9403 - Paleoclimatic changes and its impact on Nasca and Tiwanaku cultures in southern Peru ¿ new insights from circulation mechanisms

Environmental changes and cultural transitions during several periods of Peruvian history show a strong coincidence between humid and arid climatic oscillations and the rise and decline of cultures. It is noteworthy, that alternating periods of geo-ecological fragility and stability occurred in time and space between the coastal Nasca region and the high Andean northern Titicaca basin, just a few hundred kilometers to the east. Based on a multi-proxy approach to reconstruct p aleoenvironmental changes , we found that the Nasca region received a maximum of precipitation during the archaeological boom times of the Early Horizon and the Early Intermediate Period (800 BC-650 AD) as well as during the late intermediate period (1150-1450 AD), whereas, in contrast, the Titicaca region further to the south-east experienced drought and cultural depression during that time. During the Middle Horizon (650-1150 AD), the Tiwanaku agronomy and culture boomed in the Titicaca region and expanded to the west, contemporaneous with a raised lake level and more humid conditions. In the Nasca region, runoff for irrigation purposes was reduced and less reliable due to drought. Considering a coincidence between environmental and cultural changes, we state that success and decline of civilizations were controlled by hydrological oscillations, triggering fertility as well as a critical loss of natural resources. In response to spatial changing resources, cultural foci were shifted. Therefore, the success of pre-Columbian civilizations was closely coupled to areas of geo-ecological favorability, which were directly controlled by distinct regional impacts of large-scale circulation mechanisms, including El Niño – Southern Oscillation (ENSO). Changes in the position of the intertropical convergence zone (ITCZ) and the Bolivian anticyclone determined meridional shifts in moisture transport across the Andes.

Palabras claves: Nasca, Tiwanaku, paleoclimate, ITCZ

Autores: Mächtle, Bertil (Universität Heidelberg, Germany / Deutschland)
Co-Autores: K. Schittek, M. Forbriger, F. Schäbitz, M. Reindel & B. Eitel


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