Residential moblity in the Inka sacred valley: Oxygen, strontium, and lead isotopic analysis at Patallaqta, Peru

Abstract The Inka Empire (1400–1532 CE) made common practice of relocating individuals, households and entire communities throughout their expansive realm for different reasons depending on subjects’ assigned social status. Reconstructing patterns of residential mobility and both intra- and extra-regional mobility at Inka sites, particularly in the imperial heartland, could therefore permit some estimation of the social status(es) of their constituents, and thereby provide bottom-up insights into Inka statecraft and political economy. However, this is a difficult endeavor using only archaeological lines of evidence. This study presents oxygen, strontium and lead isotopic results from archaeological human remains (N = 81) from the site of Patallaqta, near Machu Picchu in the Sacred Valley of the southern Peruvian highlands. Isotopic data are used to reconstruct patterns of immigration at the site, which are in turn used to estimate the social status of the population. The resulting 87Sr/86Sr show moderate variation, with most individuals clustering within a range higher than the estimated values for the locale, while 206,7,8Pb/204Pb results show greater variation spanning multiple Pb isotope provinces, and δ18O results cluster broadly around estimated local water values. Taken together, these results are consistent with the expected distribution of groups drawn from communities within the vicinity of the Sacred Valley and possibly the Peruvian or Bolivian altiplano. These results are in notable contrast to published isotopic results from the nearby site of Machu Picchu, and suggest distinct compositions among the resident populations of each site. This study provides further insights into the intersection of residential movement and status dynamics in the Inka Empire.