Metamorphic Rocks of the Northern Tobacco Root Mountains, Madison County, Montana

Research Article| March 01, 1963 Metamorphic Rocks of the Northern Tobacco Root Mountains, Madison County, Montana ROLLAND R REID ROLLAND R REID Dept. Geology and Geography, University of Idaho, Moscow, Idaho Search for other works by this author on: GSW Google Scholar Author and Article Information ROLLAND R REID Dept. Geology and Geography, University of Idaho, Moscow, Idaho Publisher: Geological Society of America Received: 22 Dec 1959 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1963, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1963) 74 (3): 293–306. https://doi.org/10.1130/0016-7606(1963)74[293:MROTNT]2.0.CO;2 Article history Received: 22 Dec 1959 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ROLLAND R REID; Metamorphic Rocks of the Northern Tobacco Root Mountains, Madison County, Montana. GSA Bulletin 1963;; 74 (3): 293–306. doi: https://doi.org/10.1130/0016-7606(1963)74[293:MROTNT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract In the northern Tobacco Root Mountains, Pony metamorphic rocks overlie Cherry Creek metamorphic rocks; they are parts of the same depositional unit and have been subjected to the same sequence of metamorphic processes.Early in pre-Beltian time, a thick sequence of geosynclinal rocks was isoclinally folded about northeast-trending axes under high-grade metamorphic conditions; recumbent isoclinal folds were produced, accompanied by metasomatic feldspathization and metamorphic differentiation. Basalt sills and dikes were injected into the metamorphic rocks, cutting isoclinal folds and migmatitic patterns.The entire rock complex, including the basalts, was subjected to horizontal-shearing deformation under granulite-facies conditions and then under amphibolite-facies conditions.Later in pre-Beltian time in a period of concentric folding the pre-existing, approximately horizontal schistosity was deformed into large, north-plunging folds. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.