Radiocarbon Reservoir Effect and the Timing of the Late-Glacial/Early Holocene Humid Phase in the Atacama Desert (Northern Chile)

We revise substantially the regional chronology of lake-level fluctuations from the late-glacial/early Holocene humid phase along a high altitude transect (3500 to 4500 m) between 18°S and 28°S in the Southwestern Altiplano of Northern Chile. Radiocarbon dates and 210Pb profiles for limnic and terrestrial materials allow us to estimate and justify reservoir correction values for conventional 14C dates. Our chronology suggests that the latest Pleistocene/early Holocene humid phase started between 13,000 and 12,000 14C yr B.P., and that maximum lake levels were reached between 10,800 and 9200 14C yr B.P. This is significantly younger than what has been established so far for the Titicaca–Uyuni Basin in Bolivia. The paleolakes disappeared sometime between 8400 and 8000 14C yr B.P. Our revised chronology agrees with the regional history of human occupation, and is broadly synchronous with vegetation changes in subtropical continental South America, and with the onset of wetland expansion in the northern hemisphere tropics.

[1]  M. Fournier,et al.  Lake-Level Chronology on the Southern Bolivian Altiplano (18°–23°S) During Late-Glacial Time and the Early Holocene , 1999, Quaternary Research.

[2]  Martin Grosjean,et al.  Albedo changes, Milankovitch forcing, and late Quaternary climate changes in the central Andes , 1998 .

[3]  M. Grosjean,et al.  Mid- and late-Holocene limnogeology of Laguna del Negro Francisco, northern Chile, and its palaeoclimatic implications , 1997 .

[4]  C. Clapperton,et al.  Broad synchrony of a Late-glacial glacier advance and the highstand of palaeolake Tauca in the Bolivian Altiplano , 1997 .

[5]  Louis Martin,et al.  Paleohydrology and Paleoclimate of the Past 33,000 Years at the Tamanduá River, Central Brazil , 1997, Quaternary Research.

[6]  H. Behling.  Late Quaternary vegetation, climate and fire history from the tropical mountain region of Morro de Itapeva, SE Brazil , 1997 .

[7]  D. Sandweiss,et al.  Geoarchaeological Evidence from Peru for a 5000 Years B.P. Onset of El Niño , 1996, Science.

[8]  M. Grosjean,et al.  Limnogeology of Laguna Miscanti: evidence for mid to late Holocene moisture changes in the Atacama Altiplano (Northern Chile) , 1996 .

[9]  M. Fournier,et al.  Lake levels in the southern Bolivian Altiplano (19°-21°S) during the Late Glacial based on diatom studies , 1995 .

[10]  M. Grosjean,et al.  Late-glacial and early Holocene lake sediments, ground-water formation and climate in the Atacama Altiplano 22–24°S , 1995 .

[11]  J. Chappellaz,et al.  Variations in atmospheric methane concentration during the Holocene epoch , 1995, Nature.

[12]  M. Grosjean,et al.  Lateglacial, early and middle holocene environments, human occupation, and resource use in the Atacama (Northern Chile) , 1994 .

[13]  Martin Grosjean,et al.  Paleohydrology of the Laguna Lejía (north Chilean Altiplano) and climatic implications for late-glacial times , 1994 .

[14]  Murray Gray,et al.  Global Climates since the Last Glacial Maximum , 1994 .

[15]  M. Fournier,et al.  Tropical forest changes during the late quaternary in African and South American lowlands , 1993 .

[16]  L. Benson.  Factors Affecting 14C Ages of Lacustrine Carbonates: Timing and Duration of the Last Highstand Lake in the Lahontan Basin , 1993, Quaternary Research.

[17]  M. Ledru.  Late Quaternary Environmental and Climatic Changes in Central Brazil , 1993, Quaternary Research.

[18]  H. Schrader,et al.  Peruvian coastal upwelling: Late Quaternary productivity changes revealed by diatoms , 1991 .

[19]  S. Stine,et al.  A record from Lake Cardiel of climate change in southern South America , 1990, Nature.

[20]  A. Martinez,et al.  9,700 Years of Maritime Subsistence on the Pacific: An Analysis by Means of Bioindicators in the North of Chile , 1979, American Antiquity.

[21]  G. E. Hutchinson,et al.  THE NATURAL C CONTENTS OF MATERIALS FROM HARD-WATER LAKES. , 1954, Proceedings of the National Academy of Sciences of the United States of America.

[22]  M. Grosjean,et al.  Temporal Changes of the 14C Reservoir Effect in Lakes , 1997, Radiocarbon.

[23]  R. Aravena.  Isotope hydrology and geochemistry of Northern Chile groundwaters , 1995, Bulletin de l’Institut français d’études andines.

[24]  M. Servant,et al.  La dernière transition glaciaire/interglaciaire des Andes tropicales sud (Bolivie) d'après l'étude des variations des niveaux lacustres et des fluctuations glaciaires , 1995 .

[25]  M. Stuiver,et al.  High-Precision Bidecadal Calibration of the Radiocarbon Time Scale, AD 1950–500 BC and 2500–6000 BC , 1993, Radiocarbon.

[26]  M. Geyh,et al.  Absolute Age Determination , 1990 .