| 翻訳と辞書 |
| Glacial Lake Columbia ： ウィキペディア英語版 |
Glacial Lake Columbia
Glacial Lake Columbia was the lake formed on the ice-dammed Columbia River behind the Okanogan lobe of the Cordilleran Ice Sheet when the lobe covered of the Waterville Plateau west of Grand Coulee in central Washington state during the Wisconsin glaciation.〔The Wisconsin glaciation began about 80,000 years ago and ended around 10,000 years ago.〕 Lake Columbia was a substantially larger version of the modern-day lake behind the Grand Coulee Dam. Lake Columbia's overflow – the diverted Columbia River – drained first through Foster Coulee, and as the ice dam grew, through first Moses Coulee, and finally, the Grand Coulee.
==Glacial Lake Missoula==
The Cordilleran ice sheet also blocked the Clark Fork River and created Glacial Lake Missoula, rising behind a high ice dam in flooded valleys of western Montana. Over 2000 years the ice dam periodically failed, releasing approximately 40 high-volume Missoula Floods of water down the Columbia River drainage, passing through glacial Lake Columbia. The largest flood is estimated to be the initial flood at 2,500 km3 (600 mi3), with subsequent floods occurring at roughly 20 to 80 year intervals. Since Lake Columbia was impounded behind the Okanogan lobe, which rose to , this lobe effectively blocked the normal course of the Columbia River, blocking the Missoula Floods and diverting water to flow across much of eastern Washington state. The erosion from the floods created the Grand Coulee as well as the Dry Falls, Palouse Falls, and the Channeled Scablands features of eastern Washington state.〔
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「Glacial Lake Columbia」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.
|
|