VOLCANIC ROCKS OF NORTHEASTERN NEW MEXICO

Abstract

Research Article| June 01, 1949 VOLCANIC ROCKS OF NORTHEASTERN NEW MEXICO ROBERT F COLLINS ROBERT F COLLINS SMITH COLLEGE, NORTHAMPTON, MASS. Search for other works by this author on: GSW Google Scholar Author and Article Information ROBERT F COLLINS SMITH COLLEGE, NORTHAMPTON, MASS. Publisher: Geological Society of America Received: 03 Mar 1948 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1949, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1949) 60 (6): 1017–1040. https://doi.org/10.1130/0016-7606(1949)60[1017:VRONNM]2.0.CO;2 Article history Received: 03 Mar 1948 First Online: 02 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 ROBERT F COLLINS; VOLCANIC ROCKS OF NORTHEASTERN NEW MEXICO. GSA Bulletin 1949;; 60 (6): 1017–1040. doi: https://doi.org/10.1130/0016-7606(1949)60[1017:VRONNM]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 Eastern Colfax County and northern Union County in northeastern New Mexico contain over 700 square miles of basalt flows which were fissure eruptions chiefly, although extrusion loci are as yet not correlated with post-Eocene regional structure. Physiography indicates three periods of basalt extrusion, separated by active stream erosion. Scoria cones are present on flows of all periods but are most numerous on the intermediate Clayton flows. Lithologic character correlates with the age of extrusion. Olivine basalts predominate in all three periods. Clayton basalts vary most in mineralogy and include olivine basalts, olivine-free basalts, olivine basalts with quartz inclusions, feldspathoid basalts, and basanites. Recent Capulin basalts have the least olivine and the best-developed plagioclase microphenocrysts. Dacites, andesites, soda-trachytes, and phonolites are slightly older than Clayton basalts and definitely younger than the Raton basalts. The dacites are relatively uniform and form steep, eroded cones in eastern Colfax County. Soda-trachytes are rarest and closely bunched in central eastern Colfax County. Phonolites are found in central eastern Colfax County as flows, sills, and dikes. All the Quaternary igneous rocks of the area have probably originated from one magma whose original composition approximated an olivine basalt. 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.