UNDERSTANDING CHACO CANYON

Pueblo Pintado was one of the first of the Chacoan great houses to be documented. Located at the eastern end of Chaco Canyon, it was built amidst a community of smaller sites around A.D. 1060.

Understanding

Chaco Canyon

A decades-long, remarkably comprehensive research project has resulted in changing perceptions of this fascinating site.

By Tamara Stewart

Chaco Canyon is an enigma. Archaeologists who have long studied Chaco are baffled by its many contradictions. Located in a desolate, arid canyon in the San Juan Basin, which covers about 26,000 square miles of desert in northwestern New Mexico, the area would seem to have little to offer, yet it witnessed monumental building for hundreds of years. The canyon is filled with nearly a dozen spectacular multi-storied masonry pueblos known as great houses and many smaller habitation sites, yet scant evidence has been found to support the idea of a large resident population. Portions of what was once thought to be a vast network of roads connecting communities within the San Juan Basin now appear to have little utilitarian value; it’s thought that their purpose may have been ceremonial. Little direct evidence exists for an elite or ruling group that coordinated the construction of these great houses and roadways and brought hundreds of communities within Chaco Canyon’s sphere of influence, yet these massive undertakings were clearly orchestrated in some fashion.

Following nearly a century of fieldwork, analysis, and interpretation, and an unprecedented three-year series of conferences, researchers are finding that many previous explanations of Chaco are not supported by the growing body of data.

The Chaco Project—Since the late 19th century, explorers and researchers have investigated Chaco, resulting in the recovery of thousands of artifacts from the canyon’s great houses. The most comprehensive research began in 1969 with the initiation of the Chaco Project, a large-scale collaborative effort undertaken by the National Park Service (NPS) and the University of

Archaeologists excavated this pithouse during the Chaco Project. The pithouse dates to approximately A.D. 750. A fire pit is in the center; to the left of the pit is a set of upright stone slabs that separated the main living area from smaller work or storage space.

New Mexico (UNM) to document and appraise all archaeological remains within Chaco Culture National Historical Park’s 43 square miles. Between 1970 and 1985, researchers excavated 25 archaeological sites and surveyed the entire park and key adjacent lands, documenting more than 3,300 sites and revealing an extensive system of outlying communities with Chaco-like characteristics, some of which appear to be linked to each other and to Chaco by ancient roadways.

This multidisciplinary project applied new technologies—climatic reconstructions based on tree rings, archaeomagnetic dating, aerial photography, remote sensing, paleoenvironmental studies, and geochemical analysis—to source materials and artifacts. The project refined Chaco’s chronology and dramatically changed the view of Chaco from that of a major isolated site to the center of a cultural system that incorporated a large network of communities. Efforts of the Chaco Center, a branch of the NPS located at UNM in Albuquerque, led to the passage of federal legislation to preserve 33 Chacoan outlier communities and to add more than 12,500 acres of land to the park. Based on the work of Chaco Center staff, Chaco Canyon was added to the World Heritage list in 1987.

The Synthesis Project—Following 15 years of data gathering and almost 20 more of analysis and interpretation, the Park Service, with the imminent publication of two volumes summarizing this work, is bringing the project to a close. “We still needed something to tie together and sum up all of the work that had gone on since the 1980s in a contemporary way, both for professionals and for the general public,” says Bob Powers, supervisory archaeologist for the Intermountain Support Office of the NPS. “Steve Lekson had been involved with the Chaco Project for about 10 years and, with his innovative and productive thinking, he was a natural choice to head up this effort.” Lekson’s recent book, The Chaco Meridian, describes his highly controversial theories regarding ruling elites and political history at Chaco and two later centers in the Southwest.

After several meetings between Powers, Chaco Culture park archaeologist Dabney Ford, and Lekson, now a curator for the Museum of Natural History at the University of Colorado, the idea of the Chaco Synthesis Project was born. Lekson proposed small working conferences focused on Chaco’s economy and ecology, the methods of production, architecture, social and political organization, and the Chaco regional system. The conferences, which began in 1999, matched “outsider” archaeologists—those studying cultures of a comparable level of complexity in regions outside of the Southwest—with Chaco experts. A final conference was held at UNM in 2002 to synthesize the results of the earlier discussions. The inclusion of outsider archaeologists was a key element of the project that most participants felt was very useful and stimulating. Lekson enlisted their services for two reasons: to offer their interpretations of Chaco and to make them, and other researchers they work with, more aware of Chaco. “I think bringing fresh eyes in helped a lot,” Lekson says of the outsiders’ contribution.

“We need to know whether Chaco was an isolated phenomenon, relatively rare in the rest of the world, or was it common elsewhere, and what we see is simply a

Southwestern manifestation of a common occurrence,” explains W. James Judge, who for many years directed the Chaco Project. “For example, take the debate over whether downtown Chaco was a chiefdom, some other kind of formal prehistoric social organization, or purely ritual? It helps immensely to hear [outsider] Tim Earle, who has worked with chiefdoms in Hawaii and in the Old World, say he thinks Chaco was a kind of chiefdom, and to hear Colin Renfrew and Norm Yoffee, both of whom have vast experience in Europe and the Middle East, emphasize their feelings of Chaco as a ritual entity. This enables us to compare and contrast Chaco with archaeological manifestations elsewhere.”

Explaining Chaco—As researchers began to identify Chacoan communities located outside of the canyon that were characterized by a combination of features including a great house, great kiva, and often what appeared to be a road, they realized that Chaco was part of something much larger and more complex that they began to refer to as the “Chaco Phenomenon,” a term coined by the late Southwestern archaeologist Cynthia Irwin-Williams.

Great houses, the monumental buildings that are the quintessential feature of Chacoan communities, are bigger and more massive than nearby contemporaneous habitation sites. Most are multi-storied, display distinctive masonry styles, and show a higher degree of planning in scale, layout, and design than other sites. Great kivas, which in the Chaco region are circular, subterranean, or partly subterranean structures that are at least 30 feet in diameter, with some exceeding 60 feet, are usually located nearby. Based on the presence of some 150 communities, a number of which are interconnected by a system of straight, 24- to 36-foot-wide roads built with raised beds, berms, bridges, stairways, ramps, and other features, researchers began proposing various theories to explain the origin, existence, and persistence of the “Chaco Regional System.”

Archaeologists of the 1970s and ’80s largely considered prehistoric cultures to be the product of adaptation to their environment—a framework known as cultural ecology. In accordance with this view, a popular explanation for Chaco in the early 1980s was the redistribution theory put forth by Judge. According to this model, the lack of rain limited the agricultural production of the San Juan Basin, which necessitated the import of surplus foods such as corn from those outlying communities. These goods, which were

The northeast corner of Aztec West at Aztec Ruins National Monument in Aztec, New Mexico. Built in the early A.D. 1100s, Aztec West is part of a larger great house community located on a terrace of the Animas River. This structure is among the largest of the great houses. The Aztec community is thought to have been a center for the Chacoan system around A.D. 1100 to 1140. Some researchers think it was the successor to Chaco Canyon.

This map shows Central Chaco Canyon, the numerous outliers, and the road segments. Some of the road segments connected Chaco Canyon to outliers, while many others did not. It's now thought that the road segments were ceremonial in purpose.

brought into Chaco in pottery vessels, were stored within the canyon great houses, from where they were redistributed to participating communities according to their needs. The roads were thought to integrate these outlying communities into the larger system, which was considered reciprocal and voluntary, with an “administrative entity” coordinating the storage and redistribution of goods.

But an excavation within the canyon at Pueblo Alto revealed far more pottery sherds than archaeologists expected to find. The large number of sherds suggested that the pottery vessels, as well as the goods that they contained, were not redistributed to the outlying communities. Consequently, the redistribution theory was revised to one of ritual consumption of goods within the canyon, indicating that Chaco’s leaders wielded spiritual rather than economic power.

This macaw skeleton was found at Salmon Ruin, a great house constructed around A.D. 1090 and located along the San Juan River to the north of Chaco Canyon. Colorful macaws provided brilliant feathers that could be used for several purposes, especially ceremonies. They were imported from Mexico and found in the northern Southwest after A.D. 1050. This black-on-white olla was purposely placed in a pit in the floor of a late A.D. 700s-to-early800s pithouse at a small site in Chaco Canyon. The olla, which was discovered during the Chaco Project, had been plastered into place using manos and ground stone as support. It was probably used to store grain.

In the mid-1980s Judge suggested that periodic festivals or ceremonies held at Chaco Canyon could have served to regulate the exchange of goods and link the outlying communities with those in the canyon through shared religious beliefs and practices. The canyon great houses may have served to accommodate this periodic influx of people. Known as the Pilgrimage Fair model, this now popular model for Chaco posits that people living in the outlying communities periodically pilgrimaged to Chaco Canyon to receive ritual knowledge and participate in ceremonies that included fairs. In exchange, they brought goods such as corn and other foods, ceramics, raw stone, and in some cases turquoise and other exotic items, and provided labor for the construction and upkeep of the great houses and roadways. Whether participation in the network was voluntary or forced and the extent of Chaco Canyon’s influence over the participants are among the hottest topics in Chaco research today.

Gwinn Vivian, a veteran Chaco researcher with the Arizona State Museum, points out that “essentially, there are questions as to the degree of influence from Chaco Canyon—local emulation of a Chacoan style versus direct involvement of canyon leaders in the establishment of some of the outliers.”

The various models of leadership currently in debate propose that Chaco society was either egalitarian with voluntary involvement, resembling today’s pueblos, hierarchical to varying degrees, or a powerful state with centralized authority. Differences in physical stature exhibited by a few burials found at Pueblo Bonito, the canyon’s largest great house, reveal that some of these individuals were better nourished than those buried in small house sites in the canyon. To many researchers, this suggests differential access to resources and some form of status and hierarchy, but of what kind? And was leadership or elite status achieved within a person’s lifetime through successful competition with others, or was it ascribed politically or ritually (i.e., at birth)? The obvious amount of labor involved in obtaining materials and building and maintaining the great houses and roadways indicates to some researchers that a centralized authority existed to coordinate and control all of these efforts.

“The key issue to Chaco, as I understand it, is whether the great houses were run by chiefs who got their power through the accumulation of wealth, or whether they were primarily ceremonial, run by priests with ritual authority,” says Judge.

A minority of researchers see Chaco as more complex politically than modern pueblos. Lekson believes that Chaco was the center or capital of regional polity, a weakly centralized hierarchy that mimicked chiefdoms and kingdoms that were common throughout much of 11th-century North America. According to Lekson, Chaco might have been comparable to the smallest chiefdoms of the contemporary Mississippian peoples of the eastern U.S., but far less complex than contemporary Mexican kingdoms and states to the south.

In contrast to the Pilgrimage Fair model, Lynne

The two pinnacles of Chimney Rock Pueblo probably functioned as astronomical markers for a local shrine until around A.D. 1076 when a Chacoan great house was constructed on the mesa. From the great house it is possible to observe lunar anomalies near the evening of the full moon at winter solstice, a time that marks important Puebloan ceremonial events.

Sebastian of SRI Foundation in New Mexico proposes that social and political complexity in Chaco was a result of differences in people’s ability to produce and control agricultural surpluses. She suggests that clans or other groups farming the most productive lands were able to develop relationships of obligation with their less fortunate neighbors by sponsoring feasts or assisting them in times of need. Those neighbors then repaid the obligation by supplying labor to build great houses. Ultimately, great house construction is seen by Sebastian as a competitive display of power and wealth designed to attract people to join a particular group. She further argues that leadership roles became institutionalized through time, and the basis of social power shifted from the control of labor to the control of religious knowledge, such as that related to rainmaking.

Understanding Chaco Society—Many archaeologists stress the need for a better understanding of the nature of relationships within the Chaco system—a subject of considerable debate among experts—in order to explain its society and political structure. What led to the construction of massive monuments in Chaco and the surrounding region between the 10th and 12th centuries? And what followed? Vivian, Joan Mathien of NPS, and others have proposed that the differences seen within the Chaco system, such as the great house/small house dichotomy, may reflect a variety of ethnic groups, and that these groups can be traced to the outlying communities and later to the historic and modern pueblos of the Rio Grande Valley and those to the west.

Numerous Chacoan outliers were investigated in the 1990s, with excavations still being conducted at sites in Utah, Colorado, and New Mexico. So far, this work is showing great variability in relationships between the canyon and outlying communities, suggesting the outliers’ relative independence from the canyon and thus arguing against control by a centralized authority.

Research on the network of Chaco roads is also changing ideas about relationships within the Chaco system. Rather than serving primarily to connect communities, the roads are now thought to be pilgrimage paths to great houses and sacred geographic places on the landscape as well as symbolic paths marking the cardinal directions, of great importance to native peoples of historic and modern times.

For most researchers contemplating these issues, the function of the roads, of the great houses, of Chaco itself, is no longer seen as a primarily utilitarian adaptation to the en-

vironment. Much more complex propositions involving spiritual matters, which are harder to see in the archaeological record, are now being used to define Chaco. This is less the result of new research than of the different questions that are being asked and the evolution of archaeological thought since the early days of Chaco research. “Instead of arguments about how complex Chaco was, there is a much richer set of questions ranging from the sources of political leadership to the structure of economic relationships,” says Barbara Mills of the University of Arizona.

It is difficult to address the complexity of Chacoan organization when certain key elements of the equation, such as how many people lived in the canyon and surrounding areas, are still unanswered. As Linda Cordell with the University of Colorado in Boulder says, “It’s hard to get a kingdom if you’ve got only a few hundred citizens.” Early estimates for canyon population were high based on the immense size of the great houses and their assumed large resident population. The few professional excavations of canyon great houses have shown, however, that the first-floor rooms tend to have few domestic features. Little is known about the upper floors of the great houses, adding to the confusion.

Current estimates for peak population within the canyon range from around 2,000 to 6,000 (for those who believe the great houses were residential) compared with an estimate of 55,000 people living in the San Juan Basin region. Population estimates are based on the number of various features considered to be residential, such as hearths, and the number of rooms identified within communities. According to Mills, the strong contrast between population levels within the canyon and the surrounding area lends support to the Pilgrimage Fair model, in which Chaco Canyon was a ceremonial center that, in between periodic rituals, was largely empty.

Environmental studies are also critical to understand-

ing the economic aspects of canyon and outlier relationships and the canyon’s agricultural potential. New research conducted within the canyon is revealing agricultural features that may provide insight into why Chaco arose to such a position of eminence in such an unlikely place. Eric Force (University of Arizona Geosciences Department), Gwinn Vivian, Thomas Windes (NPS), and Jeffrey Dean (University of Arizona Lab of Tree Ring Research) recently conducted a study showing that Chacoans built a masonry dam in the Chaco Wash sometime around A.D. 1025. This replaced a breached natural sand dune dam that had created a “lake” within the canyon that likely increased agricultural productivity. Windes has undertaken extensive dendrochronological sampling of architectural wood at numerous great houses and a few small houses to determine when they were built, information that will inform the chronology of occupation within the canyon. “Chaco is, in many ways, the prime fact of pueblo history or, at least, pueblo archaeology,” says Lekson. “Other archaeologists working in other areas protest, with justice, that Chaco gets way too much ink and attention, and it does, but no archaeologist would argue that the history of the ancient Southwest could be written without Chaco This aerial view shows Pueblo Alto (foreground) and prehistoric road segments that front and center.” lead to the north. An excavation at Pueblo Alto led a number of archaeologists to He notes that Chaco conclude that Chaco’s leaders possessed spiritual rather than economic power. experts, examining the same data, can arrive at dramatically different conclusions. The lengthy NPS project, with its massive amount of data and fresh perspectives, did not result in a consensus as to what Chaco was. Nor will the project’s end conclude the research of or the lively debate about this mysterious place. Chaco will indeed remain in the consciousness of many researchers front and center. TAMARA STEWART is the assistant editor of American Archaeology and the Conservancy’s Southwest projects coordinator. For more information about the Chaco Synthesis Project, visit www.srifoundation.org