| 翻訳と辞書 |
| The Volcano (British Columbia) ： ウィキペディア英語版 |
The Volcano (British Columbia)
The Volcano, also known as Lava Fork volcano, is a small cinder cone in the Boundary Ranges of the Coast Mountains in northwestern British Columbia, Canada. It is located approximately northwest of the small community of Stewart near the head of Lava Fork. With a summit elevation of and a topographic prominence of , it rises above the surrounding rugged landscape on a remote mountain ridge that represents the northern flank of a glaciated U-shaped valley.
Lava Fork volcano is associated with a small group of related volcanoes called the Iskut-Unuk River Cones. This forms part of the much larger Northern Cordilleran Volcanic Province, which extends from the Alaska–Yukon border to near the port city of Prince Rupert, British Columbia. Eruptive activity at The Volcano is relatively young compared to most other volcanoes in the Northern Cordilleran Volcanic Province. Geologic studies have shown that The Volcano and its eruptive products were emplaced in the past 400 years; this is well after the last glacial period, which ended about 10,000 years ago.
==Geology==
The Volcano is the southernmost of 10 volcanoes comprising the Iskut-Unuk River Cones volcanic field, as well as the most recent to erupt.〔〔 Its structure is poorly formed and has been reduced by erosion from alpine glacial ice found at its elevation and latitude. It represents one of the few historically active volcanoes in the Northern Cordilleran Volcanic Province, with a base elevation estimated to be .〔〔 Like most cinder cones, The Volcano consists of a pile of loose volcanic ash, lapilli-sized tephra and volcanic bombs. These were deposited during periods of lava fountain activity.〔 The vent area contains volcanic bombs up to long and small deposits of sulfur precipitated from volcanic gases.〔
Like other Iskut-Unuk River Cones, The Volcano has its origins in continental rifting—a long rupture in the Earth's crust where the lithosphere is being pulled apart. This incipient rifting has formed as a result of the Pacific Plate sliding northward along the Queen Charlotte Fault, on its way to the Aleutian Trench. As the continental crust stretches, the near surface rocks fracture along steeply dipping cracks parallel to the rift known as faults. Basaltic magma rises along these fractures to create effusive eruptions. The rift zone has existed for at least 14.9 million years, and has created the Northern Cordilleran Volcanic Province.〔 Several dormant volcanoes in the province are potentially active, with The Volcano being one of the three having erupted in the last few hundred years.〔 Tseax Cone, which last erupted in the 18th century, is the southernmost volcano in the province, while Prindle Volcano in easternmost-central Alaska, which erupted more than 10,000 years ago, is generally considered the northernmost.〔
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「The Volcano (British 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.
|
|