| 翻訳と辞書 |
| Madison Limestone ： ウィキペディア英語版 |
Madison Group
The Madison Limestone is a thick sequence of mostly carbonate rocks of Mississippian age in the Rocky Mountain and Great Plains areas of western United States. The rocks serve as an important aquifer as well as an oil reservoir in places. The Madison and its equivalent strata extend from the Black Hills of western South Dakota to western Montana and eastern Idaho, and from the Canadian border to western Colorado and the Grand Canyon of Arizona.
==Age and nomenclature==
The Madison is formally known as the Madison Group. In Montana, where its thickness reaches , the group is subdivided into the Mission Canyon Formation and Lodgepole Formation. Equivalents of the Madison are named the Pahasapa Limestone in the Black Hills, Leadville Limestone (Colorado), Guernsey Limestone (Wyoming), and Redwall Limestone in the Grand Canyon. The upper part of the Madison Group, the Charles Formation in the subsurface of North Dakota and northern Montana, is not strictly an equivalent of the Madison Limestone as usually defined.〔Mississippian System, by Lawrence C. Craig, in ''Geologic Atlas of the Rocky Mountain Region'', Rocky Mountain Association of Geologists, Denver, CO, 1972: p. 100-110〕
Most of the Madison Limestones were deposited during Early to Middle Mississippian time (Tournaisian to Visean stages), about 359 to 326 million years ago. Older North American usage lists the Madison as being laid down during the Kinderhookian, Osagian, and Meramecian stages.
Neither a type locality nor derivation of the name was designated when the term "Madison Limestone" was first used by Peale (1893),〔(Peale, A.C., 1893, ''The Paleozoic section in the vicinity of Three Forks, Montana, with petrographic notes by G.P. Merrill'': U.S. Geological Survey Bulletin, 110, 56 p. )〕 but since the original work focused on the area of Three Forks, Montana, it is likely that the name relates to outcrops along the Madison River, Montana. A reference section has been designated on the north side of Gibson Reservoir in SE/4 sec. 36, T. 22 N., R. 10 W., Patricks Basin quad, Teton Co., Montana.〔Mudge, M.R., Sando, W.J. and Dutro, J.T., Jr., 1962, ''Mississippian rocks of the Sun River Canyon area, Sawtooth Range, Montana'': American Association of Petroleum Geologists Bulletin, v. 46, no. 11, p. 2003-2018〕
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「Madison Group」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.
|
|