Contraction Phenomena in Cherts

Abstract

Research Article| April 30, 1934 Contraction Phenomena in Cherts N. L. TALIAFERRO N. L. TALIAFERRO Search for other works by this author on: GSW Google Scholar Author and Article Information N. L. TALIAFERRO Publisher: Geological Society of America Received: 08 May 1933 First Online: 02 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 1934 Geological Society of America GSA Bulletin (1934) 45 (2): 189–232. https://doi.org/10.1130/GSAB-45-189 Article history Received: 08 May 1933 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 N. L. TALIAFERRO; Contraction Phenomena in Cherts. GSA Bulletin 1934;; 45 (2): 189–232. doi: https://doi.org/10.1130/GSAB-45-189 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 INTRODUCTIONData, indicating that contraction commonly takes place in cherts as they pass from a stiff gel into the true opaline phase, have been collected by the writer in the course of field work in California during a number of years. Microscopic examination of the purer cherts, especially those of the Miocene, indicates that rather irregular contraction has taken place in many instances. Although this irregular contraction toward dispersed centers is perhaps the most universal type, there are certain regular megascopic forms that are probably of greater general interest. These assume the form of concentrically banded oblate spheroids, the bands being of ordinary chert alternating with chalcedony or, more rarely, almost pure opal. The relatively pure bands of chalcedony (or opal) are often spaced with truly remarkable regularity and produce a striking effect. Such spheroids are not confined to the marine Monterey and Franciscan cherts but occur also in certain . . . 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.