A series of archaeological and bioanthropological studies reveal possible Tiwanaku colonization in the Atacama desert of northern Chile where Tiwanaku goods have been documented at several of those sites, leading archaeologists to posit competing hypotheses regarding the nature of Tiwanaku influence and expansion. Some scholars have suggested that individuals from Tiwanaku were settling in foreign zones (Berenguer and Dauelsberg Hahmann 1989; Kolata 1992, 1993a, b; Ponce Sangines 1972; Rodman 1992), while others have proposed that the Tiwanaku established colonies consisting of various ethnic groups (Mujica et al. 1983), akin to the “vertical archipelagos” proposed by Murra (1972). A third group of scholars has hypothesized that Tiwanaku goods and ideology were spread through exchange (Torres and Conklin 1995), trade and llama caravans (Dillehay and Nunez 1988), or commercial missionaries (Browman 1978) (and see also the social field interpretation by Stovel in Chapter 49 of this volume). The cases described below show how a series of studies over several decades have come together to address some of these debates.
Some researchers have suggested that Tiwanaku satellite communities may have been present in the San Pedro de Atacama desert of northern Chile during the Middle Horizon (Berenguer and Dauelsberg Hahmann 1989; Kolata 1993a), and analysis of textiles from the Middle Horizon cemetery of Coyo Oriental in the Atacama seemed to support this: local textile styles were abruptly altered, most likely by foreign individuals from the Bolivian alti-plano who may have been physically present in the Atacama (Rodman 1992). Additionally, a biodistance study analyzing cranio-facial metrics of skeletal samples from the Atacama region noted a significant increase in morphological diversity from pre-Tiwanaku to Tiwanaku times, leading the authors to suggest an infusion of new genetic material from high plateau peoples, arguing that they would have been the carriers of Tiwanaku culture (Varela and Cocilovo 2000: 129,131). However, while increased heterogeneity of craniofacial metrics was observed, those data do not locate from where the new genetic variability came. Additionally, the cranio-facial metrics used by the researchers can vary based on masticatory function, not underlying genes (see Larsen 1997); thus, the measured differences may be more related to behavior (diet, or use of the mouth as a tool), not genetic origin.
Building on these earlier studies, Torres-Rouff (2002) investigated this problem through an examination of Atacama cranial modification styles from pre-Tiwanaku to Tiwanaku periods, and hypothesized the following: if Tiwanaku foreigners were present in San Pedro de Atacama, then Tiwanaku era local cranial modification styles should differ from the pre-Tiwanaku sample. Her study documented a high frequency of tabular erect and tabular oblique cranial modification forms in the pre-Tiwanaku Atacama groups [Note 1]; thus a shift away from that pattern might suggest a Tiwanaku colonizing presence. Although there was a statistically significant difference in the frequency of moderately shaped annular forms between the pre-Tiwanaku and Tiwanaku sites, there were no “strong annular forms of the altiplano” present at either Atacama site, nor was there a statistically significant change in the frequency of individuals with cranial modification (Torres-Rouff 2002) [Note 2]. This led Torres-Rouff (2002) to conclude that there were no Tiwanaku colonists in the Atacama region during the Middle Horizon.
To examine this problem further, an analysis of strontium isotope ratios from dentition from Atacama burials was recently undertaken by Knudson (2004). Strontium isotope ratios from dental enamel reveal the geological zone of an individual’s childhood diet because the chemical compositions of foods are absorbed by enamel as dentition is forming (Grupe et al. 1997; Price et al. 2002; Price et al. 2000). By extension, if local foods are consumed, then the strontium isotope ratio in teeth can serve as a proxy for establishing the geological zone(s) where an individual may have lived during childhood. Thus, if individuals interred in the Atacama exhibited dental strontium isotope ratios different from the local strontium isotope value, then those data would indicate that they consumed large quantities of food grown in another geological zone; this would suggest that they likely spent their childhood in a different locale. In contrast, if strontium isotope values matched that of the local region, then it is likely that they were native to the area (or at least consumed foods from the local geological zone).
The interpretation put forward by Torres-Rouff (2002) was supported by data from Knudson’s (2004) isotope study; none of the dental enamel samples from Middle Horizon Atacama burials show strontium isotope ratios expected for Tiwanaku natives (i. e., from the southeastern Lake Titicaca basin). Specifically, 35 individuals interred at three Middle Horizon Atacama sites (Coyo-3, Coyo Oriental, and Solcor 3) were sampled, and while four of the 35 exhibited non-local dental strontium isotope values, none was within the range expected for a person who spent their developmental years in the Tiwanaku heartland (Knudson 2004) [Note 3]. Granted, a sample of 35 represents only 0.6% of the 632 Atacama burials, so Tiwanaku migrants may yet be identified. However, the majority of the dental samples are from those interred with Tiwanaku artifacts who may be the ones most likely to express Tiwanaku strontium isotope signatures (see Knudson 2004). Among the four Atacama burials with non-local strontium isotope values, two expressed signatures that matched expected values for the upper Osmore drainage (or another geological zone like the upper Osmore), suggesting that individuals from those Tiwanaku-affiliated sites may have migrated south to Atacama (Knudson 2004).
Immigrants (and Sojourners) to State Centers
As urban sites develop, people from surrounding and distant regions may migrate there, building its status as an important city while also creating a cosmopolitan center in which different ethnic groups interact. The city of Teotihuacan in central highland Mexico is a case in point, where studies of ceramics have identified non-local ethnic barrios (Rattray 1990; Spence 1992), and analyses of strontium isotope ratios from human tooth and bone pairs have documented foreign-born persons who migrated to and settled at this center (Price et al. 2000). In the Andes, the development of the urban center of Tiwanaku in the Lake Titicaca basin also appears to have been a magnet for immigrants; artifactual and osteological data indicate that peoples from diverse zones migrated to this highland center. Based on the diversity of ceramic styles present in distinct areas of the site—a pattern that holds over time—Janusek (2004: 159-164) proposed that people of different regions may have emigrated to the center, while maintaining close ties to their homeland for many generations. This interpretation has been supported by bioarchaeological analyses, in which two major types of cranial modification have been documented: the annular form and the fronto-occipital form (Blom 1999; Blom 2005). Because this type of body modification is likely to express ethnic identity or regional affiliation and must occur in infancy when the skull is malleable, modified head shape can serve as a proxy measure of one’s natal
Community (Blom 1999; Blom 2005; Janusek 2004). Thus, the two forms of cranial modification at Tiwanaku suggest that different ethnic groups immigrated to this center (Blom 1999; Blom 2005), an interpretation that coincides with artifactual data from the same site (Janusek 2004).
Questions regarding in-migration to the urban site of Conchopata in the Wari heartland have also been addressed through analyses of grave good associations, cranial modification, and strontium isotope ratios (Tung 2003; Tung and Cook 2006; Tung and Knudson n. d.). The bodies of 46 individuals and associated grave goods from seven multi-occupant tombs at Conchopata were examined, revealing that pre-Wari individuals seemed to be identifiable by association with local Huarpa goods and Wari-era persons by association with local Huamanga ceramics (Tung and Cook 2006). Moreover, none exhibited cranial modification such as the tabular oblique or tabular erect styles (also known as fronto-occipital modification) (Tung 2003), which are more common in coastal populations (Blom 1999; Kellner 2002; Torres-Rouff 2002; Tung 2003) [Note 4]. Thus, the artifactual and osteological data suggest that non-locals were absent in the core mortuary area of the site. To further test this, strontium isotope ratios from six individuals (one male, four females, and one newborn infant, which by extension provided a strontium isotope value for its mother) were examined to ascertain if they consumed local or nonlocal foods: a proxy measure of local or foreign status (Tung 2003; Tung and Knudson n. d.). These analyses showed that all had similar strontium isotope ratios in their teeth and bones, and that these values matched the local strontium value, which was based on small fauna that consumed locally grown vegetation (Tung 2003; Tung and Knudson n. d.). These data indicate that those six individuals interred with local goods in Concho-pata tombs had spent their childhood and adulthood in the region of the Wari heartland (their strontium isotope ratios [87Sr/86Sr] ranged from 0.7055 to 0.7061). The combined artifactual, osteological, and strontium isotope data suggest that few, if any, of those buried at Conchopata were immigrants from distant zones. Thus, unlike Tiwanaku, current data suggest an absence of immigrants at the urban center of Conchopata, yet it remains unknown if the capital site of Huari was more similar in this regard to its neighbor, Con-chopata, or to the distant center of Tiwanaku.
World History
