Petrology and Rb-Sr isotope geochemistry of intrusions in the Diablo Plateau, northern Trans-Pecos magmatic province, Texas and New Mexico

Abstract

Research Article| October 01, 1977 Petrology and Rb-Sr isotope geochemistry of intrusions in the Diablo Plateau, northern Trans-Pecos magmatic province, Texas and New Mexico DANIEL S. BARKER; DANIEL S. BARKER 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 Search for other works by this author on: GSW Google Scholar LEON E. LONG; LEON E. LONG 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 Search for other works by this author on: GSW Google Scholar G. KARL HOOPS; G. KARL HOOPS 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 Search for other works by this author on: GSW Google Scholar FLOYD N. HODGES FLOYD N. HODGES 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 Search for other works by this author on: GSW Google Scholar Author and Article Information DANIEL S. BARKER 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 LEON E. LONG 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 G. KARL HOOPS 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 FLOYD N. HODGES 1Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1977) 88 (10): 1437–1446. https://doi.org/10.1130/0016-7606(1977)88<1437:PARIGO>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 DANIEL S. BARKER, LEON E. LONG, G. KARL HOOPS, FLOYD N. HODGES; Petrology and Rb-Sr isotope geochemistry of intrusions in the Diablo Plateau, northern Trans-Pecos magmatic province, Texas and New Mexico. GSA Bulletin 1977;; 88 (10): 1437–1446. doi: https://doi.org/10.1130/0016-7606(1977)88<1437:PARIGO>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 Shallow intrusive bodies in a 65-km-long belt consist of quartz-bearing and feldspathoidal syenite, trachyte, and phonolite, all within a narrow range of composition. K-Ar ages (35 ± 2 m.y.) and modal, whole-rock chemical, Rb-Sr isotopic, and mineralogic data suggest that all the intrusive rocks were derived from one magma reservoir.Nine intrusive rock types are divisible into two groups. The older group, commonly forming sills and laccoliths, is fine- to coarse-grained and has little or no flow structure, low Rb, high Sr, and initial 87Sr/86Sr ratios of 0.703 to 0.709. The younger group, tending to form discordant sheets, is finely porphyritic and has strongly developed flow structure, high Rb, low Sr, and initial strontium ratios of 0.705 to 0.712. The younger group shows more extreme compositional variation, including the most silica-oversaturated and the most silica-undersaturated rocks. Each group contains both quartz-bearing and feldspathoidal rock types.Fractional removal of plagioclase and biotite from mugearitic liquid progressively enriched the remaining liquid in sodium while depleting it in calcium, magnesium, and titanium. Later differentiation proceeded mostly by removal of alkali feldspar. 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.