A RADIOCARBON CHRONOLOGY FOR ESTADIO DE QUILLOTA IN THE ACONCAGUA VALLEY, CENTRAL CHILE, WITH REFERENCE TO THE ADOPTION OF INTENSIVE MAIZE AGRICULTURE AND REVISITING THE TIMING OF INKA INFLUENCE ON THE SOUTHERN FRONTIER

Abstract

ABSTRACTEstadio de Quillota (EDQ) is the largest known pre-Columbian cemetery site within the Aconcagua Valley of Central Chile. Despite its importance, existing chronological data for EDQ are limited and questions remain regarding the prehistory of the Valley, particularly around the adoption and intensification of maize agriculture, as well as the timing of Inka influence reaching the region. Seventeen new AMS radiocarbon dates presented here indicate two distinct phases of use at EDQ: An earlier phase (339–196 cal BC to cal AD 128–339), and a later phase (cal AD 1280–1387 to cal AD 1413–1458). Accompanying stable isotope (δ13C and δ15N) analyses of human bone collagen (n=22) demonstrate diachronic dietary changes corresponding to these phases, with a reliance on terrestrial C3 resources during the earlier period, followed by a heavy dependence on C4-based (maize) resources during the later use. Bayesian modeling of the dates from Late Period contexts suggests Inka influence arrived in Central Chile by ca. cal AD 1400, decades before the date cited in traditional chronologies, AD 1471. Inka expansion likely occurred here with an initial phase of interaction and exchange preceding a later phase of integration. This finding supports growing evidence that the traditional chronology of the Inka Empire requires reconsideration.