Disentangling abrupt deglacial hydrological changes in northern South America: Insolation versus oceanic forcing

Abstract

Research Article| July 01, 2014 Disentangling abrupt deglacial hydrological changes in northern South America: Insolation versus oceanic forcing J. Hoffmann; J. Hoffmann * 1Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Search for other works by this author on: GSW Google Scholar A. Bahr; A. Bahr * 1Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Search for other works by this author on: GSW Google Scholar S. Voigt; S. Voigt * 1Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Search for other works by this author on: GSW Google Scholar J. Schönfeld; J. Schönfeld * 2GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Search for other works by this author on: GSW Google Scholar D. Nürnberg; D. Nürnberg * 2GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Search for other works by this author on: GSW Google Scholar J. Rethemeyer J. Rethemeyer * 3Institute for Geology and Mineralogy, University of Cologne, 50937 Cologne, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Search for other works by this author on: GSW Google Scholar Author and Article Information J. Hoffmann * 1Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany A. Bahr * 1Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany S. Voigt * 1Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany J. Schönfeld * 2GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany D. Nürnberg * 2GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany J. Rethemeyer * 3Institute for Geology and Mineralogy, University of Cologne, 50937 Cologne, Germany *E-mails: ju.hoffmann@em.uni-frankfurt.de; a.bahr@em.uni-frankfurt.de; s.voigt@em.uni-frankfurt.de; jschoenfeld@geomar.de; dnuernberg@geomar.de; janet.rethemeyer@uni-koeln.de. Publisher: Geological Society of America Received: 10 Feb 2014 Revision Received: 14 Apr 2014 Accepted: 14 Apr 2014 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (7): 579–582. https://doi.org/10.1130/G35562.1 Article history Received: 10 Feb 2014 Revision Received: 14 Apr 2014 Accepted: 14 Apr 2014 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 J. Hoffmann, A. Bahr, S. Voigt, J. Schönfeld, D. Nürnberg, J. Rethemeyer; Disentangling abrupt deglacial hydrological changes in northern South America: Insolation versus oceanic forcing. Geology 2014;; 42 (7): 579–582. doi: https://doi.org/10.1130/G35562.1 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 Paleoenvironmental studies and climate models demonstrate that fluvial runoff and moisture availability in the Caribbean hinterland react very sensitively to climatic variations. Late Pleistocene and Holocene climate records document pronounced dry and wet periods over tropical South America mainly caused by shifts of the Intertropical Convergence Zone (ITCZ). However, forcing mechanisms for changes in the ITCZ position remain controversial. Here we present high-resolution foraminiferal Ba/Ca and δ18Oseawater records from a core located within the Orinoco River outflow documenting abrupt hydrological changes in the Orinoco catchment area during the deglacial and Holocene. Our data, obtained from the surface-dwelling foraminifera Globigerinoides ruber (pink), show an abrupt increase in Ba/Ca ratios in the early Holocene, starting ∼600 yr after the end of the Younger Dryas (YD) cold interval at ca. 10.8 ka and suggesting a massive reorganization of moisture sources in northern South America. In contrast, the salinity dependent δ18Oseawater from the same samples shows a gradual decrease starting at the end of the YD. The offset of our Ba/Ca peak excludes meltwater release in conjunction with the northern Andean glacier retreat well before the end of the YD as a forcing mechanism. We suggest that the Ba/Ca record documents an abrupt increase in Ba-rich waters of a northern Andean source caused by the insolation-driven shift of the ITCZ and/or enhanced monsoon activity. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.