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A Pliocene ignimbrite flare-up along the Tepic-Zacoalco rift: Evidence for the initial stages of rifting between the Jalisco block (Mexico) and North America

2006; Geological Society of America; Volume: 119; Issue: 1-2 Linguagem: Inglês

10.1130/b25950.1

1943-2674

Holger Frey, R. A. Lange, Chris M. Hall, Hugo Delgado Granados, I. S. E. Carmichael,

Geological and Geochemical Analysis

Research Article| January 01, 2007 A Pliocene ignimbrite flare-up along the Tepic-Zacoalco rift: Evidence for the initial stages of rifting between the Jalisco block (Mexico) and North America Holli M. Frey; Holli M. Frey 1Department of Geological Sciences, 1100 N. University Ave., University of Michigan, Ann Arbor, Michigan 48109-1005, USA Search for other works by this author on: GSW Google Scholar Rebecca A. Lange; Rebecca A. Lange 1Department of Geological Sciences, 1100 N. University Ave., University of Michigan, Ann Arbor, Michigan 48109-1005, USA Search for other works by this author on: GSW Google Scholar Chris M. Hall; Chris M. Hall 1Department of Geological Sciences, 1100 N. University Ave., University of Michigan, Ann Arbor, Michigan 48109-1005, USA Search for other works by this author on: GSW Google Scholar Hugo Delgado-Granados; Hugo Delgado-Granados 2Instituto de Geofisica, Universidad Nacional Autónoma de México (UNAM), Coyoacan 04510 DF, Mexico Search for other works by this author on: GSW Google Scholar Ian S.E. Carmichael Ian S.E. Carmichael 3Department of Earth and Planetary Science, University of California, Berkeley, California 94720-4767, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Holli M. Frey 1Department of Geological Sciences, 1100 N. University Ave., University of Michigan, Ann Arbor, Michigan 48109-1005, USA Rebecca A. Lange 1Department of Geological Sciences, 1100 N. University Ave., University of Michigan, Ann Arbor, Michigan 48109-1005, USA Chris M. Hall 1Department of Geological Sciences, 1100 N. University Ave., University of Michigan, Ann Arbor, Michigan 48109-1005, USA Hugo Delgado-Granados 2Instituto de Geofisica, Universidad Nacional Autónoma de México (UNAM), Coyoacan 04510 DF, Mexico Ian S.E. Carmichael 3Department of Earth and Planetary Science, University of California, Berkeley, California 94720-4767, USA Publisher: Geological Society of America Received: 12 Dec 2005 Revision Received: 01 Jun 2006 Accepted: 19 Jul 2006 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 GEOLOGICAL SOCIETY OF AMERICA GSA Bulletin (2007) 119 (1-2): 49–64. https://doi.org/10.1130/B25950.1 Article history Received: 12 Dec 2005 Revision Received: 01 Jun 2006 Accepted: 19 Jul 2006 First Online: 08 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 Holli M. Frey, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-Granados, Ian S.E. Carmichael; A Pliocene ignimbrite flare-up along the Tepic-Zacoalco rift: Evidence for the initial stages of rifting between the Jalisco block (Mexico) and North America. GSA Bulletin 2007;; 119 (1-2): 49–64. doi: https://doi.org/10.1130/B25950.1 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 The Tepic-Zacoalco rift, a NW-trending corridor ∼50 × ∼250 km, is one arm of a triple-rift system in western Mexico. Together with the Colima rift and the Middle America Trench, it bounds the Jalisco block, a portion of western Mexico that may be moving independently of North America. The predominant basement rock types in the Tepic-Zacoalco rift are rhyolitic ash-flow tuffs and lavas, which were previously assumed to be Oligocene-Miocene in age, related to the Sierra Madre Occidental volcanic province, or older. New 40Ar/39Ar dates on 41 volcanic samples reveal a previously unrecognized, voluminous flare-up of rhyolitic ignimbrites between 5 and 3 Ma throughout the entire corridor of the Tepic-Zacoalco rift; they are often associated with Pliocene high-Ti basalts. The eruption rate during this Pliocene time period was an order of magnitude higher (hundreds of m/m.y.) than that documented in the Tepic-Zacoalco rift over the last 1 m.y. The Pliocene ash-flow tuffs have been faulted along NW-trending lineaments, producing vertical offsets up to at least 500 m. The voluminous ignimbrite flare-up in the Tepic-Zacoalco rift at 5–3 Ma may reflect the initial stages of rifting of the Jalisco block away from North America, analogous to what occurred in the proto-gulf region at 12–6 Ma, prior to the transfer of Baja California from North America to the Pacific plate.Additionally, new 40Ar/39Ar dates show that the Sierra Madre Occidental volcanic province extends across the entire width of the Tepic-Zacoalco rift and terminates abruptly at the northern boundary of the Jalisco block near the Rio Ameca. In contrast, Paleocene-Eocene basement from the Jalisco block extends northward into the Tepic-Zacoalco rift, where it is locally overlain by Sierra Madre Occidental rhyolites. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.