Archive for the ‘Archaeoastronomy’ Category


Explanatory Plaque at Sun Temple, Mesa Verde

Today is the summer solstice, on which I like to do posts about archaeoastronomy. Today I’d like to discuss a well-known site, Sun Temple at Mesa Verde, which as its name suggests has long been associated with astronomical observations. As we’ll see, however, it appears that some of the early interpretations of the site’s architecture haven’t held up under further examination. This is another good example (along with Wupatki) of the need to carefully analyze proposed archaeoastronomical alignments.

Like many sites at Mesa Verde, Sun Temple was excavated and partly reconstructed in the early twentieth century by the pioneering archaeologist Jesse Walter Fewkes. Fewkes named the site “Sun Temple” after finding a feature that he interpreted as a “sun shrine” aligned to the position of sunset on the fall equinox. After identifying this possible alignment, Fewkes looked at the orientation of the building to see if there were any other astronomical alignments present. Sun Temple is D-shaped, with the flat side of the “D” to the south (a shape and orientation that those familiar with Chaco may find familiar), so the straight front wall was an obvious place to check for alignments. Fewkes, presumably guided by the equinoctial alignment of the shrine, initially checked to see if the front wall aligned to the positions of sunrise/sunset on the equinoxes, which would be the same and would mean the wall was oriented due east-west. He found that it was not, but was rather aligned about 20 degrees north of due east at the east end, and 20 degrees south at the west end.


Sun Temple, Mesa Verde

In his published reports Fewkes went on to conclude from this alignment that the front wall was actually oriented to the summer solstice sunrise. This is an important event in modern Pueblo societies, and subsequent research has found evidence for alignments to it in prehistoric Pueblo sites as well, so on first glance this seems like a reasonable conclusion. When archaeoastronomer Jonathan Reyman began to research the site using modern techniques in the 1970s, however, he found that it didn’t hold up, and published a short article explaining why.

The basic gist of Reyman’s article is very simple: The front wall of Sun Temple is indeed oriented to about 20 degrees north of east, but this is not the same alignment as the summer solstice sunrise at this latitude, which is more like 30 degrees north of east. Fewkes appears to have simply made a simple mistake. It’s not clear exactly how this would have happened, but Reyman suggests he either made a mistake in his notes or his notes were unclear and he became confused when writing them up for publication. In any case, this is a pretty clear-cut case of a mistake in the literature being corrected, and Fewkes’s error does not seem to have been propagated since. (Note that the NPS link I gave above says nothing about a solstice alignment.)

Reyman did also confirm that the “sun shrine” is aligned to the equinoctial sunsets and may well have been used to observe them, so the name “Sun Temple” remains appropriate (or as appropriate as it ever was). This is an intriguing building for a lot of reasons, some of which do support the idea that it had an astronomical function, but that’s a discussion for later. Sun Temple is also one of the most accessible sites at Mesa Verde, being on a mesa top where it can be visited without a guided tour, and it is well worth visiting even though it’s quite different from the cliff dwellings for which the park is best known.
Reyman JE (1977). Solstice Misalignment at Sun Temple: Correcting Fewkes The Kiva, 42, 281-284

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Walls at Wijiji

Walls at Wijiji

Today is the winter solstice, and the seventh anniversary of this blog. I’ve traditionally posted about archaeoastronomy on these anniversaries, so I’m going to briefly interrupt my series on Crucible of Pueblos to discuss an interesting article on the evidence for astronomical observations at Chaco Canyon. There turns out to be some overlap, actually, which is interesting.

The article is by Andrew Munro and Kim Malville, who were also the authors of the article on building orientations that I talked about last year on this date, and it was published in the same special issue of the journal Archaeoastronomy in 2010. The content is rather different however. This article summarizes the evidence for specific locations in and around the canyon for which there is evidence of use as solar observation “stations,” including two sites which are newly identified here. (Worth noting here is that Munro left a detailed and interesting comment on last year’s post, in which he linked to his unpublished thesis which contains more detailed and up-to-date information on his approach to archaeoastronomy. I haven’t read it yet, so I’m focusing here on the published articles while recognizing that they don’t have the most recent information.)

Identifying viewing stations is more complex than simply demonstrating alignments, for a variety of reasons. For one thing, based on modern Pueblo ethnography, sun-watching locations were not necessarily marked physically with architecture, rock art, or anything else. This makes their archaeological identification difficult, and probably means that the stations that did happen to have physical markers are probably over-represented.

Identifying these stations also requires careful consideration of how exactly the observation process would have likely worked, what its specific purposes were, and how they could have been met. If, as Munro and Malville argue, the main role of these observations was to fix the dates of ceremonies marking key times in the year, there would have been a practical need to mark not just the date of the ceremony itself, but dates leading up to it which would have given time to prepare for it. Munro and Malville use the term “anticipatory” for stations that would allow prediction of an event in advance, and “confirmatory” for those that would allow observation of the date of the event. There would also need to be a system for communicating the information from the observation stations quickly and easily to other sites in the canyon and beyond.

There is also an important distinction between observation stations and shrines. The former were used for the practical purpose of making observations, while the latter were associated with those observations but used for ritual activities rather than observation, and often were not in locations from which accurate observations could be made. Munro and Malville use the terms “primary” and “secondary” to refer to these different types of sites; secondary stations could include both shrines, which could involve rock art and/or simple architecture, and alignments within or associated with buildings. The well-known, though not universally accepted, alignments at Pueblo Bonito and Casa Rinconada would fall into the secondary category, as would the “Sun Dagger” petroglyph site atop Fajada Butte. In this paper Munro and Malville focus on the primary stations, which they further divide into two categories depending on whether they could be used both to predict significant dates in the solar calendar and to observe them when they occurred, or just to observe the occurrence. For practical purposes the former type would be more useful.

Despite Chaco’s reputation for astronomy, it turns out that good locations for primary observation are pretty rare in the canyon. One key requirement for such a location is a “broken” horizon with obvious landmarks that can be used to track the sun’s (or moon’s) progress along the horizon, but from most great houses the horizon is actually pretty flat and unsuitable for observation. This is presumably due to the flat mesa tops to the north and south of the canyon itself. The number of possible locations for observation stations is therefore reduced to a few areas of the canyon where the horizon is more varied. Munro and Malville list five previously documented stations and add two more based on their own research. (A few more have since been identified.) They are briefly described below.

Fajada Butte with Green Vegetation

Fajada Butte with Green Vegetation

Piedra del Sol is a large rock near the current Chaco visitor center that has a wide variety of rock art as well as multiple astronomical alignments. Of particular interest is an apparent viewing station for summer solstice sunrise associated with a large spiral petroglyph on the northeast face of the rock. The horizon as viewed from this spot could allow for both anticipatory and confirmatory observations for the solstice. Even more intriguing, the station has a direct line of sight to the “Sun Dagger” site on Fajada Butte, suggesting that this may have been the location from which the observations were made that allowed the spiral petroglyph at that site to be placed in exactly the right position for the “dagger” of light to pierce it on the summer solstice.

There are multiple identified observation stations in the area of the Wijiji great house at the eastern end of the canyon. One site, 29SJ931, is near a pictograph site on a ledge near the great house and allows observation of the winter solstice. There are some features at the site that are similar to the sorts of features found at post-Chacoan observation sites in the Mesa Verde area, as well as evidence for later Navajo use, so it’s not clear that this site was actually used at all during the Chacoan era. Another site near Wijiji, 29SJ1655, has many Navajo petroglyphs nearby but does also have Chacoan rock art and a possible shrine, suggesting Chacoan as well as Navajo use. This site actually consists of three siting locations, allowing observation of both solstices as well as both equinoxes.

More firmly established as a Chacoan siting station is the Wijiji great house itself. From the northwest corner of the building a notch is visible on the horizon that serves as both an anticipatory and a confirmatory marker for the winter solstice: about two weeks before the solstice the sun rises at the left edge of the notch, and on the solstice itself it rises on the east edge. Since Wijiji was one of the latest great houses to be built in the canyon, it’s possible that it was sited at a location already used as a solstice observation station. As we shall see, it is not the only great house for which this appears to be the case.

Kin Kletso

Kin Kletso

Further west in the canyon, another late great house, Kin Kletso, shows a similar alignment to the winter solstice, with both anticipatory and confirmatory observations possible but in a different way. Here, looking from the southeast corner of the building toward a nearby cliff about two weeks ahead of the solstice (the same dates as the Wijiji anticipatory alignment) shows the sun rising at the base of the cliff. Over the course of the next few weeks, the same sunrise alignment is visible by gradually moving north along the east wall of the site, until on the solstice itself the alignment is visible from the northeast corner. As with Wijiji, it is possible that Kin Kletso was built at the site of an existing observation station, perhaps associated with the large boulder at the western end of the site. (I mentioned both the Wijiji and Kin Kletso observation alignments in my very first post on this site, as it happens.)

In addition to these previously identified observation stations, Munro and Malville describe two new ones based on their own recent research. Both of these are interesting partly because of what they imply about the date at which these sorts of observations began at Chaco.

29SJ2539 is in the general area of Wijiji, and also near the important Basketmaker III village of Shabik’eschee. The site itself includes a boulder with an alignment allowing for confirmatory observation of the winter solstice sunrise through a notch at the foot of a nearby cliff, along with a wide variety of artifacts and rock art indicating both Chacoan and Navajo use. An immediately adjacent site, 29SJ2538, includes a ledge overlooking the boulder that could have been used for storage but apparently wasn’t. Another nearby site is a small-house habitation that was excavated by Frank H. H. Roberts in 1926, now known as “Roberts Small House.” This site was apparently occupied over a long span of time, from Pueblo I through the post-Chacoan “Mesa Verdean” occupation of the canyon. It contained a large number of turkey bones, giving it the alternative name of “turkey house.” It also contained human remains, including some that have been argued to show evidence of cannibalism. Christy Turner, who initially made the cannibalism claim, identified the remains as dating to early Pueblo II, but Munro and Malville cite more recent research showing that they were actually from an earlier Pueblo I context. They also argue that there is no reason to associate the cannibalism evidence with the evidence for astronomical observation or related ritual practices, but without going into detail.

Looking West from Peñasco Blanco

Looking West from Peñasco Blanco

Finally, Munro and Malville identify a possible observation point for winter solstice sunrise at Casa del Rio, an early great house just west of the canyon that seems to have been an important site in the Pueblo I period, with an exceptionally large trash midden suggesting possible feasting activity involving people beyond those living at the site. From this site (Munro and Malville don’t specify the exact viewing location) the solstice sunrise is aligned with West Point, the high point on the west side of West Mesa that contains a Chacoan shrine and has direct lines of sight to the Peñasco Blanco great house as well as to other shrines from which messages could be quickly sent throughout the canyon and beyond. This close association with the signaling network, in combination with the large amounts of trash (which seems to have been primarily domestic trash associated with food consumption, unlike the more complex contents of the later, more formal mounds associated with Chacoan great houses), implies that Casa del Rio may have been a location where people gathered for feasts and other ceremonies during the Pueblo I period, with at least some of the ceremonies tied to astronomical events such as the winter solstice (or the full moon nearest to it). In this scenario, inhabitants of Casa del Rio would have watched the sunrises over West Mesa to determine the dates of their festivals, then communicated those dates to others by signaling to the shrine on West Point, from which the signal could have been transmitted to many other places.

Speaking of signaling, Munro and Malville also discuss how it could have been done. Fires or smoke signals are possibilities, but another intriguing options would have been mirrors made of selenite, a mineral that can be polished to a high reflective sheen which is found in some natural outcrops in the Chaco area, including one near the observation site at 29SJ2539. Pieces of selenite were in fact found at 29SJ2539 itself, as well as at several other sites in the canyon.

Several interesting patterns emerge from the data compiled by Munro and Malville. First, the winter solstice sunrise appears to have been the most important astronomical event observed by the ancient Chacoans, at least judging from the viewing stations that have been identified so far. This is consistent with modern Pueblo ethnography, which similarly indicates the winter solstice as the most important event and sunrise observations as generally being more important than sunset ones.

Second, there is a strong association between possible viewing stations and so-called “Late Bonito” great houses, those built in the early AD 1100s toward the end of the period of Chacoan florescence, often in the so-called “McElmo” architectural style that is sometimes associated with influence from the north. The relatively standardized sizes and shapes of these great houses, as well as their short periods of construction, suggest an aggressive building program at this time that might have been associated with an attempt to reassert Chaco’s importance at a time when regional focus was starting to shift north to Aztec. Siting these buildings at locations already used as astronomical observation points, and designing them to incorporate aspects of such observation into the buildings themselves, may have been a way for Chacoan leaders to emphasize their esoteric knowledge and spiritual power at a time when it was being challenged.

Finally, and most interestingly from the perspective of the series of posts I’ve been doing lately, Munro and Malville provide tentative but intriguing evidence for astronomical observation points in and around Chaco Canyon beginning in the Pueblo I period. This would to my knowledge make this the earliest known evidence for detailed astronomical observation in the northern Southwest, and possibly in the Southwest as a whole (evidence for the Hohokam in southern Arizona is more ambiguous). That, in turn, provides further support for my theory that the rise of Chaco was enabled in part by the development of a new ideology in which astronomy played a major role.

In this regard it is interesting that one of the early centers for astronomical observation may have been Casa del Rio, which was one of the most important local centers during the late Pueblo I period when the great houses in the canyon proper were just starting to be built. As noted in my earlier post on Pueblo I in the Chaco area, it’s clear that at this time settlement was largely focused to the west of the canyon along the lower Chaco River, which may have been a conduit for migrants leaving the villages in the Dolores, Colorado area when they collapsed in the late ninth century. It may have been these migrants, bringing the lessons they had learned from their experiments in village life and adapting to a new and very different environment, who first began to pay careful attention to the sky, perhaps in an attempt to improve their prospects of survival in an area that is exceptionally arid even for the Southwest. If their initial adaptations were successful, as they appear to have been at least in some places, they may have begun to gain prestige and to attract additional migrants from various areas, who would have brought their own ideas and lessons learned. Astronomy may have been the development that united these people and allowed them to develop a new social order that would go on to underlie the spectacular achievements at Chaco that we see evidence of even today. And when that social order began to be challenged, for reasons that are still unclear, its leaders may have sought to revitalize it through a renewed emphasis on their astronomical knowledge in the form of the Late Bonito great houses.

Obviously this is all fairly speculative, but more and more evidence has been accumulating in recent years to focus and ground such speculation in solid data. Archaeoastronomical research has been a key part of this, and this article is an important contribution to the developing picture.
Munro AM, & Malville JM (2010). Calendrical Stations in Chaco Canyon Archaeoastronomy, 23, 91-106

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Phoenix, Arizona

Phoenix, Arizona

Today is the summer solstice, so I figured I would take a break from my (slowly) ongoing series of posts on the Pueblo I period in the northern Southwest to take a look at evidence for ancient astronomical knowledge in a different part of the Southwest. This is in part an outgrowth of my recent thoughts on the role of astronomy in the rise of Chaco Canyon to regional prominence, which in turn was spurred in part by the realization that Chaco appears to show the earliest evidence for complex astronomical knowledge in the northern Southwest. The idea, which I explored exactly one year ago in this post, is that by the eleventh century AD the Chacoans developed a knowledge of astronomy that they were able to use as esoteric ritual knowledge to enhance the canyon’s role as a political and economic power throughout the region.

This idea led me to wonder, however, about the history of astronomical knowledge in the southern Southwest, which was culturally quite different from the northern areas influence by Chaco. In particular, the Hohokam of the southern Arizona deserts show both a longer history of intensive agriculture and a closer connection to Mesoamerican societies further south, both attributes that could be relevant to their knowledge and use of astronomy. If evidence for that knowledge among the Hohokam long predates that evidence at Chaco, this leads to interesting questions about the origins of Chacoan astronomy. If it doesn’t, that leads to other interesting questions about both societies.

Luckily, the same special issue of the journal Archaeoastronomy that contains an article on Chacoan astronomy that I discussed in a previous post also contains one on Hohokam astronomy. This article, written by Todd Bostwick, discusses evidence for astronomical alignments in Hohokam monumental architecture and rock art, as well as the astronomical and calendrical practices of the modern O’odham people who inhabit the same area (and whose relationship to the Hohokam is unclear and controversial, although Bostwick doesn’t discuss this). Bostwick’s focus is on the Phoenix area, which is considered the Hohokam heartland.

Bostwick documents a wide range of possible alignments in Hohokam architecture and petroglyphs, primarily solstice-oriented. These include a large number of rock-art sites in and around the mountains that show clear alignments to the solstice sunrises, particularly associated with a distinctive dot-in-circle motif that may be a sun symbol. There are also some rock art sites with complex patterns of light and shadow interacting with the petroglyphs on the solstices, similar to the famous “Sun Dagger” petroglyph on Fajada Butte at Chaco. In architecture, perhaps the most intriguing alignments are a series of holes in the upper walls of the “Big House” at Casa Grande Ruins National Monument which show possible alignments primarily to the equinox sunrise, and perhaps to some of the lunar standstill moonsets as well. There are also astronomical alignments associated with platform mounds at the villages of Mesa Grande and Pueblo Grande.

The rock art alignments are notoriously difficult to date, of course, and the aforementioned architectural features all date to relatively late in the Hohokam sequence and are therefore not very useful to understanding the origins of Hohokam astronomical knowledge. There are, however, features at the earlier village of Snaketown that may have had an astronomical purpose, although it is less straightforward than the others.

Snaketown was the preeminent village of the Hohokam during the Sedentary period, which is roughly contemporaneous with the florescence of Chaco (ca. AD 900 to 1150), although its history extends back several hundred years earlier. It was not occupied into the following Classic Period, when the other villages mentioned above reached their peaks. There is an alignment between the central plaza of Snaketown and Gila Butte, a geological formation to the southeast that is considered sacred by the O’odham. On the winter solstice, the sun rises between the two peaks of the butte when viewed from the plaza, and Bostwick suggests that the siting of Snaketown may be related to this alignment. If so, this would imply knowledge at least of solstice alignments was much earlier in the Hohokam area than further north, but without clear evidence from earlier periods this must remain speculative.

Another intriguing but ambiguous feature at Snaketown is the platform mound known as Mound 16, at the northeast edge of the plaza. This circular mound is surrounded by a series of 52 postholes, placed fairly regularly but with gaps on the northeastern, southern, and southwestern sides of the mound. There are no structures or postholes on top of the mound, but there is one hearth at the southern end associated with one of the gaps in the ring of postholes. This clearly seems to indicate some sort of ceremonial or symbolic use for the mound, although it’s not clear what that would have been. Bostwick notes that some of the posts seem to align with the solstice and equinox sunrise positions as viewed from atop the mound, and he suggests that Mound 16 may have served as a “ritual sundial” of some sort. In this respect it is very reminiscent of the “Woodhenge” ring of posts next to Monk’s Mound at Cahokia, which has also been interpreted as an astronomical marker. Still, this interpretation is rather speculative at this point and Bostwick concludes his discussion of the mound with a call for further research on its possible astronomical alignments.

Reconstructed "Woodhenge" at Cahokia

Reconstructed “Woodhenge” at Cahokia

The upshot of all this from my perspective is that the history of astronomical knowledge in the southern Southwest actually seems to be just as murky as that further north. In both cases the most apparent astronomical alignments in architecture seem to date quite late, although this doesn’t say much about the time depth of the knowledge behind them. There are a few intriguing hints in more general aspects of Hohokam society that may provide some insight, however.

One is the adoption here of the Mesoamerican ballgame, played in distinctive courts that are primarily associated with the Sedentary period and the florescence of Snaketown (which has two). As Bostwick notes, in Mesoamerica the ballgame was often associated with astronomical symbolism and particularly with the sun and the calendar. Its introduction among the Hohokam around the beginning of the Sedentary period may therefore indicate the introduction of certain religious motifs or practices from the south that emphasized celestial, and especially solar, patterns.

Bostwick also notes one admittedly speculative but very interesting theory regarding this introduction which associates it with a solar eclipse in AD 797 which would have been visible to the Hohokam, and which was followed a few years later by a series of disastrous floods. It’s possible that the Hohokam perceived the eclipse as an omen predicting the floods, and that they adopted new religious practices associated with the sky to prevent further disasters like this. Another eclipse in AD 1076 may have been associated with the abandonment of Snaketown and other major Sedentary period villages and the reorganization of Hohokam society into a new form during the Classic period. Notably, this change included the decline of the ballcourt system and the rise of new forms of ritual associated with platform mounds. A subsequent solar eclipse in AD 1379 was again followed a few years later by catastrophic floods that many scholars consider important factors in the ultimate collapse of Hohokam society.

This eclipse theory is fascinating, although it’s obviously very speculative and probably impossible to prove or disprove conclusively. There was a lot of other stuff going on at the same time as each of these societal transformations, of course, and it’s likely there were multiple factors involved in each case.

It’s still not clear what role Hohokam astronomical knowledge might have played in the development of similar knowledge at Chaco. The Chacoans may have noticed alignments in their local environment basically independently of anything similar going on further south, they might have heard rumors about Hohokam astronomy that spurred them to develop their own, or they might have had detailed knowledge of Hohokam practices that they used to implement similar practices themselves. The extent to which the Chacoans and Hohokam were aware of each other and the extent to which they interacted either directly or indirectly are important questions for understanding Southwestern prehistory, and they have not received very much attention from scholars who specialize in either society (although some of Steve Lekson’s recent work has been an important exception). The murky history of astronomical knowledge in both areas doesn’t seem to shed much light on these questions at this point, but with further research it may become more illuminating. Happy solstice.
Bostwick TW (2010). Exploring the Frontiers of Hohokam Astronomy: Tracking Seasons and Orienting Ritual Space in the Sonoran Desert Archaeoastronomy, 23, 166-189

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Looking East from Peñasco Blanco

Looking East from Peñasco Blanco

Today is the winter solstice, which means it’s also the sixth anniversary of this  blog. On these anniversaries I like to write about archaeoastronomy, which is a very interesting topic and an important one for understanding Chaco and Southwestern prehistory in general. Last year I wrote about some research indicating that in the Rio Grande valley, an area generally thought to be outside the Chaco system but that was certainly occupied at the same time as Chaco, there was a long and very consistent tradition of orienting pit structures to the east-southeast, which is the direction of winter solstice sunrise. The winter solstice is very important in the cosmology and rituals of the modern Pueblos, so it makes a lot of sense that at least some Pueblo groups would orient their dwellings based on it.

As I noted at the time, this orientation is very different from that in the San Juan region to the west, including Chaco and Mesa Verde. In this area there is an equally long tradition of orienting pit structures to either due south or south-southeast. I’ve long wondered why this might be, and an article I read recently discusses the issue and proposes some interesting potential answers.

The article is by Kim Malville and Andrew Munro and was published in the journal Archaeoastronomy in 2010 as part of a special issue on archaeoastronomy in the Southwest. Malville is an astronomer who has done a lot of research on archaeoastronomy in the Southwest and identified many potential astronomical alignments, but this article is actually largely about debunking many of the alleged alignments claimed by others, particularly Anna Sofaer and her Solstice Project. Sofaer, an artist who turned her attention to archaeoastronomy after discovering the “Sun Dagger” effect involving a spiral petroglyph on Fajada Butte that on the summer solstice appears (or appeared) to be bisected by a “dagger” of light coming through a slit between large boulders in front of it. Sofaer went on to organize surveys of the major great house sites in Chaco Canyon to identify any celestial alignments in the orientation of their walls, and her team found that virtually all of them did show alignments to the positions of the sun or moon on solstices, equinoxes, or lunar standstills.

Light Snowfall on Fajada Butte

Light Snowfall on Fajada Butte

Sofaer and her collaborators went on to publish these findings widely, and to make a well-known documentary that has often been shown on television and inspired a lot of interest in Chaco. As Malville and Munro show in this paper, however, the evidence for these alignments is very thin. There is little to no justification in Pueblo ethnography for the idea of celestial building alignments, and the alignments themselves are identified with a substantial margin for error that makes spurious positive identifications likely, especially when so many potential alignments are tested for. Particularly concerning is how many of the alignments are to the minor lunar standstill, which is not a very impressive or noticeable event. (The major lunar standstill is a different story, and there is strong evidence at Chimney Rock in Colorado that the Chacoans were familiar with it and considered it important.) Malville and Munro also argue that the fact that most of the alignments are based on the rear walls of sites is also questionable, since there is no evidence that rear wall alignments were or are important culturally to Puebloans.

Instead, they argue that the alignments of rear walls are epiphenomenal, and that they mostly result from the more solidly established concern with the orientation of the front of a site. The bulk of the article is devoting to tracing these frontal orientations across time and space, with a primary focus on Chaco itself and on the earlier Pueblo I villages in the area of Dolores, Colorado that are often seen as being partly ancestral to the Chaco system.

As I noted above, there are two main orientations that persist through time in the San Juan region. One is to due south, and the other is to the south-southeast (SSE). With pit structures these axes are typically defined by a straight line of sipapu (if present), hearth, deflector, and vent shaft. There is often also a measure of bilateral symmetry between features on either side of this line, such as support posts. When there are surface rooms behind a pit structure, they often (but not always) conform to the same alignment, and when the back of a row of surface rooms is straight, it is typically perpendicular to the main orientation. Malville and Munro argue that these perpendicular back walls on many Chacoan great houses, which Sofaer has identified as having alignments to various astronomical phenomena, are really subsidiary effects of the main emphasis on frontal orientation.

The authors start their survey of orientations with the Basketmaker III pithouse village of Shabik’eschee at Chaco. Of 15 pithouses for which they could find adequate information on orientation, 11 faced SSE with an average azimuth of 153.7 degrees and 4 faced south with an average azimuth of 185 degrees. Strikingly, none of the pithouses showed any other orientation.

The north-south orientation isn’t difficult to understand, and Malville and Munro attribute it to use of the night sky for navigation (which would have been easy enough at this time even though there wasn’t actually a north star), and they also mention the widespread presence of Pueblo traditions mentioning origins in the north. While the exact reasons for adoption of this orientation may not be clear, its consistency isn’t unexpected since it’s pretty obvious and easy to replicate.

The SSE orientation, on the other hand, is a different matter. Note that at Shabik’eschee this was much more common than the southern orientation, from which it is offset by about 20 to 30 degrees in individual cases. There is more variation in this orientation than with the southern one (standard deviation of 7.7 degrees versus 2.4), but it’s sufficiently consistent and common that it seems like there must be some specific reason for it. Unlike the southern orientation, however, it’s not at all clear what that might be. Malville and Munro, sticking to their interpretation of orientations as references to places of origin, suggest that in the case of Shabik’eschee it might reflect the fact that some people might have migrated to Chaco from an area that was more to the north-northwest than due north, which seems implausible to me but then I don’t have a better explanation myself.

McPhee Reservoir, Dolores, Colorado

McPhee Reservoir, Dolores, Colorado

In any case, this pattern continues through time. The next set of orientations Malville and Munro look at are those of the pit structures at the Pueblo I Dolores villages. What they find is that SSE orientations are dominant here too, even more so than at Shabik’eschee. In fact, all of the pit structures they looked at had SSE orientations except those at Grass Mesa Village, which mostly faced faced south (although even here there were a few SSE orientations). This is in keeping with other evidence for differences in architecture among different villages at Dolores; Grass Mesa is known for having long, straight room blocks, as opposed to the smaller and often crescent-shaped roomblocks at McPhee Village, which with it is most often compared.

The Duckfoot site, to the west of the Dolores villages but contemporaneous with them, also had a SSE orientation. Further west, however, southern orientations become more common, including at the important village sites of Yellow Jacket and Alkali Ridge, plus some of the earlier Basketmaker II sites on Cedar Mesa in Utah.

There was one more orientation used during the Pueblo I period in the Northern San Juan region, however. At Sacred Ridge, in Ridges Basin near modern Durango, Colorado, the average azimuth of the pit structures is 120 degrees, the same east-southeast orientation corresponding to winter solstice sunrise so common in the Rio Grande. Malville and Munro remark on the similarity to the Rio Grande pattern and consider it “puzzling,” positing some potential ways that it could have come about. They argue, however, that wherever this pattern came from it didn’t last in the north, and they point to the extremely violent end to the occupation of Sacred Ridge as the end of this orientation tradition in the San Juan region (although this may not be strictly true, as discussed below).

From here Malville and Munro turn back to Chaco. Specifically, they look at the great houses at Chaco during its heyday from about AD 850 to 1150. Rather than pit structures, they focus on roomblocks, and they interpret the orientation of a roomblock to be the perpendicular to its long axis (in the case of rectangular roomblocks) or the perpendicular to the ends of the crescent of roomblocks with that shape. They find that most of the great houses have a SSE orientation, in keeping with the general trend throughout the region, as do the three northern outlier great houses of Chimney Rock, Salmon, and Aztec. Since this orientation is very close to the perpendicular of the minor lunar standstill moonrise alignment that Sofaer has proposed for many of these buildings, Malville and Munro argue that this widespread orientation explains the pattern much better than the lunar alignment. Pueblo Alto and Tsin Kletzin have north-south orientations, which is unsurprising since they lie on a north-south line with each other.

A few of the great houses have a more complicated situation. Peñasco Blanco appears to face east-southeast at an azimuth of approximately 115 degrees. This is intriguingly close to the Rio Grande/Sacred Ridge winter solstice orientation, which Malville and Munro do note. Although the unexcavated nature of the site makes it hard to tell for sure, it is possible that this is in fact an example of this orientation surviving much later in the San Juan region than the destruction of Sacred Ridge, although what, if any, connection there might be between the two sites is unclear.

Pueblo Bonito from Above

Pueblo Bonito from Above

And then there’s Pueblo Bonito. While the very precise north-south and east-west cardinal alignments of some of the key walls at this site are well known, it has also long been noted that there is evidence for different alignments and change over time here. Malville and Munro interpret the early crescent shape of the building as having a SSE orientation, and like many others they relate it to the similar size, shape, and orientation of McPhee Pueblo at McPhee Village. They then describe multiple stages of drift away from this orientation toward the cardinal orientation. There is surely something to this interpretation, but a careful look at the stages of construction of the site shows that the picture is probably more complicated. The very first construction at Bonito appears to have been straight and oriented to the south, and to have been incorporated later into the SSE-facing crescent. Subsequent building stages show evidence of both orientations having been present throughout the history of the building.

The complicated situation at Pueblo Bonito provides a convenient segue to the key issue here: what was driving this long-term but consistent variation? Why were two different orientations for buildings present in close proximity for hundreds of years, even as populations moved long distances and adjusted their cultures in profound ways? Malville and Munro suggest that these orientations may reflect longstanding cultural and ethnic diversity in the prehistoric Southwest. Given how long-lived and consistent these patterns are, they propose that they were related to deep-seated cultural identities. This is an intriguing idea that may allow tracking of specific cultural groups across the Southwest over centuries. It also provides another piece of evidence that Chaco Canyon was a multicultural community, and implies that even Pueblo Bonito itself contained groups with diverse backgrounds.

The picture is probably even more complicated than Malville and Munro suggest. They tend to implicitly assume that the orientations of pit structures are the same as those of the room blocks with which they are associated, but at least at Chaco this is not necessary true, particularly for small-house sites, which they also don’t address at all in this study. There are many examples of small houses where the room blocks are oriented to the east but the pit structures are oriented to the south (and possibly also SSE, although I haven’t checked this). This eastern orientation may reflect connections to the south, which have gotten a lot less attention in the literature than connections to the north although they appear to have been pretty important in the origins of Chaco.

In any case, I think this is fascinating stuff. It may not be archaeoastronomy per se, but it seems like a fitting way to mark the solstice.
Malville JM, & Munro AM (2010). Cultural Identity, Continuity, and Astronomy in Chaco Canyon Archaeoastronomy, 23, 62-81

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Southeast Corner of Pueblo Bonito

Southeast Corner of Pueblo Bonito

Today is the summer solstice, on which I typically make posts about archaeoastronomy, so I’m going to take a break from my very gradual series of posts on tracing the connections between ancient and modern Pueblos to speculate a bit about the role of astronomy at Chaco. Briefly, what I’m proposing is that the rise of Chaco as a regional center could have been due to it being the first place in the Southwest to develop detailed, precise knowledge of the movements of heavenly bodies (especially the sun and moon), which allowed Chacoan religious leaders to develop an elaborate ceremonial calendar with rituals that proved attractive enough to other groups in the region to give the canyon immense religious prestige. This would have drawn many people from the surrounding area to Chaco, either on short-term pilgrimages or permanently, which in turn would have given Chacoan political elites (who may or may not have been the same people as the religious leaders) the economic base to project political and/or military power throughout a large area, and cultural influence even further.

I don’t have any specific research papers to discuss on this topic because as far as I know no one has really looked at it quite this way. It’s similar in some respects to the theories of the Solstice Project, although I don’t buy that astronomical alignments were quite as important in the Chacoan system as they propose. There is also some overlap with the theories of various archaeologists, but none of them have put the pieces together in quite this way. This may be because it’s demonstrably wrong, but if it is I haven’t seen the evidence that disproves it yet (but would be very interesting in doing so).

This theory first occurred to me when I was reading about Tiwanaku in Bolivia, which was a prehistoric society that, like Chaco, left very impressive physical remains in a very isolated location with few obvious economic advantages. As I noted in my post on Tiwanaku, the similarities actually go well beyond that, extending also to the shifting interpretations by archaeologists and the evidence for astronomical alignments. Most relevant in this context is the theory of John Janusek at Vanderbilt, whose theory of Tiwanaku is the model for the theory I’m suggesting here for Chaco. As he wrote in one paper, which I also quoted in the earlier post:

Tiwanaku’s long rise to power in the Andean altiplano was predicated on the integration of diverse local ritual cults and various symbolic dimensions of the natural environment into a reasonably coherent, supremely elegant and powerfully predictive religion. The shifting physicality of Tiwanaku’s religious monuments attests the construction and ongoing transformation of an urban landscape that not only visually expressed the altiplano’s ‘natural’ forces and cycles, but, via recurring construction and ritual, simultaneously shaped new social practices and Tiwanaku’s ever-increasing political influence and productive coordination, intensification and expansion. Tiwanaku was an imperfect and potentially volatile integration of religious cults, productive enterprises and societies. The material objectification of a seductive religious ideology that infused the monumental centre with numinous natural forces and simultaneously projected those forces across distant Andean realms helped drive Tiwanaku’s very worldly imperial mission.

Tiwanaku was apparently the first society in the altiplano to develop the level of astronomical skill which allowed it to develop such a “powerfully predictive” religion, and my application of a similar theory to Chaco relies on it also being the first place that developed a comparable knowledge of astronomy in the Southwest. I hadn’t really thought about this before reading Janusek’s work, but as far as I can tell it does in fact seem to be the case. Ray Williamson’s somewhat dated but still very useful book on Native North American astronomy (which I reviewed here) doesn’t mention any evidence of Southwestern astronomical knowledge predating Chaco, and I haven’t seen any other publications that do either. Granted, some of the evidence for astronomical evidence comes from rock art which is difficult or impossible to date, but at least when it comes to building alignments, which are more securely datable, the Chacoan great houses seem to be the earliest manifestation of detailed astronomical knowledge. Some earlier sites do show general alignments to cardinal directions and so forth, but the precise alignments to solstices and lunar standstills that are characteristic of Chacoan buildings do really seem to be innovative. I’m not totally certain that there aren’t counterexamples out there, though, so if anyone knows of any I’m very interested in hearing about them.

If this is in fact the case, it opens up several additional lines of inquiry. First, if Chaco was in fact the first place in the (northern?) Southwest to attain detailed astronomical knowledge, where did that knowledge come from? Many discussions of Chacoan astronomy have assumed, implicitly or explicitly, that the answer is “Mexico,” but I’m not so sure. There is definitely extensive evidence of contact with Mesoamerica at Chaco, but it’s all fairly indirect and there are lots of important aspects of Mesoamerican culture that are noticeably lacking. Mesoamerican astronomical knowledge was certainly impressive, and certainly predates the rise of Chaco, but given the general context I think it’s still an open question whether the Chacoans got their knowledge from contacts to the south (either directly or via the Hohokam and/or Mogollon) or developed it independently. This is an area that would definitely benefit from further study.

Secondly, why Chaco rather than somewhere else in the region? This is sort of the key question hanging over everything about Chaco, and so far no one has come up with a broadly convincing answer. I don’t have one either; the astronomy theory I’m proposing here answers the “how” of Chaco but not the “why.” It could be that, as some archaeologists have proposed, the physical setting of the canyon had unique attributes within the region that contributed to its ritual importance from an early period, which from my perspective would have provided the impetus for the development and/or integration of new astronomical knowledge into existing belief systems. Alternatively, as other archaeologists have argued, there could have been economic advantages to the location, which are not obvious to modern eyes but were sufficient to give Chaco an important role in the region, which may have made it a promising place for new ideas to develop or be introduced. And finally, maybe it’s all just a matter of historical contingency: this was where people happened to figure this stuff out, and that’s what made it attractive to others for both religious and economic reasons.

Another question is when this would have happened. Chaco was occupied for hundreds of years, but its florescence as a regional center was relatively brief, lasting roughly a century from AD 1030 to 1130 or so. One natural conclusion would be that the development of new astronomical knowledge happened at the start of this period, but I suspect it actually began earlier, probably during the period (roughly the late ninth and tenth centuries, or the late Pueblo I period) when Chaco was just one of several “proto-great-house” communities in the San Juan Basin that were more or less equal in size and influence. Over time, the advantages of the Chacoan rituals over the others would have become apparent, perhaps through fortuitous stretches of good weather and/or military successes by Chacoan warriors. This would have set the stage for Chacoan influence to expand on a vast scale during the eleventh century.

As the reference to military success in the previous paragraph suggests, I don’t see the expansion of Chacoan religious influence fueled by astronomical knowledge as having necessarily been entirely peaceful. Here again, the parallel to Tiwanaku is instructive. Note Janusek’s reference to Tiwanaku’s “very worldly imperial mission” in the quote above. I suspect what we would today see as “religious” and “secular” impulses were much more intertwined at Chaco, as indeed they have been shown to be in many societies.

All that said, I’m not totally convinced by this theory myself, and there are many strands of the Chacoan record that it doesn’t really seem to account for in an obvious way. I figured this was a good opportunity to toss it out there, though, to see whether it’s worth pursuing further.
Janusek, J. (2006). The changing ‘nature’ of Tiwanaku religion and the rise of an Andean state World Archaeology, 38 (3), 469-492 DOI: 10.1080/00438240600813541

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Rio Grande from Coronado State Monument, Bernalillo, New Mexico

Rio Grande from Kuaua Pueblo, Coronado State Monument, Bernalillo, New Mexico

Today is the winter solstice, which also makes it the fifth anniversary of this blog. I tend to like to post about archaeoastronomy on these occasions, and as I mentioned in the previous post I’m currently in Albuquerque and have been reading up on the archaeology of the Rio Grande Valley. Luckily, a recent article I read has a very interesting archaeoastronomical proposal specific to this region, which makes everything come together nicely. Getting to that point requires some explanation of the context first, however.

Today the northern Rio Grande Valley is one of the main centers of Pueblo population, and this was also true at the time the Spanish arrived in the sixteenth century. It’s been clear to archaeologists since the late nineteenth century that the modern eastern or Rio Grande Pueblos belong to the same overall cultural tradition as both the modern western Pueblos (Laguna, Acoma, Zuni, and Hopi) and the prehistoric Pueblo sites found all over the northern Southwest. Within this overall cultural tradition, however, there are noticeable differences in certain aspects of culture between the Rio Grande Pueblos and those further west, as well as between both groups and the prehistoric sites. The long and complicated history of interaction between the Rio Grande Pueblos and the Spanish has both led to cultural changes in this region and made the modern Pueblo residents very reluctant to reveal information about their cultures to anthropologists. Both of these phenomena make understanding the background of Pueblo diversity exceptionally difficult.

As a result, archaeological research in the northern Rio Grande area has proceeded along a somewhat different course from research further west. While extensive early research at well-preserved abandoned sites at places like Chaco Canyon and Mesa Verde led to the formulation of a robust and well-supported relative chronological scheme by the late 1920s that was soon anchored by the absolute dates provided by tree-ring dating, fitting the Rio Grande sites into this sequence proved to be a challenge. Alfred Vincent Kidder’s extensive excavations at Pecos provided clear evidence of continuity between prehistoric and historic Pueblo culture, which allowed the historic Pueblos to be easily placed at the end of the sequence, aligning earlier developments in the east and west proved to be a challenge. Pecos itself was founded quite late in prehistory, and very few other prehistoric sites had been excavated in the Rio Grande area. The so-called “Pecos System” of chronology and culture history was actually based primarily on western sites, and over time it became clear that it didn’t fit the emerging picture of Rio Grande prehistory pretty well. That picture, based primarily on survey and excavation work done by the Laboratory of Anthropology at the Museum of New Mexico starting in the 1930s, by the 1950s resulted in a new framework for eastern Pueblo prehistory.

The main architect of the new system was Fred Wendorf, an archaeologist at the Museum of New Mexico who had done a lot of the work of documenting sites in the region. He published a paper in American Anthropologist in 1954 describing his proposed system, which consisted of five periods:

  • Preceramic: Before AD 600
  • Developmental: AD 600 to 1200
  • Coalition: AD 1200 to 1325
  • Classic: AD 1325 to 1600
  • Historic: AD 1600 to present

Contrast this to the Pecos System, as presented by Joe Ben Wheat in a paper published in the same journal in the same year:

  • Basketmaker II: Before AD 400
  • Basketmaker III: AD 400 to 700
  • Pueblo I: AD 700 to 900
  • Pueblo II: AD 900 to 1100
  • Pueblo III: AD 1100 to 1300
  • Pueblo IV: AD 1300 to 1600

The most obvious difference between the two systems is that the Pecos System contains more periods. A more subtle difference is that in the Pecos System all of the periods are associated with agriculture, which appeared quite early in the Four Corners area. Exactly how early was not quite clear in 1954; Wheat says it was “about the time of Christ.” In the Rio Grande, on the other hand, the Developmental was the earliest agricultural period in Wendorf’s scheme as well as the first ceramic one, preceded by a Preceramic period that was totally undated at the time but that Wendorf suggested may have lasted quite late, even after the beginning of the Developmental.

This pattern of delayed appearance of typical “Anasazi” cultural phenomena in the Rio Grande persisted throughout Wendorf’s scheme. He defined the beginning of the Coalition period by the switch from mineral to organic pigment in pottery decoration, a trend which had been gradually diffusing east from Arizona over the past few hundred years. Similarly, the beginning of the Classic was defined by the appearance of glaze-decorated ceramics, which had appeared a few decades earlier in the Zuni area. The Historic period began with the onset of Spanish colonization. In general Wendorf’s period definitions depended heavily on trends in pottery decoration, in contrast to the Pecos periods which were defined by a broad suite of material culture changes, with architecture especially important. One reason for this was that architecture and other cultural traits were bewilderingly diverse within each of these periods, especially the Developmental, and this diversity was apparent even with the very small number of excavated sites at that time.

Palace of the Governors, Santa Fe, New Mexico

Palace of the Governors, Santa Fe, New Mexico

Wendorf’s scheme was in conflict on various points with a different scheme for Pueblo culture history as a whole developed by Erik Reed of the National Park Service. After Wendorf’s paper was published, discussions between the two led to an updated version of it published under both their names the next year in El Palacio. This paper has been extremely influential and the framework it established has been used by most archaeologists in the Rio Grande area since. The basic outlines of the framework are the same as those in Wendorf’s 1954 paper, with the changes involving the correction of the numerous typos in that paper, the addition of data from more recent excavations, and a somewhat different discussion of attempts to correlate archaeological phenomena with the complex distribution of modern linguistic groups. The latter was a particular interest of Reed, whose theories on it had been criticized by Wendorf in the earlier paper. I find it interesting as well, but I won’t get into it here.

Instead my focus here is on Wendorf and Reed’s Developmental period. Wendorf originally defined this period based on extremely limited information as a time of low population, diverse architectural styles and settlement patterns, and evidence of cultural influence from the San Juan Anasazi to the west. Population was extremely limited until about AD 900, when many more sites appear to have been inhabited and sites began to appear in the northern part of the region for the first time. This is the time of the rise of Chaco, and local Rio Grande ceramics show clear similarities to Chacoan types. Some archaeologists, including Reed, had argued that this rise in population came from an actual immigration of people from the Chaco area, but Wendorf doubted this, pointing out that other cultural traits showed considerable differences from Chacoan patterns. He suggested that while there could well have been some immigration from the west at this time, it was more likely from somewhere like the Mt. Taylor area that was part of the general Chacoan sphere of influence but closer to the Rio Grande, and that the number of people was likely small.

Architecture during the Developmental period was varied, with site sizes ranging from ten to 100 rooms and one to four kivas. The kivas were round and lacked most of the typical Chaco/San Juan features such as benches, pilasters, and wall recesses. They also usually faced east, in strong contrast to Chaco kivas, which usually faced south or southeast, even when they were associated with east-facing surface roomblocks (a common pattern for small houses at Chaco).

While the Wendorf and Reed system has remained in general use among Rio Grande archaeologists, the Developmental period in particular has seen much more data emerge from subsequent research, much of it associated with cultural resource management salvage projects. Cherie Scheick argued in a 2007 article that the period was much more diverse and complex than Wendorf and Reed had portrayed it as, illustrated by two nearby and contemporaneous sites in what is now Santa Fe that nevertheless had quite different ceramic assemblages which would place on in the Developmental period and the other in the Coalition period based on the Wendorf and Reed system. (This sort of thing is a major flaw with chronologies based mainly on ceramic styles, since time is by no means the only factor affecting differences in pottery.) Basically there seems to have been a long transitional period between the Developmental and Coalition in which communities with a variety of ceramic styles existed in close proximity. In particular, the introduction of carbon pigments seems to have been more variable than Wendorf and Reed realized, and they coexisted with mineral pigments for a substantial period. Scheick also points out that, contrary to what some earlier researchers had thought, there are no particular patterns over time in the architecture, such as larger villages developing later in the Developmental period.

Lurking in the background of all this research is the question of the abandonment of the Mesa Verde region and whether any of the apparent increases in population in the Rio Grande correspond to an influx of people from that area. Wendorf and Reed placed this migration in the middle of their Coalition period, with the appearance of a ceramic type, Galisteo Black-on-white, that is very similar to late Mesa Verde Black-on-white, and various other changes in material culture in the region that accompanied a population increase. However, recent research in the Mesa Verde region itself has suggested that the depopulation was a longer-term process beginning much earlier than previously thought, so some of the changes in the early Coalition period, could also be due to immigration. The basic problem is that while there are plenty of individual examples of similarity between San Juan/Mesa Verde culture and Rio Grande culture over a long period of time, there are no sites showing a complete package of San Juan cultural traits. There seems to be an emerging consensus that this is because the migration was primarily not of entire communities moving as units but of smaller units (families or lineages) that joined existing communities in the target region, perhaps ones that they had had earlier contact with through trade or other activities.

Round Kiva at Kuaua Pueblo, Coronado State Monument

Round Kiva at Kuaua Pueblo, Coronado State Monument, Bernalillo, New Mexico

An additional piece of evidence for this idea comes from the paper I mentioned at the beginning of this post, published by Steven Lakatos in 2007. Lakatos did an analysis of features in Rio Grande pit structures (kivas) during the Developmental period. He looked at size, orientation, and presence or absence of a hearth, an ash pit, a deflector, and a ventilator in a total of 131 excavated pit structures in the Rio Grande Valley dating to AD 600 to 1200. He looked at specific types of each of these features and came up with a wide variety of statistical comparisons. The sample sizes for most of the subsamples he looked at are so small, however, that I doubt many of these comparisons are meaningful. His overall conclusions, however, are probably reliable.

Lakatos found that there is a consistent pattern of features in pit structures throughout the Developmental period: hearth, ash pit, deflector, and ventilator, sometimes accompanied by sipapu and/or ash grinding stone, in a row aligned to the east-southeast (average azimuth from true north of 118 degrees for the Early Developmental period and 123 degrees for the late developmental). This is in strong contrast to the San Juan (Chaco/Mesa Verde) kiva pattern, where ash pits are rare, other features like benches and pilasters are common, and orientation is usually to the south or south-southeast. Lakatos notes that this Rio Grande kiva pattern continues into the Coalition period and later, as kivas become more formalized community-scale integrative structures, and while all the features in the complex potentially had originally mundane uses, the formalization of the pattern and its persistence over time suggest that at some point it acquired ritual significance. He notes the ritual importance of ash to modern Rio Grande Pueblos as a way of explaining the ash pit and ash-grinding stone as ritual features. The persistence of the pattern into the Coalition period and beyond suggests to Lakatos that immigrants to the Rio Grande from Mesa Verde and elsewhere not only joined existing communities, but largely assimilated to existing religious and cultural practices in an area that had developed a distinctive identity already. Thus, the reason it is so hard to pinpoint continuity between San Juan and Rio Grande archaeological sites is that the San Juan immigrants changed their culture to conform to Rio Grande practices.

I’m not sure I buy that there was quite as much continuity in the Rio Grande as Lakatos and other Rio Grande archaeologists tend to think. Looking at it from the outside, the ceramic evidence certainly seems to imply at least some continuity with Mesa Verde culture, and a close examination of what little ethnographic information is available on the Rio Grande Pueblos may reveal other traits of western or northern origin. Still, Lakatos’s evidence for continuity in kiva form looks convincing to me, and the patterns he identifies are certainly quite different from those of Chaco and Mesa Verde. The fact that his interpretation meshes well with other research suggesting migration by small groups into established communities is also encouraging.

So what does all this have to do with the winter solstice? Well, Lakatos also calculated the azimuth of winter solstice sunrise for the Albuquerque area in AD 1000, and it was 119 degrees east of north. This is strikingly similar to the average azimuths of the kiva alignments he analyzed, which have small standard deviations indicating strong clustering around the average values. The variation that does exist could easily correspond to local horizon variation in this rugged, mountainous region. Lakatos expresses surprise at this finding, but it makes perfect sense to me. The winter solstice is an enormously important event for the modern Pueblos, as Lakatos discusses, and pointing their kivas toward it would be a natural response to that importance. And with that in mind, I wish all my readers a happy solstice.

Lakatos, SA (2007). Cultural Continuity and the Development of Integrative Architecture in the Northern Rio Grande Valley of New Mexico, A.D. 600-1200 Kiva, 73 (1), 31-66

Wendorf, F (1954). A Reconstruction of Northern Rio Grande Prehistory American Anthropologist, 56 (2), 200-227 DOI: 10.1525/aa.1954.56.2.02a00050

Wendorf, F, & Reed, EK (1955). An Alternative Reconstruction of Northern Rio Grande Prehistory El Palacio, 62 (5-6), 131-173

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"Supernova" Pictograph

“Supernova” Pictograph

I recently finished reading Living the Sky: The Cosmos of the American Indian by Ray Williamson. This is a classic work on the archaeoastronomy of North America, and it’s the best introduction to the subject I’ve found. (Granted, there aren’t many out there.) Although it was written in the 1980s, the research it discusses is still quite relevant, and Williamson does a good job of giving a pretty comprehensive overview of research in most parts of the US. The 1970s and 1980s were kind of the heyday of archaeoastronomy in the US, and while there has been continuing research since then, it’s striking how few major discoveries have been made since Williamson’s book was published. Virtually all of the major discoveries I knew about before reading the book are included, plus many others I didn’t know about.

Williamson did quite a bit of research himself on astronomical phenomena at Chaco, which gets lots of coverage in the book. There is some discussion of the Sun Dagger on Fajada Butte, as well as of alignments at Pueblo Bonito and Casa Rinconada and the alleged “supernova petroglyph” near Peñasco Blanco. Williamson gives the latter a lot more credence than others, and actually has a whole chapter on alleged representations of the 1054 supernova in rock art, including several other sites I had not heard about. I’m pretty skeptical about the supernova stuff, but it’s interesting to hear about these other sites.

Reconstructed "Woodhenge" at Cahokia

Reconstructed “Woodhenge” at Cahokia

While the Chaco stuff is interesting, I already knew most of it and Williamson’s account doesn’t add a whole lot to anyone who is reasonably well-versed in it. Where this book really stands out for me is in its discussion of archaeoastronomy in other areas that get less attention, especially the Plains and California, which have a lot of archaeoastronomical phenomena despite their lack of impressive well-preserved architectural sites like those in the Southwest. The chapter on the East is also interesting, with discussion of the famous “Woodhenge” at Cahokia and the “SunWatch” site in Dayton, Ohio as well as other lesser-known sites. Even within the Southwest, Williamson devotes space to research at more obscure places like Hovenweep (which turns out to have a lot of interesting potential alignments) as well as major centers like Chaco.

Williamson also does a good job of connecting the archaeological data to ethnographic reports about astronomical practices among modern groups. There has historically been a tendency for archaeoastronomers, many of whom are astronomers or surveyors by training, to focus on identifying alignments without giving much consideration to the cultural context in which they may have existed. Williamson avoids this pitfall by giving extensive attention to ethnographic practices and their potential connections to the evidence from ancestral sites. He does a particularly good job with respect to the Pueblos, for which both the ethnographic and archaeological data are extensive, but he also includes extensive discussion of the Navajo, Pawnee, and Chumash, and some attention to various other groups. His interpretations of the ethnography at times show a tendency toward oversimplification, and some of his general comments about Native American societies are, well, overly general and imply more widespread commonalities among very different societies than is really reasonable, but he’s not an anthropologist and as such I think these flaws are quite forgivable given all the interesting data he presents in accessible form.

Hovenweep Castle, Utah

Hovenweep Castle, Utah

I also read a 2003 review article on archaeoastronomy in the Americas, written by prominent archaeoastronomer Anthony Aveni, to get a sense of research since the 1980s, but it didn’t add much. For one thing, as mentioned above, the pace of archaeoastronomy seems to have leveled off a lot since then, and it’s striking how many of the references in Aveni’s article are to publications from the 1970s and 1980s. Also, while the article does cover North America as one of its three main sections, it spends much more space on the other two sections, Mesoamerica and South America. This is unsurprising, since the major civilizations in these areas have written records (mostly from the contact period but in the case of the Maya precontact as well) to which archaeological data can be compared. In addition, they have just received more attention in general from archaeoastronomers than cultures further north. Aveni himself studies Mesoamerica, so he has a lot to say about research there.

That said, however, Aveni’s account of North American archaeoastronomy is also surprisingly sloppy and riddled with obvious errors. He refers to Cahokia as “part of the Adena-Hopewell culture,” which is just laughably wrong; Cahokia is the preeminent site of the Mississippian culture, which arose centuries after the decline of Hopewell. He also attributes the Poverty Point site in Louisiana to the Adena, whereas it is actually significantly earlier. His discussion of the Southwest doesn’t contain any obvious errors of that magnitude, but it is very brief and superficial, as is the whole North American section of the paper.

Fajada Butte with Green Vegetation

Fajada Butte with Green Vegetation

Overall, then, I guess I would say that Williamson’s book is a much better introduction to North American archaeoastronomy than Aveni’s article, but that is kind of a trivial conclusion since it’s also much easier to find for the general reader. Even academics who have access to the Aveni paper, though, probably won’t get much out of it on this topic.
Aveni AF (2003). Archaeoastronomy in the Ancient Americas Journal of Archaeological Research, 11 (2), 149-191 DOI: 10.1023/A:1022971730558

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