Carbon and oxygen isotopes as diagenetic and stratigraphic tools: Surface and subsurface data, Barbados, West Indies

Research Article| January 01, 1977 Carbon and oxygen isotopes as diagenetic and stratigraphic tools: Surface and subsurface data, Barbados, West Indies J. R. Allan; J. R. Allan 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912 Search for other works by this author on: GSW Google Scholar R. K. Matthews R. K. Matthews 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912 Search for other works by this author on: GSW Google Scholar Geology (1977) 5 (1): 16–20. https://doi.org/10.1130/0091-7613(1977)52.0.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. R. Allan, R. K. Matthews; Carbon and oxygen isotopes as diagenetic and stratigraphic tools: Surface and subsurface data, Barbados, West Indies. Geology 1977;; 5 (1): 16–20. doi: https://doi.org/10.1130/0091-7613(1977)52.0.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 Carbon isotopic values reported in the literature for low-magnesium calcite Pleistocene limestones are generally more negative than −4‰ PDB, while values reported for most ancient limestones are more positive than −2‰ PDB. This relationship has recently led to suggestions that subaerial diagenesis was of minor importance in forming ancient limestones. Isotopic analyses of Barbados subsurface Pleistocene limestone samples show that samples from shallow subsurface diagenetic regimes have δC13 compositions much closer to those reported for ancient rocks.In the vadose environment, Barbados limestones become systematically enriched in C13 by 3 to 4‰ with increasing depth. This δC13 versus depth relationship may prove useful for identifying subaerial exposure surfaces in ancient sequences.Barbados subsurface limestone samples, as a group, are characterized by a narrow range of δO18 compositions and a much wider range of δC13 compositions. This relationship may provide a means for identifying ancient limestones that have undergone subaerial diagenesis.Finally, our data indicate that positive δC13 PDB values are not inconsistent with diagenesis within the near-surface freshwater phreatic environment. 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.