Distinguishing base-level change and climate signals in a Cretaceous alluvial sequence (2005)

Research Article| January 01, 2005 Distinguishing base-level change and climate signals in a Cretaceous alluvial sequence T. White; T. White 1Earth and Environmental Systems Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA Search for other works by this author on: GSW Google Scholar B. Witzke; B. Witzke 2Iowa Geological Survey, Iowa City, Iowa 52242, USA Search for other works by this author on: GSW Google Scholar G. Ludvigson; G. Ludvigson 2Iowa Geological Survey, Iowa City, Iowa 52242, USA Search for other works by this author on: GSW Google Scholar R. Brenner R. Brenner 3Geoscience Department, University of Iowa, Iowa City, Iowa 52240, USA Search for other works by this author on: GSW Google Scholar Author and Article Information T. White 1Earth and Environmental Systems Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA B. Witzke 2Iowa Geological Survey, Iowa City, Iowa 52242, USA G. Ludvigson 2Iowa Geological Survey, Iowa City, Iowa 52242, USA R. Brenner 3Geoscience Department, University of Iowa, Iowa City, Iowa 52240, USA Publisher: Geological Society of America Received: 14 Jul 2004 Revision Received: 27 Sep 2004 Accepted: 01 Oct 2004 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2005) 33 (1): 13–16. https://doi.org/10.1130/G20995.1 Article history Received: 14 Jul 2004 Revision Received: 27 Sep 2004 Accepted: 01 Oct 2004 First Online: 09 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 T. White, B. Witzke, G. Ludvigson, R. Brenner; Distinguishing base-level change and climate signals in a Cretaceous alluvial sequence. Geology 2005;; 33 (1): 13–16. doi: https://doi.org/10.1130/G20995.1 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 SocietyGeology Search Advanced Search Abstract We present the results of oxygen isotope and electron-microprobe analyses of sphaerosiderites obtained from Cretaceous paleosols in Iowa. The sphaerosiderite δ18O values record Cretaceous meteoric groundwater chemistry and an overall waning of brackish groundwater inundation during alluvial-plain aggradation and soil genesis. We focus on horizons that precipitated from freshwater, in which δ18O values ranging from −3.3‰ to −6.8‰ relative to the Peedee belemnite standard are interpreted to record variations in the Cretaceous atmospheric hydrologic cycle. During relative sea-level highstands, moisture was derived from the Cretaceous Western Interior Seaway, whereas during lowstands, when the seaway narrowed and occasionally withdrew from the Midcontinent, the dominance of hemispheric-scale atmospheric moisture transport initiated in the tropical Tethys Ocean led to decreased precipitation rates. These processes did not operate like a switch, but rather as a continuum of competing moisture sources and mechanisms of transport between the nearby epicontinental sea and the distant tropics. The sphaerosiderite data demonstrate (1) temporal variation in the intensity of hemispheric-scale atmospheric moisture transport and (2) long-term amplification of the global hydrologic cycle marked by extreme 18O depletion at the Albian-Cenomanian boundary. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.