Arc-rift transition volcanism in the Puertecitos Volcanic Province, northeastern Baja California, Mexico

Research Article| April 01, 1995 Arc-rift transition volcanism in the Puertecitos Volcanic Province, northeastern Baja California, Mexico Arturo Martín-Barajas; Arturo Martín-Barajas 1CICESE, Ensenada, Mexico, P.O. Box 434843, San Diego, California 92143 Search for other works by this author on: GSW Google Scholar Joann M. Stock; Joann M. Stock 2Caltech, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar Paul Layer; Paul Layer 3University of Alaska, Fairbanks, Alaska 99775 Search for other works by this author on: GSW Google Scholar Brian Hausback; Brian Hausback 4California State University, Sacramento, California 95819 Search for other works by this author on: GSW Google Scholar Paul Renne; Paul Renne 5Institute for Human Origins, Berkeley, California 94709 Search for other works by this author on: GSW Google Scholar Margarita López-Martínez Margarita López-Martínez 1CICESE, Ensenada, Mexico, P.O. Box 434843, San Diego, California 92143 Search for other works by this author on: GSW Google Scholar Author and Article Information Arturo Martín-Barajas 1CICESE, Ensenada, Mexico, P.O. Box 434843, San Diego, California 92143 Joann M. Stock 2Caltech, Pasadena, California 91125 Paul Layer 3University of Alaska, Fairbanks, Alaska 99775 Brian Hausback 4California State University, Sacramento, California 95819 Paul Renne 5Institute for Human Origins, Berkeley, California 94709 Margarita López-Martínez 1CICESE, Ensenada, Mexico, P.O. Box 434843, San Diego, California 92143 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1995) 107 (4): 407–424. https://doi.org/10.1130/0016-7606(1995)107<0407:ARTVIT>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Arturo Martín-Barajas, Joann M. Stock, Paul Layer, Brian Hausback, Paul Renne, Margarita López-Martínez; Arc-rift transition volcanism in the Puertecitos Volcanic Province, northeastern Baja California, Mexico. GSA Bulletin 1995;; 107 (4): 407–424. doi: https://doi.org/10.1130/0016-7606(1995)107<0407:ARTVIT>2.3.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 The Neogene Puertecitos Volcanic Province of northeastern Baja California records a transition from arc-related volcanic activity to rift volcanism associated with opening of the Gulf of California. The eastern Puertecitos Volcanic Province is divided into three volcanic sequences based on mapping, petrology, and 40Ar/39Ar geochronology. The lowest sequence comprises early to middle Miocene (20–16 Ma) arc-related andesitic lava flows, volcanic necks, and proximal pyroclastic and epiclastic deposits up to 400 m in thickness, with minor basaltic lava flows. Following the initiation of crustal extension in the region (11–6 Ma), synrift volcanism produced two rhyolitic sequences that discordantly overlie the arc-related rocks. The older synrift sequence (6.4–5.8 Ma) is composed of rhyolite domes and a series of pyroclastic flows up to 300 m thick. The upper sequence (3.2–2.7 Ma) consists of ash-flow tuffs and pumice-lapilli pyroclastic flows, collectively up to 200 m thick. Minor andesite eruptions followed each episode of silicic synrift volcanism. Synvolcanic faults produced topographic relief that controlled deposition of the pyroclastic flows and caused gentler dips upsection. Rhyolite domes are aligned parallel to the predominant north-northwest to north-northeast fault pattern.All three volcanic sequences are calc-alkaline. However, the synrift andesite is characterized by lower K2O, lower incompatible element concentrations, and less fractionation of light rare earth elements than the arc-related basalt and andesite. This suggests that the primary melts were more primitive for synrift andesite than for the arc-related rocks. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.