Archive for the ‘Chaco Canyon’ Category


Fajada Butte at Sunset

Today is the winter solstice, which makes this the ninth anniversary of this blog. It’s a particularly appropriate date for the paper I’m going to discuss in this post, another chapter from Astronomy and Ceremony in the Prehistoric Southwest: Revisited. It’s by prominent archaeoastronomer J. McKim Malville, and entitled “The Enigmas of Fajada Butte.”

Fajada Butte is plenty enigmatic. Though it’s one of the most prominent landmarks within Chaco Canyon, and the “Sun Dagger” petroglyph on top of it is one of the most famous pieces of astronomically aligned rock art in the world, there has been surprisingly little detailed archaeological study of the butte itself. While there has been considerable more study of other ancient sites in the general area, that work has not really been well-integrated with what is known about the butte, which makes Malville’s integrative work in this paper extremely interesting, tentative though it is.

Much of Malville’s paper discusses cross-cultural examples of sacred mountains and stairways, as support for the idea that Fajada played this role in ancient Chacoan culture. This is plausible enough, though of course speculative, and I don’t have much more to say about it. More interesting to me is his discussion of the archaeology of the butte itself and the nearby Fajada Gap community, which contains three great kivas dating to the tenth century AD along with many small-house residential sites, some possibly dating as early as the eight century but most apparently from the tenth and early eleventh. Several of these small houses were excavated by the Chaco Project in the 1970s and are among the best-documented sites in the whole canyon. The great kivas, two of which are part of great houses (Una Vida and Kin Nahasbas), are largely unexcavated and much less thoroughly understood.

The third, isolated, great kiva (site 29SJ1253) is of particular interest to Malville, as it appears to have a winter solstice alignment with the butte. Malville presents documentation that on the winter solstice as viewed from the great kiva the sun rises over the summit of Fajada Butte. Malville suggests that the great kiva was positioned where it was in order to set up this alignment, which would have been an important ritual event for the people in the Fajada Gap community. Based on ceramic evidence, the great kiva appears to have been built in the tenth century, which makes it one of the earliest in the canyon. It is also one of the largest, with a diameter of 20 meters. Both of these characteristics suggest that it was a particularly important site from a very early point in the development of Chaco into a regional center, especially in the tenth century when the Fajada Gap community may have been particularly important, even more so than the South Gap community which may have become more prominent later.

Evidence for this importance also comes from some of the excavated small houses. 29SJ1360, the closest site to the butte, is known especially for one of its pithouses containing the remains of several people who apparently died accidentally there in the early eleventh century. One of the women was found with a necklace containing an exceptional number of beads, suggesting relatively high status in life. These are the remains, furthermore, that Nancy Akins in her biometric analysis found showed the greatest similarity to the extremely high-status burials in the north rooms of Pueblo Bonito, some of which we now know were quite early themselves (as are the rooms). 29SJ1360 contained the only macaw remains found outside of a great house context at Chaco, along with evidence that macaws may have been raised there, and it also had a cylinder jar, a high-status pottery form, perhaps used for consumption of chocolate, that is also very closely associated with the north part of Pueblo Bonito.

Overall, then, there are many indications that the people living at 29SJ1360 were of relatively high status and had connections, possibly familial, to some of the people associated with the earliest part of Pueblo Bonito. Malville documents a winter solstice alignment here as well: viewed from about 100 meters upslope, around noon on the solstice, the sun briefly disappears behind the butte then reappears. This is a less rigorous alignment than the one from the great house, obviously, but it is still suggestive, and combined with the other evidence reinforces the sense that this is an important site despite its small size.

Another small house in this community, 29SJ629 or the Spadefoot Toad site, had evidence for a workshop for the manufacture of turquoise beads, which Malville suggests indicates connections to trade routes coming up from the south. Turquoise at Chaco actually came from all over the place, but it’s true that the Fajada Gap community seems to have connections to the south, which makes sense given that the gap itself is an entrance to the canyon from that direction. As I’ve mentioned before, earlier sites to the south of Chaco are much less well understood than those to the north, but there are indications that these connections were very important in the early development of the canyon, and Malville’s argument that the spiritual status of Fajada Butte played an important role in this development is quite plausible.


Fajada Butte with Ramp (Lower Right)

So much for the community; what about the butte itself? Malville discusses two main items of interest: the ramp leading up the butte from its base, and the rooms at its top. The ramp, which appears to take advantage of some natural ridgelines but is definitely at least partly artificial especially in its upper parts, has received oddly little attention in the literature despite being an impressive accomplishment that, judging from the pottery found on it, apparently dates to the tenth century just like the nearby community sites. There are fire pits at the base and top of the ramp, which Malville suggests may have been used in winter solstice ceremonies that ritual procession up the ramp. Again, this seems pretty likely to me and may well have played an important role in Chaco’s rise to preeminence regionally.

The rooms at the top, on the other hand, appear to date much later than the ramp and to have had a quite different purpose. The pottery on them is overwhelmingly late, mostly thirteenth-century, and the construction of the rooms is rather slapdash by Chacoan standards. Extensive remains of the debris of daily life indicate that they were occupied residentially. Based on these characteristics, Malville suggests that these rooms were used as refuges by the thirteenth-century residents of canyon floor sites like the Gallo Cliff Dwelling during times of upheaval and violence. He associates them with the widespread pattern of “pinnacle” refuge sites throughout the northern Southwest during this period, which is very different from the residential patterns of the much more peaceful Chacoan heyday in the eleventh and early twelfth centuries. He notes that most of the rock art on the butte was clearly accessed from these rooms, which suggests strongly that it dates to this late period rather than earlier.

This mention of rock art brings us to what might be considered the punch line of the paper: a reevaluation of the famous Sun Dagger spiral petroglyph with its alignment to the winter solstice. Malville proposes that the “sun dagger” alignment around noon on the solstice at the site with three rock slabs was discovered serendipitously by the thirteenth-century residents of the upper butte, who pecked the spiral petroglyph to mark it. This is quite different from the interpretation that others have made, that it was a primary focus of ritual during the height of the Chacoan era, but it does explain some odd things about it pretty well. The spiral could not have easily served a direct calendrical role in calculating the date of the solstice, which some other petroglyphs with astronomical alignments elsewhere in the canyon could have done, and its noon alignment is both not particularly precise and not documented to be of particular importance in modern Pueblo religion.

Most importantly, however, this theory explains something that has always puzzled me about the Sun Dagger: it no longer works. That is, the alignment of the slabs no longer results in a dagger going through the center of the spiral. This is generally thought to be the result of the ground underneath shifting as a result of too many interested people going to look at it in the period between its (re)discovery in 1978 and its closure to general visitation in the 1980s. If this really was a key site visited by at least some Chacoan ritual specialists for hundreds of years, after which it remained intact for several hundred more years until its rediscovery, why did it only take a few years for modern visitors to impact it enough to ruin the alignment? One possible answer was that it was so important in antiquity that it was only visited by very few people with particularly important roles, and may not even have been widely known about among the general population. Malville’s theory provides what I find a more plausible answer, that it was discovered late in the prehistoric occupation of Chaco by the small population who occasionally retreated to the top of the butte for refuge, and it may not even have been particularly important to them. There is extensive evidence in modern Pueblo ethnography for individual people marking astronomical alignments and keeping solar calendars, apart from the formal roles of Sun Priests and so forth to do so for the community. (Indeed, there is evidence that some people did this because they didn’t trust the Sun Priest to get it right.) I think it makes sense to interpret the Sun Dagger as part of this tradition. (Malville also notes that recent reevaluation of the supposed secondary alignments to lunar standstills and other astronomical events hasn’t confirmed that they are real and deliberate.)

Malville’s conclusions about the Sun Dagger are controversial in some circles, I’m sure, but for the more interesting part of this paper is the part about the early alignments between the butte and sites in the Fajada Gap community. This provides nice support for the theory I’ve suggested that the rise of Chaco was due in part to it being the place where certain kinds of astronomical knowledge were first developed or introduced within the (northern?) Southwest, which gave the canyon and its residents a kind of spiritual power that they were able to translate into considerable economic and/or political power, as manifested in the monumental architecture, exotic trade goods, and other things that make Chaco such an impressive place even today.


Fajada Butte with Green Vegetation


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Changes at Chaco


New Chaco Canyon Visitor Center Exterior

Today is my birthday. I’m 33. As I’ve often done in the past few years, I’m in New Mexico this week visiting my mom. This time I decided to come visit Chaco Canyon, which I hadn’t done in quite a few years. Weather meant I couldn’t spend as much time there as I wanted this time, but I did get to see some of the changes since my last visit.


Interior of New Chaco Canyon Visitor Center

The most obvious change is the new Visitor Center. This was under construction the last time I was there, and visitor services were operating out of a temporary yurt. The yurt worked fine, but the new VC is quite nice. Importantly, it now has the wall map of the canyon on the north wall rather than the south one, so that the directions you point to on the map are the same ones as in real life. This was a constant source of confusion and frustration when I was working at Chaco, so it’s nice to have it fixed now.


Windows on East Side of New Chaco Canyon Visitor Center

The east side of the VC now has some exhibits on the geology of Chaco, as well as a series of picture windows with a nice view of Fajada Butte. The main museum is still being renovated so I wasn’t able to see it, but I’m sure it’s nice. The old one was getting quite outdated and really needed an update.


New Sign at Pueblo Bonito

There were a few other differences I noticed, like new signs in various places and further deterioration of some of the exposed wood, and I’m sure I would have noticed more changes if I’d been able to spend more time. Still, the main features of the canyon are of course the same and just as impressive this time as the many times I’ve seen them before.


Old Bonito: A Little More Wear, but Mostly the Same as Ever

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Entrance to Room 33, Pueblo Bonito

A fascinating and important article about Chaco was published last week in Nature Communications, an open-access offshoot of the venerable journal Nature (already a good sign). Since it’s open-access, the full text of the article is available free online here.

The researchers behind the article, based mainly at Penn State and Harvard but also including Steve Plog at the University of Virginia and a couple of people at the American Museum of Natural History, sequenced the mitochondrial genomes of several of the people buried in Room 33 at Pueblo Bonito in an attempt to determine if they were related. This addresses a number of outstanding issues in the interpretation of the Chaco Phenomenon, particularly those revolving around the political economy of Chaco and the degree to which it was a hierarchical society. They also radiocarbon-dated the remains and did some additional genetic analysis to confirm the sexes of the people and try to determine any close genetic relationships among them.

The results were striking. All of the tested remains had identical mitochondrial genomes, indicating that they were all related through the maternal line, which in turn suggests strongly that Chaco was a matrilineal society in which this particular maternal lineage had an enormous amount of power and wealth that led it to have the most elaborate burials in the history of Pueblo societies. The radiocarbon dating suggests in addition that people from this lineage continued to be buried in the special crypt in Room 33 throughout the florescence of Chaco, starting in the early ninth century AD and continuing until the early twelfth century. (What exactly happened then remains obscure.) The DNA sex determinations matched those previously determined through osteological analysis 100% as well.


Old Bonito from Above

These results, which are based on carefully controlled analyses and seem very solid, are not exactly surprising, but they do provide apparent confirmation of certain models of Chaco and apparent falsification of others. Specifically, they support models involving robust social hierarchy and inequality, with some lineages having more authority than others and one at the top. Most recent evidence has pointed in this direction, but this study is a particularly strong support for it. Also, they provide support for the idea that Chacoan society was more like the ethnographic Western Pueblos, which are matrilineal and structured around kin groups known as “clans” that derive their power and status from their control of esoteric religious knowledge, than the Eastern Pueblos, which are patrilineal and structured around non-kin-based groups known as “societies” that derive their power and status from similar bases. (If this distinction seems fairly minor, that’s because it is. But in attempting to reconstruct historic societies it’s important.)

It’s important to note that while these results do provide support for a matrilineal model of Chaco, that’s very different from saying they support a matriarchal one, as some media coverage I’ve seen has either implied or stated explicitly. Reckoning descent through the mother’s line is very different from having women run things with men in a subordinate position. The former is quite common cross-culturally, while I’m not sure if the latter exists at all in the ethnographic record. The fact that several of the people buried in Room 33 appear to have been related maternally doesn’t negate the fact that the two most elaborate burials were both of men, and in general there’s no reason to think that Chacoan society wasn’t strongly patriarchal, and plenty of reason to think it was.

Finally, from a methodological perspective this is a particularly interesting paper. The authors say that it appears to be the first use of genomic analysis to determine family relationships in a prehistoric society (i.e., without the availability of written records to check the results). I’m not completely sure that’s correct, but this has certainly not been a common type of study. In discussing DNA evidence a while back, I mentioned that in the Southwest it had mostly been used so far just for determining mitochondrial haplogroups, which provide some useful information but not nearly as much as can be provided by genomic analysis, which at that time hadn’t really been used at all in the Southwest. This paper marks the first major use of this type of analysis in the region, and it shows how powerful it can be. Now that the precedent has been set, it can be used in other contexts to see where this particular matrilineage shows up elsewhere in Southwestern prehistory both before and after Chaco, as well as to address other issues of kinship and identity within Chaco.
Kennett, D., Plog, S., George, R., Culleton, B., Watson, A., Skoglund, P., Rohland, N., Mallick, S., Stewardson, K., Kistler, L., LeBlanc, S., Whiteley, P., Reich, D., & Perry, G. (2017). Archaeogenomic evidence reveals prehistoric matrilineal dynasty Nature Communications, 8 DOI: 10.1038/ncomms14115

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Room 33, Pueblo Bonito

In my post about the recent radiocarbon dating of macaw remains from Chaco Canyon, I mentioned another paper I’ve been meaning to post about. Published in 2010 by Steve Plog and Carrie Heitman of the University of Virginia, it takes a close look at burial practices at Chaco, particularly focusing on the northern burial cluster within Pueblo Bonito. Within that cluster it focuses on Room 33, the location of the most elaborate burial assemblages ever found in the Southwest.

Plog and Heitman take advantage of their Chaco Archive project, which is collecting and making available lots of archival material on excavations at Chaco that was previously very hard to access, to look back at the field notes from the excavators of Pueblo Bonito, particularly those of George Pepper, who excavated this part of the site in the 1890s as part of the Hyde Exploring Expedition. Pepper took very detailed notes, especially by the standards of the time, and particularly for the rooms in the northern burial cluster he kept track of artifact locations and the positioning of skeletal remains, which makes it possible for Plog and Heitman to plot the vertical and horizontal positions of the burials and grave goods in Room 33 to see what patterns there may be.

They find some interesting patterns in the burial and artifact locations, but the most important data they report are radiocarbon dates, directly on the bones, from ten of the burials, including the ones with the most elaborate funerary assemblages, known as Burials 13 and 14. Burials 13 and 14 had actually already been dated for a different study a few years earlier, which I have discussed before, but Plog and Heitman redated them to see if they the earlier results would be replicated. (They were.)

At this point I should back up and review some basic facts about Room 33 and its burials, as well as some assumptions that had seeped into the Chacoan literature over the years despite not being well-supported by evidence.


Type I Masonry in Room 33, Pueblo Bonito

Facts: Pepper found 14 identifiable individual burials in Room 33. He numbered them in order of discovery, which roughly corresponds to vertical distance from the roof beams, so 13 and 14 were the lowest. Burials 13 and 14 had the most elaborate grave goods by far, including vast numbers of turquoise beads and other ornaments. They were intact and undisturbed, and were separated from the higher burials by a “floor” of wooden planks. The burials above this floor were accompanied by grave goods, but they were mostly disarticulated and appeared to have been disturbed at some point after burial. Pepper proposed that they had been scattered by water flowing into the room at some point.

Assumptions: At some point over the years, the idea entered the literature that these burials dated to the time of the “florescence” of Chaco starting around AD 1030 and lasting for about 100 years. Despite the fact that Room 33 is in the oldest part of Pueblo Bonito and its masonry style indicates that it dates to early in the site’s construction, many archaeologists (starting with Pepper himself) have suggested that it was not originally constructed as a mortuary chamber, and that the burials reflect a reuse of a room that originally had a different purpose. I don’t know where the idea that this reuse coincided with the rise of Chaco as a regional power, or with the advent of monumental construction in the canyon at roughly the same time, originated, but it makes a certain amount of intuitive sense to see the establishment of a crypt with unusually elaborate grave goods would happen at the same time as the enormous labor effort reflected in the expansion of Pueblo Bonito and other early great houses, along with the building of many new ones. However, it’s important to note that there was never a rigorous argument made for a late dating of the burials, bringing in support from the pottery styles reflected in the grave assemblages or any other independent lines of evidence.

And, in fact, the most comprehensive study of Chaco burials to date, that of Nancy Akins as part of the Chaco Project in the 1970s, concluded that the pottery types in Room 33 covered a potentially long timespan, which could mean the burials themselves were deposited over a long period of time. On the other hand, it could also mean that certain “heirloom” vessels of styles that were no longer being produced but that had been kept around might be buried with particularly important people, so this evidence wasn’t dispositive about the late-burial theory.


Old Bonito from Above

Plog and Heitman’s radiocarbon dates, on the other hand, provide firm evidence that the burials do indeed date to a long period, more or less corresponding to the full span of Chaco’s importance as a regional center. Burials 13 and 14 both date to quite early in the history of Pueblo Bonito, with 95% confidence ranges of AD 682 to 870 and 687 to 870 respectively. When averaged with the dates from the earlier study, which were comparable but slightly later, the 95% ranges become AD 691 to 877 and 690 to 873.

That’s very early! It means that these two burials, at least, could easily have occurred at the same time as the initial construction of Room 33, which was likely in the late ninth century. One other burial above the plank floor dates to this period as well. (The bones got relabeled at some point and it’s not clear which sets correspond to which numbers assigned by Pepper, so it’s not possible to say for sure that this was one of the burials immediately above the floor, but it’s a reasonable surmise.) Despite the near-identical age determinations on Burials 13 and 14, the vertical distance between them is by far the highest in the room. This suggests strongly that the large amount of sand separating the two vertically was brought in deliberately rather than accumulating naturally, and they could well have occurred at exactly the same time, or nearly so, very early in the occupation of Pueblo Bonito.

From then on, the dates are more or less continuous up to around AD 1200. The ranges are too wide to come to very firm conclusions on exactly where these later burials fall in the Chacoan sequence, but they do suggest that Room 33 continued to be used as a high-status burial chamber throughout the Chaco Era after beginning to serve that role early on.

This is all very interesting, and Plog and Heitman draw a number of tentative conclusions from it. They argue that this shows that social hierarchy arose earlier in the canyon than often assumed, well before the beginning of construction on a monumental scale, and suggest that the concept of “house society” may be a useful way to interpret Chacoan great houses, with symbolically important spaces like Room 33 serving to legitimize the position of elites through a connection to illustrious ancestors. They also argue that the preservation of the delicate placement of burials and artifacts, as demonstrated in Pepper’s notes, makes it very implausible that the scattering of remains he mentions could have resulted from water intruding as we suggested. Instead, they suggest that some of the scattering could have resulted from disturbance of earlier burials in the course of creating new ones in this small space over the centuries. Another possibility they suggest is that some of the burials are actually secondary, and were placed in Room 33 after having been left to decompose somewhere else for a while. This practice is not documented among the historic Pueblos, but then again lots of the other aspects of the Room 33 burials don’t have obvious modern parallels either.

The evidence for unexpectedly early import of macaws starting around AD 900 in the more recent paper reinforces the evidence in this one for an early development of complexity at Chaco. It’s still not clear exactly what was going on at Chaco in the ninth century, but it’s becoming increasingly clear that it was very important for the subsequent history of the canyon and of the Southwest as a whole.
Plog, S., & Heitman, C. (2010). Hierarchy and social inequality in the American Southwest, A.D. 800-1200 Proceedings of the National Academy of Sciences, 107 (46), 19619-19626 DOI: 10.1073/pnas.1014985107

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Welcome Sign at North Entrance to Chaco Canyon

Today is the centennial of the establishment of the National Park Service on August 25, 1916. It’s getting more media attention than I had expected, although I had noticed that the NPS had mounted a noticeable publicity campaign in the lead up to the date itself, so I probably shouldn’t be surprised. Anyway, it’s a good milestone to mark. I have my issues with the way the NPS works and some of the things it does and has done, but it’s definitely a hugely important institution both to the country as a whole and to me personally.

I started this blog in December 2008 when I was working for the NPS at Chaco Canyon, and the early posts were mostly attempts to put the information from my tours and my background reading into a more permanent form so I could refer people to them long after I had left the park and moved on to other things. It’s worked quite well for that, although in the meantime the internet has moved on and blogs like this are much less of a focus for interaction than they were then. I’ve kept it up, though at a much less frequent pace of posting, because I like having a platform like this to talk about the things that interest me, and I now have a fairly small but consistent reader base that is interested as well. (Which is not easy to find for what is after all a pretty esoteric interest.)

But beyond being the starting point for this blog, the NPS is an important institution for setting me on the path my life has taken in more general ways too. That job at Chaco allowed me to really delve deep into the backstory of the area where I was born and where my family has a long history (at least by white-people standards). What I learned there has had a profound effect on my life since in all sorts of ways, and I expect that to continue indefinitely. This blog may have slowed in posting frequency in recent years, but it’s not from any decline in my interest in the subject matter, which I’m sure I will continue to write about for many years to come, not necessarily just here. I have some ideas for books I might want to write on related topics at some point, although I’ve been realizing recently that it’s awfully hard to find the time for a project of that magnitude while also working full time. But someday.


Welcome Sign at Alaska/Yukon Border

The influence of the Park Service on my life goes even further than the Chaco stuff, though. It was an internship with the NPS that brought me to Alaska a little less than five years ago, and my experience there, while frustrating in some ways, led me to discover the first place I had ever lived where I could seriously imagine living permanently. It’s not at all clear that I will actually end up settling down here, and the Alaska of 2016 is so different from the Alaska of 2011 that it’s hard to even explain the difference. But that feeling of finding a place I liked enough to stay, even if I didn’t necessarily have a lot in common with most of the people here, was important to me and it set a standard that anywhere else I might end up will have to meet or exceed for me to stay permanently. And I have the Park Service to thank for that too.

I may or may not ever work for the NPS again. My career path has never been along an established route, and I have no idea how much longer I’ll stay in my current job or what I’ll do next. Some of the most important factors in the future of my career are totally out of my control. But others are mine to control, and I’ll probably have to make some serious decisions in the next few years, if not sooner, about where I want my life to go next. I have to be honest that working for the Park Service again is not my top choice for a next step. It really was a frustrating place in some ways, for a variety of reasons, some of which are I think inherent to the structure and culture of the agency. But it’s a large organization, and I’m sure there are some positions within it that I would find congenial, so it’s definitely still on the list.

Anyway, despite my ambivalence about it, the Park Service has done a lot of good for me and I am very appreciative of that. I’m very happy to celebrate 100 years of this complex, occasionally infuriating but just as often inspiring, American institution. Happy birthday, NPS!


National Park Service Alaska Regional Office, Anchorage, Alaska

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Macaw Feathers and Copper Bell on Display at Chaco Visitor Center Museum

One of the most exciting recent developments in the study of Chaco Canyon is the increasing use of scientific analysis of artifacts and other material remains to test and challenge previous theories based more narrowly on traditional archaeology. This includes the use of radiocarbon dating, which is widely used as a basis for developing chronologies in most other parts of the world but has been underused in the Southwest due to the availability of tree-ring dating for chronology building. Particularly with the development of accelerator mass spectrometry (AMS) radiocarbon dating, which requires vastly less material than earlier methods, however, it is now possible to gain direct dates on a very wide variety of materials, including many artifact types as well as plants and human and animal bones. This allows an independent check on dating of material by association with tree-ring dated architecture and pottery, which has been the traditional approach. The increasing use of AMS on the museum collections excavated decades ago from Pueblo Bonito, in particular, is starting to lead to some unexpected and surprising conclusions. This work is largely being done by archaeologists associated with the University of Virginia led by Steve Plog, in collaboration with colleagues at many other institutions.

One recent paper, about a year old now, reported some surprising results from the dating of the bones of one of the most distinctive species found at Chaco: scarlet macaws. These birds are not native to anywhere near the Southwest, and they must have been brought up from very far south in Mexico. They are disproportionately found at only a few sites in the Southwest, one of which is Pueblo Bonito. Traditionally it has been thought that the importation of macaws was associated with the “florescence” of Chaco, the roughly 100-year period starting around AD 1040 when most of the monumental great houses in the canyon were built and Chacoan influence is seen over a very large part of the northern Southwest. For this study, the researchers dated 14 macaws from Pueblo Bonito: 11 from Room 38, which had the highest concentration of macaw remains at the site, two from Room 78, and one from Room 71. Both of these latter rooms are in fairly close proximity to Room 38 within the site. They also dated four macaws from Mimbres sites in southwestern New Mexico, another area with a relatively high concentration of these birds that lies between Chaco and Mexico and thus could played a role in their procurement, and two from Grand Gulch in Utah, which is on the far fringes of the ancient Pueblo world and yet has produced a few macaw specimens.

The results were surprising, and they challenge the traditional association of macaws with the Chacoan florescence. Six of the Chaco birds dated to between AD 885 and 990 (all dates given here are at 95% probability), well before the florescence and a time when Chaco would have been much less impressive architecturally. This is, however, a time when population in the canyon was increasing rapidly through immigration from various areas that were affected by the big changes at the end of the Pueblo I period, as we have seen in my recent series of posts on Pueblo I. The authors of this paper don’t mention this population movement specifically, but they do suggest that this indicates that the later period of monumental construction and other signs of sociopolitical complexity was the result of a long period of developing complexity, which fits the demographic evidence pretty well.


Room 38, Pueblo Bonito

Six other birds date between AD 970 and 1035, which would put them shortly before or possibly at the very beginning of the florescence and building boom. This suggests that trade relations with the far south continued beyond the initial period when macaws were introduced to the canyon. The final two date between AD 1015 and 1155, which suggests they probably were procured sometime during (or even shortly after) the period of florescence. Overall the dates suggest that macaws were procured throughout most of the period of Chaco’s rise from the period when Chaco was first rising to regional preeminence in the ninth and tenth centuries until its loss of preeminence (I think “collapse” is too strong a term for this still poorly understood phenomenon) in the twelfth.

One thing you may have noticed about those date ranges, however, is that they all overlap. Given the statistical uncertainty of radiocarbon dates, this means that it’s possible that these dates indicate a continuous process of importation of macaws from Mesoamerica. (There is no evidence for breeding of macaws at Chaco, unlike at the later site of Casas Grandes in northern Chihuahua.) The clustering of sets of dates, however, suggests on the contrary that importation was sporadic, with possibly just three individual procurements of multiple birds at a time. And additional complication is that the shape of the radiocarbon calibration curve differs at different times through this sequence, which can lead to certain time periods being over- or under-represented in series of dates. To test these hypotheses, the authors did some simulation of random dates throughout the period in question and compared the resulting distributions with the actual distribution of macaw dates. The results were that the early cluster of dates did conform to what might be expected from the effects of the shape of the curve, the middle cluster had more dates than would be expected and the late cluster fewer. This suggests that while it is possible that procurement of macaws was a continuous process, it does appear that a larger number of birds were imported in the late tenth and early eleventh centuries than earlier or later. Of course, this is a small sample, and these apparent patterns may change with more data.

As for the non-Chaco macaws, one of the Mimbres ones dated to AD 895 to 1020, straddling the first two clusters of dates at Chaco, while the other three all dated from around AD 1015 to 1155, as did the two Grand Gulch specimens. This suggests that macaws were present earlier at Chaco than in areas to either the north or south, which further suggests that at least initial importation of macaws to Chaco didn’t necessarily depend on Mimbres middlemen. Macaws have also been found at Hohokam sites in southern Arizona that appear to be in earlier contexts than the ones at Chaco, but none of these have yet been directly dated.


Room 33, Pueblo Bonito

While it may appear initially surprising, the early dates for macaws at Chaco do actually fit with increasing evidence from other sources suggesting that the rise of Chaco and its social and economic power significantly predated its “florescence” as seen in monumental architecture. This includes a study from a few years ago, from the same group of Virginia researchers, that dated human remains from Room 33 in Pueblo Bonito, including the two burials that were associated with enormous numbers of valuable grave goods, and found those two burials long predated the Chacoan florescence and may in fact have been contemporary with the earliest construction at the great house in the mid-ninth century or even earlier. (That paper really deserves a post of its own, which I keep meaning to write, but this brief summary will have to do for now.)

Taken in conjunction with the evidence for regional population movement in late Pueblo I, this study provides more support for the idea that the influx of populations into the canyon in the late ninth century, some bringing ideas developed in the earlier short-lived villages to the north in Colorado, set the stage for the development of new ideas about social organization and hierarchy which may have led to new ideologies and the importation of both goods and ideas from areas far away. The fact that macaws would have to have come from the south, where the archaeology of areas immediately adjacent to the Chacoan region is much more poorly known than that of comparable areas to the north, points to the importance of developing a better understanding of those areas. We still know very little about the exact routes of trade connections to the south, even as the importance of those connections becomes increasingly apparent.
Watson, A., Plog, S., Culleton, B., Gilman, P., LeBlanc, S., Whiteley, P., Claramunt, S., & Kennett, D. (2015). Early procurement of scarlet macaws and the emergence of social complexity in Chaco Canyon, NM Proceedings of the National Academy of Sciences, 112 (27), 8238-8243 DOI: 10.1073/pnas.1509825112

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Third-Story Walls with Type I Masonry at Una Vida

The final chapter in Crucible of Pueblos offers, in the words of its title, “a synthesis of sorts.” Authored by the noted Chaco specialist John Kantner, it gives a brief chronological overview of the period covered by this book, combining the information from the other chapters to create a picture as complete as possible given current evidence. As Kantner notes several times, current evidence is very sparse for certain regions and periods, and the resulting synthesis is therefore tentative on many issues.

Kantner starts with the period AD 600 to 725, which some but not all of the regional chapters cover. He focuses on the idea that this period was marked by a “Neolithic Demographic Transition” of the sort seen in other parts of the world following the adoption of agriculture. In this case he sees the catalyst for the transition not being the initial introduction of domesticated plants to the northern Southwest, which an increasing body of evidence has shown was actually much earlier, but on the idea that new varieties of maize that were introduced at this time caused a widespread shift to a farming-based lifestyle, whereas earlier cultigens had just been added into a hunting and gathering system as a minor component. This theory has been advanced by several archaeologists in recent years, and it is certainly plausible, but I think the data is still not quite there to establish it firmly. In any case, Kantner sees the immediate result of the shift to intensive agriculture being a sharp increase in population, which led at least in some areas to increases in site size (but only to slightly larger hamlets in most cases), as well as possibly to violence and warfare, as evidenced by an increasing number of stockaded hamlets. Sites were still generally quite small and loosely clustered around a variety of types of public architecture. He claims not to see much evidence of migration between regions during this period, which sounds dubious to me given how much we see later. As he acknowledges, though, the data for this early period is particularly limited, especially for less-researched areas, and it’s hard to draw any firm conclusions.

His next period, AD 725 to 825, definitely does show a lot of migration, and Kantner sees that and increasing settlement aggregation as being the two major processes evidence in the archaeological record. Data gaps are an issue here as well, however, and the details of these processes are much clearer in some regions (especially the Northern San Juan/Mesa Verde area) than others. All this migration and aggregation seems to have led to increasingly ethnically diverse communities, although identifying “ethnicity” in this sort of context is tricky as material culture traits that might be used to identify groups don’t always cluster neatly. Despite this diversity, Kantner sees less evidence in this period for violence than in the previous one, at least until the very end of it when there are some spectacular examples like the apparent massacre at Sacred Ridge, which may have been ethnically motivated. Less spectacularly, the presence of defensive sites in Southeast Utah also seems to increase at the end of this period, again suggesting conflict. Interestingly, though, there seems to be little or no evidence for this sort of conflict further south, although again it’s important to note that southern regions have seen much less research. This period saw possibly the earliest examples of settlements aggregated enough to call “villages,” although Kantner notes that a large portion of the population was still living in dispersed hamlets. The question of why some but not all people chose to begin living in greater proximity is an important one that remains largely unanswered.

The trends of migration and aggregation continue into Kantner’s next period, AD 825 to 880. This is especially apparent in the well-studied Central Mesa Verde region, but it appears to have continued in other areas as well, with a general trend toward settlement in well-watered areas, which may signify another episode of agricultural intensification. This is also suggested by the increased storage capacity of the new villages, some of which might indicate community-level storage of grain. Kantner notes that larger villages might also have been able to mobilize more people for hunting and therefore increased hunting success, a reminder that even a heavily emphasis on agriculture doesn’t necessarily replace all other subsistence pursuits. There also is some evidence for changes in gendered labor at this time, again likely tied to subsistence changes: greater emphasis on stored food, presumably largely in the form of cornmeal/flour, would require more time spent on particular types of processing work. This would potentially include both grinding itself and other tasks required by new ways of preparing food, especially making more pots in which the ground meal would need to be cooked. These are presumed to have been primarily female tasks, so the increased time investment in them may have affected gender roles and relations between the sexes. This is an interesting idea that I think could use more elaboration.


Great Kivas A and Q, Pueblo Bonito

Public architecture continues to be diverse but there are some interesting patterns in what types occur in the new villages, especially between great kivas and what Kantner (among others) calls “oversized pit structures.” He makes some suggestions about correlations between these architectural forms and other factors, such as the idea that great kivas may be associated with periods of social instability and the idea that oversized pit structures were more exclusive than great kivas but the ritual in them may have been more ostentatious, judging by the unusual deposits left behind, such as exotic animal remains and redware pottery. He notes the theory that oversized pit structures and their accompanying U-shaped roomblocks may have been associated with emerging ritual leaders, who may have competed with each other for status and power based on their increased storage capacity, access to game meat, and possibly capacity to control craft activities as well. I think there’s a lot of merit to this idea, although it does still rely quite heavily on data from the well-studied Central Mesa Verde area and new research elsewhere might complicate it.

It’s worth noting again, however, that despite the many very visible and interesting changes resulting from increased aggregation a large portion of the population was still living outside of villages. How these people would have interacted with the villages and how their lives might have differed are under-studied but important questions.

Kantner refers to his next and last period, starting in AD 880, as “the Dawn of Chaco,” which seems reasonable given the emerging picture. The key change at this time is the abandonment of the villages that arose in the previous period and the almost complete abandonment of the Central and Eastern Mesa Verde regions, with their residents apparently moving both west into Utah and south into New Mexico, where some of them very likely contributed to the early development of the regional center at Chaco Canyon. This may have been associated with a period of favorable rainfall in the Chaco area compared to a difficult time in the north, but the climatic details are not yet clear. Kantner notes that recent evidence has suggested that the prior population in the Chaco area was a lot smaller than had once been thought, but he also notes that there definitely was an existing population in and around Chaco, and that some sites like Pueblo Bonito were already established before this migration. This population seems to have had ties to the south and was likely different ethnically from the people moving in from the north. There is some evidence for violence that might have accompanied the initial stages of the migration, but it appears that the groups reached an accommodation of some sort over time that led to the development and florescence of the Chaco Phenomenon over the next three centuries. Kantner suggests that the instability of the early period, and possible inequities between the groups, may have contributed to this process of “social elaboration,” which is another interesting idea meriting further study. There are some clear continuities in architecture between the earlier villages and the communities that developed at Chaco, but the question of what had changed to make Chaco so much more successful and long-lived than the northern villages remains open.

In closing, Kantner reiterates some of the caveats he has mentioned before about interpreting this emerging picture. Why didn’t everyone join villages? This seems like a particularly important question to me, and one that has not received enough attention in the development of aggregation models. It’s a particular problem for models that emphasis “push” factors like the need for defense in an increasingly crowded landscape, though Kantner suggests that this may have been a bigger factor for immigrant groups entering a potentially hostile new area than for the indigenous groups they encountered. He has more discussion of “pull” factors, such as economies of scale for intensified work on activities like farming, hunting, and craft production, but ultimately suggests that a complex combination of pushes and pulls may account for the notable variation in village forms that we see throughout this period. Another important question is why these early villages failed. Kantner suggests changes in the above-mentioned balance of push/pull factors, as well as the possibility that aggregation created its own new problems and stresses on the emerging social systems. Whatever the details, it seems increasingly clear that the lessons from the complicated processes covered by this book formed the basis for the later emergence of Chaco and the immense changes in the Pueblo world that it would entail.


Sign at State of New Mexico Archives Building, Santa Fe, New Mexico

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