Crustal evolution of southern Laurentia during the Paleoproterozoic: Insights from zircon Hf isotopic studies of ca. 1.75 Ga rocks in central Colorado

Abstract

Research Article| July 01, 2008 Crustal evolution of southern Laurentia during the Paleoproterozoic: Insights from zircon Hf isotopic studies of ca. 1.75 Ga rocks in central Colorado M.E. Bickford; M.E. Bickford 1Department of Earth Sciences, Syracuse University, Syracuse, New York 13244-1070, USA Search for other works by this author on: GSW Google Scholar P.A. Mueller; P.A. Mueller 2Department of Geological Sciences, University of Florida, Gainesville, Florida 32611-2120, USA Search for other works by this author on: GSW Google Scholar George D. Kamenov; George D. Kamenov 2Department of Geological Sciences, University of Florida, Gainesville, Florida 32611-2120, USA Search for other works by this author on: GSW Google Scholar Barbara M. Hill Barbara M. Hill 3Department of Earth Sciences, Syracuse University, Syracuse, New York 13244-1070, USA Search for other works by this author on: GSW Google Scholar Author and Article Information M.E. Bickford 1Department of Earth Sciences, Syracuse University, Syracuse, New York 13244-1070, USA P.A. Mueller 2Department of Geological Sciences, University of Florida, Gainesville, Florida 32611-2120, USA George D. Kamenov 2Department of Geological Sciences, University of Florida, Gainesville, Florida 32611-2120, USA Barbara M. Hill 3Department of Earth Sciences, Syracuse University, Syracuse, New York 13244-1070, USA Publisher: Geological Society of America Received: 11 Dec 2007 Revision Received: 21 Feb 2008 Accepted: 09 Apr 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2008 Geological Society of America Geology (2008) 36 (7): 555–558. https://doi.org/10.1130/G24700A.1 Article history Received: 11 Dec 2007 Revision Received: 21 Feb 2008 Accepted: 09 Apr 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation M.E. Bickford, P.A. Mueller, George D. Kamenov, Barbara M. Hill; Crustal evolution of southern Laurentia during the Paleoproterozoic: Insights from zircon Hf isotopic studies of ca. 1.75 Ga rocks in central Colorado. Geology 2008;; 36 (7): 555–558. doi: https://doi.org/10.1130/G24700A.1 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 SocietyGeology Search Advanced Search Abstract Lu-Hf depleted mantle model (TDM) ages, obtained by analysis of zircons previously dated by U-Pb methods, demonstrate that ca. 1.75 Ga bimodal Paleoproterozoic rocks in the Gunnison-Salida region of central Colorado, and by extension in much of the southwestern U.S., were formed by partial melting of preexisting crustal rocks, the ages of which mostly ages greater than 2.0 Ga indicate that range from 1.83 to 1.87 Ga. Some calculated Lu-Hf TDM even older crust was probably involved, consistent with the limited presence of ca. 2.5 Ga xenocrystic zircons in some rocks. These results suggest that rocks related to the Trans-Hudson and Penokean orogens are cryptically present much farther to the south than previously believed. Coupled with the bimodality of the volcanic suite in central Colorado, and indeed in much of the southwestern U.S., these results indicate that, in contrast to current juvenile arc-accretion models, melting of older crust related to extensional tectonics played an important role in the genesis of many magmatic rocks between 1.6 and 1.8 Ga. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.