Research Article| July 01, 1973 Tertiary Volcanic Rocks, Mogollon-Datil Province, New Mexico, and Surrounding Region: K-Ar Dates, Patterns of Eruption, and Periods of Mineralization WOLFGANG E. ELSTON; WOLFGANG E. ELSTON 1University of New Mexico, Albuquerque, New Mexico 87106 Search for other works by this author on: GSW Google Scholar PAUL E. DAMON; PAUL E. DAMON 2University of Arizona, Tucson, Arizona 85721 Search for other works by this author on: GSW Google Scholar PETER J. CONEY; PETER J. CONEY 3Middlebury College, Middlebury, Vermont 05753 Search for other works by this author on: GSW Google Scholar RODNEY C. RHODES; RODNEY C. RHODES 1University of New Mexico, Albuquerque, New Mexico 871065Present address: Rhodes, Geological Survey of South Africa, Pretoria, South Africa. Smith, University of Wisconsin–Parkside, Kenosha, Wisconsin 53140. Search for other works by this author on: GSW Google Scholar EUGENE I. SMITH; EUGENE I. SMITH 1University of New Mexico, Albuquerque, New Mexico 871065Present address: Rhodes, Geological Survey of South Africa, Pretoria, South Africa. Smith, University of Wisconsin–Parkside, Kenosha, Wisconsin 53140. Search for other works by this author on: GSW Google Scholar MICHAEL BIKERMAN MICHAEL BIKERMAN 4University of Pittsburgh, Pittsburgh, Pennsylvania 15213 Search for other works by this author on: GSW Google Scholar Author and Article Information WOLFGANG E. ELSTON 1University of New Mexico, Albuquerque, New Mexico 87106 PAUL E. DAMON 2University of Arizona, Tucson, Arizona 85721 PETER J. CONEY 3Middlebury College, Middlebury, Vermont 05753 RODNEY C. RHODES 1University of New Mexico, Albuquerque, New Mexico 871065Present address: Rhodes, Geological Survey of South Africa, Pretoria, South Africa. Smith, University of Wisconsin–Parkside, Kenosha, Wisconsin 53140. EUGENE I. SMITH 1University of New Mexico, Albuquerque, New Mexico 871065Present address: Rhodes, Geological Survey of South Africa, Pretoria, South Africa. Smith, University of Wisconsin–Parkside, Kenosha, Wisconsin 53140. MICHAEL BIKERMAN 4University of Pittsburgh, Pittsburgh, Pennsylvania 15213 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1973) 84 (7): 2259–2274. https://doi.org/10.1130/0016-7606(1973)84<2259:TVRMPN>2.0.CO;2 Article history 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 WOLFGANG E. ELSTON, PAUL E. DAMON, PETER J. CONEY, RODNEY C. RHODES, EUGENE I. SMITH, MICHAEL BIKERMAN; Tertiary Volcanic Rocks, Mogollon-Datil Province, New Mexico, and Surrounding Region: K-Ar Dates, Patterns of Eruption, and Periods of Mineralization. GSA Bulletin 1973;; 84 (7): 2259–2274. doi: https://doi.org/10.1130/0016-7606(1973)84<2259:TVRMPN>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 K-Ar dates and field relations show that mid-Tertiary volcanic rocks usually assigned to the Datil Formation or Group in southwestern New Mexico can be interpreted as consisting of three major, slightly overlapping, volcanic cycles, which erupted about 28 to 38 + m.y., 23 to 28 m.y., and 20 to 23 m.y. B.P., respectively. Each cycle consists of lava flows, ranging in composition from andesite to rhyolite, and of voluminous silicic ash-flow tuff (ignimbrite) deposits, and is terminated by basaltic andesite and associated calc-alkalic rocks. Mid-Tertiary volcanism ceased at about 20 m.y. B.P., coincident with the beginning of Basin and Range faulting. Tholeiite and alkali basalt became the most common types of volcanic rocks after 20 m.y. B.P., although some felsic volcanism persisted.The timing of mid-Tertiary events imposes constraints on plate-tectonic or other interpretations of volcanism and tectonism in western North America. Models designed to explain volcanism in the Great Basin could be expected to fit conditions in southwestern New Mexico also; the time of inception, type, variation trends, and volume of volcanism are essentially the same. The ∼20 m.y. date for the beginning of Basin and Range faulting is consistent with the constant-rate model of Atwater (1970). There is no evidence in New Mexico for progressive outward spreading of volcanism as described from the Great Basin by Armstrong and others (1969). As in the Great Basin, the mid-Tertiary rocks of southwestern New Mexico become progressively enriched in alkalis and depleted in calcium with time. This can be most clearly demonstrated by comparing rocks of pre-28 m.y. and post-28 m.y. age. In documenting a plate-tectonic model, Christiansen and Lipman (1972) and Lipman and others (1972) recognized a petrologic transition at about 28 m.y. They correlated it with the start of Basin and Range faulting, in conflict with the ∼20 m.y. date given here.Porphyry-type mineralization is shown to be partly older than mid-Tertiary volcanism and partly contemporaneous with it. This content is PDF only. Please click on the PDF icon to access. 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.