Significance of K-Ar Ages of Tertiary Rocks from the Lake Mead Region, Nevada-Arizona

Abstract

Research Article| February 01, 1972 Significance of K-Ar Ages of Tertiary Rocks from the Lake Mead Region, Nevada-Arizona R. ERNEST ANDERSON; R. ERNEST ANDERSON U. S. Geological Survey, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar CHESTER R LONGWELL; CHESTER R LONGWELL Department of Geology, Stanford University, Stanford, California 94305 Search for other works by this author on: GSW Google Scholar RICHARD LEE ARMSTRONG; RICHARD LEE ARMSTRONG Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520 Search for other works by this author on: GSW Google Scholar RICHARD F MARVIN RICHARD F MARVIN U. S. Geological Survey, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Author and Article Information R. ERNEST ANDERSON U. S. Geological Survey, Federal Center, Denver, Colorado 80225 CHESTER R LONGWELL Department of Geology, Stanford University, Stanford, California 94305 RICHARD LEE ARMSTRONG Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520 RICHARD F MARVIN U. S. Geological Survey, Federal Center, Denver, Colorado 80225 Publisher: Geological Society of America Received: 29 Apr 1971 Revision Received: 30 Jul 1971 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1972, 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 (1972) 83 (2): 273–288. https://doi.org/10.1130/0016-7606(1972)83[273:SOKAOT]2.0.CO;2 Article history Received: 29 Apr 1971 Revision Received: 30 Jul 1971 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 R. ERNEST ANDERSON, CHESTER R LONGWELL, RICHARD LEE ARMSTRONG, RICHARD F MARVIN; Significance of K-Ar Ages of Tertiary Rocks from the Lake Mead Region, Nevada-Arizona. GSA Bulletin 1972;; 83 (2): 273–288. doi: https://doi.org/10.1130/0016-7606(1972)83[273:SOKAOT]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 ages for 43 igneous and tuffaceous rocks of the Lake Mead region, Nevada-Arizona, are reasonably consistent with mapped stratigraphic and structural relations. They serve to establish age ranges for episodes of Miocene and Pliocene volcanism, plutonism, and tectonism in the region. The late Tertiary geology of the northwestern part of the region contrasts sharply with that of the southeastern part. The northwestern part was characterized by active sedimentation in local basins followed by intense disruption by normal and transcurrent faults. The southeastern part was characterized by brief episodes of overlapping volcanism, plutonism, extreme tensional rifting, followed by severe local uplift. Although diverse in style, the tectonism of the two areas appears to have been largely synchronous.The synchronous character of the brief igneous and tectonic processes suggests strong genetic ties between them. The southeastern part of the region may be a volcanic rift zone that originated as a zone of tension near the end of a major transcurrent fault—the Las Vegas shear zone. 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.