A Mylonite Belt in the Southeastern San Gabriel Mountains, California

Research Article| November 01, 1948 A MYLONITE BELT IN THE SOUTHEASTERN SAN GABRIEL MOUNTAINS, CALIFORNIA RAYMOND M ALF RAYMOND M ALF WEBB SCHOOL OF CALIFORNIA, CLAREMONT, CALIF. Search for other works by this author on: GSW Google Scholar GSA Bulletin (1948) 59 (11): 1101–1120. https://doi.org/10.1130/0016-7606(1948)59[1101:AMBITS]2.0.CO;2 Article history received: 15 Aug 1947 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 RAYMOND M ALF; A MYLONITE BELT IN THE SOUTHEASTERN SAN GABRIEL MOUNTAINS, CALIFORNIA. GSA Bulletin 1948;; 59 (11): 1101–1120. doi: https://doi.org/10.1130/0016-7606(1948)59[1101:AMBITS]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 San Gabriel Mountains are the somewhat dissected remnants of an elevated fault block. At their southeastern end they are wedged between the Mojave desert mass and the depressed northwestern portion of the Perris fault block. The southeastern San Gabriel range is made up of pre-Upper Cretaceous metamorphic rocks and late Jurassic or early Cretaceous plutonic rocks.An east-west zone through the middle of the area is characterized by extensive mylonitization. Chemical analyses and other data indicate that the mylonites were derived chiefly from a dark quartz diorite, and to a lesser extent from a paler quartz monzonite, without much mixing of the two source materials. The mylonite zones were intruded by the quartz monzonite and probably by the quartz diorite. Possibly the main mass of mylonite was formed by the crushing of a barely consolidated upper portion of a quartz diorite pluton, as one or more tectonic episodes during the general period of plutonic intrusion. 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.