Syngenetic origin of concretions in shale

Abstract

Research Article| December 01, 1921 Syngenetic origin of concretions in shale W. A. TARR W. A. TARR Search for other works by this author on: GSW Google Scholar Author and Article Information W. A. TARR Publisher: Geological Society of America Received: 16 Apr 1921 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 1921 Geological Society of America GSA Bulletin (1921) 32 (4): 373–384. https://doi.org/10.1130/GSAB-32-373 Article history Received: 16 Apr 1921 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation W. A. TARR; Syngenetic origin of concretions in shale. GSA Bulletin 1921;; 32 (4): 373–384. doi: https://doi.org/10.1130/GSAB-32-373 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 IntroductionConcretions may be divided into two classes as to origin: (1) syngenetic, or those which were deposited or formed at the same time as the inclosing beds, and (2) epigenetic, or those which have been formed subsequent to the deposition of the surrounding beds. The syngenetic concretions would be older than the beds under them and younger (for the most part, at least) than the beds over them, and the epigenetic concretions would be younger than any of the surrounding beds, because they are due to growth by the addition of material from the surrounding rocks.This classification differs from that of Todd,2 but includes his four classes in two, grouping them on a basis of their age relative to the surrounding rocks rather than on the movement of the materials in the concretions proper. Grabau3 follows Todd in his classification.There is evidence to support each class, but . . . 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.