Residential Mobility in the Late Pre-hispanic Osmore Drainage: Isotopic Analyses of Hair from the Estuquiña

I examine, through isotopic analyses, individual and regional interactions in Peru following the collapse of the large polity, Tiwanaku. After its collapse in the 11th century, former territories experienced violent instability, as new communities formed during the Late Intermediate Period, or LIP (1000-1400s AD). I analyze naturally mummified human hair from the later LIP Estuquiña (1250-1470s AD) in the Moquegua Valley of southern Peru to examine patterns of regional mobility in the aftermath of political fragmentation. Reconstructing residential mobility through isotope analyses is methodologically established, and has been instrumental in understanding mobility, exchange, colonization, and regional interactions during Tiwanaku’s height. However, less is known about these processes following the disbursement of individuals and groups of people after the early LIP when instability transitioned into a different form of uncertainty, caused by environmental factors. Using heavy isotope analysis, I test the oral tradition and ethnohistoric accounts of the origins of members of the LIP Estuquiña cultural group, which suggested populations moved from around the southern Lake Titicaca region into the middle Moquegua Valley of Southern Peru during the Late LIP. I analyzed bulk samples of archaeological hair from ten naturally mummified individuals from the site of Estuquiña, located in the middle Moquegua Valley, Peru. I characterized 87Sr/86Sr and 206Pb/204Pb, 207Pb/204Pb, and 208Pb (206,7,8Pb/204Pb for brevity). Additionally, I analyzed ratios of the same isotopes in a subset of individuals (N = 2), using 1cm increments from roughly thirty strands of hair per individual, aligned by the hair follicles. This allowed me to examine incremental variation in isotope ratios during each month or so leading up to death. Hair 87Sr/86Sr and 206,7,8Pb/204Pb results indicate that only one individual, M6-4203, was distinctly from the altiplano, while two more individuals may have also been from outside, but near to, the region. Most individuals appear to have been locals, isotopically speaking, to the middle Moquegua Valley. These data support recent work by Sutter and Sharratt (2019) arguing that the Estuquiña inhabitants were a contiguous population extending back to the Middle Horizon, rather than a replacement community from highland Lupaqa cultures or other far-flung regions