Basaltic rocks in the Umpqua formation

Abstract

Research Article| June 30, 1935 Basaltic rocks in the Umpqua formation† FRANCIS G. WELLS; FRANCIS G. WELLS Search for other works by this author on: GSW Google Scholar AARON C. WATERS AARON C. WATERS Search for other works by this author on: GSW Google Scholar Author and Article Information FRANCIS G. WELLS AARON C. WATERS Publisher: Geological Society of America Received: 10 Sep 1934 First Online: 02 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 1935 Geological Society of America GSA Bulletin (1935) 46 (6): 961–972. https://doi.org/10.1130/GSAB-46-961 Article history Received: 10 Sep 1934 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 FRANCIS G. WELLS, AARON C. WATERS; Basaltic rocks in the Umpqua formation. GSA Bulletin 1935;; 46 (6): 961–972. doi: https://doi.org/10.1130/GSAB-46-961 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 INTRODUCTIONIn 1930, during a study of the geology of an area in west-central Oregon within which occur the quicksilver deposits of Blackbutte, Elk-head, Bonanza, and Nonpareil, a series of extrusive and intrusive basaltic igneous rocks were encountered. Part of this area lies within the Roseburg quadrangle, mapped by Diller in 1898. Diller called all these rocks “diabase.” 1 It is the purpose of this paper to show that the basaltic rocks include amygdaloidal and ellipsoidal basalt flows, olivine basalt dikes, norite sills and necks, and hypersthene-augite basalt dikes and that they represent more than one period of igneous activity.SUMMARY OF GEOLOGYA full discussion of the geology of this area is found in a recent bulletin of the United States Geological Survey,2 it can be briefly summarized as follows:The southwestern part of the area (Fig. 1) is underlain by the Umpqua formation, a series of interbedded sandstones . . . 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.