AGE OF THE MAJOR PRECAMBRIAN REGIONAL METAMORPHISM IN THE NORTHERN FRONT RANGE, COLORADO

Research Article| April 01, 1967 AGE OF THE MAJOR PRECAMBRIAN REGIONAL METAMORPHISM IN THE NORTHERN FRONT RANGE, COLORADO CARL E HEDGE; CARL E HEDGE U. S. GEOLOGICAL SURVEY, DENVER, COLORADO (HEDGE AND PETERMAN) Search for other works by this author on: GSW Google Scholar ZELL E PETERMAN; ZELL E PETERMAN U. S. GEOLOGICAL SURVEY, DENVER, COLORADO (HEDGE AND PETERMAN) Search for other works by this author on: GSW Google Scholar W. A BRADDOCK W. A BRADDOCK UNIVERSITY OF COLORADO, BOULDER, COLORADO (BRADDOCK) Search for other works by this author on: GSW Google Scholar Author and Article Information CARL E HEDGE U. S. GEOLOGICAL SURVEY, DENVER, COLORADO (HEDGE AND PETERMAN) ZELL E PETERMAN U. S. GEOLOGICAL SURVEY, DENVER, COLORADO (HEDGE AND PETERMAN) W. A BRADDOCK UNIVERSITY OF COLORADO, BOULDER, COLORADO (BRADDOCK) Publisher: Geological Society of America Received: 23 Jun 1966 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1967, 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 (1967) 78 (4): 551–558. https://doi.org/10.1130/0016-7606(1967)78[551:AOTMPR]2.0.CO;2 Article history Received: 23 Jun 1966 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 CARL E HEDGE, ZELL E PETERMAN, W. A BRADDOCK; AGE OF THE MAJOR PRECAMBRIAN REGIONAL METAMORPHISM IN THE NORTHERN FRONT RANGE, COLORADO. GSA Bulletin 1967;; 78 (4): 551–558. doi: https://doi.org/10.1130/0016-7606(1967)78[551:AOTMPR]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 Rubidium-strontium dating of whole-rock and feldspar samples indicates that the major regional metamorphism in the northern Front Range occurred 1.75 ± 0.03b.y. ago (λ = 1.39 X 10−11/yr). Sedimentation and folding predate this metamorphism. Syntectonic and late tectonic igneous rocks give a concordant age of 1.71 ± 0.07b.y. Microcline and plagioclase from a concretion pegmatite yield an age of 1.76 ± 0.08 b.y. and a relatively high initial Sr87/Sr86 ratio consistent with their being locally derived during metamorphism. 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.