Carbon isotopes as indicators of dispersal patterns in Devonian-Mississippian shales of the Appalachian Basin

Research Article| June 01, 1981 Carbon isotopes as indicators of dispersal patterns in Devonian-Mississippian shales of the Appalachian Basin J. B. Maynard J. B. Maynard 1H. N. Fisk Laboratory of Sedimentology, Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221 Search for other works by this author on: GSW Google Scholar Author and Article Information J. B. Maynard 1H. N. Fisk Laboratory of Sedimentology, Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1981) 9 (6): 262–265. https://doi.org/10.1130/0091-7613(1981)9<262:CIAIOD>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation J. B. Maynard; Carbon isotopes as indicators of dispersal patterns in Devonian-Mississippian shales of the Appalachian Basin. Geology 1981;; 9 (6): 262–265. doi: https://doi.org/10.1130/0091-7613(1981)9<262:CIAIOD>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 SocietyGeology Search Advanced Search Abstract Measurement of the carbon isotopic composition of organic matter in about 200 samples from the Devonian shale sequence of the eastern United States shows a definite transition from nonmarine values of around −25‰, through intermediate values in prodelta samples, to distal, basinal samples with values around −30.5‰. This trend matches very closely that found for paleocurrents in the sequence from sole markings on turbidite siltstone beds. Thus, the carbon isotopes suggest that the organic matter, and hence the enclosing shale, had the same dispersal pattern as the silt-stones. Furthermore, the steady westward change to more marine values indicates that the Cincinnati Arch was never sufficiently positive to act as a source of organic matter. The nonmarine carbon has an isotopic composition very similar to that of coal and so probably represents woody material. The basinal values, however, are much lighter than modern marine plankton. This may be a diagenetic effect or it may reflect a difference in the Devonian plankton. 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.