Duration of Late Cretaceous–early Tertiary magmatism in east-central Sonora, Mexico

Abstract

Research Article| April 01, 2001 Duration of Late Cretaceous–early Tertiary magmatism in east-central Sonora, Mexico Fred W. McDowell; Fred W. McDowell 1Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar Jaime Roldán-Quintana; Jaime Roldán-Quintana 2Instituto de Geología, Universidad Nacional Autónoma de México, Estación Regional del Noroeste, Apartado Postal 1039, Hermosillo, 83000 Sonora, Mexico Search for other works by this author on: GSW Google Scholar James N. Connelly James N. Connelly 3Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Fred W. McDowell 1Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Jaime Roldán-Quintana 2Instituto de Geología, Universidad Nacional Autónoma de México, Estación Regional del Noroeste, Apartado Postal 1039, Hermosillo, 83000 Sonora, Mexico James N. Connelly 3Department of Geological Sciences, University of Texas, Austin, Texas 78712, USA Publisher: Geological Society of America Received: 21 Apr 1999 Revision Received: 04 May 2000 Accepted: 05 May 2000 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2001) 113 (4): 521–531. https://doi.org/10.1130/0016-7606(2001)113<0521:DOLCET>2.0.CO;2 Article history Received: 21 Apr 1999 Revision Received: 04 May 2000 Accepted: 05 May 2000 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Fred W. McDowell, Jaime Roldán-Quintana, James N. Connelly; Duration of Late Cretaceous–early Tertiary magmatism in east-central Sonora, Mexico. GSA Bulletin 2001;; 113 (4): 521–531. doi: https://doi.org/10.1130/0016-7606(2001)113<0521:DOLCET>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 Late Cretaceous–early Tertiary arc magmatism in east-central Sonora includes the Sonoran batholith and the volcanic rocks of the Tarahumara Formation. The Tarahumara Formation consists predominantly of propylitically altered andesitic to dacitic lava, agglomerate, and volcanic breccia, all of local derivation, along with subordinate felsic pyroclastic components. Relatively thin volcaniclastic intervals with intercalated freshwater limestone that contains Late Cretaceous plant fossils occur within the upper third of the formation. Six new U-Pb zircon ages from the Tarahumara Formation extend the known duration of Late Cretaceous–early Tertiary magmatism in east-central Sonora. Four of the samples yield ages between 73 and 70 Ma, and the other two are 90 and 89 Ma (errors are generally <1 m.y.). All of these ages are older than 65 to 55 Ma K-Ar and U-Pb ages for plutons of the Sonoran batholith in east- central Sonora determined in other studies. Combined, the ages indicate arc magmatism over at least 35 m.y. Initiation of magmatism in eastern Sonora by 90 Ma is much earlier than predicted by regional trends, which are largely based on geochronology of plutons. It appears that a full history of the regional evolution of this magmatic arc will require substantial age information from its volcanic rocks.A component of inherited zircon was detected in five of the six dated samples from the Tarahumara Formation. Although ages calculated from upper concordia intercepts are mostly imprecise, all are consistent with the presence of one or more Proterozoic components. In one sample, a persistent inherited component provided a precise upper-intercept age of 1448 Ma. These small cores surrounded by new zircon growth must represent material incorporated into the magma chamber prior to eruption. The results record the presence of Laurentian basement 200 km south and east of known outcrops in Sonora. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.