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.     

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.     

The cleaning of burned and contaminated archaeological maize prior to Sr/Sr analysis

Accurate trace-metal and strontium-isotope analyses of archaeological corn cobs require that metal contaminants be removed prior to chemical analysis. Archaeological cobs are often coated with construction debris, dust, or soil which contains mineral particles. In addition, most archaeological cobs are partially or completely burned and the burned parts incorporate mineral debris in their hardened residual structures. Unburned cobs are weak ion exchangers and most metals within a cob are not firmly bound to cob organic matter; therefore, immersing cobs in acids and rinsing them in deionized water to remove mineral contaminants may result in the undesirable loss of metals, including strontium, from the cob.     

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.     

Development and evaluation of geochemical methods for the sourcing of archaeological maize

Strontium (Sr)-isotope values on bone from deer mice pairs from 12 field sites in the Chaco Canyon area, New Mexico, were compared with isotope values of synthetic soil waters from the same fields. The data indicate that mice obtain Sr from near-surface sources and that soil samples collected at depths ranging from 25 to 95 cm contain Sr that is more accessible to the deep roots of maize; thus, synthetic soil solutions provide better data for the sourcing of archaeological maize. However, the Sr-isotope composition of mice may be more valuable in sourcing archaeological remains of animals such as rabbit, turkey, and deer.     

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.     

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.     

Oxygen isotopes in cellulose identify source water for archaeological maize in the American Southwest

Maize (Zea mays) was a primary food crop for aboriginal societies of the arid American Southwest. Water used for maize production in these arid zones could have come from precipitation and runoff during the summer monsoon, from perennial streams and springs, or from stored soil water fed by snowmelt. The oxygen stable isotope ratio (δ¹⁸O) of summer and winter precipitation on the Colorado Plateau naturally differ by more than 10‰ providing a powerful tool for distinguishing winter- from summer-derived water sources used in cultivation of maize. We investigated whether variation in δ¹⁸O of potential source waters is preserved in the δ¹⁸O of cellulose (δ¹⁸O_cellulose) of maize cobs by growing four aboriginal and one modern maize variety in pots irrigated with water of known δ¹⁸O composition. The δ¹⁸O_cellulose values of cobs ranged from 26.8 to 36.4‰ (averaged within varieties) and were highly correlated with δ¹⁸O values of the source irrigation water (−15.8 to −8.2‰). Cob δ¹⁸O_cellulose from five archaeological sites on the Colorado Plateau in southeastern Utah ranged from 27.3 to 34.6‰, closely matching the range of values observed in experimental plants. A δ¹⁸O_cellulose model developed originally for tree rings was parameterized and applied to the archaeological maize cobs. The model indicated that monsoonal precipitation accounted for 0–20% of the moisture for archaeological cob samples from a site adjacent to a perennial stream and 43–98% for samples from an upland site, more distant from a perennial water source. These results reveal the potential for using δ¹⁸O_cellulose to investigate prehistoric irrigation practices and source water used for maize production in the American Southwest.     

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.     

Strontium Isotopes in the Investigation of Early Glass Production: Byzantine and Early Islamic Glass from the Near East*

⁸⁷Sr/⁸⁶Sr ratios have been determined for glasses from four production sites, dated to between the sixth and the 11th centuries, in the Eastern Mediterranean region. On the basis of elemental analyses, the glasses at each location are believed to have been melted from different raw materials. Two glass groups, from Bet Eli‘ezer and Bet She‘an, in Israel, are believed to have been based upon mixtures of Levantine coastal sands and natron, and have ⁸⁷Sr/⁸⁶Sr ratios close to 0.7090, plus high elemental strontium, confirming a high concentration of modern marine shell (⁸⁷Sr/⁸⁶Sr ~ 0.7092) in the raw materials. The isotopic compositions of these two groups of glasses differ slightly, however, probably reflecting a varying ratio of limestone to shell because the sands that were utilized were from different coastal locations. Natron‐based glasses from a workshop at Tel el Ashmunein, Middle Egypt, have ⁸⁷Sr/⁸⁶Sr values of 0.70794–0.70798, and low elemental strontium, consistent with the use of limestone or limestone‐rich sand in the batch. High‐magnesia glasses based on plant ash, from Banias, Israel, have ⁸⁷Sr/⁸⁶Sr values of 0.70772–0.70780, probably reflecting the isotopic composition of the soils that were parental to the plants that were ashed to make the glass. Strontium and its isotopes offer an approach to identifying both the raw materials and the origins of ancient glasses, and are a potentially powerful tool in their interpretation.     

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.     

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.     

Earthen Architecture at the Bluff Great House Site in SE Utah

Abstract

An earthen terrace has been identified at Bluff Great House, a Chacoan site located in SE Utah. The Bluff site was part of the Chacoan regional system that operated in the northern part of the American Southwest between about A.D. 900 and 1150 and was focused on Chaco Canyon in NW New Mexico. Several types of earthen structures have been identified at great houses in Chaco Canyon and throughout its region, usually associated with the construction of ritual landscapes. The Bluff terrace is part of this tradition of earthen construction, but is unlike most other reported examples. It seems to express the same concern with creating an appropriate setting, however, and may be interpreted as part of the ritual landscape that surrounded and defined the Bluff great house, although other interpretations are considered. It dates not only to the Chaco era, but also to the first part of the post-Chaco era (A.D. 1150–1225).     

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.     

The Huldremose Iron Age textiles,Denmark: an attempt to define their provenance applying the strontium isotope system

Archaeological textiles recovered on two occasions from the Huldremose bog, Denmark, represent some of the best preserved and complete garments from the Danish Iron Age (500 BC–AD 800). In order to address the question regarding the provenance of the textile's raw material, we applied a recently developed method based on strontium isotopes to wool and plant fibres from these ancient garments. Textile plant fibres from Huldremose I find are of non-local provenance, whereas the wool from which the garment was made stemmed from sheep grazing on glaciomoraine soils developed on Cretaceous–Tertiary carbonate platform sediments widely found in Denmark. The Huldremose II find consists of an unusually large and well preserved garment, which is composed of wool from at least three different provenances. One source is again local, whereas the other two sources, characterized by elevated ⁸⁷Sr/⁸⁶Sr ratios, are compatible with geologically older (Precambrian) terrains which are typical for Northern Scandinavia, e.g. Norway or Sweden. Our study suggests that wool and plant fibres were either traded or brought as raw materials for textiles more commonly and over longer distances than previously assumed.     

Isotope sourcing of prehistoric willow and tule textiles recovered from western Great Basin rock shelters and caves – proof of concept

Isotope and trace-metal analyses were used to determine the origin of plants used to manufacture prehistoric textiles (basketry and matting) from archaeological sites in the western Great Basin. Research focused on strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (¹⁸O/¹⁶O) isotope ratios of willow (Salix sp.) and tule (Schoenoplectus sp.), the dominant raw materials in Great Basin textiles. The oxygen-isotope data indicated that the willow and tule used to produce the textiles were harvested from the banks of rivers or in marshes characterized by flowing water and not from lakes or sinks. The strontium-isotope data were useful in showing which plants came from the Humboldt River and which came from rivers headed in the Sierra Nevada.     

PATTERNS OF IRON AGE HORSE SUPPLY: AN ANALYSIS OF STRONTIUM ISOTOPE RATIOS IN TEETH*

This paper presents a pilot study of strontium (Sr) isotope ratios from Iron Age horse tooth enamel samples. It compares ⁸⁷Sr/⁸⁶Sr ratios from horse teeth to estimates for local ranges of biologically available strontium, to investigate whether horses were being bred at the sites where their remains were discovered. A horse from Middle Iron Age Rooksdown, Hampshire, was not bred at the site but, rather, came from as far away as Wales, Scotland or continental Europe. Horse teeth from Middle Iron Age Bury Hill, Hampshire, returned ⁸⁷Sr/⁸⁶Sr values typical of local chalkland.     

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.     

Baseline data for Andean paleomobility research: a radiogenic strontium isotope study of modern Peruvian agricultural soils

While the use of radiogenic strontium isotope values to examine paleomobility is increasingly common in the Andes, and beyond, many questions about baseline variability remain. To better understand baseline radiogenic strontium isotope compositions in the Andes, we present new ⁸⁷Sr/⁸⁶Sr values from Peruvian soil samples. Modern soil samples were collected from agricultural fields from the following areas in central and southern Peru: Arequipa, Atico, Camaná, Chala, Cusco, Ica, Ilo, Lima, Mejía, Moquegua, Nazca, Ocoña, Palpa, Pisco, Puno, Tacna, and Yauca. Samples were partially dissolved to better approximate the bioavailable strontium. Radiogenic strontium isotope values from the partially dissolved soil samples range from ⁸⁷Sr/⁸⁶Sr?=?0.70202 to 0.71894 and, for all soil samples, have a mean of ⁸⁷Sr/⁸⁶Sr?=?0.70773?±?0.00166 (1σ, n?=?114). In general, the ⁸⁷Sr/⁸⁶Sr values measured for soil samples collected from modern agricultural fields reflect the expected ⁸⁷Sr/⁸⁶Sr values based on bedrock geology. Comparing our new soil data with published radiogenic strontium isotope data for bedrock, soil, water, and faunal samples provides constraints on the regions in the Andes that can, and cannot, be distinguished through radiogenic strontium isotope analysis.     

Migration in the Nile Valley during the New Kingdom period: a preliminary strontium isotope study

The value of strontium isotope analysis in identifying immigrants at numerous archaeological sites and regional areas has been demonstrated by several researchers, usually by comparing ⁸⁷Sr/⁸⁶Sr values of human tooth enamel and/or bone with the local strontium isotope signature determined by faunal and environmental samples. This paper examines the feasibility of using ⁸⁷Sr/⁸⁶Sr ratios to investigate residential mobility in the Nile Valley region, specifically at the New Kingdom period (∼1050–1400 BC) archaeological site of Tombos (ancient Nubia). Archaeological and textual information regarding this period indicates that immigrant Egyptians and local native Nubians were likely interacting at this site during a period of Egyptian colonial occupation. The results of this study suggest that non-local individuals may be distinguished from locals using ⁸⁷Sr/⁸⁶Sr values and that colonial agents in the Tombos population were probably both local native Nubians and immigrants.