Archive for the ‘Una Vida’ Category

Visitor Center and Fajada Butte from Una Vida

Visitor Center and Fajada Butte from Una Vida

Chapter five of Crucible of Pueblos brings us to Chaco Canyon and the surrounding area. This is an area of particular interest for me, and I presume for most readers of this blog as well. While the rise of Chaco in the tenth and early eleventh centuries AD was clearly a development rooted in earlier events, there has long been less information available for the area of Chaco itself than for the areas to the north that have seen extensive relatively recent excavations of sites dating to the Pueblo I period. The Pueblo I occupations of those areas, the subjects of the earlier chapters in this book, are now fairly well understood, although there of course remain a lot of questions and gaps to fill. Further south the picture is still much murkier.

This chapter is written by prominent Chaco specialists Tom Windes and Ruth Van Dyke, and is particularly important and useful because it includes the first published synthesis of the work Windes has been doing for many years to identify sites in and around Chaco dating to the Pueblo I period. This work was written up as part of the series of reports on the work of the Chaco Project, but that report, dated 2006, remains unpublished. I presume that this is a deliberate decision on the part of the National Park Service to keep sensitive information on site locations from becoming public (although I don’t actually know for sure). This chapter, then, appears to serve as the published record of this important work, which significantly alters the conventional interpretation of Pueblo I in Chaco.

The authors define their geographic scope as what they call the “Chaco Basin,” which is essentially equivalent to what is commonly know in the Chaco literature as the “San Juan Basin.” I think this is a useful change to the terminology, since “San Juan Basin” in the hydrographic sense refers to a much larger area than it is used for in this context, and while some use terms like “San Juan Physiographic Basin” to clarify this, it’s more straightforward to redefine the area and use a new term. “Chaco Basin” is a good term to use because the area more or less corresponds to the drainage basin of the Chaco River, including its tributaries, although it extends a bit beyond to the east and south into the Puerco Valley and Red Mesa Valley respectively. However it’s labeled, this region is roughly bounded by the San Juan River to the north, the Chuska Mountains to the west, the Zuni Mountains to the south, and the Jemez Mountains to the east.

Temporally, the authors restrict their attention in this chapter to the period from AD 700 to 925, unlike some other authors in this volume who also address the preceding Basketmaker III period. This is understandable but in some ways unfortunate, since there was an important Basketmaker III occupation of Chaco Canyon that was likely important in setting the context for Pueblo I developments, just as those developments were important in setting the context for Pueblo II. Confusingly, they use the term “Pueblo I” for sites dating from AD 700 to 875 and “late Pueblo I” for sites dating from AD 875 to 925. As we’ll see below, the distinction between these two periods is important in this region, as population and settlement patterns changed significantly at around AD 875. The specific terms they use still seem odd and liable to cause confusion, however.

Part of the reason the authors argue that the Pueblo I occupation in this region is poorly understood is that the ceramic chronology is different from that of the better-known sites to the north, and using the same types to identify time periods for sites in both regions leads to problems. They carefully define the types they use to identify sites to time period, and also use architectural criteria (which are however difficult to apply to unexcavated sites).

Most of this chapter is a summary of what is known about Pueblo I settlement in each subregion of the Chaco Basin, based in large part on hitherto unpublished fieldwork. As a result, I will structure this post according to the same subregions in the same order and summarize the information on each.

Northern and Northeastern Areas

The heading for this section says “Northwestern” rather than “Northeastern,” but it’s clear from the text that this in error. These areas, north and northeast of the Chaco River but still within the drainage of the San Juan, were sparsely populated throughout the Pueblo period. Windes and Van Dyke note that the Largo and Gobernador canyons, to the northeast of Chaco, may have served as conduits for populations migrating south from the Mesa Verde region into the Chaco Basin in late Pueblo I. A recently discovered village at the confluence of Largo and Blanco Washes included a great kiva and at least 22 habitation sites, with tree-ring dates from the great kiva pointing to construction at about AD 828. This area is roughly due south of the Cedar Hill and Ridges Basin areas of the Animas Valley, considered part of the Eastern Mesa Verde region in this volume, which had extensive but short-lived populations early in Pueblo I. The tree-ring dates from the Largo-Blanco village suggest that it may have been associated with the initial migration out of the Ridges Basin/Durango area in the early 800s rather than the larger migration in the late 800s. The Chaco River may have been another conduit for migrants from the north, as Windes and Van Dyke note that surveys have found a major increase in sites dating to the late 800s along the east side of the Chaco, compared to a virtual absense of sites for earlier in Pueblo I. This will be a recurring pattern in the region.

Chaco Canyon Proper and Environs

The initial survey work of the Chaco Project in the 1970s identified a fairly extensive Pueblo I occupation in and around the canyon, and publications from that time posited a gradual increase in population over the course of Pueblo I leading up to the florescence of Chaco as a regional center in Pueblo II. Based on his more recent work with ceramic classification and dating, however, Windes disputes this account. He argues that the number of sites assigned to Pueblo I in those surveys is vastly inflated, and that for most of the Pueblo I period the Chaco area had a small population which increased dramatically, presumably due largely to immigration, in the late Pueblo I period. In this chapter Windes and Van Dyke (though clearly this part is mostly Windes) summarize the results of Windes’s reevaluations of the Pueblo I occupation in and around the canyon, moving from east to west.

Pueblo Pintado Great House at Sunset

Pueblo Pintado Great House at Sunset

At the east end of Chaco Canyon, the Pueblo Pintado area was apparently unoccupied until about AD 875, when it was colonized by two groups who had markedly different material culture and appear to have come to the canyon from different directions. They formed separate site clusters about 3 km apart, north and west of the later great house of Pueblo Pintado.

The first cluster, located just north of the great house, includes one exceptionally large roomblock more than 50 meters long, accompanied by a trash midden that is also unusually large. Based on the temper of early ceramics in this cluster, the people appear to have come from the Mesa Verde region to the north, presumably as part of the mass exodus following the collapse of the Dolores villages in the late ninth century.

The second cluster, 3 km west of the first one, appears to have also been founded around AD 875 but continued in use well into the Pueblo II period. The ceramics are quite unusual in manufacture for the Chaco area and indicate origins to the south in the Mt. Taylor area. Interestingly, the roomblocks in this cluster were aligned along the road connecting the Pueblo Pintado community to the core area of Chaco Canyon, implying that this road may date to the late Pueblo I period.

Moving west, the next major cluster of Pueblo I sites is what is known as the Chaco East community, which also featured a later great house. This area also appears to have been unoccupied until about AD 875, when it was colonized by a group occupying small residential sites, possibly only seasonally. In the 900s the community grew considerably, and initial construction of the great house may date to this period, although it’s impossible to tell for sure without excavation.

Third-Story Walls with Type I Masonry at Una Vida

Third-Story Walls with Type I Masonry at Una Vida

Fajada Gap, at the eastern end of the main concentration of sites in Chaco during Pueblo II, is one of the areas where early surveys indicated a dense Pueblo I occupation which Windes disputes based on current understandings of the ceramic chronology. In fact, while there was unquestionably a small occupation of the area throughout Pueblo I involving scattered hamlets, this appears to be yet another part of the canyon where there was an influx of people in the late 800s who established the basis for the community that developed subsequently. There are two great houses in this community, Una Vida and Kin Nahasbas, both of which were constructed beginning in the late ninth century.

The largest Pueblo I (pre-875) settlement in the Chaco area is actually outside the canyon, along the South Fork of the Fajada Wash. This community contained 26 sites in an arc along the west side of the South Fork; no contemporary sites are present on the east side. The community is loosely clustered around a complex of four roomblocks which were connected by a short road to a great kiva, and it likely included about 230 people overall. Its main occupation was around AD 800, making it contemporary with the earlier villages in the Mesa Verde region, but the layout of the community is more like later villages such as those at Cedar Hill and in the Largo drainage. (The description of the community in this chapter is very confusing and it’s hard to tell in what respects it’s being described as similar to or different from villages in other regions.)

Many of the potsherds from the South Fork community were tempered with chalcedonic sandstone, which is typical of sites to the south near the modern community of Thoreau. There is also an unusually high abundance of yellow-spotted chert among the chipped stone assemblage, again indicating connections to the south. This type of chert occurs in the Zuni Mountains near Thoreau and is common in sites in that area.

Although this was the largest Pueblo I community in the Chaco area, it appears to have been very short-lived, with little trash accumulation. This suggests that the Pueblo I period was a dynamic time of extensive population movements in this area just as it was in the better-understood areas to the north. The subsequent Pueblo II occupation of the South Fork was much more extensive than the Pueblo I occupation and quite different, with sites dispersed up and down the valley rather than clustered in one area. A similar though somewhat smaller cluster of sites dating to the Pueblo I period was also present in the upper reaches of Kin Klizhin Wash to the west of Fajada Wash.

Old Bonito

Old Bonito

Returning to the main canyon, there were a few scattered Pueblo I hamlets between Fajada Gap and South Gap, but the occupation doesn’t seem to have been extensive. Even in South Gap itself, an area of considerable density during Pueblo II and the location of the cluster of great houses known as “Downtown Chaco,” Pueblo I occupation was sparse, with a few scattered sites in the gap. Apparently the only Pueblo I site known in this part of the canyon proper is Pueblo Bonito, where the earliest construction of the great house, known as “Old Bonito,” dates to the mid-800s (or possibly even earlier) and there is also an earlier pit structure excavated by Neil Judd in the 1920s. Judd thought the pit structure reflected an earlier occupation unrelated to the great house, but with improved dating showing that the great house was begun earlier than had been thought the idea of continuity is beginning to seem more likely.

There is no evidence for Pueblo I occupation between South Gap and the mouth of the canyon, possibly on account of flooding creating an intermittent lake on the canyon floor. At the mouth of the canyon itself, the Peñasco Blanco great house, begun in the late 800s, sits atop West Mesa, and right next to it is the important Basketmaker III village of 29SJ423. The period between these two important occupations, however, appears to have involved only minor settlement, although there are a few scattered Pueblo I sites. Just west of the mouth of the canyon, however, is Padilla Wash, which had a substantial Pueblo I occupation (possibly even more extensive than current records indicate, since many Pueblo I sites may have been misclassified as Basketmaker III in earlier surveys), another example of the main centers of Pueblo I population in the Chaco core being outside the canyon proper. Windes and Van Dyke note that Peñasco Blanco may have been an important focal point for migration into the canyon from the west and north during late Pueblo I, and that it was likely more important than Pueblo Bonito at this time.

The Chaco River

As noted above, the Chaco River (formed by the confluence of the Chaco and Escavada Washes at the mouth of Chaco Canyon) was likely one of the main conduits for migrants from the north, but it was much more than that. Pueblo I communities existed all along the Chaco and its tributaries, and some of these communities included early great houses that would have been influential in the development of the great house phenomenon that found its greatest expression in Chaco Canyon in the eleventh century. Windes and Van Dyke discuss a number of these communities, based on field research by Windes to reevaluate areas identified by early surveys as Chacoan outlier communities and to look for evidence of Pueblo I settlement and early great houses.

Just west of Padilla Wash is Kin Klizhin Wash, which was the site of extensive Pueblo II occupation but only has a few Pueblo I sites aside from the cluster at its upper reaches mentioned above. There is a late Pueblo I great kiva known as Casa Patricio in the upper part of the drainage, accompanied by a number of late Pueblo I residential sites; it’s not clear from the writeup here what relationship this site cluster has to the earlier Pueblo I cluster.

Just downstream from the mouth of Kin Klizhin Wash is the very important early site known as Casa del Rio. While this was initially labeled a large Chacoan great house, reexamination indicated that it is actually a composite of two building stages, both relatively early, with much of the bulk of the structure provided by a Pueblo I roomblock measuring 112 meters in length, with a later masonry great house built over the central portion beginning in the late ninth century. The early roomblock is by far the largest in the Chaco Canyon region, more than twice the length of the earliest construction stage at Pueblo Bonito, and it is estimated to have housed about 16 households or 88 residents. Windes and Van Dyke describe it as “reminiscent of those north of the San Juan River,” although again it is not clear what specific characteristics this refers to. A large number of food preparation tools were found in the area, although other residential sites are scarce. This was clearly an important site during the Pueblo I period which may have played a key role in attracting migrants to the area.

Looking North from Kin Bineola

Looking North from Kin Bineola

One of the most important tributary drainages of the Chaco River is Kim-me-ni-oli Wash, which extends from the Dutton Plateau north past the current site of Crownpoint. The drainage of this wash includes several great houses and extensive Pueblo settlement, and it likely served as an important conduit between Chaco Canyon and areas to the south and southwest. The extent of Pueblo I occupation, however, seems to be unclear. Windes and Van Dyke mention large circular structures near the Bee Burrow great house that resemble Pueblo I great kivas, as well as small Pueblo I roomblocks in the same general area. The area around the Kin Ya’a great house at the upper end of the drainage appears to not have any Pueblo I occupation based on existing survey data, although there is a large Basketmaker III-Pueblo I site just west of Crownpoint and one arc-shaped roomblock near Kin Ya’a recorded as dating to Basketmaker III looks a lot more like a Pueblo I site. At Kin Bineola, site of a major great house dating to the early 900s or possibly slightlier earlier, there is a very small Pueblo I occupation that increased substantially after AD 875 as in many other parts of the region.

At the mouth of the Kim-me-ni-oli Wash near the current Lake Valley Mission there is a small cluster of Pueblo I sites “architecturally identical” to the South Fork cluster, with very sparse refuse indicating a very short occupation. A later occupation in the late 800s was more substantial, with three masonry roomblocks “sometimes portrayed as small great houses” and “enormous amounts of refuse” that Windes and Van Dyke describe as “excessive for normal domestic activities.”

Further down the Chaco drainage, the Willow Canyon area is unusual in showing evidence of both middle and late Pueblo I occupation in close proximity. The middle Pueblo I community consists of eight sites that show the typical “scattered hamlet” settlement pattern, while the eleven late Pueblo I sites are tightly clustered and associated with a large amount of refuse, leading the authors to interpret this as “a large group” that immigrated into the valley together. These sites show unusual amounts of Type I masonry, associated with later great house construction, although the authors declare that there is no “obvious” great house. It’s not clear what definition of “great house” they are using here, as one site in particular (known as the “House of the Weaver”) shows not only Type I masonry but a prominent mesa-top location with a broad view of the surrounding area, another common characteristic of later great houses. Another community south of Willow Canyon near the later Whirlwind great house also shows a similar pattern but has less information available. The Great Bend area, where the Chaco River turns from flowing west to flowing north toward the San Juan, also shows this pattern. The possible use of the river as a corridor for populations migrating from the north after the collapse of the Dolores villages makes this potentially an important area for understanding regional prehistory.

Chuska Mountains from Peñasco Blanco

Chuska Mountains and Chaco River from Peñasco Blanco

The eastern flanks of the Chuska Mountains, which parallel the north-flowing segment of the Chaco River and form the western side of its drainage basin, are also important for understanding Pueblo I settlement but are poorly known. The general pattern seems to be the same as elsewhere in the Chaco Basin, with a scattered occupation in early and middle Pueblo I that sees a huge increase, presumably from immigration, in late Pueblo I after AD 875, but due to depositional factors it’s likely that the earlier Pueblo I occupation has been underestimated. A few sites dating to this period have been excavated through salvage projects. Late Pueblo I sites are more common and seem to provide more evidence for the use of the river as a corridor from the north. The largest concentrations are in the Skunk Springs and Newcomb areas, both of which would become major Chacoan outlier communities in Pueblo II. At Newcomb, at least, there seems to be some evidence of a preexisting Pueblo I occupation. It’s not clear if there is any similar evidence at Skunk Springs, where the earliest stage of construction on the great house seems to date to late Pueblo I. Given the importance of Chuskan imports to Chaco at its peak, more research on the background of these communities would be helpful in understanding Chaco’s origins.

The Red Mesa Valley

The Red Mesa Valley is the area between the Dutton Plateau on the north and the Zuni Mountains on the south. It is topographically rather than hydrologically defined, and straddles the Continental Divide, with the western part drained by the Rio Puerco of the West and the eastern part drained by the Rio San Jose. This means it falls outside of the “Chaco Basin” as hydrologically defined, of course, but its culture history means that it makes sense to include it with areas to the north for purposes of this chapter. This valley was presumably an important travel corridor prehistorically, as it certainly was historically with the railroad and Route 66 running through it and remains today with Interstate 40.

Casamero Pueblo

Casamero Pueblo

This area has been the main focus of Van Dyke’s research, and it is clear that she rather than Windes is responsible for most of this section of the chapter. The same issues of ceramic identification as in the Chaco Basin make understanding the Pueblo I sequence here difficult, but the same basic pattern appears to apply as further north. Early in Pueblo I there was a small, scattered occupation, exemplified by a site on the mesa above the later Chacoan outlier community of Casamero. This site consists of at least two arcs of surface rooms fronted by five to seven pit structures, and resembles White Mound Village further west along the Puerco, which was excavated by Harold Gladwin in the 1940s and dates to the late 700s and early 800s. Another site like this from the same period was excavated near Manuelito during the construction of I-40 in 1961.

This sparse population expanded immensely in late Pueblo, when many of the later Chacoan great house communities were founded. Some of the earliest great house construction in the region took place in these communities, which Van Dyke has elsewhere used to argue that great houses were not initially associated particularly with Chaco Canyon specifically. The huge increase in population at this time seems to indicate immigration, but this chapter doesn’t address the issue of where the people in this area might have come from. Given the similarities to the communities to the north in the Chaco Basin, that seems like an obvious point of origin (with earlier origins probably further north in the Mesa Verde region), but developments to the south are poorly understood and can’t be ruled out as important factors. As noted above, some of the immigrants to Chaco Canyon and its surrounding area appear to have come from the south rather than the north, and southern origins would presumably be even more likely for the Red Mesa Valley populations given their location. The fact that the influx here appears to happen at the same time as the northern one is an interesting complication, however.

The Eastern Chaco Basin

This area, stretching from the area south of Chaco Canyon across the Continental Divide to the Rio Puerco Valley of the East, shows very little evidence for Pueblo I occupation. Today this is a very sparsely populated area used mainly for cattle ranching, primarily on private land, so there has been little archaeological survey, but what survey has been done shows very little prehistoric occupation at all. Only two exceptions are noted by Windes and Van Dyke. One is a recently discovered Pueblo I community southeast of Mt. Taylor, about which little is known. Detailed information from the survey that identified this community is apparently not going to be released. It’s not clear from the brief writeup if this has anything to do with the fact that the survey was for proposed uranium mining.

The other exception is the Puerco Valley of the East, around the later Chacoan outlier of Guadalupe. Here, survey by Eastern New Mexico University in the 1970s identified a “modest but scattered” Pueblo I occupation, which increased substantially in late Pueblo I and Pueblo II, culminating in the Guadalupe community with its apparently close connections to Chaco Canyon. Windes and Van Dyke note that the Puerco may have served as an important conduit connecting the Chaco Basin to areas further east, although it remains poorly understood. The eastern associations of Chaco are poorly understood in general, and this appears to be the case as much for Pueblo I as for Pueblo II.

Storm in the Distance through Fajada Gap

Storm in the Distance through Fajada Gap

After going through the detailed geographical summaries, the authors briefly address some region-wide issues important for understanding the patterns they describe. They acknowledge environmental factors as probably important in understanding population shifts, pointing in particular to an apparent “spike” in rainfall in the immediate area of Chaco Canyon between AD 885 and 905 that might have served as a “pull” factor bringing people in from other areas. Conditions in the Chuskas and Red Mesa Valley appear to have been generally unfavorable during this period in which they, too, saw significant immigration, so clearly rainfall totals weren’t the only factor.

They also discuss violence, noting that there is very little evidence for it in this region, particularly in the central Chaco Basin, during Pueblo I, especially compared to areas further north where burned structures are common. There are more burned structures in the Chuskas and near Mount Taylor, on the edges of this region, however, and it is possible that the lack of them in the central basin relates more to the lack of construction wood than to any lack of violence. The authors suggest that, given the known evidence for strife and community abandonment in the Mesa Verde region, one attraction of the Chaco Basin might have been its relative emptiness, which may have drawn people into this much harsher and less fertile region. There’s a general tendency for settlement to cluster around drainages and particularly at  confluences of drainages, likely because these locations offered the best agricultural potential in a very dry area even by Southwestern standards. Regardless of what it was that initially drew people into this area, it’s becoming increasingly clear that this influx of population was a key factor in the later rise of Chaco.

Peñasco Blanco Framing Huerfano Mesa

Peñasco Blanco Framing Huerfano Mesa

The authors also discuss visibility and sacred geography, which has been a key concern of Van Dyke’s in her previous work. Many of the prominent community buildings in late Pueblo I sites in this region, whether or not they can be considered “great houses,” are situated in locations where important regional landmarks can easily be seen. This indicates that the concern with visibility associated with later Chacoan great houses likely had its roots in this period.

Finally, the authors summarize community settlement patterns in the region. One interesting pattern they note is that in late Pueblo I communities great houses and great kivas don’t tend to occur together, with great houses being more common in the Chaco Basin and great kivas in the Red Mesa Valley. This suggests that two different community integration systems may have been in place in the region during this time. The great house pattern at more northerly sites is interesting in the context of the “proto-great-houses” apparently present at some Dolores area communities further north, especially McPhee Village, and it’s quite likely that there is a direct connection between the two. Great kivas are also common further south, and while they were present at some Mesa Verde Pueblo I sites they weren’t very common. This suggests that at least some of the Red Mesa Valley late Pueblo I communities were in fact settled by immigrants from the south rather than from the Chaco Basin. Some of the earliest communities showing both features were in Chaco Canyon, and it may well be that one factor in the rise of Chaco was the ability of emerging elites there to combine the two traditions into a new social and ideological system, one that would spread far and wide, remaking the course of Southwestern prehistory.

Great Kivas A and Q, Pueblo Bonito

Great Kivas A and Q, Pueblo Bonito

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Room 6, Pueblo Bonito

The “Chacoan era” is a period of about 100 years in the eleventh and early twelfth centuries AD during which Chaco Canyon was at the center of some sort of system that covered a large portion of the northern Southwest.  The exact nature and exact extent of that system are endlessly debated, but the period during which it existed is fairly well-established.  The exact dates given for the duration of the system vary among different researchers, and I’ve given various versions of them myself.  Probably the most common ending date is AD 1130, which coincides both with the approximate end of apparent construction in the canyon and the onset of a 50-year drought that is generally thought to have had something to do with the decline of Chaco.  To make it an even century, 1030 is a useful starting date for the Chacoan era, although it doesn’t actually correspond to anything special in the canyon as far as we can tell.  A better starting date might be 1040, which is approximately when the expansion of Pueblo Bonito began, or 1020, which is about when construction began at Pueblo Alto.  Using these starting dates with the hundred-year span gives ending dates of 1140 or 1120, which again are roughly equivalent to the end of major construction in the canyon.  (It’s a lot easier to date the beginnings of phenomena in the ancient Southwest than the ends of them, due largely to the reliance on tree-ring dates.)

Whenever we say the Chacoan era began, it was long after the first great houses in Chaco Canyon were built.  Indeed, the canyon had a long and probably very eventful history well before things really got going in the early 1000s.  During the 900s it may not yet have been important on as large a scale as it became later but it was definitely already a place where things were happening.  The origins of Chaco lie even earlier, however.

Type I and Type II Masonry Abutting at Peñasco Blanco

The first three great houses built in the canyon were Pueblo Bonito, Una Vida, and Peñasco Blanco.  Una Vida is mostly unexcavated and Peñasco Blanco is completely so, so the dating of them relies mainly on tree-ring sampling of exposed wood.  This has shown that these two sites probably date originally to the late 800s, with extensive expansion in the 900s.  The earliest cutting date at Una Vida is from AD 861, while Peñasco Blanco has a cluster of cutting dates at AD 898.  Both have clusters of dates in the 900s that suggest that much of the early construction dates to this period, and both also show expansion later, during the Chacoan era itself.  Beyond that, though, not much can be said about the chronology of these sites.

Pueblo Bonito is a different story.  It’s almost completely excavated, and while the excavation took place a long time ago, it left a lot more exposed wood than at most other sites.  The recent Chaco Wood Project, which sought to sample every piece of exposed wood in the canyon to develop as full a chronology as possible, had its most spectacular results at Bonito.  These were reported in part in an article in 1996 by Tom Windes and Dabney Ford, and the implications of the new dates for the architectural history of the site were more fully explained by Windes in a subsequent book chapter published in 2003.

Beams Sampled for Tree-Ring Dating in Room 227, Pueblo Bonito

To get a sense of the scale of this project, before it began in 1985 there were 163 pieces of wood from Pueblo Bonito that had been tree-ring dated.  By the time the 1996 Windes and Ford article was published, this figure had risen to 4,294.  That’s a big difference!  We now have a much better idea of when different parts of Bonito were constructed, and that has shed important light on developments in the canyon at large and their relationship to events elsewhere in the Southwest.

Before this project, Pueblo Bonito was thought to have been initially constructed in the early 900s, with some reuse of beams from earlier structures accounting for a handful of dates in the 800s.  This interpretation, expressed most influentially by Steve Lekson in his 1986 book on Chacoan architecture, was based largely on a tight cluster of cutting dates at AD 919 from Room 320 in the western part of “Old Bonito.”  The enlarged sample, however, showed that it was actually this cluster that was a fluke, and that other beams from this wing produced dates in the mid-800s that more likely represent the initial construction of this part of the site.  This seems particularly likely because the types of wood represented by these beams are largely piñon, juniper, and cottonwood, locally available species that were widely used early on, before the beginning of large-scale, long-distance procurement of large beams of ponderosa pine and other high-elevation woods.  This suggests that the beams in Room 320 which dated to 919 were probably replacement beams rather than original construction.  This block of rooms at the western end of Old Bonito was probably built around 860.

Room 320, Pueblo Bonito

Lekson thought this roomblock was probably the earliest part of the site.  As it turns out, it was even older than he thought, but evidence from other parts of Old Bonito suggests that it was not actually the earliest part.  A cluster of cutting dates at AD 891 in the northeast part of Old Bonito, which was clearly added onto the north-central part to the west of it, suggests that it was the north-central part that was actually first.  This makes sense just from looking at the plan of the rooms, actually.  This part of the site is less regular and formal in organization than the east and west wings of Old Bonito, and since it lies between them it seems logical that they would have been added on to the original central room suites.  This is a bit hard to interpret, however, since the places where these different parts of the Old Bonito arc would have come together are mostly buried under complicated later construction.

Windes suggests in his 2003 paper that the very oldest part of the site was the block consisting of Rooms 1, 2, 4/5, 6, 35, 36, 37, and 61.  None of these rooms produced wood that could be dated.  Room 6 contains a considerable amount of original wood, which can be seen today under a modern roof put on to protect it, but this is mostly cottonwood, which is very difficult to date.  As noted above, however, the use of local types of wood like cottonwood is a characteristic of very early construction at Chaco, so even though these beams couldn’t be dated they do still provide some evidence that this part of the site is very early.  The western roomblock, dating to around 860, was probably added onto this one.  This implies that the north-central block predates 860, and Windes says it is “probably much earlier” even than that (although he doesn’t explain why he thinks this).

Intact Roof Beams in Room 6, Pueblo Bonito

How much earlier?  It’s hard to say.  The earliest cutting date at Bonito is 828, from Room 317 in the western roomblock, which both Lekson in 1986 and Windes and Ford ten years later considered likely to be a reused beam.  Since the overall distribution of dates in this block suggests construction around 860, this is probably right, and it’s hard to say where the beam would have come from.  Probably not the north-central roomblock, which would probably have still been in use in 860.  Interestingly, this beam is of ponderosa pine.

The north-central roomblock could well date to around 800 or even earlier, and that brings us to an interesting point.  There are a bunch of pitstructures buried deep under later construction in what would have been the original plaza of Old Bonito; these were not extensively excavated, but they probably correspond to the room suites that make up Old Bonito and therefore date to the 800s.  There are two even earlier pitstructures, however, further south in the later plaza of the expanded Bonito.  Neil Judd, who excavated the site in the 1920s, didn’t pay much attention to them because he thought they were too early to have anything to do with Pueblo Bonito itself.  They apparently date to the Pueblo I or late Basketmaker III period.  Back when the consensus was the Bonito itself wasn’t built until 919, it made sense to agree with Judd that these pithouses were too early, but now that we know that the earliest parts of Old Bonito date well back into Pueblo I it starts to look more plausible that there is actually some continuity here.  Since Judd didn’t look very closely at the early pithouses, we have no way of dating them, which is unfortunate, but one possibility that is looking increasingly plausible is that there was no hiatus at all between the occupation of those pithouses and the earliest occupation of Old Bonito.  In that case, Pueblo Bonito as an important, inhabited location (rather than as the building we see today) might actually date back to Basketmaker III.  And, importantly, whoever lived there at that time wouldn’t have been alone in the canyon.  But that’s an issue for another post.
Windes, T., & Ford, D. (1996). The Chaco Wood Project: The Chronometric Reappraisal of Pueblo Bonito American Antiquity, 61 (2) DOI: 10.2307/282427

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Peñasco Blanco

Returning to my theory that the large square rooms with hearths and other residential features found at some great houses in Chaco and elsewhere were in some sense replacements for earlier kivas, I think the best evidence for this at Chaco itself (as opposed to at outlying great houses like Salmon) comes not from Pueblo Bonito, which is just too complicated a palimpsest to make something like this easy to see, but from the other early great houses: Una Vida and Peñasco Blanco.  These at least seem to have simpler layouts than Bonito, though the extent to which this is just an effect of their being (mostly) unexcavated is unclear.  Nevertheless, at least some parts of these two great houses do seem to show basically the pattern that I’m proposing for the development of residential room suites at great houses.

To recap the idea: The very earliest great houses, those built in the AD 800s, seem to show a pattern of suites similar to that seen at small houses or unit pueblos, with each suite consisting of one rectangular room backed by two smaller rooms.  In front of each roomblock there are subterranean kivas, usually with slightly fewer than would be expected if each suite had its own kiva.  This suggests to me that the suites housed individual nuclear families, but that they were grouped into larger units, perhaps extended families, which shared kivas.  Whatever rituals these residential units would have conducted would probably have been in the kivas, but for the most part these were still residential structures, similar to the pithouses occupied in earlier centuries but with some of their functions transferred to the rectangular front rooms of the roomblocks.  The smaller rooms in the back would have been used for storage.  A typical great house would contain a few of these suites, with a kiva for every two or three.  It’s unclear what the relationships among different kiva-units within a great house would have been, but they could have either been separate extended families within the same real or fictitious “clan” or “lineage,” or they could have been separate lineages that were politically or ceremonially allied.  Importantly, all of these buildings are still residential at this point, although the residents may well host rituals or feasts open to the whole community either to solidify their political authority or because generosity is expected of them in exchange for community acceptance of their greater wealth or political/religious authority.  The main difference between great houses and small houses is just that great houses are bigger, with multiple stories in some instances and generally bigger rooms, as well as more extensive use of masonry rather than adobe or jacal construction.

Room 330, Pueblo Bonito

Then, at some point in the 900s, a change takes place in some (all?) great houses.  Use of the kivas is discontinued, and instead the activities that had been conducted in them are transferred to square surface rooms added onto the existing roomblocks.  This definitely seems to be what happens at Una Vida and Peñasco Blanco, although the extent to which there were earlier kivas is unclear given the lack of excavation.  In great houses newly begun during this time (it’s unclear how many of these there were in Chaco itself, but Kin Nahasbas may be an example), room suites were built without any kivas but with large, square rooms in front and smaller rectangular rooms varying in number behind them for storage.  This pattern continues well into the 1000s, at least at some great houses, and it’s associated with the very formal, symmetrical, rectilinear layout seen at sites such as Hungo Pavi, Chetro Ketl, and Pueblo Alto.  Some outlying great houses, such as Kin Bineola and (especially) Salmon, show this pattern as well.  Salmon seems to show that new great houses with (almost?) exclusively square rather than round living rooms were still being built as late as 1090, and if the early construction at Aztec is in the same pattern, which seems to be a matter of some dispute, it would still be going on well into the early 1100s.  This is probably also what we see at Pueblo Bonito too, with the possible addition of square rooms like 329 and 330 to the older suites at the west end of Old Bonito and the later addition of linear suites to the south of these rooms at the southwest corner of the site.

At some point in the late 1000s, however, a different type of room suite begins to arise at some Chaco great houses.  This is still a linear suite, sort of, but it consists of a round kiva built aboveground into a first-story square room, with one or two rows of two- or three-story rectangular rooms extending back from it.  These are the “blocked-in” kivas that are probably the most famous innovation of Chacoan architecture.  I see them as still residential spaces, in combination with the rooms behind them.  Their appearance at most outlying great houses indicates residential use of those sites, perhaps by local elites.  It’s not clear what the relationship is between these plaza-facing blocked-in kiva suites and the “elevated” kivas surrounded by rectangular rooms that start to appear at the centers of the rectilinear great houses with the square living rooms around this same time.  If those rooms are still residential, they’re pretty damn fancy residences.  They’re also quite unlike the other residential rooms at these sites, which are still square.  The “Tower Kiva” at Salmon is one example, as are the corresponding kiva at Hungo Pavi and the numerous examples at Chetro Ketl.  The central placement and unusual elaboration of these structures has led many to assume that they were ceremonial rather than residential in function, but I’m not so sure.  These sites do generally have great kivas, which pretty much everyone agrees were community-scale ceremonial/integrative structures, and they look quite different from elevated kivas (although it’s not clear to what extent the unique features of great kivas are due to structural requirements following from their size).

Kivas in the Southeast Part of Pueblo Bonito

In any case, the best examples of the plaza-facing blocked-in kiva suites are at Pueblo Bonito in the southeast and southwest wings.  These appear to have been built over earlier construction, so it’s not totally clear what was going on with these multiple, quite rapid changes in site layout during this period.  Again, though, they’re also obvious at Una Vida and Peñasco Blanco, where some (but not all!) of the earlier square living rooms are replaced by blocked-in kivas.  This also appears to have happened in the west wing of Chetro Ketl, but it’s unexcavated so it’s hard to say for sure.  There definitely are two blocked-in kivas there, though, and they appear to have rooms behind them like at Pueblo Bonito.

Then, at some point toward the very end of the eleventh century or very early in the twelfth, a totally new type of room suite begins to appear at Chaco great houses.  This is the famous “McElmo unit,” with a central blocked-in kiva surrounded on three or four sides by rectangular rooms, most of them significantly higher (three or four stories), creating a sort of “patio” over the kiva.  These rarely have ground-floor exterior walls, and they are remarkably uniform and modular in form.  The most famous of these structures are the freestanding ones, including New Alto, Casa Chiquita, and Kin Kletso (which comprises two adjacent units), but clearly analogous forms can be seen within certain great houses, including the north and south wings of Pueblo del Arroyo and the Kiva B complex at Pueblo Bonito.  Similar units that are just outside of existing great houses can be seen at Chetro Ketl and Peñasco Blanco.  The masonry of most of these is very different from that used at earlier great houses, being composed of blocky yellow sandstone rather than fine, hard, dark sandstone, and this has been used to argue that they represent influence from the north.  The masonry may indeed reflect northern influence (though in a different way from what the original proposers of this idea thought), but the form predates the shift in masonry and probably developed locally in Chaco.

Kiva E, Kin Kletso

There has been a lot of debate over the function of McElmo units.  Some see them as warehouses, while others see them as ritual (or possibly astronomical) special-use sites.  I’m increasingly thinking that all this speculation is based on an overemphasis on their differences from earlier great houses, and that they were probably residential and represent the final version of the Chacoan room suite.  More on this later.

McElmo units may represent the final development of Chacoan architecture in terms of form, but the great houses continued to be occupied for quite some time after the construction of these roomblocks in the early 1100s.  What we see at this point is an increased emphasis on the blocked-in kiva concept, with new kivas, often of “non-Chacoan” form, being built into earlier square or rectangular rooms.  Some call these “intra-mural” rather than “blocked-in” kivas, to emphasize that they were built into earlier rooms rather than having square rooms built around them, and I think this is a helpful distinction.  These really proliferate at Pueblo Bonito late in the occupation period, and this also happens at Aztec and Salmon during their “post-Chacoan” (also called “secondary” or “Mesa Verdean”) occupations.  At the same time, many great houses also see the construction of new subterranean kivas in the plazas, often with accompanying small blocks of square rooms.  These aren’t usually datable directly, but they appear to be very late.   Pueblo Bonito has particularly many of these, and there are a few in the southeast corner of Chetro Ketl too.  These appear to represent the construction of typical small-house or unit-pueblo style residential units within earlier great houses, and they may or may not represent an occupational discontinuity of some sort.

So basically, what we see is a sequence of underground kiva to above-ground square room to above-ground kiva.  There are plenty of variations and complications, but that’s the general sequence.  The later use of intra-mural kivas, especially at Pueblo Bonito, has tended to obscure the middle stage here, but it really seems to represent something meaningful at least as a chronological marker in Chacoan architecture.  Does it mean anything else culturally?  That part I’m still looking into, but it may.

Fajada Butte from Una Vida

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Reconstructed Great Kiva, Aztec Ruins National Monument

Although the idea that the small round rooms that area so common at Chacoan sites are ceremonial “kivas” has been increasingly challenged recently, it is still widely accepted that the large, formal, round structures known as “great kivas” were in fact community-wide ceremonial or integrative facilities.  Even Steve Lekson agrees, and he continues to use the term “kiva” in referring to these structures even as he calls the small “kivas” “round rooms” instead.  (He also uses the term “kiva” in referring to “tower kivas,” yet another form of round structure with proposed ceremonial associations.)  Ruth Van Dyke‘s chapter in The Architecture of Chaco Canyon, New Mexico is a good summary of current knowledge about Chacoan great kivas.  The great kiva is an architectural form that predates Chaco, and it may or may not have outlasted it.  The Chacoan form is distinctive, however, and found even in areas without a long history of pre-Chacoan great kivas.  It is highly standardized in both size and features, and is one of the surest indications of Chacoan influence wherever it is found.

Floor Features of Kiva Q, Pueblo Bonito

The following features are always found at Chacoan great kivas, although their specific realization can vary a bit:

  1. Four post holes, arranged in a square, to support the beams or columns that hold up the roof.  The holes may be either round or square.  Generally the columns themselves would be huge wooden beams, stubs of which have sometimes been found in the post holes during excavation.  Sometimes, such as in the great kiva at Aztec Ruins, square masonry columns, possibly with small poles in them, would be used instead.  It’s apparently not totally clear if the use of square rather than round post holes necessarily indicates the use of pillars rather than beams, since the beams would typically be held in place by shale and this could be done in either a square or a circular space.  When beams were used, they were supported at the bottom by several stacked stone disks, presumably to distribute the weight.  Offerings of turquoise and other valuables were often found in the beam holes, apparently placed during construction.
  2. Around the circumference of the kiva is a bench, sometimes doubled.  These benches were often refaced with new masonry, sometimes in connection with more general renovation of the kiva features and sometimes not.
  3. There is typically a series of wall niches around the circumference of the chamber, above the bench.  These vary in dimensions and number, but there are usually about 30 of them, especially in later great kivas.  Sometimes there is more than one series of niches at different levels, as at Casa Rinconada.  The purpose of the niches is unclear; some of them had offerings sealed into them, but these may have been construction offerings rather than indicating anything about post-construction use.
  4. Entrance is from a staircase leading down from an antechamber.  There would probably have been a smokehole in the roof as well, but it is unclear whether there would have been a ladder providing entrance through the roof as was the case in smaller round rooms.  An intact great kiva roof has never been found, which is unsurprising since the roofs would have been enormously heavy and very likely to cave in once the structure was no longer maintained.  The antechamber is on the north side in most cases.  Kiva Q at Pueblo Bonito has an apparent staircase and antechamber on the south side instead, but Van Dyke suggests that this may have been an error of reconstruction.  She doesn’t go into any more detail about this, however, and it’s unclear what the implications are if the room on the south side of Kiva Q is not an antechamber.  Casa Rinconada has antechambers with staircases on both the north and south sides.
  5. Along the central north-south axis, slightly offset to the south from the center point, is a firebox.  This is usually a masonry cube with a circular or oval firepit in it.
  6. Just south of the firepit there is a deflector.  This is a common feature in small kivas, which usually have a ventilation shaft on the south side, but since great kivas don’t have ventilation shafts and usually have their entrances on the north side it is unclear how useful this deflector would have been in practice.  Assuming there was a smokehole, a great kiva was big enough that it’s unlikely ventilation would have been a major concern.
  7. Attached to the two southern postholes on the north side, and sometimes running all the way to the northern postholes, there are two rectangular masonry “vaults.”  They are usually but not always subterranean.  The function of these is unclear.  Some have claimed that they are “foot-drums,” which would have had boards on top of them and people dancing on them, but not everyone accepts this interpretation and I don’t find it very convincing.  Small kivas sometimes have a single subfloor vault on one side of the firepit, but it is unclear if there is any connection between that type of feature and the much more formal vaults of great kivas.

These are the basic features that are repeated again and again at Chacoan great kivas.  Relatively few have been excavated, but all of those that have show these same features with minor variations.  Van Dyke provides a comprehensive list of the known great kivas at Chaco.  There are 21 of them, of which 11 have been excavated.  Ten of these are associated with the great houses Pueblo Bonito (4 great kivas), Chetro Ketl (3), and Kin Nahasbas (3).  (Note that Van Dyke is counting remodeled versions of earlier great kivas separately here.)  The only “isolated” great kiva to be excavated is Casa Rinconada.  It is also the largest excavated great kiva in the canyon at 19.5 meters in diameter, although it is not the largest excavated great kiva (the one at Village of the Great Kivas, a Chacoan outlier on the Zuni Reservation, is 23.7 meters in diameter), nor is it the largest great kiva in the canyon (the unexcavated northwest great kiva at Peñasco Blanco is 23 meters in diameter).

Casa Rinconada, Looking North

Van Dyke explicitly cautions her readers to be careful about the possibility of overemphasizing the importance of Rinconada just because it is so well known, and this is an important warning.  It does appear that Rinconada is unusual among all known great kivas in several ways, including the two antechambers and the “secret tunnel” leading from a back room of the north antechamber to a subsurface round enclosure around the northwest posthole.  It is also positioned in a very significant location, across from Pueblo Bonito, and there may be astronomical alignments encoded into it.  However, it is important to note that like the other great kivas at Chaco that are visible today, Rinconada has been substantially reconstructed.  In general Chaco has had a much lighter touch with reconstruction than many other parks, but great kivas, which are typically found in a substantially reduced state with large v-shaped breaches in the upper walls, are an exception.  Kivas A and Q at Pueblo Bonito as well as Casa Rinconada have all been built up to what their excavators considered a reasonable approximation of their original condition.  The great kiva at Aztec, of course, has been completely reconstructed to give an impression of what it might have looked like, and while there was apparently once talk of doing something similar at Casa Rinconada nothing ultimately came of it.

In addition to the excavated great kivas, there are ten unexcavated ones at Chaco.  It is hard to tell much about these, since they are basically just big recessed circles in the ground, but they are generally at least in the same size range as the excavated examples and can probably be assumed to be similar.  There may well be additional unknown ones, either associated with great houses or isolated.  It is particularly likely that early great kivas would not be apparent on the ground, since they are generally smaller than later ones and the excavated examples (or possible examples) all come from within early great houses where they are often overlain by later construction.

Northwest Great Kiva at Peñasco Blanco

The known unexcavated great kivas associated with great houses include two at Una Vida, one at Hungo Pavi, and four at Peñasco Blanco.  There are also three “isolated” great kivas, all of them at the east end of the canyon: one in Fajada gap, one on the south side of the canyon across from Wijiji, and one in a side canyon at the foot of Chacra Mesa below the Basketmaker III village known as Shabik’eshchee.  As noted above, the northwest one at Peñasco Blanco is huge, probably the largest at Chaco.  The one in Fajada gap appears to be about 20 meters in diameter, which puts it in the same size range as Casa Rinconada, although the difficulty of measuring diameter precisely with unexcavated great kivas makes it impossible to say if it is actually bigger than Rinconada or not.  One interesting thing about these isolated great kivas is that they are all on the south side of the canyon, as is Casa Rinconada.  This contrasts with the tendency of great houses to be on the north side and provides some support for the idea that the great kiva is conceptually separate from the great house and has its own history as a form.  It’s hard to say how to interpret this in the context of the postulated attempt by great-house elites to incorporate great kivas into their great houses as a way to legitimize their authority, which Van Dyke proposes as an explanation for why most great kiva construction at great houses didn’t take place until the mid-1000s.

And, indeed, early great house construction does seem to be notably bereft of great kivas.  Or does it?  Tenth-century “great kivas” are in fact postulated at Pueblo Bonito, Una Vida, and Kin Nahasbas, and Van Dyke includes them on her list, but it is unclear whether they really “count” as great kivas.  They are smaller than the later versions, which may just be because they are older.  They are also poorly documented, however; the ones at Pueblo Bonito and Kin Nahasbas have been excavated, but records about them are scarce and scanty.  The one at Pueblo Bonito is about 10 meters in diameter, which Van Dyke considers “within the range known for domestic pitstructures,” and furthermore it lacks postholes for roof support beams but does appear to have pilasters on its bench, which implies a roofing system like that of small kivas.  Since the roofing system is one of the most consistent features of classic Chacoan great kivas, this is a major strike against great kiva status for this one.  However, it’s possible that the specialized roofing system for later great kivas was an innovation to handle the large size of the ones built from the mid-1000s on, and that earlier structures with “regular” kiva roofs may have had “great kiva” functions in the 900s.  (This reminds me that I should do a post on small-kiva roofing, which is an interesting and surprisingly contentious issue.)

Kin Nahasbas from Una Vida

Evidence that the specialized roofing system for great kivas was already in place in the 900s comes from the early “great kiva” at Kin Nahasbas, which was more thoroughly excavated than the one at Pueblo Bonito.  It underlies the two later great kivas, which had classic great kiva features.  Its own features were largely obscured by the later construction, but it does appear to have postholes.  It couldn’t be dated directly, but the excavators concluded that it was probably associated with the tenth-century greathouse behind it.  This implies that there was at least one great kiva this early, but that the one at Pueblo Bonito was not one.  Interestingly, the diameter of this great kiva was only 7 meters, making it smaller than the Pueblo Bonito example and suggesting that size isn’t everything when it comes to great kivas.

The early great kiva at Una Vida is very poorly known and may not exist at all.  There is certainly another, later great kiva at the site.  Van Dyke refers to William Gillespie’s account of Una Vida’s architecture in Steve Lekson’s Great Pueblo Architecture of Chaco Canyon, New Mexico as the source for the idea that there is a great kiva associated with the early-tenth-century construction there, but Gillespie is very vague about the basis for his speculation that such a great kiva existed, and says only that “surface evidence is inconclusive.”  Van Dyke lists the diameter of this postulated great kiva as 17 meters, which is remarkably large for such an early structure and only slightly smaller than the later great kiva, which is much more obvious and has a diameter of about 18 meters.  Una Vida is a very confusing and poorly understood site, so the lack of clarity regarding its great kiva(s) is not really surprising.

The only other early great house, in addition to these three, at Chaco is Peñasco Blanco.  It apparently has four great kivas, none of which has been dated.  It’s quite possible that one or both of the two great kivas in the plaza dates to the 900s, but neither has been excavated.  It is also possible that there are additional early great kivas either underlying the later ones or elsewhere in the site.  The number of apparent great kivas is one of the many reasons I think this site is likely much more important to Chaco than is usually appreciated.  It is both one of the earliest sites at Chaco and one of the largest, and it may have served as an important connection to the communities downstream on the Chaco River, where many of the early great houses were, as well as with the Chuska Mountains beyond.  Van Dyke has little to say about it in this chapter, which is understandable since the great kivas are unexcavated (as is the rest of the site).

Snow at Kiva A, Pueblo Bonito

The upshot of all this is that there probably was at least one great kiva built at Chaco in the 900s, and there may have been more, but it does seem to be true that great kiva construction increased dramatically after around 1030.  This is the same time that a lot of other changes were happening in the canyon, including massive construction projects of various sorts at several great houses, and it is probably the time when Chaco first became the regional center for the San Juan Basin (though it had likely been an important center for a long time).   Van Dyke argues that part of this was the appropriation of the great kiva form, which in previous times had been particularly common in communities to the south, by emergent local elites attempting to legitimate their increasingly hierarchical authority and control over periodic regional gatherings in the canyon that were beginning to draw pilgrims from throughout the Basin (and perhaps beyond).  In another article she argues that this process was part of a “tipping point” or “qualitative social transformation” that changed a predominantly egalitarian society into a more hierarchical one.  In this context, the use of great kivas may have been an attempt to establish links with the past by incorporating an old, traditional architectural form into the new and potentially threatening form represented by the great house.  I’m not sure I buy this entire story, but I think at least parts of it are likely true and it’s certainly thought-provoking.

Great Kiva at Lowry Pueblo, Colorado

Wherever they came from and whenever they became part of the Chacoan architectural repertoire, by the height of the Chacoan era great kivas were among the most standardized parts of the highly standardized Chacoan “system,” whatever it was.  There are plenty of puzzles remaining about them, as is true with most everything associated with Chaco, but regardless of whether we are ever able to answer all the questions they pose they are still among the most impressive achievements of this very impressive society.
Van Dyke, R. (2008). Temporal Scale and Qualitative Social Transformation at Chaco Canyon Cambridge Archaeological Journal, 18 (01) DOI: 10.1017/S0959774308000073

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Pueblo Bonito from Peñasco Blanco

The paper I discussed earlier about evidence that corn was imported to Chaco was interesting, but while it provided important information about the poorly understood “Mesa Verdean” period after the fall of the Chaco system it didn’t address the question of food imports during the operation of that system.  This has been a topic of considerable debate, and the extent to which corn was being imported to Chaco from outlying areas versus being grown in the canyon itself has major ramifications for which theories about the nature of the system seem most plausible.  Luckily, however, that paper was just one in a long series reporting on research done by Larry Benson and others on this topic, and a slightly earlier one by Benson, H. E. Taylor, and our old friend John Stein addresses the question of earlier (and later) periods.

Peñasco Blanco from Pueblo Bonito

This paper uses the same basic methodology of the other one, based on strontium isotope ratios, and it also attempts to use concentrations of other trace elements to further narrow down source areas for corn cobs from archaeological sites.  Unfortunately, however, most of the trace elements the researchers looked at had their concentrations heavily skewed by post-depositional contamination, which made them useless for determining sources.  The only elements that seemed to be mostly unaffected by this problem were potassium and rubidium, so the paper uses the ratio of these two elements as an additional marker for places where the cobs may have been grown, although it cautions that it’s not yet totally clear that this ratio is actually as meaningful as the analysis implies.

Aztec West Great House, Aztec Ruins National Monument

This study looks at more cobs than the other one.  These are from both Chaco and Aztec, and the Chaco ones come from a variety of sources.  The most numerous are from Gallo Cliff Dwelling and are part of the large group with nearly identical radiocarbon dates in the late 12th century that was analyzed in the more recent paper.  This paper conducts a similar analysis and comes to similar conclusions about the wide range of possible sources for these cobs.  This group also includes a few cobs from Pueblo Bonito, Chetro Ketl, and Kin Kletso, although the authors caution that the late dates on these cobs don’t necessarily imply that these great houses were still occupied at this late date; the cobs could also result from people living in small sites like the Gallo Cliff Dwelling dumping their trash in the abandoned buildings.  While most of the Chaco cobs come from this narrow time period, and the Aztec cobs (which have not been carbon-dated) likely date from a roughly comparable time as well, some Chaco cobs are dated to both earlier and later times.  The later ones, some of which date to the nineteenth century, are presumed to reflect the later Navajo occupation of the area.  It’s the earlier ones that are of interest for the light they can shed on the operation of the Chaco system in its heyday.

Pueblo Bonito from Above

There are six cobs with carbon dates earlier than the major drought of the mid-12th-century.  Five of these come from Pueblo Bonito, and one comes from the Gallo Cliff Dwelling.  The Gallo one is puzzling, since all the other Gallo cobs date to much later and cluster tightly together, and the site itself was probably not occupied early enough to account for the early cob.  It’s possible that this date is due to something odd going on with the radiocarbon dating, and in any case it seems hard to generalize from, so I’m not going to discuss it further here and will instead focus on the five cobs from Pueblo Bonito.

Interior T-Shaped Doorway, Pueblo Bonito

Four of these come from Room 3; the other one comes from Room 170.  These are both interesting rooms in their own right, but first let’s talk about the cobs.  Although the authors of the paper classify them only as “pre-AD-1130” (i.e., before the drought that is thought to have coincided with the fall of Chaco), they actually all date considerably earlier than that.  The earliest, which unfortunately seems to have been contaminated and thus unusable for the strontium analysis, is from Room 3 and has a calibrated radiocarbon date range of AD 765 to AD 902 with 95% confidence (2σ).  The other four are somewhat later and cluster tightly together, with 95% confidence intervals of AD 944–1052 (this is the one from Room 170), AD 892–1034, AD 893–1026, and AD 889–1021.  This means that these cobs all date to a period before the Chaco system reached its full florescence, which is generally dated to the late eleventh century.  They also seem to date earlier than the expansion of Pueblo Bonito in the 1040s.  The 95% confidence interval for the cob from Room 170 does make it possible that it dates to the period of the expansion, but at a lower level of confidence (1σ) it has a tighter range of AD 974 to AD 1040, which means it too probably predates the expansion.

Old Bonito

Thus, all these corn cobs seem to have been grown and eaten during the period when Pueblo Bonito consisted only of the original arc of rooms, constructed with early, Type I masonry, that we now call Old Bonito.  This makes their geographical origin even more interesting to investigate.  During this period, consisting of the ninth, tenth, and early eleventh centuries, Chaco Canyon seems to have been growing in regional importance, as evidenced by the construction of the early great houses, but it doesn’t seem to have yet attained the preeminent position and centrality it would achieve in the late eleventh and early twelfth centuries before its collapse.  The earliest cob, which probably dates to the ninth century, which is when the early great houses were first being constructed, would be of particular interest in determining where the people in Chaco were getting their food at that time.  It’s very unfortunate, then, that its origin can’t be determined from strontium analysis because of its apparent contamination.  The other three cobs, however, which probably date to the late tenth or early eleventh century, were included in the strontium analysis, so it’s worth looking closely at what the results of that analysis can tell us.

Type I and Type II Masonry Abutting at Peñasco Blanco

These cobs date to a period when there seems to have been little or no construction at Pueblo Bonito, Una Vida, and Peñasco Blanco, the three earliest great houses in the canyon.  All three saw extensive construction in the late ninth and early tenth century, and major expansion starting in the middle of the eleventh.  The time of the cobs, then, seems to have been a relatively quiet period in the canyon, although the early stages of construction at some of the other great houses, such as Chetro Ketl and Hungo Pavi, may date to this period.  There doesn’t seem to have been a whole lot of great-house construction outside of the canyon, either; there were already quite a few great houses out there, especially to the south in the Red Mesa Valley and to the west along the Chuska Slope, but most had already been built, and the biggest of the outliers, especially to the north, wouldn’t be built until considerably later.

Side Wash by Chetro Ketl

So, if the strontium evidence were to suggest that the cobs from this period were grown in the canyon, that would suggest that local agricultural production was important at Chaco, and it would support theories that attribute Chaco’s rise to regional dominance as having to do at least in part with agricultural surplus during favorable climatic conditions.  If, on the other hand, the strontium evidence were to suggest that the cobs were grown outside of the canyon, that would be evidence in favor of other theories that see the rise of Chaco as due not to local production but to the Chacoans’ ability to somehow acquire food from other areas with better growing conditions.  This would be particularly the case if the cobs came from areas that had early outliers.  It would also be interesting if the cobs came from areas that aren’t known to have had outliers this early but did have them later (e.g., the Totah).  These theories propose a variety of answers for how the Chacoans could have done this, of course, ranging from coercive political domination to inspirational spiritual power.

High Walls at Kin Bineola

So, with that in mind, what does the strontium (and potassium/rubidium) evidence say?  In brief, it supports the latter option.  The strontium ratios in the cobs are close to the values at a few of the sampled sites in and around the canyon, but when the potassium/rubidium ratios are added in, they narrow the potential sources down considerably, and none of the local Chaco sources makes the cut.  So, to the extent that the potassium/rubidium evidence is useful (which, remember, is still not totally clear), it seems that the Chacoans were importing corn at least as early as the early eleventh century, and possibly a century earlier.  This seems to support the theories that hold that local agricultural production was not the main driver of Chaco’s rise, although this is of course a very small sample and it would be foolish to draw too many firm conclusions from it.

Sign at Kin Bineola

So if the corn wasn’t being grown at Chaco, where was it grown?  Unlike with the later cobs, and again likely owing at least in part to the small sample size, the number of potential source areas identified here is pretty small.  A couple are in the Totah near Aztec, but all the rest are in the area surrounding Chaco often called the “Chaco Halo” and consisting of the parts of the Chaco Wash drainage both upstream and downstream from the canyon, including the South Chaco Slope area on the north side of Lobo Mesa.  The specific sampling sites with matching ratios were near a number of important Chacoan outliers, including Kin Ya’a, Kin Klizhin, Kin Bineola, and Pueblo Pintado.  Interestingly, of these four only Kin Bineola is known to have been built at this time, and the others were not built until considerably later, at least in their current form.  The fact that Kin Bineola is one potential source area, as are a few smaller early great houses that were present at this time, suggests that the later outliers may have been built on top of earlier versions, or at least that the communities surrounding them may have been incorporated into the Chaco system earlier than the dates of their great houses would imply.  Of course, it’s also possible that all of these cobs came from one or a few of the areas with known early great houses; the fact that a large number of areas could have grown these cobs doesn’t mean that they all did, and in fact given the small number of cobs it would be impossible for all the areas identified to have contributed to growing them.

Kin Bineola from a Distance

It’s not necessarily surprising to find that nearby areas known to have been in close contact with Chaco would have been supplying it with corn.  Indeed, many of these areas are considerably better for agriculture than the canyon, and there has long been speculation that at least some of the outliers were founded specifically in order to supply the canyon with food.  What is somewhat surprising here, however, is the early date at which this appears to have already been happening.  The great houses at Chaco would not necessarily have been any more impressive than those in many other local communities at this point, and given the lack of construction activity in the canyon it would be quite reasonable to suppose that Chaco was not yet considered exceptional within the region.  This evidence, however, suggests that there was already something unusual going on in the canyon, and that something was getting people around it to supply it with at least some food.

Early Masonry at Kin Bineola

One more thing to consider about these cobs is where they were found.  Since Pueblo Bonito was definitely around at the time they were grown, imported, eaten, and presumably thrown away, and since they were found at Pueblo Bonito, it seems logical to conclude that the rooms where they were excavated were the same rooms where they had originally been tossed.  This is almost certainly not true, however.  Rooms 3 and 170, where they were found, had not yet been built in the early eleventh century.

Room 3, Pueblo Bonito

Room 3 is part of an arc of rooms fronting on the western section of Old Bonito.  Unlike the rooms behind it, however, it is built out of late core-and-veneer masonry, and it was likely built considerably later than those rooms, which are built with early masonry.  The difference is quite noticeable.  The spaces later enclosed by it and the other plaza-facing rooms in this arc was probably originally enclosed by a ramada or awning, or perhaps a wattle-and-daub (or “jacal”) wall, which was later replaced with masonry.  The sequence of construction in this part of the site is hard to untangle, and Room 3 produced no tree-ring dates, but it is pretty clear that it must have been constructed at some point after AD 1040, just judging from the masonry, and the presence of the cobs in it likely dates to a time long after its initial construction when it was used for dumping trash.  One of the other cobs found in this room was part of the late-12th-century date cluster, so that may be when this trash deposit originated.

Room 170, Pueblo Bonito

Similarly, Room 170 is part of the southernmost block of rooms, which was one of the last parts of the site to be built.  It seems to have been built as part of the construction of the southeast corner of the site, one of the largest single building projects in Chaco’s history, which probably took place around AD 1080.  Room 170 has an odd set of internal features; its first story was at some point divided by an east-west wall, and the part of the room north of the wall was filled in, with a space left, however, to allow access to the second floor of both it and the room north of it.  There is also a small opening just south of the dividing wall leading into the next room west, and a step below it.  Again, this room was likely not originally used for trash dumping, and the trash deposits in it likely date to a later period.

Metate Fragment at Pueblo Bonito

Since neither of these rooms was used for dumping trash until quite late, perhaps even after the fall of Chaco as a regional center, why did they contain corn cobs from centuries earlier?  Probably because the trash being dumped in them was being moved from wherever it had originally been dumped.  Where that would have been, who would have been doing this, when, and why are all very difficult questions to answer, but I don’t see any other explanation to reconcile the dates of the corn cobs with their locations.  This also means that, while these cobs were found at Pueblo Bonito, they weren’t necessarily originally brought there.  They may have been, of course, and I’d even go so far as to say that they probably were, but it’s also possible that the trash deposit in which they were originally placed was somewhere else in the canyon, perhaps even associated with another site.

Sealed Vent, Pueblo Bonito

Like all good papers about Chaco, this one answers some questions but opens up others, and it definitely provides plenty of (imported) food for thought.  There’s still a lot we don’t know about the Chacoans, even such basic things as where they  got their food, but the process of finding these things out is quite a ride and full of surprises.
BENSON, L., STEIN, J., & TAYLOR, H. (2009). Possible sources of archaeological maize found in Chaco Canyon and Aztec Ruin, New Mexico Journal of Archaeological Science, 36 (2), 387-407 DOI: 10.1016/j.jas.2008.09.023

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Una Vida Sign

Una Vida Sign

One of the questions we get most often at Chaco from visitors who have just arrived is whether it’s a walking or a driving thing.  It’s both, really.  For most of the sites, especially the really impressive ones, you drive a few miles from the Visitor Center then walk a few hundred yards and do a self-guided tour (or, if there is one available, a guided tour).  This is how it works for Pueblo Bonito, Chetro Ketl, Pueblo del Arroyo, and the other sites in the “Downtown Chaco” area, which is about 4 miles down the loop road from the Visitor Center.

Una Vida from a Distance

Una Vida from a Distance

There is one site, however, which is accessible by a short walking trail directly from the Visitor Center parking lot.  It isn’t the most impressive of the sites, but it has a certain charm to those who are willing to seek it out.  This site is the great house known as Una Vida.

Una Vida in the Snow

Una Vida in the Snow

Like most of the other major great houses in Chaco Canyon, Una Vida was first documented and named by the Lt. James Simpson of the Washington Expedition in 1849.  Simpson relied heavily on one of the expedition’s guides, a Hispanic man from the nearby village of San Ysidro named Carravahal, and as a result most of the names he wrote down for the sites were Spanish.  “Una Vida” (meaning “One Life”) is one of these; the reason for the rather odd name is obscure.

Walls at Una Vida

Walls at Una Vida

Unlike most of the other great houses, Una Vida looks today much as it did when Simpson first saw it.  We often describe it as “unexcavated,” but this isn’t strictly true.  A few rooms in Una Vida were excavated at various times during the twentieth century, but they have all since been backfilled, so while there has been a bit of excavation it isn’t apparent from looking at the site.  As a result, Una Vida is one of the best places to see what the sites looked like before being excavated.  Basically, it looks like a huge mound of sand, covered with shrubby vegetation, with significant standing walls sticking out at various points.  It’s clear that there is a building there, and it’s clear what its overall size and shape is, but it isn’t clear how many rooms it contains or where the divisions between them are.

View from Plaza of Una Vida

View from Plaza of Una Vida

Moving up to Una Vida from the parking lot and entering the plaza, one is surrounded by high mounds of sand, which obscure most of the building and the ridge upon which it is built.  It is hard to tell from here quite what the building would have looked like when it was in use, but it’s quite obvious that it was very impressive in scale.

Navajo Corral at Una Vida

Navajo Corral at Una Vida

Looking around the plaza, there are a few enclosures of varying sizes made out of the same sort of stone found in the walls of the great houses but with very different masonry, dry-laid without any mortar.  These were actually not present when Simpson came by in 1849, but were built later by the Navajo inhabitants of the canyon.  They weren’t here in 1849 because the Washington Expedition had been sent to fight the Navajos, who weren’t about to wait around to be attacked.  After the conclusion of the tumultuous wars between the US government and the Navajos with the return of the Navajos from the ill-fated reservation at Bosque Redondo in southeastern New Mexico in 1868, however, the canyon was reoccupied and the Navajos built a variety of structures, many of which are still standing in some form.

Navajo Hogan at Una Vida

Navajo Hogan at Una Vida

In general the Navajos avoid ruined sites like Una Vida.  Navajo tradition involves a lot of taboos about death and places associated with it, and sites associated with the Anasazi are particularly problematic.  There is very little trace of Navajo occupation in the Downtown Chaco area around South Gap and Pueblo Bonito, for example.  In some other parts of the canyon, including the Fajada Gap area where Una Vida is, certain Navajos seem to have been less concerned about the taboos and, perhaps, more inspired by the abundant building stone from the fallen walls.  In any case, they built a few hogans (traditional Navajo dwellings) and a large corral in the plaza of Una Vida, and the remnants of these can still be seen today. In general there is little trace of the Navajo presence at Chaco within the park today, due in no small part to deliberate Park Service policy in the mid-twentieth century that involved kicking out the Navajos living in the park.  Here at Una Vida, however, some of that history is still visible in a subtle way.

Third-Story Walls with Type I Masonry at Una Vida

Third-Story Walls with Type I Masonry at Una Vida

Moving on from the plaza to the west wing, one can see the typical row of blocked-in round rooms fronting the plaza and backed by higher stories of rectangular rooms.  This is pretty standard for Chacoan great houses, but here it’s interesting on account of the fact that this room block is made largely of early masonry.  This part of the building seems to have been constructed sometime in the 900s using Type I simple masonry.  It goes up three stories at the south end, and this seems to be the only part of Una Vida that was ever three stories.  The immense height of some other parts of the building is due largely to its being built on a natural ridge.  There’s no evidence for any other construction above two stories.  It’s pretty striking that the three-story rooms are among the best-preserved despite their early masonry.

Petroglyphs above Una Vida

Petroglyphs above Una Vida

Moving along the west side, one comes to the place where a spur trail leads partway up the cliff to an area of quite remarkable petroglyphs.  These are among the most impressive in publicly accessible parts of the park, and are also among the easiest to get to.  As usual with rock art, they are difficult to interpret, but some clearly seem to show animal figures which may be either highly stylized representations of real animals or images of mythical or legendary beasts.  There is also an anthropomorphic figure with two horns which has been identified by Hopi consultants as a symbol of the Two-Horn Society.

Una Vida from Petroglyph Area

Una Vida from Petroglyph Area

From the petroglyph site, one can get a very good view of Una Vida and finally get some sense of its overall size and shape, which is particularly difficult to get a sense of from ground level because of its unexcavated nature.  It’s basically L-shaped, with an arc of plaza-enclosing rooms linking the ends of the L.  Fajada Butte, Fajada Gap, and the Visitor Center are also clearly visible from up here.

Visitor Center and Fajada Butte from Una Vida Petroglyphs

Visitor Center and Fajada Butte from Una Vida Petroglyphs

Coming back down from the petroglyphs and continuing along the trail, next comes the earliest part of Una Vida, a small block of rooms built in the 800s and later shored up with what looks like McElmo-style masonry (typical of the early 1100s).  This block is similar to the oldest part of Pueblo Bonito, which was built around the same time, and it’s likely that Peñasco Blanco, which has tree-ring dates from the same period, has a similar early block somewhere, although given its unexcavated state it’s impossible to identify it.  These three early great houses, the earliest in Chaco Canyon, are located at the three main entrance points to the canyon: Fajada Gap, South Gap, and the end of the canyon where the Escavada Wash and the Chaco Wash join together.  This is likely not a coincidence.

Earliest Part of Una Vida

Earliest Part of Una Vida

Continuing along the trail, the next notable part of the site is a single room with particularly well-preserved standing walls and an intact doorway.  This part of the site, the east wing, is a later addition using Type IV core-and-veneer masonry, which is quite apparent in this room.

Doorway at Una Vida

Doorway at Una Vida

Finally, the trail comes back to the Navajo corral and completes the loop, heading back toward the Visitor Center.  Although there is less to see at Una Vida than at, say, Pueblo Bonito, its mostly unexcavated state and unusual features offer a window into some aspects of Chaco that don’t get that much attention, and it’s definitely worth a visit.

Lizard on Type I Masonry at Una Vida

Lizard on Type I Masonry at Una Vida

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