Late Quaternary paleohydrology of the central Atacama Desert (lat 22°–24°S), Chile

Abstract

Research Article| March 01, 2002 Late Quaternary paleohydrology of the central Atacama Desert (lat 22°–24°S), Chile Jason A. Rech; Jason A. Rech 1Department of Geosciences and Desert Laboratory, University of Arizona, 1675 West Anklam Road, Tucson, Arizona 85745, USA Search for other works by this author on: GSW Google Scholar Jay Quade; Jay Quade 1Department of Geosciences and Desert Laboratory, University of Arizona, 1675 West Anklam Road, Tucson, Arizona 85745, USA Search for other works by this author on: GSW Google Scholar Julio L. Betancourt Julio L. Betancourt 2U.S. Geological Survey and Desert Laboratory, University of Arizona, 1675 West Anklam Road, Tucson, Arizona 85745, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2002) 114 (3): 334–348. https://doi.org/10.1130/0016-7606(2002)114<0334:LQPOTC>2.0.CO;2 Article history received: 10 Nov 2000 rev-recd: 13 Jun 2001 accepted: 24 Aug 2001 first online: 01 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 Jason A. Rech, Jay Quade, Julio L. Betancourt; Late Quaternary paleohydrology of the central Atacama Desert (lat 22°–24°S), Chile. GSA Bulletin 2002;; 114 (3): 334–348. doi: https://doi.org/10.1130/0016-7606(2002)114<0334:LQPOTC>2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract In northern Chile, precipitation in the High Andes (>3500 m) recharges groundwater systems that flow down the Pacific slope and feed large aquifers in the hyperarid Atacama Desert. Wetlands, which are often found along the base of the Andes, mark locations where the water table intersects the land surface. At these locations, paleo–wetland deposits, which are present as terraces between 3 and 20 m above modern wetlands, record past water-table heights along the Andean front and are used to reconstruct changes in groundwater discharge. Paleo–wetland deposits in the central Atacama Desert (lat 22°–24°S) record an episode (>15.4–9 ka) of high water tables followed by an episode (8–3 ka) of moderately high water tables. Elevated water tables result from increased groundwater discharge and ultimately from enhanced recharge in the Andes. The concordance of results from three separate hydrologic systems suggests that changes in groundwater discharge and recharge are regional and reflect climatic fluctuations. This interpretation is supported by close agreement with other paleoclimatic records in the region. The periods of greater groundwater discharge were separated by episodes (9–8 and 3–0 ka) of significant groundwater lowering and stream incision, implying greatly diminished discharge.The central Atacama and Andes (lat 22°– 24°S) receive precipitation mainly from moist air masses transported from the Amazon Basin by the South American Summer Monsoon (SASM). Increases in groundwater recharge are therefore thought to reflect an increase in the frequency and/or moisture content of SASM air masses crossing the Andes. Fluctuations in SASM precipitation have previously been linked to summer insolation in the Southern Hemisphere. The wettest period in the central Atacama (>15.4–9 ka), however, coincides with a minimum in austral-summer insolation at 10 ka, suggesting that regional summer insolation is not a dominant influence on the SASM. Instead, intensification of the SASM may be linked to extraregional forcings such as the Walker Circulation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.