Isotopic, geochemical, and temporal characterization of Proterozoic basement rocks in the Quitovac region, northwestern Sonora, Mexico: Implications for the reconstruction of the southwestern margin of Laurentia

Abstract

Research Article| January 01, 2004 Isotopic, geochemical, and temporal characterization of Proterozoic basement rocks in the Quitovac region, northwestern Sonora, Mexico: Implications for the reconstruction of the southwestern margin of Laurentia Alexander Iriondo; Alexander Iriondo 1Department of Geological Sciences, University of Colorado at Boulder, Boulder, Colorado 80309, USA and U.S. Geological Survey, MS 974, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar Wayne R. Premo; Wayne R. Premo 2U.S. Geological Survey, MS 963, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar Luis M. Martínez-Torres; Luis M. Martínez-Torres 3Departamento de Geodinámica, Universidad del País Vasco, Apartado 644, E-48080 Bilbao, Spain Search for other works by this author on: GSW Google Scholar James R. Budahn; James R. Budahn 4U.S. Geological Survey, MS 974, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar William W. Atkinson, Jr.; William W. Atkinson, Jr. 5Department of Geological Sciences, University of Colorado at Boulder, Boulder, Colorado 80309, USA Search for other works by this author on: GSW Google Scholar David F. Siems; David F. Siems 6U.S. Geological Survey, MS 973, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar Blanca Guarás-González Blanca Guarás-González 7Alava Museum of Natural Sciences, Siervas de Jesús, 24, E-01001 Vitoria-Gasteiz, Spain Search for other works by this author on: GSW Google Scholar Author and Article Information Alexander Iriondo 1Department of Geological Sciences, University of Colorado at Boulder, Boulder, Colorado 80309, USA and U.S. Geological Survey, MS 974, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Wayne R. Premo 2U.S. Geological Survey, MS 963, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Luis M. Martínez-Torres 3Departamento de Geodinámica, Universidad del País Vasco, Apartado 644, E-48080 Bilbao, Spain James R. Budahn 4U.S. Geological Survey, MS 974, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA William W. Atkinson, Jr. 5Department of Geological Sciences, University of Colorado at Boulder, Boulder, Colorado 80309, USA David F. Siems 6U.S. Geological Survey, MS 973, Box 25046, Denver Federal Center, Denver, Colorado 80225, USA Blanca Guarás-González 7Alava Museum of Natural Sciences, Siervas de Jesús, 24, E-01001 Vitoria-Gasteiz, Spain Publisher: Geological Society of America Received: 25 Feb 2003 Revision Received: 12 Jun 2003 Accepted: 01 Jul 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2004) 116 (1-2): 154–170. https://doi.org/10.1130/B25138.1 Article history Received: 25 Feb 2003 Revision Received: 12 Jun 2003 Accepted: 01 Jul 2003 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 Alexander Iriondo, Wayne R. Premo, Luis M. Martínez-Torres, James R. Budahn, William W. Atkinson, David F. Siems, Blanca Guarás-González; Isotopic, geochemical, and temporal characterization of Proterozoic basement rocks in the Quitovac region, northwestern Sonora, Mexico: Implications for the reconstruction of the southwestern margin of Laurentia. GSA Bulletin 2004;; 116 (1-2): 154–170. doi: https://doi.org/10.1130/B25138.1 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 SocietyGSA Bulletin Search Advanced Search Abstract A detailed geochemical characterization of 19 representative Proterozoic basement rocks in the Quitovac region in northwestern Sonora, Mexico, has identified two distinct Paleoproterozoic basement blocks that coincide spatially with the previously proposed Caborca and "North America" blocks. New U-Pb zircon geochronology revises their age ranges, the Caborca (1.78–1.69 Ga) and "North America" (1.71–1.66 Ga) blocks at Quitovac, and precludes a simple age differentiation between them. In addition, Grenvillian-age granitoids (ca. 1.1 Ga), spatially associated with the Caborca block have been identified at Quitovac.Nd isotopes and major- and trace- element geochemistry support the distinction of these Paleoproterozoic blocks. Granitoids of the "North America" block are characterized by depleted εNd values (3.4–3.9) and younger Nd model ages (1800–1740 Ma) and have lower K2O, Y, Rb, Ba, Th, REE, and Fe/Mg values than coeval rocks of the Caborca block. The Caborca block granitoids are likewise characterized by slightly less depleted εNd (0.6–2.6) and older Nd model ages (2070–1880 Ma). Despite the subtle differences, granitoids from both the Caborca and "North America" blocks exhibit island arc-like affinities.We propose that the Proterozoic basement rocks from the Quitovac region are an extension of the Proterozoic crustal provinces in the southwestern United States. Specifically, rocks of the Caborca block exhibit an affinity to rocks of either the Yavapai province or the Mojave– Yavapai transition zone, whereas rocks of the "North America" block have signatures similar to those of the Mazatzal province or possibly the Yavapai province of Arizona.The new isotopic ages and geochemical data do not support the existence of the Late Jurassic Mojave–Sonora megashear at Quitovac, as originally proposed. However, the Quitovac region accounts only for a small fraction of the Proterozoic basement in Sonora, so these findings do not eliminate the possibility of a megashear elsewhere in northern Sonora.Our new data create the possibility of alternative hypotheses for the distribution of Paleoproterozoic crustal provinces in southwestern North America that affect reconstructions of the original southwestern margin of Laurentia, and reduce uncertainties in the configuration, timing, and existence of the Proterozoic supercontinent, Rodinia. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.