Andesite breccia dikes near Blairsden, California

Abstract

Research Article| March 01, 1944 Andesite breccia dikes near Blairsden, California CORDELL DURRELL CORDELL DURRELL Search for other works by this author on: GSW Google Scholar GSA Bulletin (1944) 55 (3): 255–272. https://doi.org/10.1130/GSAB-55-255 Article history received: 28 Jan 1943 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation CORDELL DURRELL; Andesite breccia dikes near Blairsden, California. GSA Bulletin 1944;; 55 (3): 255–272. doi: https://doi.org/10.1130/GSAB-55-255 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 Eight hornblende andesite breccia dikes intrude Tertiary andesite mudflows and lava of the Sierra Nevada near Blairsden, California. Similar dikes occur elsewhere in the vicinity and farther south. The dikes consist of blocks of andesite in a fine matrix rich in a clay of the montmorillonite group. The dikes are essentially the same age as their wall rocks, have the same primary mineralogy and textures, and therefore represent the same magma. They differ from the wall rocks in the kind and extent of alteration.It is concluded that the dikes represent andesite magma injected into cold wet wall rocks and that the brecciation was due to expulsion of the volatiles on chilling and crystallization. Brecciation occurred before completion of intrusion, and breccia was erupted to the surface. The alteration occurred during and immediately after brecciation, under nonoxidizing conditions, and was due to the attack of the escaping volatiles. This is thought to have taken place at low temperature followed immediately by condensation of the vapors producing a mud matrix from the comminuted andesite and clay derived from it. 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.