High resolution isotopic and faunal evidence for climatic variability in the Lucre Basin, Cuzco region, Peru, over the last 2000 years
by
Michael R. Frogley
Centre for Environmental Research, School of Chemistry, Physics and Environmental Science, University of Sussex, Brighton BN1 9QJ, UK
Coauthors: Alex Chepstow-Lusty (Department of Biological Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA)

The Andes have long been recognised as a centre for biological and cultural diversity that has given rise to a series of major civilisations over the past few millennia. These include the Tiwanaku (ca. AD 300 - ca. AD 1100), the Wari (ca. AD 550 - ca. AD 1100), and the Inca, which at its height (AD 1400-1536) stretched from present-day southern Colombia to central Chile. The collapse of the Tiwanaku/Wari has been attributed by some researchers to their apparent inability to adapt their agricultural practices in the face of a possibly globally significant climatic shift (known in Europe as the Medieval Warm Period, MWP), which manifested itself in the Titicaca region as a change towards increasing aridity. The fledgling Inca state (ca. AD 1200), on the other hand, developed around the Cuzco area, over 400km north-west of Lake Titicaca, in the central Peruvian Andes. Despite experiencing similar climatic conditions, this region nevertheless still received seasonal rainfall along with constant melt-water from the surrounding mountain areas. The Inca responded by adopting a series of environmentally efficient agricultural practices with regard to irrigation, field management and soil stabilisation.

Despite several independent lines of evidence, some researchers question the true significance and magnitude of any climatic shift with regard to the demise of the Tiwanaku/Wari. One way of resolving some of these arguments would be to obtain a continuous, high-resolution palaeoclimatic record from a site that is close to one of the major archaeological localities in question, but likely to document regional rather than local changes.

One such site is the Lucre Basin, situated 3100 m above sea-level, ca. 30 km south-east of Cuzco. The basin is close to a number of important archaeological sites, foremost amongst them being the Wari site of Pikillacta (a major administration and storage centre of economic importance). A preliminary faunal and geochemical investigation of a high-resolution sedimentary sequence taken from the margin of the present-day lake reveals a detailed history of climatic change. Chronological control for the sequence (provided by a combination of AMS radiocarbon dates and several 'golden spikes') indicates that the record spans approximately the last 2000 years. The analysis of multiple proxies throughout the sequence at a sub-centennial sampling resolution therefore affords us an opportunity to assess the detailed timing and character of climatic change across the region during the time of the Tiwanaku/Wari collapse.

Date received: August 17, 2002

Copyright © 2002 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caji-60.