U/Pb geochronology of Devonian and older Paleozoic beds in the southeastern Maya block, Central America: Its affinity with peri-Gondwanan terranes

Abstract

Research Article| May 01, 2010 U/Pb geochronology of Devonian and older Paleozoic beds in the southeastern Maya block, Central America: Its affinity with peri-Gondwanan terranes Uwe Martens; Uwe Martens † 1Department of Geological and Environmental Sciences, 450 Serra Mall, Building 320, Stanford University, Stanford, California 94305, USA †E-mail: umartens@stanford.edu Search for other works by this author on: GSW Google Scholar Bodo Weber; Bodo Weber 2División Ciencias de la Tierra, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), 22860 Ensenada, Baja California, Mexico Search for other works by this author on: GSW Google Scholar Victor A. Valencia Victor A. Valencia 3Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Uwe Martens † 1Department of Geological and Environmental Sciences, 450 Serra Mall, Building 320, Stanford University, Stanford, California 94305, USA Bodo Weber 2División Ciencias de la Tierra, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), 22860 Ensenada, Baja California, Mexico Victor A. Valencia 3Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA †E-mail: umartens@stanford.edu Publisher: Geological Society of America Received: 09 Jan 2008 Revision Received: 09 Feb 2009 Accepted: 23 Mar 2009 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2010 Geological Society of America GSA Bulletin (2010) 122 (5-6): 815–829. https://doi.org/10.1130/B26405.1 Article history Received: 09 Jan 2008 Revision Received: 09 Feb 2009 Accepted: 23 Mar 2009 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Uwe Martens, Bodo Weber, Victor A. Valencia; U/Pb geochronology of Devonian and older Paleozoic beds in the southeastern Maya block, Central America: Its affinity with peri-Gondwanan terranes. GSA Bulletin 2010;; 122 (5-6): 815–829. doi: https://doi.org/10.1130/B26405.1 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 Paleozoic rocks of the Maya (Yucatan) block of Central America include granitoids, rhyolitic-dacitic volcanic rocks, clastic sedimentary strata ranging from conglomerate to shale/phyllite, and minor limestone. To date, published isotopic ages, paleontologic data, and interpretations of field relations have been contradictory. For instance, U/Pb ages of zircon and monazite from granitoids yield Silurian-Devonian ages (ca. 420–405 Ma); the granitoids are bordered by metasedimentary contact aureoles, yet the bulk of their protolith has been assigned to the Pennsylvanian-Permian (Macal Formation or Santa Rosa Group).In this paper, we resolve the paradox by showing that pre–Lower Devonian beds are present in the Maya Mountains and constitute the wall rock for the intrusions. We dated 23 igneous zircons from a rhyolite interbedded with conglomerates obtaining a 406 +7/−6 Ma (2s) median U/Pb age, which represents the time of eruption of the previously recognized volcaniclastic Bladen Formation. Furthermore, U/Pb geochronology of detrital zircon grains from a sandstone cobble, and outcrops of sandstone and quartzite yielded equivalent age spectra, indicating that they represent a separate geologic unit, which we herein define as the Baldy unit. Recognition of a distinct, pre-Devonian unit is justified because the sandstone cobble was collected from a conglomerate associated with the dated rhyolite, implying that the Baldy unit must have been deposited, lithified, exposed, and eroded before deposition of the Bladen Formation. The Baldy unit predates Silurian–Devonian magmatism because it does not contain interbedded volcanic rocks and is intruded by the dated granites. The five youngest detrital zircons of Baldy sedimentary rocks yielded ages in the 600–520 Ma range. These features imply that Baldy deposition took place some time between the Cambrian and Silurian. Baldy zircon age spectra have peaks at ca. 1.52 Ga, ca. 1.21 Ga, and ca. 1.02 Ga, consistent with provenance from Baltica or Amazonia, not Laurentia. Based on our new data and previously known geologic attributes of the Maya block, we propose that, during the Cambrian–Silurian, the block's position was along the West Amazonia side of Gondwana's periphery. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.