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Animas River, Durango, Colorado

Animas River, Durango, Colorado

The fourth chapter of Crucible of Pueblos discusses the eastern portion of the Mesa Verde region, essentially the northern portion of the watershed of the San Juan River from the La Plata drainage east to the San Juan headwaters. This area has seen less research than some other parts of the Southwest, but several major salvage projects in recent decades have added a lot of data on Pueblo I period settlement in particular. The most important of these has been the Animas-La Plata Project associated with the inundation of Ridges Basin to create Lake Nighthorse south of Durango. These projects haven’t revolutionized our understanding of the Pueblo I period the way the Dolores Project did in the Central Mesa Verde region in the 1980s, but they have added large bodies of systematically collected data to broaden our understanding of the period.

The picture that emerges from this evidence shows the Pueblo I period to have been a dynamic, complex time in this region. Indeed, in some respects “chaotic” might be an appropriate descriptor. Population movement, both within the region and between it and other regions nearby, was frequent, sites were short-lived, and evidence for violence is abundant. The population fluctuated wildly but was never very large compared to other areas, but even this small population seems to have been culturally and perhaps ethnically diverse, which may have contributed to the instability and violence. Some of the earliest aggregated villages in the northern Southwest arose in this region during the eighth century AD, but they all appear to have been highly unstable: none lasted more than a few decades, and most appear to have met violent ends. Perhaps relatedly, these villages never held more than a small portion of the overall regional population, in contrast to early villages in some other regions. By the end of the Pueblo I period around AD 900 most parts of the region were largely depopulated, with the residents apparently moving primarily to the south, where many of them likely ended up at Chaco Canyon and were involved in the rise of the Chaco Phenomenon over the course of the tenth and early eleventh centuries.

The authors of this chapter divide their region into four “districts”: La Plata, Durango, Piedra, and Navajo Reservoir/Fruitland. While showing similarities in material culture suggesting connections with each other, the districts have markedly different demographic trajectories, and it seems clear that there was significant population movement among them over the course of the Pueblo I period.

Despite an earlier Basketmaker II occupation, Basketmaker III period settlement was limited to nonexistent in most of the districts, implying that the Pueblo I occupation was primarily the result of migration into the region. Only the La Plata district shows clear evidence for a small BMIII occupation, and even this is probably too small to account on its own for the larger population in the district during Pueblo I. It appears, then, that beginning in the AD 720s there was a migration of people into the La Plata and Durango districts, probably from the south. Site densities increased markedly around 750, especially around Durango, suggesting a further wave of migration, again from the south. It was at this time that the earliest villages began to develop in these areas, although most of the population continued to live in widely scattered hamlets and individual residences. These villages were short-lived and seem to have collapsed in the early 800s, in some cases with evidence for intense violence including, at Sacred Ridge in Ridges Basin, the earliest evidence for the sort of “extreme processing” (probably including cannibalism) of human remains that would recur periodically in later periods of Pueblo prehistory.

The collapse of the early villages in the Durango district appears to have coincided with a general depopulation of that district, with residents emigrating in multiple directions. Some went west and appear to have contributed to the rise of large villages in the Central Mesa Verde region, particularly in the Dolores area, where one large and well-documented community, Grass Mesa Village, shows evidence in its material culture for strong ties to the east. Other Durango people may have gone south into the Frances Mesa area in the lower Animas River valley, possibly mixing with other groups migrating north at the same time. This occupation was short-lived and may have ended with the people moving north into the Dolores area to join the villages there. Some Durango people may also have gone east to form the first Pueblo I occupation in the Piedra district, although this area has seen less research than others and the picture isn’t as clear. Recent surveys do suggest that the Piedra was somewhat marginal to developments elsewhere in the region during Pueblo I, and that its population was both smaller than had been thought and mostly limited to the late Pueblo I period. The fate of the La Plata population is less clear, but there is a definite decline in site numbers after AD 800 coinciding with an increased number of sites in the Mancos River drainage to the west, suggesting emigration to the west there as well.

Chimney Rock Great House

Chimney Rock Great House

As it turned out, the Dolores villages weren’t very stable either, and after their collapse in the mid- to late ninth century people seem to have migrated back into the eastern Mesa Verde region. A surge of immigration into the Fruitland/Navajo Reservoir district after about 880 contributed to the highest regional population of the whole Pueblo I period, although it still wasn’t very high (3,000 people at most regionwide, and likely more like 2,000). The Piedra district also saw a considerable increase in population at this time. The Fruitland/Navajo Reservoir occupation was short-lived, with more evidence of violent ends for some village sites, and it seems that most or all of the people moved south, with at least some of them joining the growing communities in and around Chaco Canyon. There may have been some migration south from the Piedra district as well, but it continued to be occupied into the Pueblo II period after 900. The Piedra people seem to have been somewhat isolated from developments elsewhere in the Pueblo world during early Pueblo II, which is unsurprising given that they were left quite isolated geographically by the depopulation of the Animas drainage and Navajo Reservoir area. They don’t seem to have been completely cut off, however, and ongoing contact with Chaco in particular is suggested by the development of the Chimney Rock great house with its remarkable astronomical alignments in the eleventh century.

There are several noteworthy characteristics of this pattern of settlement and migration, which the authors of this chapter point out. One is the obvious importance of population movement, versus natural increase or decrease, in explaining the wild demographic swings both in the region as a whole and among its individual districts during this period. It was a very dynamic period, when people rarely lived in the same place for more than two or three generations. It’s not clear entirely why, but one reason is likely linked to one of the other noteworthy characteristics: widespread violence, including some of the most extreme violent incidents in the whole archaeological record of the Southwest. Interestingly, much of this violence, including the “extreme processing” incident at Sacred Ridge, appears to have been linked to internal conflicts within communities, especially the early villages. This may in turn explain why relatively few people in this region lived in villages, although it still leaves open the question of why anyone did. The authors suggest that one factor may have been the perception of safety in numbers in a chaotic era, although this ultimately proved to be illusory. It’s not clear to what extent warfare between communities was actually occurring, however, and the widespread popularity of a scattered settlement pattern suggests it may not have been that major a concern for most people. On the other hand, palisades around individual residents units are fairly common in the region, so it may be primarily a matter of different strategies for dealing with violence.

One other noteworthy thing about the violence is that the “extreme processing” phenomenon appears to have been exclusive to the eastern Mesa Verde region during this period. This is interesting because in later periods it occurs in other regions, most notably in the Central Mesa Verde region during the mid-twelfth century, where it is possibly associated with the collapse of the Chaco system. There has been much dispute and discussion about the occurrence of cannibalism as part of at least some of these assemblages, which I’ve discussed at length before. The fact that it appears earliest in the eastern Mesa Verde region during Pueblo I, when it appears to be limited to that region, adds an important piece of context for understanding the phenomenon. While the occurrence of ritual cannibalism in Mesoamerica has led some to look there for the roots of cannibalism in the Southwest, there are some important differences in the apparent practices behind the assemblages that make a Mesoamerican source difficult to document, and if the eastern Mesa Verde region was in fact the part of the Southwest where these practices originated that makes the Mesoamerican connection even more tenuous. While the exact connections between specific Basketmaker and Pueblo populations in different areas are hard to pin down, it’s generally thought that the eastern Basketmakers were both ancestral to later Pueblo populations in the same areas and descended from earlier Archaic populations. Importantly, these eastern groups generally show much less evidence for Mesoamerican influence than western groups, among whom “extreme processing” events are both much rarer and, when they do occur, much later than in the east. Obviously it’s not that there was no Mesoamerican influence among eastern groups, since they did have maize agriculture and so forth, but there’s much less evidence for specific, direct influence than in the west. This implies that “extreme processing,” including cannibalism, may actually have been a practice that developed indigenously in the eastern Mesa Verde region and spread to other parts of the northern Southwest as part of the widespread population movements following Pueblo I.

Finally, the violent and chaotic nature of the Pueblo I period in the eastern Mesa Verde region, whatever the underlying reasons for it, adds some context for the attractiveness of new social formations in other regions, such as the Pueblo I villages in the Dolores area and the emerging great-house communities of early Pueblo II in and around Chaco. While the Dolores villages were not ultimately able to deliver the kind of peace and stability that immigrants from the eastern Mesa Verde region may have been looking for, Chaco apparently was. Furthermore, once Chaco rose to regional prominence in the eleventh century it was able to extend that peace and stability over an unprecedentedly large area of the northern Southwest, including the eastern Mesa Verde region itself. Understanding how the system that emerged in Chaco Canyon was able to achieve this remarkable feat when no one had succeeded at anything like it before is one of the most important questions in Southwestern prehistory, and it is still very much an unanswered one. One important piece of the puzzle, however, is clearly the Pueblo I context in the Chaco area itself, and it is to this that we now turn.

Chaco Street in Aztec, New Mexico

Chaco Street in Aztec, New Mexico

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Utah Welcome Sign

Utah Welcome Sign

The third chapter of Crucible of Pueblos deals with the western part of the Mesa Verde or Northern San Juan region, which basically corresponds to what is now the southeastern corner of Utah. In this context the area is bounded by Cedar Mesa on the west and the Abajo Mountains on the north, as well as by the borders with Colorado and Arizona on the east and south. This is a fairly standard way to define this area archaeologically except that the western boundary is more restrictive than usual, which appears to mainly be a decision based on the near-total lack of sites dated to the Pueblo I period west of the eastern edge of Cedar Mesa. (There are actually Pueblo sites dating to this period much further west in southwestern Utah and southern Nevada, the so-called “Virgin Anasazi,” but they aren’t included in this book at all for some reason.)

The authors divide their study area into a series of physiographic sub-regions based primarily on elevation, which is a useful way to track changes in occupation patterns over the course of the period they discuss. It’s also a different approach to defining sub-regions than most of the other chapters in the book use. These sub-regions are important because the differences in precipitation and growing season length among them seem to have been important factors behind shifting settlement patterns during the period of interest. These shifts seem to have mainly taken place across the region rather than separately in spatial sub-regions such as drainages, as was the case in some other regions.

One way this region differs from others, and especially from the Central and Eastern Mesa Verde regions, is that there has been a relative lack of large-scale salvage excavation projects to provide large amounts of detailed archaeological data. Instead, most data is from surveys and small-scale excavations, and detailed chronological information in particular is missing for most sites that have been recorded. Rough dating of sites to Pecos Classification period at best based on frequencies of a few ceramic types is the norm here, which limits the comparability of data on trends in settlement over time. Nevertheless, the authors of this chapter do their best to come up with a coherent narrative of settlement during the Basketmaker III and Pueblo I periods in this area, which seems to have been an important one for understanding the cultural development of early farming populations and the origins of aggregated villages.

The most striking pattern in the population dynamics of this region in the Basketmaker III and Pueblo I periods is of apparent cycles of population growth and decline on the scale of decades and of greater magnitude than can be explain by internal demographic processes, implying migration into and out of the region multiple times. Most interestingly, these cycles appear to be largely complementary to similar cycles in other nearby regions, especially the Central Mesa Verde region just to the east. This strongly implies that one of the major factors in population changes in both these regions was movement between them.

To go into greater detail, the story told in this chapter begins in the seventh century AD with the expansion of Basketmaker III populations across the region from the narrow area of Basketmaker II settlement along the San Juan River and its major tributaries. The authors attribute this expansion in part to the introduction of beans and pottery, which freed farming populations from dependence on outcrops of limestone to cook with their corn for nitrogen-fixing purposes. Population spread especially into the upland areas with deep soils well-suited to dry farming. Over the course of the Basketmaker III period scattered hamlets began to consolidate into “proto-villages” with public architecture such as oversized pit structures surrounded by scattered households. The authors note the similarity of this pattern to the later Pueblo II great house communities, which is indeed an interesting parallel.

There appears to have been a regional population decline in the early eighth century, although this may be an artifact of the limited data set and difficulty assigning sites to precise time periods. In any case, there is evidence of a noticeable population increase after AD 750, with several villages of tightly clustered households containing public architecture appearing, along with a considerable number of smaller residential sites and a few sites in highly defensive locations, especially at the western edge of the region near Cedar Mesa. The population increase was accompanied by the introduction of a strikingly different type of pottery, Abajo Red-on-orange, which shows many similarities to pottery from the Mogollon region far to the south and likely reflects long-distance migration of some sort. There were still many continuities in architecture and other aspects of material culture, however, which suggests that these migrants combined with local populations rather than replacing them.

The largest and most famous of the villages that developed during this early Pueblo I period is Alkali Ridge Site 13, excavated by J. O. Brew in the 1940s. This site consisted of a series of long, continuous arcing roomblocks, made up of “room suites” of one “habitation” room backed by two smaller “storage” rooms. This is a pattern that would become standard for Pueblo I villages at a slightly later date, and would endure in various forms for centuries. Site 13 consists of six of these arcs, four of which were excavated by Brew. Three of the arcs excavated by Brew also had oversized pit structures with highly formalized features suggesting possible use as public architecture of some sort.

There were other village-sized sites that were established at this time, although few have been excavated. These are among the earliest sites of this size and level of organization in the northern Southwest, and continuities with later sites in other regions suggest they may have been very influential on later developments.

In addition to the early village sites, defensive sites on high, inaccessible promontories began to appear during the early Pueblo I period. These sites have not been studied in any depth, and little is known about them. Some appear to have evidence of extensive residential populations and/or public architecture, while others don’t. One intriguing pattern is an apparent line of them at the western edge of the region along the eastern margins of Cedar Mesa. This, combined with the lack of Pueblo sites to the west, has suggested to some researchers that there was a buffer area or “no-man’s-land” between the Pueblo population in southeastern Utah and early Fremont populations northwest of the Colorado River during this period. It’s worth noting, however, that there were also a few of these apparent defensive sites well within the Mesa Verdean Pueblo region, including the Fortified Spur site near the Colorado-Utah border, so tensions may have been internal as well as external at this point.

During the middle Pueblo I period from AD 825 to 880 there appears to have been a regional population decline, although again this may be due in part to data gaps. It is noteworthy, however, that this is the period of a major population increase in the Central Mesa Verde region to the east, including the formation of the well-known cluster of aggregated villages in the Dolores River Valley, some of which show some striking similarities to earlier Utah villages such as Site 13. It is reasonable to postulate that a pattern of emigration from southeast Utah into southwest Colorado led to this pattern. Southeast Utah wasn’t completely depopulated, however. In addition to scattered small sites throughout the region, there are a very few larger communities firmly dated to this period, including an intriguing site on Elk Ridge called the Pillars that has extensive evidence for middle Pueblo I residential architecture and some tentative evidence for public architecture as well. There are several other sites in the same general area that have more tentative evidence for occupation during this time, and it seems this may have been one of a handful of population clusters in the region during a time of otherwise low population.

After AD 880 population rapidly increased again, and many large villages were built between this point and AD 950. This was a period of rapid depopulation in the Central Mesa Verde region, again suggesting a complementary pattern of migration between the two regions. Many of these new village sites were in highly defensive locations, including some that were nowhere near the frontiers of the region. There is also an intriguing pattern of continuity in location between these early villages and later Pueblo II great house communities from the eleventh century. This pattern is made even more intriguing by two phenomena:

  1. Some of these sites, such as Red Knobs and Nancy Patterson Village, have evidence for masonry roomblocks similar to the “proto-great houses” known from many sites in New Mexico in and around Chaco Canyon during this same time.
  2. There seems to have been another depopulation of southeastern Utah around AD 950, implying that population at these sites was not actually continuous despite these similarities.

It has long seemed to me that southeastern Utah is a crucial area for understanding Chaco. There are several lines of evidence suggesting that at least some people living in Chaco Canyon and involved in its rise to regional dominance had strong ties to Utah, and I suspect those ties were more important in the emergence of the Chaco system than has been generally recognized. This chapter adds some much-needed context on the earlier history of Pueblo populations in Utah, and to me it strongly reinforces those ideas about the importance of Utah to Chaco. The exact nature of these relationships and their importance is still unclear, and the relatively sketchy data available make it harder to figure out, but it still definitely seems like there is something important here.

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McPhee Reservoir and Mesa Verde Escarpment from McPhee Campground

McPhee Reservoir and Mesa Verde Escarpment

The second chapter of Crucible of Pueblos discusses the Central Mesa Verde region, which is defined as basically the southwestern corner of Colorado, bounded on the west and south by the modern borders with Utah and New Mexico, on the east by the La Plata River valley, and on the north by the highlands north of the Dolores River. This is the region where Pueblo I period villages have been most extensively studied, primarily by the Dolores Project during the construction of McPhee Reservoir in the 1980s and in subsequent research by archaeologists building on that work. As a result, there’s not a whole lot that’s new in this chapter for someone who has been following the literature on this topic, although it does make a good introduction to the subject for someone who hasn’t. It also discusses some parts of the area, especially the northern and eastern fringes, that have seen much less research than the well-studied Great Sage Plain (including the Dolores sites) and Mesa Verde proper. Overall, the data assembled here is among the most detailed and reliable available to analyze demographic trends and population movements during the Pueblo I period in the northern Southwest.

Among the key factors that the authors discuss are the inherent attractiveness of this region to early farmers because of its good soil and relatively favorable climatic conditions compared to other nearby areas. Indeed, this is the only part of the northern Southwest that has seen extensive dry farming in modern times, and it is still primarily agricultural in use. This makes it unsurprising that early farmers would have concentrated here, as indeed they did, starting in the Basketmaker III period ca. AD 600 and increasing steadily in population through about 725. These early sites generally consisted of scattered hamlets presumably housing individual families. Villages, which in this context means clusters of multiple residential roomblocks in close proximity, began to appear around 750, often in association with great kivas, which had previously been rare in this region for reasons that are unclear.

Villages to both the west and east, discussed in subsequent chapters, date to the same period as these early ones in the Central Mesa Verde villages, and there was a striking variety in community organization and layout across the broader region. The dissolution of the eastern and western villages seems to have contributed to an influx of population into the Central Mesa Verde area in the early ninth century, resulting in the largest and densest concentration of population seen to that date. Village layout also became more standardized, with two main patterns dominating, one associated with great kivas and another including U-shaped roomblocks that were likely ancestral to later “great houses.” These villages, most extensively documented at Dolores, were however short-lived, and by the early tenth century the area was almost completely depopulated, with the former inhabitants apparently moving primarily to the south, into the southern part of the San Juan Basin, where they seem to have played a key role in the developments that led to the rise of Chaco Canyon as a major regional center in the eleventh century.

As I said before, none of this is groundbreaking information at this point, and I’ve discussed some of the implications of the Dolores data before. It is however useful to have a synthesis of this region during this important period to refer to, and this chapter works well for that purpose.

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McPhee Reservoir, Dolores, Colorado

McPhee Reservoir, Dolores, Colorado

A few years ago I did a series of posts called “Aftermath” that consisted of short commentaries on the chapters in The Prehistoric Pueblo World, a volume edited by Michael Adler that synthesized information on the archaeology of the Pueblo III period (AD 1150 to 1350) in various regions of the Southwest. This period postdated the decline of Chaco Canyon as a major regional center, and understanding it is important for understanding the relationship between Chaco and the modern Pueblos, as well as for understanding some aspects of Chaco itself.

Another period that is of perhaps even greater interest for understanding Chaco is the Pueblo I period (generally defined as AD 750 to 900, but see below), which immediately predates Chaco’s rise to regional dominance. I was therefore pleased to see the publication in 2o12 of Crucible of Pueblos: The Early Pueblo Period in the Northern Southwest, a volume synthesizing information on the Pueblo I period along the same lines as Adler’s effort for Pueblo III. It’s edited by Rich Wilshusen, Gregson Schachner, and James Allison, all of whom have made important recent contributions to understanding of this under-researched period. I’m just now getting around to reading it, and I decided to do a similar series of posts commenting on the chapters as I read them. I’m entitling the series “Foreshadow” to indicate the way developments during this period seem to, well, foreshadow later developments at and involving Chaco.

This post addresses the introduction, which is by the three editors of the volume along with Kellam Throgmorton, who is not otherwise a familiar name (at least to me) but who is thanked in the acknowledgments for his work “reimagining” this chapter. He was apparently a graduate student at the University of Colorado at the time, and has since graduated and is now “doing contract archaeology work in New Mexico.” The introduction as it stands is very engaging and readable, so if that was Throgmorton’s doing I can see why the volume editors took care to thank him specifically.

This introductory chapter is primarily a history of archaeological research on the Pueblo I period in the Southwest, but it also situates that history in the context of archaeological understanding of that period and how it relates to others, which has changed markedly over time. It also explains the reasoning for this volume’s use of “Early Pueblo” rather than “Pueblo I” to describe the period of interest, which is defined more broadly than Pueblo I has traditionally been. As with so much else in Southwestern archaeology, the issues here go back to the classification developed at the first Pecos Conference in 1927. As this chapter makes clear, this was initially primarily a developmental sequence rather than a chronological one, and the Pueblo I period in particular has been misunderstood on this account. This volume therefore uses a more general “Early Pueblo” period of circa AD 650 to 950 to frame the developments in the regions it discusses, which covers the various definitions that have been used for Pueblo I in different areas, as well as parts of Basketmaker III in some because of the importance of immediately preceding events for understanding Pueblo I.

The bulk of this chapter relates the history of understanding of the Pueblo I period by archaeologists. This history follows the familiar sequence of culture history/classification followed by processualism/environmental determinism followed by post-processualism/neohistoricism, but with an emphasis on how the Pueblo I period tended to be subsumed by larger theoretical constructs until the rise of large cultural resource management projects in the 1970s and 1980s massively increased the data available and forced a reevaluation of the period. The most influential of these efforts was the Dolores Project, which happened to occur in an area that was one of the most important centers of Pueblo I village development. The massive scale of this project, the largest ever in the US at the time, led to a much more detailed understanding of the Pueblo I period and the recognition that, rather than a brief interlude in the sequence of development from small hamlets to large pueblos, this was a time of rapid formation of the first major agricultural villages in the northern Southwest, followed by their equally rapid dissolution and a massive outmigration of people from the region. The precision of tree-ring dating allowed for very fine-grained understanding of the chronology, and the results of the project showed a level of dynamism in population movement and culture change that was totally unexpected and hard to fit in the gradual progression paradigm underlying the traditional Pecos classification.

Furthermore, certain aspects of the short-lived Dolores villages were strikingly reminiscent of the well-known Chacoan communities that emerged to the south shortly afterward, which led to the increasingly accepted idea that the formation and dissolution of villages during Pueblo I in the Dolores area were events that directly influenced the rise of Chaco. Indeed, it is now considered quite likely that many of the people who were involved in the development of early great houses at Chaco had moved there from Dolores.

So that’s the main message in this chapter, which also serves as an introduction to the volume itself and the other chapters in it. The next few chapters cover the specifics of settlement patterns in several parts of the northern Southwest, including not just the Mesa Verde region (the focus of most Pueblo I research so far) but also Chaco and its surroundings as well as areas further south and east. The latter two areas are often not addressed very well in research on this period, so I’m very interested in seeing the information on them presented here. The next few chapters cover a few broad thematic issues of interest for understanding this period across all the regions, then there are concluding chapters by Steve Lekson and John Kantner putting all this in a larger perspective. Overall this seems like a well-designed and desperately needed synthesis of an important but poorly understood period in Southwestern prehistory, and I’m eager to dive into the details.

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Looking East from Casamero Pueblo

Looking East from Casamero Pueblo

Unmanned aerial vehicles (UAVs), popularly known as “drones,” have become increasingly common in recent years as the technology behind them has developed. Some uses are controversial, such as military applications and uses that might violate privacy expectations or be dangerous to other aircraft, but other uses are more benign and can potentially open up new frontiers.

In archaeology, UAVs are increasingly being used for aerial photography and remote sensing in many places around the world. These are types of research that have been established for decades, but that until recently were prohibitively expensive for most archaeologists since they required both expensive camera equipment and the use of airplanes or helicopters. With the development of both lighter, less expensive cameras and UAVs that are robust enough to carry them, this type of research is now much more practical.

A recent paper by a team of researchers including Jesse Casana of the University of Arkansas and John Kantner of the University of North Florida reported on research using a UAV to take infrared thermal imagery, or aerial thermography, as well as color photography, of sites in the Blue J community south of Chaco Canyon, New Mexico. (Casana has the paper posted on his Academia.edu page.) Kantner has been studying Blue J and the surrounding area for several years and has come up with some interesting results.

Blue J is in an area at the southern edge of the San Juan Basin that is thick with Chacoan outlier communities, most of which date to fairly early in the Chacoan era and many of which were apparently abandoned while the Chaco system was flourishing. Casamero Pueblo is one site very close to Blue J where a great house has been excavated and is open to public visitation. These communities typically have one or more great houses and great kivas, and in fact it is unusually common for communities here to have multiple great houses compared to other Chacoan outlier communities. At Blue J, however, Kantner has so far not identified any great houses or great kivas. As he says on his website:

Turquoise, marine shell, jet, azurite, malachite, and other exotic materials attest to the success of Blue J’s inhabitants. Oddly, however, what was originally thought to be a great house turned out to be a normal residential structure, making Blue J the only community for miles around without Chacoan architectural influence.

Now, part of what’s going on here may have to do more with how archaeologists define “great house” than with anything about Blue J specifically. The function of the monumental buildings that have been given this label remains a point of active contention among scholars, with some arguing that they were primarily residential, perhaps housing community elites or religious leaders, and others arguing that they were non-residential public architecture, perhaps with ritual significance as sites of pilgrimage and/or communal feasting. Kantner belongs to the latter camp, so finding “normal” residential features at a suspected great house removes it from consideration as such, whereas another archaeologist might interpret such findings differently. (It’s worth noting that many if not most excavated “great houses” have showed at least some evidence for residential use, and in some cases they have not been noticeably different from other residential structures in a community except in size and location.)

The focus of the recent study was on demonstrating the potential for using UAVs to do fast, inexpensive survey of large sites and to identify buried features. Blue J is well suited for this on both counts. It is located at the foot of a steep cliff, which has resulted in many sites in the community being covered with substantial deposits of sediment carried by water and wind, making them difficult to identify on the surface. It is also fairly large for a Chacoan outlier community, with over 50 residential sites identified through previous surveys, which makes a fast method of survey over a large area an attractive proposition.

The study consisted of doing several flights with a UAV over the site, at different times of day and night, primarily with the infrared thermal camera to capture differences in temperature that are expected to be present between archaeological features and the dry desert soil. The original intent was to do some of the flights in the hottest part of the afternoon, but high winds ended up making this impossible. The results were nevertheless impressive: one site that had been previously identified through survey and limited excavation showed up clearly in the imagery, with buried walls visible in some of the images. Several other sites that had been identified but not excavated showed up as well, with buried walls again visible. A large circle showing a possible great kiva is particularly interesting given that no great kiva has yet been identified from surface survey.

Obviously further work is necessary to confirm some of the results from the imaging, but this is a very successful demonstration of the potential for this technology to improve survey and site identification so that further research can be focused on the most promising locations for sites. Other sensing techniques such as ground-penetrating radar have also been tried in the Southwest, but they are much slower and can be thrown off by some characteristics of the desert environment. Aerial thermography using UAVs offers another option that seems to have a lot of potential and it will be interesting to see how it is used as the technology continues to advance.
ResearchBlogging.org
Casana, J., Kantner, J., Wiewel, A., & Cothren, J. (2014). Archaeological aerial thermography: a case study at the Chaco-era Blue J community, New Mexico Journal of Archaeological Science, 45, 207-219 DOI: 10.1016/j.jas.2014.02.015

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Plaque Commemorating the Founding of Harvard College, Cambridge, Massachusetts

Plaque Commemorating the Founding of Harvard College, Cambridge, Massachusetts

I’m still working on the follow-up to my DNA post, but in the meantime I’ve seen a few new reports of interesting research in other parts of the world using techniques similar to what I was talking about. This will provide some context for the Southwest-specific research I’ll discuss later, which is still at a much more rudimentary level that hasn’t yet produced such striking results.

First, commenter ohwilleke, in addition to leaving a long and informative comment about analytical techniques and the usefulness of full-genome sequencing as opposed to mitochondrial studies, points to a recent study of modern inhabitants of Rapanui (Easter Island) that shows clear evidence of prehistoric genetic mixture with people from South America. There have long been theories that there was contact between these populations, but this appears to confirm them with the most solid evidence yet, and provides another glimpse of the complexity of human history. (I’ll address the issue of full genomic sequencing, which has not yet been used on any ancient remains from the Southwest to my knowledge, in the follow-up post.)

Second, there have apparently been two new articles (only one of which I could find, since the news story doesn’t even give the title of the journal the other one was published in) using aDNA techniques on ancient remains from Europe. One study, by a large team including David Reich of Harvard Medical School, found three major sources of ancestry for ancient Europeans: early hunter-gatherers, presumably of African origin; early farmers of Near Eastern origin (which seems to strongly support theories that the spread of agriculture across Europe had migration of people as an important component) who apparently interbred with the hunter-gatherer population to some extent; and a previously unknown group with links to Central Asia and possibly associated with the introduction of Bronze Age material culture. The second study, which looked at remains from later dates than the first, appears to have also found a fourth group that entered eastern Europe during the Iron Age.

Finally, reaching back to a much earlier date, a bone found in a riverbank in Siberia yielded the oldest human genome sequenced to date. Radiocarbon-dated to between 43,000 and 47,000 years ago, the genome is particularly noteworthy because it contains a higher proportion of segments of Neanderthal origin than modern human genomes, which apparently has important implications for theories about the initial peopling of the world by modern humans.

Now, I don’t have access to any of these papers so I haven’t read any of them myself. My comments about them are based on the abstracts and the coverage they’ve gotten in the media, which is of course notoriously unreliable when it comes to highly technical subjects. Still, this should give a sense of the kinds of topics DNA studies are weighing in on. As I said before, DNA research in the Southwest is still at a much more rudimentary level, so don’t expect to see this kind of thing any time soon. It is developing, though, and has great potential to answer important questions of archaeological interest. I’ll explain more about the work that has been done in the next post.

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Primary Sources: Free!

Smithsonian Institution, National Museum of National History

Smithsonian Institution, National Museum of Natural History, Washington, DC

I’ve been diligently working on the DNA post, but it looks like I may not be able to finish it tonight, and I’d hate to let a whole month go by without a post. So I’ll just do a quick post here to mention some resources I’ve recently found where the full text of important primary sources on Southwestern archaeology are available for free. Keep in mind that in general these are just scans of the print documents converted to PDFs, which means the files are very large and can take a long time to download.

First, the Smithsonian has done a lot of work recently on digitizing its old publications, but they aren’t very easy to find. The publications most relevant to archaeology are the Smithsonian Miscellaneous Collections and the Bulletins of the Bureau of American Ethnology, both of which are available in the Biodiversity Heritage Library. The BAE Bulletins are listed under Bulletin / Smithsonian Institution, Bureau of American Ethnology, while Miscellaneous Collections are listed under Smithsonian miscellaneous collections. Both of these series include important primary sources on Southwestern archaeology, including Neil Judd’s reports on Pueblo Bonito and Pueblo del Arroyo in the Miscellaneous collections and Frank H. H. Roberts’s reports on Shabik’eshchee, Kiatuthlanna, and the Village of the Great Kivas in the BAE Bulletins. The Bulletins in particular also include a huge amount of other research on American anthropology, and it’s really amazing to have all that available for free online. There’s probably other useful stuff in the Biodiversity Heritage Library that I haven’t found yet; its collections go well beyond the Smithsonian publications.

Secondly, the American Museum of Natural History in New York has put its Anthropological Papers online. The most important of these for Chacoan purposes are George Pepper’s report on Pueblo Bonito and Earl Morris’s reports on Aztec Ruin. Again, there are a lot of other reports of general anthropological interest in this series, so it’s well worth checking out.

Since these documents are generally scans of printed versions, many of them hundreds of pages long, the files are huge and may take a long time to download. It’s also important to note that these are not popularizations of research in any sense; they really are original reports, and are likely to strike the general reader as quite dry. For those of us with a serious interest in the details of this research, however, they are both fascinating and invaluable, and I applaud their publishers for making them available.

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