Measure and Date of Movement on Las Vegas Valley Shear Zone, Clark County, Nevada

Abstract

Research Article| June 01, 1974 Measure and Date of Movement on Las Vegas Valley Shear Zone, Clark County, Nevada CHESTER R. LONGWELL CHESTER R. LONGWELL 1Department of Geology, Stanford University, Stanford, California 94305 Search for other works by this author on: GSW Google Scholar Author and Article Information CHESTER R. LONGWELL 1Department of Geology, Stanford University, Stanford, California 94305 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1974) 85 (6): 985–990. https://doi.org/10.1130/0016-7606(1974)85<985:MADOMO>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 Email Permissions Search Site Citation CHESTER R. LONGWELL; Measure and Date of Movement on Las Vegas Valley Shear Zone, Clark County, Nevada. GSA Bulletin 1974;; 85 (6): 985–990. doi: https://doi.org/10.1130/0016-7606(1974)85<985:MADOMO>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 Large-scale offsetting, by fracturing and bending of major geologic units, indicates clearly that a fault zone with large right-lateral displacement extends northwest across a pattern of ranges bordering Las Vegas Valley. Evidence indicating the date and measure of the movement is supplied by an unusual sedimentary unit within the Frenchman Mountain block east of Las Vegas. The Thumb Formation, dated isotopically as being Miocene in age (±17 m.y.), contains large landslide masses of brecciated metamorphic and granitic rock. These masses moved southward from an area in which only a thick section of sedimentary strata is now widely exposed. The granite is recognized as part of the distinctive Gold Butte Granite, a conspicuous unit in the South Virgin Mountains near the Nevada-Arizona border. The only present exposures of that unit near the projected location of the shear-zone axis are more than 64 km east-southeast from the landslide masses within the Thumb section.The thick Muddy Creek Formation, the basal part of which is dated as being early Pliocene, was laid down after movement on the shear zone ended. 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.