Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence

X-ray fluorescence analysis of obsidian artifacts from sites located in Chaco Canyon and from three Chaco-era communities in New Mexico permits determination of their geological origin. These source data are used to describe patterning in obsidian procurement in sites located in Chaco Canyon dating from A.D. 500–1150, and in a three non-Canyon communities occupied during the period of Chaco Canyon's regional prominence (ca. A.D. 875–1150). These data demonstrate that the most proximate sources generally dominate the sourced obsidian assemblages from sites of all periods, but also suggest differences in procurement patterning both over time and across space. Within Chaco Canyon, there is a notable shift from Mount Taylor obsidian to use of Jemez Mountains sources over time. These data also suggest that earlier analyses of obsidian from sites in Chaco Canyon misidentified some obsidian artifact sources; these new data indicate the central areas of disagreement and provide a revision of procurement patterning. In the Chaco-era communities located outside Chaco Canyon, procurement patterning diverges. The Blue J community shows an increase in use of the nearby Mount Taylor source over time. Two communities located toward the southern extent of the Chaco great house distribution reveal a markedly distinct procurement pattern, obtaining nearly all of their obsidian from southern sources largely unrepresented at Chaco Canyon. Combined, these data provide new insights into raw material procurement and artifact production at sites in Chaco Canyon, and in communities occupied during the Chaco Phenomenon, the period of the Canyon's greatest regional influence.     

Modeling agricultural potential in Chaco Canyon during the Bonito phase: a predictive geospatial approach

This study presents a geospatial analysis of surficial hydrology and geomorphology and their relationship to potential agricultural productivity in order to better understand the economic role of water in Chaco Canyon during the Bonito Phase (ca. AD 850–1150). Defined as the Natural Agricultural Suitability Analysis, the foundation of this study is a hierarchical geospatial analysis that integrates six key natural factors: slope, soil texture, soil depth, non-catastrophic overbank flooding potential, drainage flow length, and drainage proximity and flow potential. These factors are combined through a raster weighted overlay function to generate composite suitability map that offers a testable proxy for variability in relative agricultural potential during the Bonito Phase at Chaco. The rationale for including this set of natural factors is based largely on ethnographic and modern agricultural studies, but the predictive model differs from previous studies of agricultural potential in that it is independent of the specific archaeological distribution of evidence of agriculture in the study area. The results of this analysis suggest that previous models of Chacoan agricultural productivity have underestimated local production capacity. Previous studies have focused solely on floodplain contexts, whereas this study points to a more comprehensive and geographically distributed use of the landscape.     

Recent Research on Chaco: Changing Views on Economy, Ritual, and Society

Current research on Chaco Canyon and its surrounding outlier communities is at an important juncture. Rather than trying to argue for the presence or absence of complexity, archaeologists working in the area are asking different questions, especially how Chacoan political, economic, ritual, and social organization were structured. These lines of inquiry do not attempt to pigeonhole Chaco into traditional neoevolutionary types, but instead seek to understand the historical trajectory that led to the construction of monumental architecture in Chaco Canyon and a large part of the northern Southwest in the 10th through 12th centuries. This review discusses the conclusions of current research at Chaco including definitions of the Chaco region, recent fieldwork, histories of Chaco archaeology, chronology, paleoenvironmental reconstruction, demography, political organization, outlier communities, economic organization, social organization, ritual, violence, and the post-Chacoan reorganization. Although many issues are hotly debated, there is a growing concensus that power was not based in a centralized political organization and that ritual organization was a key factor in the replication of Chacoan architecture across a vast regional landscape. Exactly how ritual, social, and political organization intersected is a central question for Chaco scholars. The resolution of this problem will prove to be of interest to all archaeologists working with intermediate societies across the globe.     

Pilgrimage as costly signal: Religiously motivated cooperation in Chaco and Nasca

Religiously motivated cooperation in the form of pilgrimage is a neglected element in discussions of the dynamics of cooperative behavior among humans. In this paper, we invoke costly signaling theory to propose how pilgrimage centers emerge in some contexts. On one hand, as has been suggested by other scholars, monumental centers are costly signals of the authority and influence of competing centers’ leadership, which can include the leaders’ influence over supernatural forces. We argue that equally important is the pilgrimage itself, which serves as a costly signal of the pilgrims’ commitment to the religious system and the beliefs and values associated with it; this in turn facilitates cooperation and other prosocial behaviors among pilgrims who otherwise might be strangers. To explore the utility of this approach to pilgrimage, we compare Chaco Canyon in the US Southwest and Cahuachi in the Nasca region of Peru, two prestate sociocultural settings in which pilgrimage was an important component in maintaining cooperation, group cohesion, and identity. While specific patterns are distinct in each society, we argue that pilgrimage had a significant impact in the development of both prosocial behavior and religious leadership in Chaco and Nasca.     

Glaze-paints,technological knowledge,and ceramic specialization in the fourteenth-century Pueblo Southwest

The advent of glaze-painted ceramics by Ancestral Pueblo peoples in the US Southwest occurred during an important period of cultural change. In east-central Arizona, potters used glaze-paints to decorate a striking, representational-style pottery during the early fourteenth-century AD. We evaluate the possibility that these vessels were manufactured by emergent specialists who possessed crafting-knowledge that was not widely shared with others in their communities. Time of flight-laser ablation-inductively coupled plasma-mass spectrometry (TOF-LA-ICP-MS) was used to characterize the composition of a large sample of red ware sherds from sites in the Silver Creek area. This analytical approach precisely measures the chemical composition of paints, which can then be used to model ancient technological “recipes.” Our study highlights the complexities of craft production in small-scale societies and the utility of practice-based versus typological approaches to specialization.     

Ancestral pueblo population aggregation and abandonment in the North American Southwest

After over a century of archaeological research in the American Southwest, questions focusing on population aggregation and abandonment continue to preoccupy much of Pueblo archaeology. This article presents a historical overview of the present range of explanatory approaches to these two processes, with a primary focus on population aggregation in those regions occupied by historic and prehistoric Pueblo peoples. We stress the necessarily complementary nature of most of these explanations of residential abandonment and aggregation. Case studies from the northern Southwest illustrate the continuous nature of these processes across time and space. We suggest that additional explanatory potential will be gained by the use of well-defined theoretical units to frame our current approaches. We extend the use of the local community concept as a theoretical unit of organization that, along with explicit archaeological correlates, should help advance our research into population aggregation and abandonment in this and other regions of the world.     

“…being weary,they had rebelled”: Pueblo subsistence and labor under Spanish colonialism

Native American responses to Spanish colonialism are explored through an analysis of multiple lines of evidence concerning subsistence practices, diet, and health in the Salinas Pueblo area of central New Mexico. Zooarchaeological and paleoethnobotanical data from three Pueblo villages that experienced different degrees of Spanish missionization are the focus of this study. In addition, human osteological data from one village provide important information on activity patterns and health. These data are used to document the kinds of changes that occurred in Pueblo labor patterns, food consumption, and health from the pre-colonial to colonial periods. Synthetic analyses document the development of some degree of inter-village specialization in large game hunting, hide processing, and corn farming, presumably in response to Spanish tribute levies in corn and antelope hides, and demands on Pueblo labor in other arenas. There also appears to be a degree of divergence in women’s and men’s lives in the colonial period. These southwestern data are then compared with similar information from the southeastern US to identify patterns of similarity and difference in Native American experiences of and strategies for dealing with Spanish colonization.     

The prehistoric drug trade: widespread consumption of cacao in Ancestral Pueblo and Hohokam communities in the American Southwest

We propose the existence of extensive trade and interaction among the peoples of the American Southwest and Mesoamerica. We base this inference on our detection of the widespread presence of theobromine, the biomarker for cacao, in 50 of 75 vessels used by Ancestral Puebloans (previously referred to as Anasazi) elites and non-elites from the Four Corners area and Hohokam elites of the Gila and Salt river valleys in the prehistoric American Southwest. We used a non-invasive, non-destructive aqueous sampling procedure that provides conservation advantages over the current methods that require crushing and boiling sherds or removing residues from vessel surfaces. Analysis of these samples by sensitive LC-MS instrumentation capable of detecting nanogram quantities of material revealed theobromine in non-local vessel forms found in elite burials in great house and platform mound sites as well as in local vessel forms used by non-elites living in small unit-pueblos. After elimination of plants native to the Southwest as the source of theobromine, we conclude that either Theobroma cacao or Theobroma Bicolor was imported from its homeland in the Mesoamerican tropical coastal lowlands. Our results are at odds with the current consensus that there was little systematic commerce between Mesoamerican and Southwestern polities. We suggest that cacao was exchanged for high quality turquoise such as that mined in the Cerrillos, New Mexico mining district. We conclude that, far from being isolated developmentally, this trade integrally tied populations in the American Southwest to the socio-political and economic activities of Mesoamerican states.     

Early agriculture and sedentism in the American Southwest: Evidence and interpretations

Recent archaeological research in the American Southwest is rapidly altering long-held perspectives on early agricultural adaptations. The adoption of maize and squash is now reliably dated to ca. 1200 B.C., rather than 4000–2000 B.C. as previously thought, and new sites have been found in a variety of unexpected ecological settings. These emerging spatiotemporal patterns suggest that the development of sedentary communities after A.D. 500 may have been the result of changing systems of foraging, instead of simply a greater dependence on agricultural production.     

Surface Rotations on and Around a Semi-Parabolic Canyon in an Elastic Half-Space Induced by Out-of-Plane SH-Waves,I: Torsion

The surface displacement amplitudes excited by out-of-plane SH waves on and around a semi-parabolic canyon had solution that was introduced over twenty years ago. In 2015, such solution was updated to much (5 times) higher frequencies, using a transformation involving the Wronskian. The same excitations also introduce rotations on and around the parabolic canyon. This article is the first of two that discuss the torsional component of rotations, with the rocking components discussed in the subsequent article. The rotational amplitudes of motions, as much as the displacement amplitudes, play an important role in studying the surface responses of structures, and can lead to a better understanding of the behavior of surface topographies in the event of seismic excitation.     

Changes in regional organization and mobility in the Zuni region of the American Southwest during the Pueblo III and IV periods: insights from INAA studies

The transition from the late Pueblo III (AD 1200–1275) to Pueblo IV (AD 1275–1400) period marks one of the most dramatic eras of demographic and social upheaval in the American Southwest. At this time, much of the northern Southwest was depopulated as thousands of ancestral Pueblo people moved to new homelands. In the Zuni region, this transition included a residential shift from dispersed, largely household-scale settlements to massive, multi-storied pueblos housing hundreds of people and a simultaneous contraction of regional settlement to a central core along the Zuni River and its major tributaries. This article presents a synthesis of our recent independent efforts to utilize instrumental neutron activation analysis (INAA) to investigate changes in social interaction in the Zuni region before and after this transition. We suggest that in addition to significant local and regional settlement shifts, the Pueblo III–IV transition in the Zuni region was accompanied by a major reorganization of pottery distribution networks as clear social boundaries began to emerge between village clusters. More generally, our combined study also highlights the iterative nature of INAA data analysis, the benefits of large sample sizes, and the utility of a diachronic interpretative approach.