Archive for the ‘Archaeoastronomy’ Category


Cliff Palace and Sun Temple, Mesa Verde

In addition to reports of potential astronomical features at prehistoric sites and speculations on the role of astronomy in ancient societies, Astronomy and Ceremony in the Prehistoric Southwest: Revisited contains some chapters giving guidance on methodology for archaeoastronomical research, particularly aimed at developing increased rigor that can make the results of this research more useful for archaeologists. One of these chapters, by Gregory Munson, focuses on archaeoastronomy at Mesa Verde National Park and how it can be supported or challenged by using a methodology he calls architectural documentation or “ArcDoc.”

Munson spends much of the paper laying out the details of how to do ArcDoc, which basically amounts to a standardized set of recording procedures for sites and a commitment to fully research historical archives for materials relating to site excavation and restoration. The formal procedures are apparently those used by park management at Mesa Verde, but the basic ideas here are standard pretty much anywhere archaeologists have put in place a rigorous site documentation program (e.g., on most public lands in the US).

Munson then turns to specific examples of how ArcDoc has helped clarify findings from archaeoastronomy, focusing on three sites at Mesa Verde: Cliff Palace, Balcony House, and Sun Temple. In each case, archival research has either significantly challenged findings from initial archaeoastronomical research or otherwise improved understanding of the sites.


Cliff Palace, Mesa Verde

With Cliff Palace, Munson focuses on two features in the well-known “Tower” part of the site, both of which have been proposed to have associations with lunar standstill observations. One is a vent in the wall of the tower that has been demonstrated to align with moonset over Sun Temple during the southern major lunar maximum. The other is a nearby pictograph of four vertical lines with horizontal “ticks” that has been proposed to be a record of four 18.6-year lunar standstill cycles.

The vent alignment turns out to be very questionable after looking back at records of excavation and reconstruction of the site beginning with the work of Gustav Nordenskiöld in the 1890s and Jesse Walter Fewkes in the 1900s. Photographs from before the partial reconstruction of the site by Fewkes in 1909 show that this whole portion of the tower had largely collapsed, and the original size and shape of the vent in question is impossible to determine. Furthermore, the current vent that has the documented alignment isn’t even the result of Fewkes’s reconstruction, but of a later one by Earl Morris and Al Lancaster in the 1930s that replaced it. Munson claims that there is another opening in the wall that is more original and seems to display the same alignment, but this is an important cautionary tale for archaeoastronomers who, like many visitors, all too often assume that what they see at a site today is exactly what was there when it was originally occupied.

A similar problem affects the pictograph. The current version turns out to be a partial reconstruction by Lancaster in 1934 after two of the vertical lines had severely deteriorated, and the number of ticks on these lines does not match what appears to have been the original pictograph based on a photo taken in 1902, which Lancaster appears to not have had access to when doing his reconstruction. The numbers are still fairly close and Munson argues they could still be a record of lunar standstill cycles given the level of precision that might be expected for these observations, but still, another cautionary tale. Especially at a well-known, heavily visited, and actively managed site like Cliff Palace, you can’t assume that everything you’re seeing is original. (I used to make this point frequently to visitors at Chaco, and toward the beginning of my tours of Pueblo Bonito I would explain which parts of the masonry are and are not original.)

At Balcony House, Munson explains that proposed summer solstice and equinox alignments are thrown into question, in one case because an editing error resulted in results from observations at a different site being attributed to this one in publication, and in another case because archival research showed that a wall opening with a purported alignment had been partially sealed before impacts from recent visitation. These issues aren’t as major as those with Cliff Palace mentioned above, but they are noteworthy because they affect Munson’s own previous research, and he deserves a lot of credit for being straightforward and transparent about them.


Sun Temple, Mesa Verde

Finally, a happier story from Sun Temple. Fewkes excavated here in 1915, and a 1916 publication of his illustrates two prayer sticks found in these excavations. However, the collections from this work, housed at the park, do not include any prayer sticks. Where did they go?

Through some archival sleuthing in Fewkes’s papers at the Smithsonian’s National Anthropological Archives, it turned out that he had also excavated at Oak Tree House in 1915, and the collections from this work are now held at the Smithsonian. And sure enough, this collection turned up two prayer sticks that could be matched to those in the illustration through their shapes and distinctive cracks. The fact that these actually appear to have come from Sun Temple rather than Oak Tree House helps to better understand the history and use of both sites.

In all these cases, the understanding of potential astronomical or ritual use of specific sites has been improved by carefully examining the archival history of their excavation and reconstruction. Archaeologists are increasingly aware of the importance of looking at this history when trying to understand sites like this, but this awareness is only beginning among archaeoastronomers, and Munson’s contribution here is a welcome illustration of its value.


Vent at Sun Temple, Mesa Verde


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Fajada Butte at Sunset

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

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

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

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

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

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

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


Fajada Butte with Ramp (Lower Right)

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

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

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

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

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


Fajada Butte with Green Vegetation

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Star Wars


Four-Pointed Star Petroglyph with Bird Imagery, Albuquerque, New Mexico

When I was in New Mexico in September, my lovely girlfriend bought me a book for my birthday. The book is Astronomy and Ceremony in the Prehistoric Southwest: Revisited, a collection of papers from a conference in 2011 on Southwestern archaeoastronomy that is in some ways a follow-up to a previous collection of papers published in 1987 as a volume titled Astronomy and Ceremony in the Prehistoric Southwest. That volume collected papers from a 1983 conference that was an important event in the early development of Southwestern archaeoastronomy, but it is out of print and hard to find, so I haven’t read it myself.

I recently started reading the new book, and I decided to do a series of blog posts about some of the chapters in it. I’m not going to do a post on every chapter the way I have for some books in the past, but just talk about the ones I find particularly interesting. The one I’ll start with is Polly Schaafsma’s paper on “The Morning Star/Rain/Maize Complex in the American Southwest.”

Schaafsma’s name may sound familiar to longtime readers from her theory of the origin of the kachina cult tying it to the Jornada style of rock art. She’s a prominent authority on Southwestern rock art, and in fact literally wrote the book on the subject. In this paper she discusses evidence, largely from late prehistoric rock art iconography but also from the Pueblo ethnographic record, for the presence in the Southwest of a version of the Mesoamerican ideological complex connecting the planet Venus, warfare, and maize agriculture.

In Mesoamerica this ideology is highly developed, and closely associated with both the calendar and the practice of human sacrifice, neither of which existed in the Southwest on anything like a Mesoamerican scale. In the late prehistoric period after about AD 1050, however, there do appear to have been some major changes in Southwestern religious ideology, as evidenced by new styles of pottery, architecture, and especially rock art. Many scholars, including Schaafsma, have interpreted these changes as evidence for a wave of Mesoamerican influence bringing new ideas into the area, though the exact routes of transmission and reasons for adoption are unclear. The kachina cult, however, seems to have originated through this process, and in this paper Schaafsma makes an interesting case for a version of the “Venus complex” linking the Morning and Evening Stars to warfare and fertility having been transmitted at the same time.


Boulder at Petroglyph National Monument with Various Symbols Including Stars

The core of her argument is the presence of four-pointed star imagery in the Rio Grande Style of rock art, found in the northern Rio Grande Valley and adjacent areas and dating to roughly AD 1350 to 1600. (This is the style that predominates at Petroglyph National Monument on the West Mesa of Albuquerque, where many examples of these stars can be found.) These four-pointed stars are not found in earlier styles of rock art, and they are often associated with imagery suggesting warfare, such as projectile weapons, warrior figures, and characteristics of birds of prey. In Pueblo oral traditions there is also an association between warfare and stars, which were traditionally feared. Stars are also associated with ice and cold, and projectile weapons are associated with lightning, rain, and moisture that helps corn germinate, as are the warrior societies that may have been the mechanism for carrying this ideological package into and through the Pueblo world. Schaafsma admits that there isn’t really a “picture trail” connecting this imagery to its purported Mesoamerican origin, but the story she tells is suggestive, and there are a few links along the way. Some related imagery shows up on Mimbres pottery, which is intermediate both temporally and spatially between Classic-Period Mesoamerica and the late prehistoric Pueblo world, so the story is definitely plausible if not exactly proven.

One final note is that this all postdates the time of Chaco Canyon, where despite evidence for Mesoamerican connections the rock art is quite different, and in fact the spread of these apparently new ideas and images in the late prehistoric period is one of the reasons it is very difficult to interpret Chaco by looking at modern Pueblo ethnography. A lot can change in a thousand years, and in this case definitely has. There are likely still many cultural phenomena among the modern Pueblos that go back to Chaco, but disentangling them from those that developed later is an enormously complicated task that I don’t think anyone has made much progress on so far.

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Park Map Sign, Pinson Mounds, Pinson, Tennessee

Today is the summer solstice, on which I traditionally post about archaeoastronomy, which is a major topic of interest in studying Chaco Canyon. Lately, however, I’ve been very busy and have not been keeping up on recent developments in Chaco studies (not helped by the fact that I don’t currently have access to the academic databases where recent research can be found), so this time I thought I would talk about the archaeoastronomy of a fascinating and unjustly obscure site in a different part of North America, the Pinson Mounds site in western Tennessee.

I visited Pinson a few years back more or less on a whim; I was driving across the country after finishing grad school, taking a meandering route and hitting a variety of archaeological and historical sites as I went. Pinson was not originally on my list of sites to visit, but for some reason that I no longer remember I decided to go there as I made my way through the Mid-South. It was a good decision.


Sauls Mound, Pinson Mounds, Pinson, Tennessee

There are a lot of prehistoric mound sites in the Southeast, and at first glance Pinson doesn’t seem particularly distinctive among them except that one of its mounds, known as Sauls Mound or Mound 9, is unusually large. And indeed, although the site was first documented in 1823 it was not until the 1970s when it became a Tennessee state park that extensive archaeological work was done there and its true nature became apparent. There are various types of mounds at Pinson, but the most prominent, including Sauls, are of the type known as “platform mounds” which are square or rectangular, often with buildings of presumed ritual function at the top, and are generally associated with the Mississippian period of circa AD 900 to 1600. Earlier Woodland period mound sites are more known for burial mounds, which are typically rounded or conical without buildings on top, with the Hopewell Culture sites in Ohio being the most prominent examples.

The platform mounds at Pinson, along with a single house of Mississippian “wall-trench” form excavated back in the 1960s, led most archaeologists to assume that this was a relatively minor Mississippian site until the excavations of the 1970s and the resulting radiocarbon dates showed that it actually dated to the Middle Woodland period in the early centuries AD, contemporaneous with Hopewell. And some of these dates were directly associated with the platform mounds, demonstrating clearly that they too dated to this early period! This led to a major reëvaluation of the Middle Woodland period in the Midsouth, which is in some ways still ongoing. It also led to the reëvaluation of some other platform-mound sites in the same general area which also ended up dating to the Middle Woodland. It remains unclear what the exact nature was of the relationship between these precocious southern platform-mound sites and the contemporaneous Hopewell sites to the north, and the same is true of their relationship to the later Mississippian sites.


Stairs to the top of Sauls Mound, Pison Mounds, Pinson, Tennessee

One thing that does appear to be true of these sites, however, as well as of the Hopewell ones, is that they were primarily ritual or ceremonial centers without substantial residential components. They appear to have served dispersed communities of small hamlets, who were likely small-scale farmers growing indigenous plants of the Eastern Agricultural Complex. This is in contrast to Mississippian mound centers, which are now considered to have been large residential settlements of farmers growing crops of Mesoamerican origins (especially maize). Also unlike the strongly hierarchical Mississippian chiefdoms, Middle Woodland communities are also generally thought to have been relatively egalitarian in structure.

Some of these ideas may seem familiar to those familiar with Chaco. A similarly egalitarian structure has been proposed by some archaeologists to explain Chacoan great-house communities, based on models proposed by earlier generations of archaeologists to explain the Classic Maya polities. These models are now falling out of fashion for Chaco, much as they eventually did for the Maya, based on new research that makes them less tenable. It might seem odd that they have remained so tenacious for the Hopewell and other Middle Woodland societies in the east, but they have, which to me suggests that they really might be on to something here. I know a lot of people find these explanations of Chaco as an empty ceremonial center for a dispersed society of small-scale egalitarian farmers inspiring as a vision of what a society can be; as Chacoan research makes this a less plausible reconstruction they may wish to turn their eyes eastward, and further back in time, for a better example.

Anyway, on to the astronomy. The arrangement of the mounds at Pinson, as at many other Hopewell/Middle Woodland sites, has suggested to archaeologists for a while that there might be astronomical aspects to the site. One extensive, though admittedly speculative, exploration of this idea was published by Charles H. McNutt in a 2005 paper, which I will focus on here. McNutt proposed that Sauls Mound was the central focus of a set of astronomical alignments with other mounds at the site, and he compared the angles of these various inter-mound alignments to rising and setting positions of the sun, moon, and stars.


Sign at Mound 28, Pinson Mounds, Pinson, Tennessee

The most straightforward of the alignments he found were to solar events, i.e., the solstices and equinoxes. Mound 29 is due east of Sauls Mound within a circular feature known as the Eastern Citadel (which may have its own internal astronomical features), and it appears that this relationship may represent an equinox sunrise marker. Mound 28, northeast of Sauls Mound at a similar distance to Mound 29, has been proposed as a summer solstice sunrise marker (as indicated by a sign posted at the site, even), but McNutt found that it is not really close enough to the solstice alignment for this to be plausible. However, another mound indicated on early maps of the site, but not visible today, does appear at the proper angle on those maps to have been a solstice marker.

McNutt describes other possible alignments, to the lunar standstills as well as various stars, but he is rightly cautious about these and notes that the stellar alignments in particular are dubious because there are so many stars that alignments can easily arise due to chance. He then goes on to look at other contemporaneous mound sites in the same general area to determine if they have similar possible alignments, and finds that they do, although the quality of the data is not great for all of them and these too need to be treated with caution.


Mound 28, Pinson Mounds, Pinson, Tennessee

Finally, McNutt ties the existence of these celestial alignments back to the presumed reliance of the Middle Woodland people on agriculture, specifically of the crops of the Eastern Agricultural Complex. Farming peoples do rely on accurate calendars, it is true, and this may well have been the impetus for the astronomical observations that appear to be encoded at Pinson and other sites. I would note, however, that the immense effort required to build these mounds, especially for a dispersed and relatively egalitarian society, suggests that something more than utilitarian timekeeping needs led to their construction. But this may ultimately be a matter of perspective and emphasis more than anything else.

I may have more to say about Pinson in the future; it really is a fascinating place, well worth visiting. But for now I just want to draw some attention to it on this solstice day. Happy solstice!


Turtle at Pinson Mounds, Pinson, Tennessee

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Entrance Sign at Hovenweep National Monument

Today is the winter solstice, which also makes it the eighth anniversary of this blog. I like to mark these astronomical occasions with posts about archaeoastronomy, which is one of the most interesting fields of study relating to Chaco Canyon and other prehistoric sites of the Southwest. Today I just have a brief and fairly speculative post connecting some other suggestions I’ve made about how astronomy related to the larger cultural systems of these societies.

In Ray Williamson’s book Living the Sky: The Cosmos of the American Indian, which as I’ve noted is still a very good introduction to the subject despite being more than 30 years old now, he opens the chapter on the ancient Pueblos with fieldwork he had personally done at Hovenweep National Monument. Hovenweep is one of the more obscure Park Service units in the Southwest, consisting of several different clusters of ruins scattered on both sides of the Colorado-Utah state line just north of the Four Corners. The sites themselves are quite impressive, however, and well worth visiting. The most prominent and striking are the “towers” that tend to be placed along the edges of canyons near their heads, which are generally quite well preserved. These have not been extensively studied by archaeologists, and this area is not very well understood compared to many other parts of the Colorado Plateau


Hovenweep Castle

From what little we do know, the towers and related sites seem to be post-Chaco in age, and they don’t show much evidence of Chacoan influence. Williamson mentions tree-ring dates at Hovenweep Castle, the largest tower site in the Little Ruin Canyon/Square Tower group near the monument’s visitor center, of AD 1166 and 1277, which is after the main florescence of Chaco and contemporary with the cliff dwellings at Mesa Verde. The towers do have some architectural similarities to the cliff dwellings, and overall seem to fit into the Mesa Verde or Northern San Juan tradition. They don’t show any particular resemblance to Chacoan “great houses” in either size or form.

Williamson measured potential alignments to the solstices and equinoxes at Hovenweep Castle and a smaller site nearby called Unit Type House, as well as at another group of sites within the monument. These alignments generally involved small “ports” or holes in the exterior walls through which sunlight shines on or near the days in question. The beams coming through these ports tend to fall on opposite corners, suggesting that they were being used as calendars to track the progress of the sun, presumably to schedule rituals and/or agricultural activities. There is ample evidence in the modern ethnographic record that the modern Pueblo “Sun Priests” and other officials used solar observations similarly.


Unit Type House, Hovenweep

What I want to note here, however, is that Williamson found ports with solar alignments both at Hovenweep Castle, the largest site in the Little Ruin Canyon group and plausibly either a public/ritual facility or the residence of a community leader (or both), and at Unit Type House, which in keeping with its prosaic name is a smaller site that was likely a more mundane residence. This suggests that watching the sun and keeping calendars was a practice not limited to chiefs or priests at Hovenweep, but was practiced by ordinary people as well. But why?

A possible answer comes from Frank Cushing’s pioneering ethnographic work at Zuni in the late nineteenth century, which is quoted by Williamson in this connection. According to Cushing, while the Sun Priest was responsible for the official observation of the sun to set the ceremonial calendar,

many are the houses in Zuni with scores on their walls or ancient plates imbedded therein, while opposite, a convenient window or small port-hole lets in the light of the rising sun, which shines but two mornings in the three hundred and sixty five in the same place.

Cushing implies that the reason so many people had their own calendars like this was to check the accuracy of the Sun Priest’s observations, which implies that the people didn’t necessarily trust him to get it right.


Plaque at Fajada Butte View Describing the “Sun Dagger” Petroglyph

So far, so good, and in keeping with the general tendency toward egalitarian ideology and mistrust of hierarchical authority for which the modern Pueblos are known. But what I find interesting is the contrast here with Chaco, where many astronomical alignments are known for the great houses and other sites that were potentially ritually important (like the “Sun Dagger” petroglyph atop Fajada Butte), but none as far as I know in the small houses where most of the population would have lived. Did the Chacoans trust their sun priests more than the later people of Hovenweep and Zuni?

I think they just might have, and this brings me back to another theory I’ve proposed: that the rise of Chaco to a position of regional dominance in the tenth and eleventh centuries AD may have been associated with Chacoan elites’ control of new and ritually important astronomical practices. The astronomical alignments at Chaco appear to be the earliest known ones in at least the northern Southwest, and possibly the Southwest as a whole, and it’s possible that the development (or acquisition) of observation techniques that allowed Chaco’s leaders to demonstrate unprecedented powers of prediction fueled their rise. As long as those powers seemed to hold, they may have been able to keep close control over knowledge of their techniques, or the common people may simply have not thought to question them.

But Hovenweep, with its apparently more “democratic” distribution of astronomical knowledge, dates to only slightly later than Chaco. So what happened in between?


Small House across from Pueblo Bonito

It’s hard to say, and this is one of the enduring mysteries of Chaco, but this period (roughly the middle decades of the twelfth century) does appear to have been a time of great change throughout the northern Southwest, with the ultimate result being the loss of Chaco’s regional influence, although the canyon itself wasn’t completely abandoned until the whole region was at the end of the thirteenth century. There were some major droughts that occurred during this period, which seem to coincide with some of the cultural changes, so maybe the Chacoan elites’ esoteric calendrical knowledge no longer seemed to have the control over rain and fertility that they had claimed, and people began to trust them less and to try to do their own observations too. Or maybe there was a more general spread of astronomical knowledge that undermined Chaco’s influence even if its power didn’t appear to fail. It’s very hard to tell exactly what happened, but the patterns are intriguing.

Anyway, that’s my solstice/anniversary post for this year. Thanks to my long-time readers for sticking with me all these years.


Winter Solstice Sunset

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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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