High-resolution δ13C stratigraphy of the Chuar Group (ca. 770–742 Ma), Grand Canyon: Implications for mid-Neoproterozoic climate change

Abstract

Research Article| January 01, 2005 High-resolution δ13C stratigraphy of the Chuar Group (ca. 770–742 Ma), Grand Canyon: Implications for mid-Neoproterozoic climate change C.M. Dehler; C.M. Dehler 1Department of Geology, Utah State University, 4505 Old Main Hill, Logan, Utah 84322-4505, USA Search for other works by this author on: GSW Google Scholar M. Elrick; M. Elrick 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA Search for other works by this author on: GSW Google Scholar J.D. Bloch; J.D. Bloch 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA Search for other works by this author on: GSW Google Scholar L.J. Crossey; L.J. Crossey 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA Search for other works by this author on: GSW Google Scholar K.E. Karlstrom; K.E. Karlstrom 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA Search for other works by this author on: GSW Google Scholar D.J. Des Marais D.J. Des Marais 3Mail Stop 239-4, Ames Research Center, Moffett Field, California 94035-1000, USA Search for other works by this author on: GSW Google Scholar Author and Article Information C.M. Dehler 1Department of Geology, Utah State University, 4505 Old Main Hill, Logan, Utah 84322-4505, USA M. Elrick 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA J.D. Bloch 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA L.J. Crossey 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA K.E. Karlstrom 2Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA D.J. Des Marais 3Mail Stop 239-4, Ames Research Center, Moffett Field, California 94035-1000, USA Publisher: Geological Society of America Received: 16 Aug 2003 Revision Received: 10 May 2004 Accepted: 07 Jun 2004 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2005) 117 (1-2): 32–45. https://doi.org/10.1130/B25471.1 Article history Received: 16 Aug 2003 Revision Received: 10 May 2004 Accepted: 07 Jun 2004 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 C.M. Dehler, M. Elrick, J.D. Bloch, L.J. Crossey, K.E. Karlstrom, D.J. Des Marais; High-resolution δ13C stratigraphy of the Chuar Group (ca. 770–742 Ma), Grand Canyon: Implications for mid-Neoproterozoic climate change. GSA Bulletin 2005;; 117 (1-2): 32–45. doi: https://doi.org/10.1130/B25471.1 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 A high-resolution C-isotope record based on δ13Corg from organic-rich shales and δ13Ccarb from dolomites in the ca. 770–742 Ma Chuar Group provides important new data for evaluating the significance of large-magnitude C-isotope anomalies in Neoproterozoic climate change. Three successive, large-magnitude isotopic excursions (8–15‰) are interpreted to represent primary seawater values based on a series of diagenetic tests, and they are not associated with evidence of significant long-term (106–107 m.y.) sea-level change nor glaciomarine deposits. Intrabasinal correlation of δ13Corg values suggests that most Chuar shales record primary values and is consistent with previously reported H/C ratios of >0.49 indicating that Chuar shales experienced minimal thermal alteration. Although some Chuar dolomites reveal early diagenetic alteration, their δ13Cdol values typically fall near those of coeval "least-altered" dolomites or organic-rich shales (relative to dolomite values). The Chuar carbon record is interpreted to reflect predominantly primary organic carbon δ13C values and contains sufficient primary carbonate δ13C data to use for calculating Δδ13C values and for comparison with other mid-Neoproterozoic successions.The Chuar δ13C shifts are in phase with dolomite-poor/dolomite-rich litho stratigraphic sequences and with shale petrologic and mineralogical trends. These data sets collectively indicate long-term (m.y.-scale) wetter-to-drier climate change and concomitant low-amplitude sea-level change. The Chuar basin may be a proxy for mid-Neoproterozoic low-latitude basins that accommodated significant organic carbon burial during this time. Models for other Neoproterozoic long-term δ13C anomalies may not require significant continental (and) or low-latitude glaciation as a mechanism for generating large-magnitude C-isotope shifts. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.