Fused Tuff and Pépérites in South-Central Washington

Abstract

Research Article| March 01, 1967 Fused Tuff and Pépérites in South-Central Washington HANS-ULRICH SCHMINCKE HANS-ULRICH SCHMINCKE Mineralogisch-Petrographisches Institut, Laboratorium für Sediment-forschung, Berliner Strasse 19, 69 Heidelberg, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information HANS-ULRICH SCHMINCKE Mineralogisch-Petrographisches Institut, Laboratorium für Sediment-forschung, Berliner Strasse 19, 69 Heidelberg, Germany Publisher: Geological Society of America Received: 26 Jul 1965 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1967, 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 (1967) 78 (3): 319–330. https://doi.org/10.1130/0016-7606(1967)78[319:FTAPIS]2.0.CO;2 Article history Received: 26 Jul 1965 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 HANS-ULRICH SCHMINCKE; Fused Tuff and Pépérites in South-Central Washington. GSA Bulletin 1967;; 78 (3): 319–330. doi: https://doi.org/10.1130/0016-7606(1967)78[319:FTAPIS]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 The Pomona Basalt, an extensive tholeiitic lava flow of the Columbia River Basalt, overlies an airfall vitric tuff in south-central Washington. In many places, this tuff was welded at the contact from the heat and pressure of the overlying basalt. Textures and minerals (mainly Na-sanidine and cristobalite) formed in the tuff during and after welding are identical to those of welded ash flow tuffs. Heat conduction from the lava could have accomplished the welding, as shown by calculations, although water vapors greatly aided in heat transfer. Welding was completed prior to deuteric crystallization of the Pomona Basalt. In other places, where the tuff was probably thicker, the Pomona flow burrowed into the tuff, fragmented it, and formed spectacular breccias (pépérites). The pépérites occur sporadically between outcrops of the un-brecciated Pomona in an area of about 5400 km2 (2100 miles2). 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.