Articles | Volume 8, issue 1
Clim. Past, 8, 287–306, 2012

Special issue: Climate variations in South America over the last 2000 years

Clim. Past, 8, 287–306, 2012

Research article 21 Feb 2012

Research article | 21 Feb 2012

Hydroclimate variability in the low-elevation Atacama Desert over the last 2500 yr

E. M. Gayo1,2, C. Latorre1,2, C. M. Santoro3,4, A. Maldonado5,6, and R. De Pol-Holz7,8 E. M. Gayo et al.
  • 1Center for Advanced Studies in Ecology and Biodiversity (CASEB) and Departamento de Ecología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
  • 2Institute of Ecology and Biodiversity (IEB), Las Palmeras 3425, Ñuñoa, Santiago, Chile
  • 3Instituto Alta Investigación (IAI), Universidad de Tarapacá, Casilla 6-D, Arica, Chile
  • 4Centro de Investigaciones del Hombre del Desierto (CIHDE), Avda. Gral. Velásquez 1775, Oficina 18, Arica, Chile
  • 5Laboratorio de Paleoambientes, Centro de Estudios Avanzados en Zonas Aridas (CEAZA), Colina del Pino s/n, La Serena, Chile
  • 6Dirección de Investigación, Universidad de La Serena, Benavente 980, La Serena, Chile
  • 7Earth System Science Department, University of California, Irvine, California, USA
  • 8Departamento de Oceanografía, Universidad de Concepción, Casilla 160-C, Barrio Universitario s/n, Concepción, Chile

Abstract. Paleoclimate reconstructions reveal that Earth system has experienced sub-millennial scale climate changes over the past two millennia in response to internal/external forcing. Although sub-millennial hydroclimate fluctuations have been detected in the central Andes during this interval, the timing, magnitude, extent and direction of change of these events remain poorly defined. Here, we present a reconstruction of hydroclimate variations on the Pacific slope of the central Andes based on exceptionally well-preserved plant macrofossils and associated archaeological remains from a hyperarid drainage (Quebrada Maní, ∼21° S, 1000 m a.s.l.) in the Atacama Desert. During the late Holocene, riparian ecosystems and farming social groups flourished in the hyperarid Atacama core as surface water availability increased throughout this presently sterile landscape. Twenty-six radiocarbon dates indicate that these events occurred between 1050–680, 1615–1350 and 2500–2040 cal yr BP. Regional comparisons with rodent middens and other records suggest that these events were synchronous with pluvial stages detected at higher-elevations in the central Andes over the last 2500 yr. These hydroclimate changes also coincide with periods of pronounced SST gradients in the Tropical Pacific (La Niña-like mode), conditions that are conducive to significantly increased rainfall in the central Andean highlands and flood events in the low-elevation watersheds at inter-annual timescales. Our findings indicate that the positive anomalies in the hyperarid Atacama over the past 2500 yr represent a regional response of the central Andean climate system to changes in the global hydrological cycle at centennial timescales. Furthermore, our results provide support for the role of tropical Pacific sea surface temperature gradient changes as the primary mechanism responsible for climate fluctuations in the central Andes. Finally, our results constitute independent evidence for comprehending the major trends in cultural evolution of prehistoric peoples that inhabited the region.