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rinconadasolsticewindow

Opening at Casa Rinconada That Channels Sunbeam at Sunrise on Summer Solstice

Today is the summer solstice, so I thought I’d pop back in to do a post about archaeoastronomy, as is my wont. This time it isn’t about the archaeoastronomy of Chaco Canyon per se, but the larger context in which it would have developed, namely that of the civilizations of Mesoamerica to the south.

I’ve mentioned before that I have a tentative theory that part of the impetus for the rise of Chaco as a regional center may have been that its leaders were the first in the Southwest, or at least the northern Southwest, to develop a ritual system based on astronomical observation and alignments, which would have enhanced their ritual authority and consequently their economic and political authority as well. It can be very difficult to date archaeoastronomical phenomena, but it does appear based on my research so far that Chaco does indeed have the earliest datable evidence for astronomical alignments in the northern Southwest, and possibly in the Southwest as a whole. (There is some possible evidence for earlier alignments among the Hohokam of southern Arizona, but it’s somewhat questionable.) This provides some tentative support for the theory.

I don’t think it’s likely that the Chacoan leaders developed their astronomy on their own, though. There is plenty of evidence for contact and communication between them and Mesoamerica, though it isn’t always clear how direct this may have been (as opposed to indirect and mediated through groups in between such as the Hohokam). The much more complex societies of Mesoamerica also had much more elaborate astronomical and calendrical systems than anyone in the Southwest, so they are an obvious source for this as well.

They also presumably developed their knowledge earlier, so as I was thinking about my Chaco theory it occurred to me that it would be good to look into when exactly astronomical alignments and other evidence of this knowledge appear in Mesoamerica and how they spread and changed over time. Basically, the question is whether what is known about the origin and spread of astronomical knowledge in Mesoamerica is consistent with what appears to be true of the origin and spread of similar knowledge further north. Also, it would be helpful to know just how similar the alignments and other phenomena known from Mesoamerica are to those in the Southwest, again to judge the plausibility of a connection.

Luckily for me, an article published last year addressed this exact issue. Written by the Slovenian scholar Ivan Šprajc, it was published in the Journal of Archaeological Research and discusses the temporal and spatial distribution of different building alignments in Mesoamerica. It’s actually a bit odd that this article was published in this journal, which mostly publishes review articles giving a broad overview of recent research on a certain topic in archaeology. Šprajc’s article is in the form of such a review, more or less, but it actually primarily discusses a specific research project done by him and several collaborators, in which they collected very precise and complete data on the alignments of major buildings at many archaeological sites throughout most of the Mesoamerican culture area and analyzed them statistically to come up with general patterns of alignment and see what patterns emerged.

The results were very interesting, especially from an outside perspective. You might expect alignments to the summer and winter solstice sunrises and sunsets to be common, and they were to some extent, but they were by no means the most common. (Alignments to cardinal directions were also present but were even less common.) Much more common, especially in the Maya region, were alignments to certain points on the horizon that do appear to reflect particular sunrises and sunsets, but on different days than the solstices. The specific days cluster in February and October for sunrises and April and August for sunsets. Based on comparisons to ethnohistoric and modern ethnographic accounts of agricultural cycles, Šprajc proposes that these dates marked significant points in the cycle of planting and harvesting cycle, especially for maize, and that marking them would have been part of a very practical system of timekeeping that would also presumably have had ritual importance.

Furthermore, the numbers of days separating many of these dates that pattern together at particular sites tend to reflect multiples of 13 and 20, which are key numbers in the Mesoamerican calendar system, particularly in the 260-day ritual calendar. (Note that 260 is 13 times 20.) Based on the practices of some modern Maya communities that still measure their agricultural cycles this way, it appears that the alignments to mark the key dates would have allowed people to count from those points to figure out the rest of the cycle using these intervals. Since the same dates recur at these intervals in the ritual calendar, which is not calibrated to the solar year, people could have easily used them to keep track of the times for specific activities without worrying about a general calibration.

As a simplified example, if the alignment of a building in a community marked the beginning of the planting season based on the position of the sun, and the community knew that the harvest would come 260 days later, they could take note of the ritual calendar date (number and day-sign) of the beginning day marked by the alignment, the correspondence of which to the solar calendar would vary from year to year, and know that when that date came up again it would be time for harvest. This seems to me like a clever way to deal with the eternal problem of calibrating a solar calendar to seasonal cycles.

Be that as it may, it seems reasonably clear that nothing nearly this elaborate in either calendrical development or architectural alignment was present in the ancient Southwest (though it would be interesting to check some building alignments to see if any of these particular ones show up, which as far as I know no one has done). More interesting to me from my Southwestern perspective is Šprajc’s regional and temporal analysis, which does seem to tentatively provide some support for my Chaco theory.

Šprajc finds, perhaps unsurprisingly, that solstice alignments are the earliest, and that they are particularly characteristic of Preclassic sites in several regions, including Central Mexico, the Olmec region on the Gulf Coast, and the Pacific Coast of Guatemala. What he calls “quarter-day” orientations, which are not strictly to the equinoxes but to the calculated points in between the solstice alignments, are also common in early sites and often associated with solstice alignments. (He is dubious that actual equinox alignments really existed because they are difficult to observe.) In contrast, these alignments are fairly rare in early Maya sites.

The more complex calendrical alignments also appear fairly early, especially in Oaxaca but also in some Olmec sites as well as some in Central Mexico. It appears to be at Teotihuacan in the Early Classic period where two of the widespread calendrical alignments appear together for the first time, accounting for this major city’s well-known layout featuring two slightly different street grids. The subsequent spread of these alignments may be due in part to influence from Teotihuacan throughout Mesoamerica during the Classic period.

Among the areas of apparent Teotihuacan influence in alignment were northern and western Mesoamerica, which are the areas through which influence would presumably have flowed on its way to the Southwest. Šprajc notes, however, that the pattern of alignments shows a lot more diversity in these areas than elsewhere, with solstice and even cardinal alignments retaining substantial influence, and the northern site of Alta Vista may even have a true equinox alignment. From following the references to the more detailed report, it appears that the northern and western sites in the sample are all relatively late, with none earlier than the Early Classic. This is consistent with a spread of at least solstice alignment concepts, and possibly some other ideas, spreading gradually in this direction from the Mesoamerican heartland, eventually reaching Chaco by its rise in the Early Postclassic.

Finally, a word on the moon. Lunar standstill alignments have been identified at some Chacoan sites, especially Chimney Rock, but are controversial due to their general rarity worldwide. I found it intriguing, therefore, that Šprajc does identify some of these in Mesoamerica, but clustered primarily into specific subregions, especially the northeast coast of the Yucatan Peninsula and the Usumacinta drainage at the western edge of the Maya Lowlands. These alignments seem to be to the major lunar standstill and are associated with solstice alignments, implying that perhaps it was the full moons near the solstices that were primarily observed. They also seem to be associated with worship of a particular moon goddess, which helps to distinguish them from alignments to Venus, which are similar and were present in other subareas. This is way on the other end of Mesoamerica from the part most likely to have influenced the Southwest, so direct influence seems unlikely, but it’s interesting to note.

Overall, this article provides very interesting context for understanding Chaco and the role astronomy may have played in its florescence. Happy solstice!

 

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Changes

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Winter Solstice Sunset, Chaco Canyon

Today is the winter solstice, which means it’s the tenth anniversary of this blog.

Ten years is a long time for this sort of thing, and the online landscape has changed a lot in the time I’ve been doing this. When I started, blogging was still a relatively hip new thing, and there were blogs starting up all over the place on all sorts of topics. Social media as we know it today was in its infancy, and while most of the major platforms did exist they didn’t have nearly the reach or the cultural position that they do now.

Over those ten years, blogging has waned as a medium, and a lot of the discursive energy that made it so interesting migrated to various social media platforms. It never totally went away, as it’s a very good medium for the sort of long-form, infrequent content that does not fit easily into social media, and my own blogging has increasingly moved into that mode as well. I get few comments and fewer active discussions in comment threads these days, although that is partly due to the fact that I rarely engage in the comment threads myself anymore. Blogging has just become a different beast than it once was.

I also haven’t had as much time for it in recent years as I used to. My posting frequency has declined over time, and in recent years it’s generally been once a month. I’ve made a point of never missing a calendar month, although it’s been a close call a few times. Some of the posts I’ve done to meet those deadlines have been pretty insubstantial, though, and I’m not very proud of them. I’ve continued to do occasional longer, more in-depth posts, but I just don’t have as much time in my life for blogging as I used to.

I’m not quitting, though. I’ve considered it, and even considered using this anniversary post to announce it, but I still have more to say. Tim Burke had a post recently about the decline of blogging, and a lot of it resonated deeply with me although not all of it is relevant to the type of blogging I do here. Particularly resonant was his conclusion:

And yet, I remain hopeful about blogging. I am not sure why. I am not sure when. This remains open for business, nevertheless.

Likewise, this site remains open for business, but with some changes. I still have plenty to say about the ancient Southwest as well as other topics, but I’ll be restricting my writing here to the former. I may find a new outlet (or more than one) for writing about other topics, including some that I’ve written about here in the past, and if I do I’ll mention it here. But in view of the particular audience for this site and its history, I think it’s best to keep the focus here fairly narrow going forward. I haven’t been as able to keep up on recent research on Chaco Canyon as I used to, but there’s been a lot of it and I’m sure I will return to it at some point. When I do, I’ll discuss it here.

I’m also going to dispense with the artificial monthly schedule and just post whenever I have something to say. The sorts of posts I have in mind, some of which I’ve been thinking about for years, will be long and take a while to write, and I don’t want to either rush them or put them off even longer in an effort to post with a consistent rhythm. Stay tuned.

Finally, to give this post a little bit of substantive content in addition to my blathering on, here’s a nice post, written fifteen years ago by another old-school blogger, Kieran Healy, about the Irish megalithic site of Newgrange and its solstice alignment. Healy’s conclusion about it is thought-provoking and seasonally appropriate, now more than ever:

A society—a civilization, if you like—is a hard thing to hold together. If you live in an agrarian society, and you have only stone, wood, and bone for tools, and you are on the western edge of Europe, few times are harder than the dead of Winter. The days are at their shortest, the sun is far away, and the Malthusian edge is right in front of you. It’s no wonder so many religious festivals take place around the solstice. Here were a people, more than five millennia ago, able not only to pull through the Winter successfully, but able also to build something like a huge timepiece to remind themselves that they were going to make it.

Times change, but we’ll make it too. Happy solstice.

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Chetro Ketl, the Talus Unit, and Pueblo Bonito from the Cliff Top

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bclighthouse

Lighthouse on the Coast of British Columbia

In the previous post, I mentioned that the study of Native California solstice observation that I was discussing found that southern California groups had types of observation resembling those in the Southwest, while northern California groups had observation types more like those of the Northwest Coast. This makes sense in terms of the larger cultural patterns tying these California groups to these other regions in general. However, when I started thinking more about this particular pattern I realized that there was something odd, or at least unfamiliar, about it.

The Southwest is of course very well known for its Native astronomy, both ancient and modern. The same is not true of the Northwest, however. This region is ethnographically very well-studied, and is well known for its cross-culturally unusual pattern of complex hunter-gatherer societies with a variety of elaborate social institutions. Astronomical observations, however, are not among the institutions widely associated with the Northwest. In contrast to the wide-open skies, sunny weather, and distant, varied horizons of the Southwest, the Northwest is a humid, rainy area of dense forests and mountains that come all the way to the sea. This would be a hard place to observe the sun! What’s more, astronomy and calendars are often associated with agriculture and the need to keep track of seasons for planting and harvesting, but the Northwest tribes had no agriculture and instead relied on hunting, gathering, and especially fishing for their subsistence. Did they really observe the sun and keep track of the solstices?

To try to answer this question, I followed the references from the California paper and found that those relating to the Northwest pretty much all came back to one publication, a monograph by Leona Cope published in 1919 entitled Calendars of the Indians North of Mexico. This is a systematic survey of the ethnographic information available at that time about the calendrical systems in this large region. To my knowledge there has never since been a similarly comprehensive study with updated information, which is unfortunate as the data available 100 years ago for many tribes and areas was quite sketchy and incomplete.

Be that as it may, Cope did quite well with the information she had available. She divided the types of calendars into three categories, based on the origin of the names of the months or “moons”:

  • Descriptive Type, by far the most common and found throughout the continent. The months are named descriptively, often after natural seasonal phenomena but sometimes after cultural phenomena such as ceremonies.
  • Numerical Type, the rarest and most restricted in distribution, running discontinuously along the Pacific coast from southern Alaska to northern California. Some or all of the months are numbered rather than named, though very few calendars use numbers exclusively.
  • Astronomical type, the one of most interest for my purposes here. The calendar, while based on lunar months like the other types, is calibrated in some way to one or both of the solstices. Found in three regional clusters: the Southwest (plus southern California), the southern Northwest Coast, and the central and eastern Inuit groups in Arctic Canada and Greenland.

This is a very interesting distribution of solstice observations! Cope attributes the Inuit observation practices to the unusual seasonal conditions of the far north, which is fair enough though it should be noted that not all of the Arctic or Subarctic groups in her study have astronomical calendars. She notes that the Inuit track the sun by indirect observation of shadows cast by rocks, in contrast to the direct observation of the sun used in the Northwest and Southwest (though recent archaeoastronomical work in the Southwest strongly suggests that at least some indirect observation was done there in the past as well).

Cope also has some information on the function of solstice observation among some of the Northwest tribes. She says of the Nuu-chah-nulth of Vancouver Island:

The observation of the solstice is of great economic importance. If one
wishes to be successful in the hunting season, he must perform certain magical rites when the days are getting longer and the moon is waxing.

Again, very interesting! This is quite different from the ideology surrounding sun-watching among Southwest agriculturalists, but it has a clear logic to it that would provide an incentive to undertake the difficult task of making these observations in the Northwest.

Also noteworthy is the distribution of solstice observations within the Northwest. Many of the more “complex” features of Northwest Coast societies are generally considered to reach their highest level of complexity at the northern end of the area, among such groups as the Tlingit, Haida, and Tsimshian of southeast Alaska and adjacent parts of British Columbia. Cope’s data show clearly, however, that the area of astronomical calendars and solstice observation is focused on the southern Northwest Coast, with the most detailed accounts of observations and the ideology behind them associated with the Wakashan-speaking groups on and around Vancouver Island. (Cope does classify the Haida and Tsimshian as part of her Astronomical Type, but only because they include a “between period” in their calendars to rectify the lunar months with the solar year. Her data show no trace of an astronomical calendar among the Tlingit.)

These Wakashan-speaking groups are distinctive in other ways; the Nuu-chah-nulth and related tribes are known for their focus on whaling rather than salmon fishing as the basis of their lifestyle, for example. It’s conceivable that solstice observation was originally a Wakashan trait associated with the ideology mentioned above, which later spread to some but not all neighboring groups but not necessarily with the ideological content intact. That’s largely a speculation on my part, though, and I need to research this more to see if it holds up.

After reading this study and seeing the intriguing evidence for ethnographic astronomical observance in the Northwest, I started reading up on the archaeology of this area to see if there has been any research on potential material correlates. The answer appears to be essentially “no,” in striking contrast to the situation in the Southwest where the ethnographic and archaeological evidence is routinely used in combination to better understand both. One major reason for this is surely the environmental context, which is not nearly as good for preservation of structures as the dry Southwest, except in certain unusual circumstances where sites get completely waterlogged. There’s just not much there to study, in other words, if you’re looking for alignments of buildings to astronomical phenomena.

Rock art, however, which is another frequently studied locus for archaeoastronomy, is common in the Northwest. Petroglyph sites here tend to be on beaches and to be associated with the sea, so they may be less likely to have astronomical associations here than in other areas, but it doesn’t appear that anyone has ever really checked.

More fundamentally, it seems like the archaeology of the Northwest has been so heavily dominated by research on economic issues and attempts to explain the complexity of ethnographic societies that things like astronomy don’t really enter into the literature much at all. There is also likely a bias toward focusing on phenomena that can be easily matched to the richly documented ethnographic cultures.

This bias became clear to me when I saw a passing reference in a review article on the archaeology of British Columbia to undated burial mounds on the South Coast. Burial mounds? In the Northwest? This is another phenomenon often associated with “complex” societies that is not often mentioned in connection with the Northwest Coast, presumably in this case because there is no ethnographic evidence for it having survived into the recent past. Mounds are also often associated in other areas with astronomical observations and alignments, which is why this reference piqued my particular interest.

I followed the reference, which went to a 1947 paper in a local historical journal summarizing a lot of information on these burial mounds, often called “cairns” as they were typically built with large rocks covering a burial in a complex but very regular pattern. Earthen examples are also known, however. The area of the mounds seems to have been focused once again on Vancouver Island, but in this case the focal point seems to have been the area now occupied by the city of Victoria. This area is occupied in modern times by speakers of Salishan rather than Wakashan languages, so there may not be any connection to the astronomical pattern. It is intriguing, however.

The 1947 article focuses largely on the excavations of the mounds in the late nineteenth century by an early settler named James Deans, who reported much of his work in brief letters to a local newspaper though he did write at least one longer unpublished report. Many of them were later excavated in the 1890s by the Jesup North Pacific Expedition, with Deans’s assistance. This expedition was a groundbreaking and highly influential project, with its results including the mound excavations extensively published in reports by the American Museum of Natural History in New York, which at the same time was also sponsoring the Hyde Exploring Expedition excavations far away at Chaco Canyon. The presence of prehistoric mounds in the Northwest Coast was hardly obscure, that is to say. And yet it seems to have been largely forgotten in the modern archaeological literature of this region, or at least rarely seems to rate even a mention in a review article.

Part of this puzzling lack of continued attention to the mounds was likely due to the fact that virtually all of them have since been destroyed by urban and agricultural development, so unlike in other areas known for mounds there’s no longer anything to see. Out of sight, out of mind, as it were. I suspect that the other factors I mentioned above also played a role, however.

While mounds in other areas often have archaeological associations, there is no evidence that I can see that these burial mounds did, though again they have not been studied from this perspective. Another of Deans’s letters to the newspaper provides evidence for a different sort of prehistoric phenomenon which also seems to have disappeared and been forgotten. These are straight, paired stone alignments, of considerable age and consistent orientation to 12 degrees north of east. This is the sort of thing that may indeed have had an astronomical function, although that azimuth is not particularly meaningful as far as I can tell. Sadly, when Deans wrote in 1872 they were already mostly destroyed so there is presumably no way of studying them now.

I don’t really have a point here as I’m continuing to study all this, but it sure is fascinating. You just never know what’s out there.

 

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californiasign

California Welcome Sign

Today is the summer solstice, on which I tend to write about archaeoastronomy. This time I’d like to briefly discuss an area with a rich heritage of Native astronomy that seems to get relatively little discussion: California.

California is known in anthropological circles for the astonishing variety of cultural and sociopolitical groups that traditionally inhabited this climatically favorable, highly productive area. Although these groups were all devastated to varying degrees by the influx of Anglo settlers in the nineteenth century, and some were also heavily affected by earlier Spanish colonization starting in the late eighteenth, most of them are fairly well documented ethnographically due to the extensive “salvage ethnography” pioneered by Alfred Kroeber and his students at Berkeley in the early twentieth century. There is therefore a rich base of data in which to look for evidence of Native astronomical observations, and a paper published in 1979 by Travis Hudson, Georgia Lee, and Ken Hedges does just that, in addition to reporting some early archaeoastronomical observations at California archaeological sites. The paper focuses specifically on solstice observations, which tend to be among the most important astronomical practices in many cultures.

The authors’ review of the literature shows that observation of the solstices was widespread in Native California. The vast majority of groups they investigated had some record of solstice observation, and most of those that did not may just not have had it documented. Only two groups were associated with definite statements that they did not observe any solstices, and even these might be due to mistaken information.

The winter solstice was by far the most commonly observed, with relatively few groups also observing the summer solstice and none observing summer but not winter. This ties in to a widespread pattern of keeping a calendar that often began with the winter solstice. A general geographic pattern held that Southern California groups were more likely to observe both solstices, while Northern California groups tended to only observe the winter one. This is in keeping with broader geographic patterns, with Southwestern groups generally observing both solstices but Northwest Coast groups focusing on the winter. There are many other cultural patterns connecting these two parts of California to these adjacent culture areas as well.

In addition to the ethnographic data, the authors report on several observations of potential solstice observation alignments at archaeological sites, mostly those involving rock art. These again showed a general pattern of most often aligning with the winter rather than the summer solstice. In some cases the rock art associated with these observation points contained apparent solar imagery, and in a few cases the authors even suggest that some of the rock art symbols represent the actual horizon line along which the sun was observed. This is a fascinating suggestion that I have not seen made of any other area, so it may be distinctively Californian if it holds up. They include examples of other rock art of similar form that may also be interpreted this way, although it has not been tested for alignments.

All in all, this is a fascinating introduction to the astronomy of a culture area that doesn’t get as much attention in this respect as others like the Southwest and Plains. While this was an early paper in the development of archaeoastronomy and not all of its conclusions may hold up, it is still an excellent starting point. Happy solstice!

 

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cliffpalacesuntemple

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.

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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.

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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.

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Vent at Sun Temple, Mesa Verde

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Salmon Ruins Sign

One of the most interesting chapters in Astronomy and Ceremony in the Prehistoric Southwest: Revisited reports on archaeoastronomical research at Salmon Pueblo (also known as Salmon Ruins), a large Chacoan “outlier” great house near modern Bloomfield, New Mexico. The paper is by Brooks Marshall and Larry Baker of the San Juan County Museum Association, which manages the site, and it argues that one particular room at Salmon was likely used as an observation station for both solar and lunar events.

The room, known as Room 82, is in the southeast corner of the central room block on the north side of the plaza, just southeast of the elevated “tower kiva” in the center of the block. When it was excavated in the 1970s, the excavators found that it had several unusual features that suggested it was used for specialized non-domestic purposes, though it was not clear to them at the time what those might be. In addition to the commonly found hearths, milling bins, and T-shaped doorways, there was an unusual opening in the east wall which Marshall and Baker call a “window” (unfortunately they don’t explain why they use this term, which is generally not used in describing Chacoan architecture), an adobe platform in the northwest corner that had two shallow pits at its north end, and a dividing wall in between of uncertain original height. The platform and wall were destroyed in the course of excavation, while the window has deteriorated a bit over time but is still there.

The unusual nature of these features and their east-west alignment made Marshall and Baker suspect an astronomical role, so in 2008 they created a replica of the adobe platform out of plywood and positioned it where they calculated it would be hit by light through the window at equivalent times to the original, taking into consideration the higher floor level due to backfilling of the room. In 2009, a stabilization project removed the backfill and allowed them to place the replica in the original location of the platform to verify their results. Further testing in 2010 and 2011 involved simulating the original size and shape of the window opening. Throughout these tests they placed two rocks on the platform to simulate the two pits at the north end of the original, known as Features 71 and 72.

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Central Roomblock at Salmon Ruin

Their results were striking. They found that the northernmost pit, Feature 72, was lit by sunlight coming through the window only on the summer solstice, and when the original window opening was simulated the light was quite narrowly focused on this feature. Feature 71, despite being only a few centimeters away, was never lit up by the sun at all. It was, however, lit by moonlight during the major lunar standstill, when the moon rises at its most extreme position relative to the sun for a few years. It’s long been known that the first major period of construction at Salmon in AD 1089 and 1090 corresponds to the lead-up to a major lunar standstill, and indeed Marshall and Baker’s calculations showed that it was in these years that moonlight would have first illuminated the features at the north end of the platform. By the standstill itself, which lasted from AD 1093 to 1095, moonlight would have hit about three quarters of the platform. Marshall and Baker propose that the south end, which is never nit by moonlight, may have served as an observation point where someone could sit and observe the moonlight move across the platform over time, possibly allowing the prediction of the standstill.

Obviously the wall in between the window and the platform adds a complication to all this, as it would have blocked at least some light from coming through. There’s no way to tell how high it initially was, so Marshall and Baker ran some calculations based on different heights to see how they effected the illumination patterns they documented. They found that at a certain height the wall would have prevented the beam of light coming through the window from moving beyond the platform onto the floor, which may have been intentional. At higher heights it would have blocked the beam entirely, but the base of the wall was fairly thin and probably couldn’t have supported a full-height wall.

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Excavated Rooms at Salmon Ruin

This is exciting research for several reasons. It’s always interesting to see a careful study of architectural alignments to celestial phenomena that takes into consideration excavation history and possible confounding factors. It’s particularly interesting that this study seems to have shown strong evidence for alignments even taking those other factors into consideration. The solstice alignment seems like the best established to me, which is unsurprising since solstice alignments in general are the best documented phenomena in ancient Pueblo archaeoastronomy. What I find most intriguing, however, is the possible lunar alignment and its relation to the construction dates at Salmon, since despite a lot of talk about lunar alignments at Chacoan sites very few have been securely documented, and unlike solar alignments there is no support for them in modern Pueblo ethnography. If this lunar alignment really does hold up, it helps strengthen the argument that the Chacoans really did observe and care about these subtle lunar cycles.

The strongest evidence so far for Chacoan observance of lunar standstill cycles comes from Chimney Rock Pueblo, further north in Colorado. The evidence here is quite strong indeed, as the full moon rises between twin spires of rock as seen from the great house only during the major lunar standstill, and this accounts for the otherwise very puzzling location of the great house atop a high, steep mesa. There is also some evidence from the dates of construction at Chimney Rock that some building periods were related to specific lunar cycles. The lack of support from other Chacoan sites, however, has made the seemingly solid evidence fr,om Chimney Rock hard to integrate into the picture as a whole. If people at Salmon, which is fairly close to Chimney Rock and is connected to it by an easy travel corridor along the San Juan River, were also marking the lunar standstill cycle, the picture begins to fill out a bit.

That said, this research is still fairly preliminary and I wouldn’t go as far as to say that the lunar alignment proposed here has been definitely established. More research is certainly necessary to confirm and interpret the patterns documented here. It is certainly suggestive, however, and very interesting.

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Backfilled Rooms at Salmon Ruin

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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.

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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.

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Fajada Butte with Green Vegetation

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