Geologic origins of salinization in a semi-arid river: The role of sedimentary basin brines

Research Article| December 01, 2007 Geologic origins of salinization in a semi-arid river: The role of sedimentary basin brines James F. Hogan; James F. Hogan 1Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar Fred M. Phillips; Fred M. Phillips 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona, 85721, USA Search for other works by this author on: GSW Google Scholar Suzanne K. Mills; Suzanne K. Mills 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona, 85721, USA Search for other works by this author on: GSW Google Scholar Jan M.H. Hendrickx; Jan M.H. Hendrickx 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona, 85721, USA Search for other works by this author on: GSW Google Scholar Joaquin Ruiz; Joaquin Ruiz 3Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar John T. Chesley; John T. Chesley 3Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar Yemane Asmerom Yemane Asmerom 4Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA Search for other works by this author on: GSW Google Scholar Author and Article Information James F. Hogan 1Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85721, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona 85721, USA Fred M. Phillips 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona, 85721, USA Suzanne K. Mills 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona, 85721, USA Jan M.H. Hendrickx 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA, and SAHRA—Center for Sustainability of Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, Arizona, 85721, USA Joaquin Ruiz 3Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA John T. Chesley 3Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Yemane Asmerom 4Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA Publisher: Geological Society of America Received: 09 Apr 2007 Revision Received: 10 Jul 2007 Accepted: 15 Jul 2007 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 The Geological Society of America, Inc. Geology (2007) 35 (12): 1063–1066. https://doi.org/10.1130/G23976A.1 Article history Received: 09 Apr 2007 Revision Received: 10 Jul 2007 Accepted: 15 Jul 2007 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation James F. Hogan, Fred M. Phillips, Suzanne K. Mills, Jan M.H. Hendrickx, Joaquin Ruiz, John T. Chesley, Yemane Asmerom; Geologic origins of salinization in a semi-arid river: The role of sedimentary basin brines. Geology 2007;; 35 (12): 1063–1066. doi: https://doi.org/10.1130/G23976A.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 Semi-arid and arid rivers typically exhibit increasing salinity levels downstream, a trend often attributed to irrigated agriculture, primarily due to evapotranspiration. In contrast, the results of our investigations in one salinized river suggest that geological sources of salt added by groundwater discharge are more important than agricultural effects. We performed detailed synoptic sampling of the Upper Rio Grande–Rio Bravo, an arid-climate river with significant irrigated agriculture, and identified a series of salinity increases localized at the distal ends of sedimentary basins. Using Cl/Br, Ca/Sr, 87Sr/86Sr, and 36Cl/Cl ratios and δ234U values as environmental tracers, we show that these increases result from localized discharge of high-salinity groundwater of a sedimentary brine source. These groundwater fluxes, while very small (<1 m3s−1), are the dominant solute input and, combined with downstream evapotranspirative concentration, result in salinization. Furthermore, 36Cl/Cl ratios and δ234U values for these brines are close to secular equilibrium, indicating brine ages on the order of millions of years. The recognition of a substantial geologic salinity source for the Rio Grande implies that alternative salinity management solutions, such as interception of saline groundwater, might be more effective in reducing salinity than changes in agricultural practices. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.