a tributary of Glacier Creek, about above its mouth. The latter flows into Turnagain Arm from the northern side. The mountains at its head are high and rugged and form the divide between the waters that flow to Turnagain Arm and those tributary to Knik Arm. They are broken at the head of Crow Creek by Crow Creek Pass at an altitude of about , which affords a fairly good route from Crow Creek to Raven Creek, a tributary of Eagle River. From its source in the pass to its mouth, Crow Creek is about long. Near its head, it is precipitous, descending in waterfalls and rapids for a vertical distance of over within of the pass. It is fed by several small glaciers, and during the summer its waters are turbid. Below the pass the stream emerges from its narrow stream-cut gorge into a gravel-filled basin.
The basin is bordered at its lower end by a terminal moraine from a lateral valley, and the gravel fill is the result of the lessened gradient behind this morajnal dam. Through its boulder-like channel across the moraine the stream descends in rapids, to emerge into a narrow gravel-floored valley bordered by benchlike terraces of gravel and snowing no rock outcrops. These conditions prevail to a point within half a mile of the mouth of the valley, where the stream enters a rock canyon, with nearly vertical walls, that extends to its mouth. Throughout the basin of Crow Creek, the bedrock consists predominantly of interbedded argillites or shales and graywackes, with some conglomerates, cut by numerous granitic dikes and sills. Locally, the shale beds have been metamorphosed, with the development of slaty cleavage, and in places the metamorphism has been intense enough to produce a somewhat schistose structure. The prevailing strike of the beds in this basin is northeast, but locally the beds diverge considerably from this general trend. Near the mouth of Crow Creek, they dip prevailingly at high angles to the southeast, but at the head of the valley folding has occurred, and the general trend of the structure swings around to an easterly direction.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Crow Creek (Alaska)」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|