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.     

The Chaco Connection: Evaluating Bonito-Style Architecture in Outlier Communities

Because architecture shapes and is shaped by human actions and perceptions, architectural variability has the potential to provide information about relationships among prehistoric social groups. This study examines communicative and enculturative information contained in Bonito-style architecture constructed in Chaco Canyon and outlying communities during the late eleventh century A.D. Does the appearance of Bonito-style architecture at outliers constitute direct involvement on the part of a centralized, Chacoan entity or could local people have been emulating Bonito-style architecture they saw at Chaco or in neighboring communities? These questions have implications for existing models of Chacoan social organization. To investigate, a comparative architectural analysis uses data from 61 great houses in 55 outlier communities. Analysis is based on the premise that outlier similarity should reflect a unified, direct Chacoan source for Bonito-style architecture, and diversity should reflect the converse. Because highly visible, external architectural characteristics can be emulated, five internal, low-visibility great-house architectural attributes were selected for comparison. Results indicate substantial diversity is contained within the Chacoan world. A variety of relationships probably existed between outlier communities and Chaco Canyon, and a range of explanatory models is necessary. Bonito-style architecture is more likely to be associated with a struggle to legitimate social power than with spontaneous, cooperative communal activity. Competitive emulation may account for the appearance of Bonito-style architecture in outlier communities toward the local end of the outlier spectrum.     

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.     

Agriculture and community in Chaco Canyon: Revisiting Pueblo Alto

The Bonito Phase (ca. AD 860–1140) in Chaco Canyon is widely recognized as one of the primary sources of information about emergent social complexity in prehispanic North America. Large masonry buildings called “great houses,” such as Pueblo Bonito, are iconic symbols of the rapid rise of a powerful society based on the ability to harness labor to prolonged construction projects. It is clear that the political forces at work during the Bonito Phase had an agricultural foundation, presumably in the financing of construction through food surpluses, but the actual nature of farming in Chaco is surprisingly opaque to archaeologists. Indeed, many researchers have concluded that farming in Chaco Canyon was too constrained by poor soils to have supported the dynamic developments associated with the massive stone structures and extensive trade systems of the Bonito Phase. The popular perspective that Chaco was mysterious or enigmatic is largely a response to this view of the canyon as agriculturally marginal. In this study we argue that a predictive model of potential agricultural productivity that includes other portions of the canyon besides the floodplain indicates that Chaco was not marginal for farming. The results of this analysis suggest that great house communities may have been sited to control local production zones and that some great houses may have been linked to others in order to manage multiple agricultural areas.     

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.     

Possible sources of archaeological maize found in Chaco Canyon and Aztec Ruin,New Mexico

Maize played a major role in Chaco's interaction with outlying communities in the southern Colorado Plateau. This paper seeks to determine where archaeological corn cobs brought to Chaco Canyon were grown. Strontium-isotope and trace-metal ratios of 180 soil-water and 18 surface-water sites in the Southern Colorado Plateau have revealed possible source areas for some of 37 archaeological corn cobs from Chaco Canyon and 10 archaeological corn cobs from Aztec Ruin, New Mexico. The most probable source areas for cobs that predate the middle-12th-century drought include several Upper Rio Chaco sites (not including Chaco Canyon). There are many potential source areas for cobs that date to the late A.D. 1100s and early 1200s, all of which lie in the eastern part of the study area. Some Athapascan-age cobs have potential source areas in the Totah, Lobo Mesa, and Dinetah regions. One Gallo Cliff Dwelling cob has a strontium-isotope ratio that exceeds all measured soil-water values. Field sites for this cob may exist in association with Paleozoic and Precambrian rocks found 80–90 km from Chaco Canyon. Potential source areas for most Aztec Ruin cobs (many of which were found in rooms dating to the first half of the 13th-century) appear to be associated with a loess deposit that blankets the Mesa Verde and McElmo Dome regions.     

Evaluating the Reliability of Fluoride Dating at Two Prehistoric Mound Sites in Mississippi

Abstract

Ion-selective electrode fluoride dating is used to address chronological problems at two mound sites located in Mississippi. At the Mississippian period (A.D. 900–1520) Lyon's Bluff site, 220K520, the fluoride content of deer and human bone is compared with radiocarbon dates and stratigraphic levels to evaluate the reliability of the fluoride dating method for understanding relative burial chronology. At a second site, Pocahontas Mound A (22HI500), fluoride content of deer bone is used to corroborate radiocarbon dates and to establish the proper chronology of levels associated with two distinct occupations (Archaic and Coles Creek/Plaquemine) identified in a large midden area. Fluoride analysis also is used to date a second midden area at this site. For Lyon's Bluff; fluoride dates did not correspond with accelerator mass spectrometry (AMS)-dated burials and midden strata. In contrast, fluoride dating proved very useful in determining chronological placement of midden levels and dating other areas at Pocahontas Mound A. Sample age, site location, soil, and bone preservation are considered as possible causes for the negative results at Lyon's Bluff.     

Who provided maize to Chaco Canyon after the mid-12th-century drought?

Between A.D. 1181 and 1200, in the early part of a climatically wet period, corn was imported to Chaco Canyon from a region outside the Chaco Halo (defined in this paper as the region between the base of the Chuska Mountains and Raton Wells). Strontium-isotope (⁸⁷Sr/⁸⁶Sr) analyses of 12 corn cobs dating to this period match ⁸⁷Sr/⁸⁶Sr ratios from five potential source areas, including: the Zuni region, the Mesa Verde-McElmo Dome area, the Totah, the Defiance Plateau, and Lobo Mesa. The latter two areas were eliminated from consideration as possible sources of corn in that they appear to have been unpopulated during the time period of interest. Therefore, it appears that the corn cobs were imported from the Zuni region, the Mesa Verde-McElmo Dome area, or the Totah area during a time when the climate was relatively wet and when a surplus of corn was produced in regions outside Chaco Canyon. Based on proximity to and cultural affiliation with Chaco Canyon, it is hypothesized that the corn probably was imported from the Totah.     

Open-area excavations at the Mitchell Prehistoric Indian Village,South Dakota (A.D. 1000–1150): New interpretations of site function from interdwelling areas

Abstract

Excavations at the Mitchell Prehistoric Indian Village (A.D. 1000–1150), an Initial Middle Missouri period Plains earthen lodge village site in eastern South Dakota, revealed new data regarding the lifeways and cultural systems of its prehistoric inhabitants. While extensive excavations had been conducted at the site and at a large number of other Middle Missouri sites prior to the present project, our open-area approach revealed new and significantly different information. New features in the areas between the dwellings were uncovered, features that are rarely studied in the context of the Middle Missouri cultural tradition. Other finds included Mississippian-influenced ceramics, Avonlea projectile points, and ceremonial goods that indicate long-distance cultural interaction. The discovery of large, complex features in the interdwelling areas of the site changes our understanding of Middle Missouri lifeways and settlement structure.     

Reduced Population Variance in Strontium Isotope Ratios Informs Domesticated Turkey Use at Chaco Canyon,New Mexico,USA

Traditionally, strontium isotopes (⁸⁷Sr/⁸⁶Sr) have been used as a sourcing tool in numerous archaeological artifact classes. The research presented here demonstrates that ⁸⁷Sr/⁸⁶Sr_bioapatite ratios also can be used at a population level to investigate the presence of domesticated animals and methods of management. The proposed methodology combines ecology, isotope geochemistry, and behavioral ecology to assess the presence and nature of turkey (Meleagris gallopavo) domestication. This case study utilizes ⁸⁷Sr/⁸⁶Sr_bioapatite ratios from teeth and bones of archaeological turkey, deer (Odocoileus sp.), lagomorph (Lepus sp. and Sylvilagus sp.), and prairie dog (Cynomys sp.) from Chaco Canyon, NM, USA (ca. A.D. 800–1250). Wild deer and turkey from the southwestern USA have much larger home ranges and dispersal behaviors (measured in kilometers) when compared to lagomorphs and prairie dogs (measured in meters). Hunted deer and wild turkey from archaeological contexts at Chaco Canyon are expected to have a higher variance in their ⁸⁷Sr/⁸⁶Sr_bioapatite ratios, when compared to small range taxa (lagomorphs and prairie dogs). Contrary to this expectation, ⁸⁷Sr/⁸⁶Sr_bioapatite values of turkey bones from Chacoan assemblages have a much lower variance than deer and are similar to that of smaller mammals. The sampled turkey values show variability most similar to lagomorphs and prairie dogs, suggesting the turkeys from Chaco Canyon were consuming a uniform diet and/or were constrained within a limited home range, indicating at least proto-domestication. The population approach has wide applicability for evaluating the presence and nature of domestication when combined with paleoecology and behavioral ecology in a variety of animals and environments.     

A case of treponematosis from pre‐Columbian Chaco Canyon,New Mexico

Although numerous cases of treponemal infection have been identified in prehispanic New World skeletal remains, none has been reported from Chaco Canyon, New Mexico. Chaco Canyon was the epicentre of a broad culture system that spanned the Four Corners region of the pre‐Columbian Southwestern United States. A burial recovered from the central Great House of Chaco Canyon, Pueblo Bonito, exhibits lesions indicative of treponematosis. However, the pathological condition of this individual has heretofore been only tentatively diagnosed because the skeleton was collected from a commingled context and distributed across four separate catalogue numbers. Now reassociated, these remains exhibit a pattern of pathological changes strongly indicative of treponemal disease. This case not only adds to the growing body of literature on the clinical expression and geographic distribution of pre‐Columbian treponematosis, but also demonstrates the utility of painstaking reassociation of commingled human remains. Copyright © 2009 John Wiley & Sons, Ltd.     

PREHISTORIC ROCK ART FROM PAINTED BLUFF AND THE LANDSCAPE OF NORTH ALABAMA ROCK ART

Abstract

Painted Bluff in northern Alabama is one of the richest and most elaborate open-air rock art localities in the Eastern Woodlands, rivaling some of the Southeast’s dark zone cave art sites discovered over the past several decades. Known for more than a century, the site has never seen detailed documentation until now. Painted Bluff contains motifs similar to iconography associated with Mississippian ceremonial objects, and a radiocarbon age determination (cal A.D. 1300–1440) would indicate contemporary use of the site. More than 80 images were painted on the cliffs, most using red mineral pigments but some reflecting polychromatic use of differently colored minerals. We present examples of the Painted Bluff artwork and discuss the site in the broader context of prehistoric rock art on the southern Cumberland Plateau and in northern Alabama.     

Wood deterioration in Chacoan great houses of the southwestern United States

Abstract

‘Great houses’ built by the Ancestral Puebloans (Anasazi) (900–1200AD) still contain thousands of pieces of wood used as beams, secondary roof supports and lintels. The wood is an integral part of the surviving Chacoan architecture and has served as a valuable resource for determining the exact age of the structures and for obtaining information about raw material production, procurement and harvesting methods. An assessment of wood deterioration at the great houses in Aztec Ruins National Monument and Pueblo Bonito, Pueblo del Arroyo and Chetro Ked located in Chaco Culture National Historic Park in New Mexico have revealed that both microbial and non-biological deterioration was taking place. The major type of decay found throughout the structures was caused by soft-rot fungi. Cavity formation in secondary walls of conifer woods and an erosion of cell walls in aspen woods was prevalent. A brown-rot type of wood degradation was also found, primarily associated with areas of subterranean termite damage. Another form of deterioration present in some of the woods was a chemical de fibration of wood. This corrosive attack, caused by high concentrations of salts, destroyed the middle lamella between cells, resulting in a stringy mass of loosely attached fibres. Reburial of great house structures as an effective conservation strategy will require an environment that is not conducive to decay, since active wood-destroying fungi are present in the prehistoric woods. If moisture and other conditions suitable for decay exist, the wood will be destroyed and this important historical resource lost.     

Development and application of methods used to source prehistoric Southwestern maize: a review

Archaeological cobs free of mineral contaminants should be used to source the soils in which they were grown. Mineral contaminants often contain much higher concentrations of metals than vegetal materials and can alter a cob’s apparent metal and heavy-isotope content. Cleaning a cob via immersion in an acid solution for more than a few minutes will result in the incongruent and sometimes complete leaching of metals, including strontium (Sr), from the cob. When using ⁸⁷Sr/⁸⁶Sr to determine the location of potential agriculture fields, it is best to either integrate several depth-integrated soil samples or to integrate several vegetation samples from individual fields. Biologically labile Sr in semi-arid Southwestern soils largely originates from eolian source or sources and usually is not derived from underlying bedrock. Existing Sr-isotope data indicate that archaeological cobs from Aztec Ruins came from either the Mesa Verde-McElmo Dome or Totah areas, that Pueblo Bonito and Chetro Ketl cobs, from Chaco Canyon that predate A.D. 1130, probably came from the Rio Chaco corridor, and that cobs from Chaco Canyon, that postdate A.D. 1130, probably came from either the Totah or Zuni areas.     

A Mississippian conflagration at East St. Louis and its political-historical implications

Abstract

A walled portion of the extensive Precolumbian civic-ceremonial precinct of East St. Louis, near present day St. Louis, Missouri, enclosed a cluster of as many as 100 small buildings or huts. The huts were associated with a walled ritual-residential zone or elite compound dating to the late Stirling phase (a.d. 1150–1200) and, importantly, were burned in a single conflagration. The burning of East St. Louis may have resulted from a ritual commemoration, an act of aggression, or an accidental fire; circumstantial evidence primarily supports the first scenario. With strongly diminished mound and architectural construction at the site in subsequent decades, and with the coeval disappearance of key ritual-residential buildings from the regional landscape after the burning, the ancient East St. Louis fire was part of a larger pattern of historical events that mark a downward turning point in the social and political history of Greater Cahokia.     

87Sr/86Sr sourcing of ponderosa pine used in Anasazi great house construction at Chaco Canyon,New Mexico

Previous analysis of ⁸⁷Sr/⁸⁶Sr ratios shows that 10th through 12th century Chaco Canyon was provisioned with plant materials that came from more than 75 km away. This includes (1) corn (Zea mays) grown on the eastern flanks of the Chuska Mountains and floodplain of the San Juan River to the west and north, and (2) spruce (Picea sp.) and fir (Abies sp.) beams from the crest of the Chuska and San Mateo Mountains to the west and south. Here, we extend ⁸⁷Sr/⁸⁶Sr analysis to ponderosa pine (Pinus ponderosa) prevalent in the architectural timber at three of the Chacoan great houses (Pueblo Bonito, Chetro Ketl, Pueblo del Arroyo). Like the architectural spruce and fir, much of the ponderosa matches the ⁸⁷Sr/⁸⁶Sr ratios of living trees in the Chuska Mountains. Many of the architectural ponderosa, however, have similar ratios to living trees in the La Plata and San Juan Mountains to the north and Lobo Mesa/Hosta Butte to the south. There are no systematic patterns in spruce/fir or ponderosa provenance by great house or time, suggesting the use of stockpiles from a few preferred sources. The multiple and distant sources for food and timber, now based on hundreds of isotopic values from modern and archeological samples, confirm conventional wisdom about the geographic scope of the larger Chacoan system. The complexity of this procurement warns against simple generalizations based on just one species, a single class of botanical artifact, or a few isotopic values.     

Cacao consumption during the 8th century at Alkali Ridge,southeastern Utah

Theobroma cacao was detected in the ceramic assemblage at the 8th century Site 13, Alkali Ridge, southeastern Utah. The presence of this Mesoamerican beverage during the Pueblo I period is the earliest reported use of cacao in the northern American Southwest, coming centuries earlier than the recently documented Pueblo II consumption of cacao in cylinder jars, sharp-shouldered pitchers and shallow bowls at Pueblo Bonito, Chaco Canyon. Analogous to the situation at Chaco, cacao was found at Site 13 in a new vessel form decorated with a distinctive design system that contrasted markedly with designs and vessel forms in the local black-on-white ceramic assemblage. We postulate that Abajo R/O at Site 13 represents a ceramic tradition brought by one of the many groups moving into the northern Southwest. The detection of cacao in their ceramic vessels represents new evidence for the migration model that for centuries brought people with Mesoamerican beliefs, ritual practices and a new subsistence lifeway into the American Southwest.     

Physical evidence revealed during the cleaning and the excavations of the outer wall of the land walls of Constantinople at the Porta ROmanus

Abstract

During the clearance, excavations and conservation of the Land walls of Constantinople in 1992–93 at the Porta Romanus (Topkapi) some original details of the Theodosian construction techniques and the subsequent repairs were found. It was seen that the structural system of the outer wall which supports the parapet walk and the battlement had been altered during the Late Byzantine era. It was also affirmed that the inner and the outer terrace had been used as a burial ground and ceramic pipes for the water supply system of the moat and stone culverts for the disposal of the ground water of the inner terrace were found.     

Cultural Identity and the Archaeological Construction of Historical Narratives: An Example from Chaco Canyon

The Bonito Phase (ca. AD 850 to 1140) in Chaco Canyon, New Mexico, is widely assumed by archeologists to reflect the growth and decline of a coherent sociopolitical entity, one of the classic examples of emergent social complexity among ancient indigenous North American populations ending in a societal collapse. This understanding of Chaco is based, in part, on the interpretation of temporal changes in material culture as intentional efforts to maintain cultural identity and continuity in the face of social disruption. In this study, I suggest that the Bonito Phase actually encompassed at least one major episode of cultural discontinuity, calling into question the perception of a distinct “Chaco society.” Instead, patterns of material production in Chaco point to multiple cultural identities linked to serial reoccupation of the canyon.     

DETERMINING THE SEASON OF MISSISSIPPIAN HOUSE CONSTRUCTION FROM PLANT IMPRESSIONS IN DAUB

Abstract

It has been suggested that Mississippian farmsteads in some parts of the Southeast were abandoned in the late fall/early winter, with concomitant population concentration in large, palisaded villages. This assertion is contradicted by published data on plant impressions in daub which indicate farmstead house construction during the fall. Missing from this debate has been information on the season of house construction at mound centers. Plant impressions in daub from a structure at the Lyon’s Bluff site (22OK520) in Mississippi indicate that house construction took place during early to midspring. When coupled with other data, year-round construction at this mound and village complex is suggested. Although these results do not solve the question of the season of house construction at farmsteads, they do suggest that house construction at mound sites was not confined to any particular season of the year, as might be expected with seasonal influxes of farmstead inhabitants.