Integration of ancient DNA with transdisciplinary dataset finds strong support for Inca resettlement in the south Peruvian coast.

Ancient DNA (aDNA) analysis provides a powerful means of investigating human migration, social organization, and a plethora of other crucial questions about humanity's past. Recently, specialists have suggested that the ideal research design involving aDNA would include multiple independent lines of evidence. In this paper, we adopt a transdisciplinary approach integrating aDNA with archaeological, biogeochemical, and historical data to investigate six individuals found in two cemeteries that date to the Late Horizon (1400 to 1532 CE) and Colonial (1532 to 1825 CE) periods in the Chincha Valley of southern Peru. Genomic analyses indicate that these individuals are genetically most similar to ancient and present-day populations from the north Peruvian coast located several hundred kilometers away. These genomic data are consistent with 16th century written records as well as ceramic, textile, and isotopic data. These results provide some of the strongest evidence yet of state-sponsored resettlement in the pre-Colonial Andes. This study highlights the power of transdisciplinary research designs when using aDNA data and sets a methodological standard for investigating ancient mobility in complex societies.

Underwater ritual offerings in the Island of the Sun and the formation of the Tiwanaku state.

Considerable debate surrounds the economic, political, and ideological systems that constitute primary state formation. Theoretical and empirical research emphasize the role of religion as a significant institution for promoting the consolidation and reproduction of archaic states. The Tiwanaku state developed in the Lake Titicaca Basin between the 5th and 12th centuries CE and extended its influence over much of the south-central Andes of South America. We report on recent discoveries from the first systematic underwater archaeological excavations in the Khoa Reef near the Island of the Sun, Bolivia. The depositional context and compositional properties of offerings consisting of ceramic feline incense burners, killed juvenile llamas, and sumptuary metal, shell, and lapidary ornaments allow us to reconstruct the structure and significance of cyclically repeated state rituals. Using new theoretical tools, we explain the role of these rituals in promoting the consolidation of the Tiwanaku polity.

Feasting and the evolution of cooperative social organizations circa 2300 B.P. in Paracas culture, southern Peru.

Recent theoretical innovations in cultural evolutionary theory emphasize the role of cooperative social organizations that unite diverse groups as a key step in the evolution of social complexity. A principal mechanism identified by this theory is feasting, a strategy that reinforces norms of cooperation. Feasts occur throughout the premodern world, and the intensification of feasting is empirically correlated to increased social complexity. A critical factor in assessing the evolutionary significance of this practice is the scale and range of the feast from that focused on a single community to ones that draw from a large region or catchment zone. This work addresses the degree to which hosts draw on a local area vs. a regional one in initial prehistoric feasting. We report on excavations at a locus of intensive feasting-a ceremonial sunken court-in a fifth- to third-century BCE Paracas site on the south coast of Peru. We selected 39 organic objects from the court placed as offerings during major feasting episodes. We analyzed the radiogenic strontium isotope (87Sr/86Sr) values to determine the geographical origin of each object. The 87Sr/86Sr data plus additional archaeological data support a hypothesis that the catchment of the court was quite extensive. The initial strategy of political and economic alliance building was macroregional in scope. These data indicate that the most effective initial strategy in early state formation in this case study was to build wide alliances at the outset, as opposed to first consolidating local ones that subsequently expand.

The Final Days of Paracas in Cerro del Gentil, Chincha Valley, Peru.

This article describes and analyzes a highly significant archaeological context discovered in a late Paracas (400-200 BCE) sunken patio in the monumental platform mound of Cerro Gentil, located in the Chincha Valley, Peru. This patio area was used for several centuries for ritual activities, including large-scale feasting and other public gatherings. At one point late in this historical sequence people deposited a great deal of objects in what is demonstrably a single historical event. This was quickly followed by a series of minor events stratigraphically immediately above this larger event. This entire ritual process included the consumption of liquids and food, and involved the offering of whole pottery, pottery fragments, botanical remains, bone, lithics, baskets, pyro-engraved gourds, mummies, and other objects. We interpret these events as an "abandonment ceremony" or "termination ritual" during the late Paracas period, one that may have lasted for weeks or even months. The subsequent Topará occupation at the site (ca. 200 BCE- AD 100) involved the architectural enhancement of the mound area, but the pattern of use of the patio itself ended. Such a termination ritual signals a reorganization in the regional political structure of Paracas society.

A 2,300-year-old architectural and astronomical complex in the Chincha Valley, Peru.

Recent archaeological research on the south coast of Peru discovered a Late Paracas (ca. 400-100 BCE) mound and geoglyph complex in the middle Chincha Valley. This complex consists of linear geoglyphs, circular rock features, ceremonial mounds, and settlements spread over a 40-km(2) area. A striking feature of this culturally modified landscape is that the geoglyph lines converge on mounds and habitation sites to form discrete clusters. Likewise, these clusters contain a number of paired line segments and at least two U-shaped structures that marked the setting sun of the June solstice in antiquity. Excavations in three mounds confirm that they were built in Late Paracas times. The Chincha complex therefore predates the better-known Nasca lines to the south by several centuries and provides insight into the development and use of geoglyphs and platform mounds in Paracas society. The data presented here indicate that Paracas peoples engineered a carefully structured, ritualized landscape to demarcate areas and times for key ritual and social activities.

War and early state formation in the northern Titicaca Basin, Peru.

Excavations at the site of Taraco in the northern Titicaca Basin of southern Peru indicate a 2,600-y sequence of human occupation beginning ca. 1100 B.C.E. Previous research has identified several political centers in the region in the latter part of the first millennium B.C.E. The two largest centers were Taraco, located near the northern lake edge, and Pukara, located 50 km to the northwest in the grassland pampas. Our data reveal that a high-status residential section of Taraco was burned in the first century A.D., after which economic activity in the area dramatically declined. Coincident with this massive fire at Taraco, Pukara adopted many of the characteristics of state societies and emerged as an expanding regional polity. We conclude that organized conflict, beginning approximately 500 B.C.E., is a significant factor in the evolution of the archaic state in the northern Titicaca Basin.

Direct evidence of 1,900 years of indigenous silver production in the Lake Titicaca Basin of Southern Peru.

Archaeological excavations at a U-shaped pyramid in the northern Lake Titicaca Basin of Peru have documented a continuous 5-m-deep stratigraphic sequence of metalworking remains. The sequence begins in the first millennium AD and ends in the Spanish Colonial period ca. AD 1600. The earliest dates associated with silver production are 1960 + or - 40 BP (2-sigma cal. 40 BC to AD 120) and 1870 + or - 40 BP (2-sigma cal. AD 60 to 240) representing the oldest known silver smelting in South America. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis of production debris indicate a complex, multistage, high temperature technology for producing silver throughout the archaeological sequence. These data hold significant theoretical implications including the following: (i) silver production occurred before the development of the first southern Andean state of Tiwanaku, (ii) the location and process of silverworking remained consistent for 1,500 years even though political control of the area cycled between expansionist states and smaller chiefly polities, and (iii) that U-shaped structures were the location of ceremonial, residential, and industrial activities.