Limnogeology of Laguna Miscanti: evidence for mid to late Holocene moisture changes in the Atacama Altiplano (Northern Chile) |
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| Authors: | Blas L Valero-Garcés Martin Grosjean Antje Schwalb Mebus Geyh Bruno Messerli Kerry Kelts |
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| Institution: | (1) Limnological Research Center, University of Minnesota, 220 Pillsbury Hall, 55455 Minneapolis, MN, USA;(2) Department of Physical Geography, University of Bern, Hallerstrasse 12, CH-3012 Bern, Switzerland;(3) State Geological Survey, Lower Saxony, Hannover-Buchholz, D-3000 Hannover 51, Germany;(4) Present address: Instituto Pirenaico de Ecologia, Estación Experimental de Aula Dei, CSIC, Apdo 202, 50088 Zaragoza, Spain |
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| Abstract: | Sedimentological, mineralogical and geochemical analyses of sediment cores from 9 m-deep, saline Laguna Miscanti, Chile (23 ° 44 S, 67 °46W, 4140 m a.s.l.) together with high-resolution seismic profiles provide a mid to late Holocene time series of regional environmental change in the Atacama Altiplano constrained by 210Pb and conventional 14C dating. The mid Holocene was the most arid interval since the last glacial maximum, as documented by subaerial exposure and formation of hardgrounds on a playa surface. Extremely low lake levels during the mid Holocene appear consistent with lower effective moisture recorded at other sites along the Altiplano and in the Amazon Basin. Termination of this arid period represented a major shift in the regional environmental dynamics and inaugurated modern atmospheric conditions. The cores show a progressive upward increase in effective moisture interrupted by numerous century-scale drier periods of various intensities and durations that characterize a fluctuating late Holocene climate. In spite of chronological uncertainties, the major environmental changes seem to correlate with the available paleorecords from the region providing a coherent account of effective moisture variability in the tropical highlands of South America.This is the 16th in a series of papers published in this special AMQUA issue. These papers were presented at the 1994 meeting of the American Quaternary Association held 19–22 June, 1994, at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Linda C. K. Shane served as guest for these papers. |
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| Keywords: | Atacama Holocene limnogeology South America paleoclimatology lake sediments |
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