ABSTRACT
The timing of Tiwanaku's collapse remains contested. Here we present a generational-scale chronology of Tiwanaku using Bayesian models of 102 radiocarbon dates, including 45 unpublished dates. This chronology tracks four community practices: residing short- vs. long-term, constructing monuments, discarding decorated ceramics, and leaving human burials. Tiwanaku was founded around AD 100 and around AD 600, it became the region's principal destination for migrants. It grew into one of the Andes' first cities and became famous for its decorated ceramics, carved monoliths, and large monuments. Our Bayesian models show that monument building ended ~AD 720 (the median of the ending boundary). Around ~AD 910, burials in tombs ceased as violent deaths began, which we document for the first time in this paper. Ritualized murders are limited to the century leading up to ~AD 1020. Our clearest proxy for social networks breaking down is a precise estimate for the end of permanent residence, ~AD 1010 (970-1050, 95%). This major inflection point was followed by visitors who used the same ceramics until ~AD 1040. Temporary camps lasted until roughly ~AD 1050. These four events suggest a rapid, city-wide collapse at ~AD 1010-1050, lasting just ~20 years (0-70 years, 95%). These results suggest a cascading breakdown of community practices and social networks that were physically anchored at Tiwanaku, though visitors continued to leave informal burials for centuries. This generation-scale chronology suggests that collapse 1) took place well before reduced precipitation, hence this was not a drought-induced societal change and 2) a few resilient communities sustained some traditions at other sites, hence the chronology for the site of Tiwanaku cannot be transposed to all sites with similar material culture.
Subject(s)
Burial , Ceramics , Humans , Bayes Theorem , Homicide , Archaeology/methodsABSTRACT
Tiwanaku civilization flourished in the Lake Titicaca basin between 500 and 1000 CE and at its apogee influenced wide areas across the southern Andes. Despite a considerable amount of archaeological data, little is known about the Tiwanaku population. We analyzed 17 low-coverage genomes from individuals dated between 300 and 1500 CE and demonstrated genetic continuity in the Lake Titicaca basin throughout this period, which indicates that the substantial cultural and political changes in the region were not accompanied by large-scale population movements. Conversely, the ritual center of Tiwanaku revealed high diversity, including individuals with primarily local genetic ancestry and those with foreign admixture or provenance from as far as the Amazon. Nonetheless, most human offerings associated with the Akapana platform exhibited pure Titicaca basin ancestry and dated to ca. 950 CEthe onset of Tiwanaku's decline as a sociopolitical center. Our results strengthen the view of Tiwanaku as a complex and far-reaching polity.
