Holy Wars in Holy Lands

Chuska Mountains from New Mexico Highway 371

In the year AD 1098 a spruce tree was chopped down in the Chuska Mountains, which run roughly along what is now the border between Arizona and New Mexico.  We don’t know who cut it down, exactly, since the people living in the area at the time had no system of writing and have therefore not left us any explanation of their actions.  We do know why it was cut down, however, and what became of it, and that gives us some clue to who might have wielded the axe.  It was likely either the local inhabitants of the Chuskas or the inhabitants of Chaco Canyon, 45 miles to the east, who had close connections to the Chuskas and may have traveled there regularly to do things like cut down trees.

After the bark and branches of the tree were carefully stripped from the trunk, and its ends laboriously ground flat, it was probably left to dry out for a couple of years.  At the end of that period, a group of men carried it carefully, by hand, the 45 miles to Chaco, where it was used in the construction of Kiva G at Chetro Ketl, the prominent elevated round room that can still be seen prominently at the site today.  This room was built over the remains of earlier round rooms, and the architectural history of this part of Chetro Ketl is very complicated and hard to unravel.  This particular beam, now known as CK-168, was used as a “tie beam” in the northeast corner of the square room into which Kiva G was built.  I take this to mean that it was used to span the interstitial space roughly tangent to the outside of the circle of Kiva G as part of the elaborate support structure of beams that was necessary to support the “blocked-in” kivas like this one that are so typical of Chacoan great house architecture.  The stage of construction involving Kiva G, and therefore beam CK-168, was one of the latest at Chetro Ketl, and Kiva G is noteworthy for displaying the “McElmo” style of masonry, which is a relatively late style at Chaco that echoes the style of masonry found to the north at sites such as Aztec Ruins.

Elevated Kiva G at Chetro Ketl from the North

We know when and where beam CK-168 was cut down because of two types of analysis that have been done on this and many other pieces of wood from Chaco and other prehistoric archaeological sites in the American Southwest.  The first is tree-ring dating, which allows the determination of the date a given tree was cut down with amazing precision, potentially to the calendar year.  Not every beam that is analyzed produces what is called a “cutting date,” indicating the exact year in which it was cut, but CK-168 did, and this is how we know it was cut down in 1098.  The other technique, which was developed much more recently, is strontium isotope ratio analysis, which at its current level of development allows the determination of the general area in which a tree (or a person) lived.  Many fewer pieces of wood have undergone this type of analysis than have been tree-ring dated, but CK-168 is one that has, and it is from this testing that we know it came from the Chuskas.  We don’t know exactly where in the Chuskas it came from, but we can be reasonably sure it was somewhere in the range.  These techniques are more or less the state of the art in wringing information from the archaeological remains of the prehistoric Southwest, and the amount of information available from them in this arid region with good preservation of materials like wood is quite remarkable by the standards of prehistoric archaeology in general.

At the same time the tree that became beam CK-168 was being cut down and left to dry out, on the other side of the world a group of heavily armed men was rampaging through a country that was not yet under their control but soon would be.  These were the Crusaders, a group of pious Christian knights and others, mostly from the various lands that are now part of France, who had heeded Pope Urban II’s call in 1095 to aid the Byzantine emperor in fending of the Turks who were threatening his lands and who at some point added the goal of conquering the holy city of Jerusalem from the Turks as well.  This expedition is now known as the First Crusade, and by 1098 it had reached the Holy Land and begun to conquer parts of it.  In June of that year they captured the important coastal city of Antioch (now in Turkey) after an eight-month siege and began to move on toward Jerusalem.  One group, under the command of Count Raymond of Saint-Gilles, arrived at the nearby city of Ma’arra (now in Syria) on November 28 and began to lay siege to it.  This siege, in striking contrast to the long, miserable one at Antioch, lasted only two weeks, and on December 12 the Crusaders entered the city after having destroyed its defenses.  They then remained at Ma’arra for another month as Raymond and the other commanders who had assisted him in the siege argued over how to divide up the spoils of their conquests.  On January 13, 1099 the ordinary soldiers, who were impatient to get to Jerusalem, finally prevailed on Raymond to move on and the army left Ma’arra.  They reached Jerusalem in early June and, assisted by a group of Genoese sailors who landed at Jaffa on June 17 and disassembled their ships to make siege engines, seized the city on July 15.  They then massacred the majority of the inhabitants.

Villages in Syria from the Golan Heights

In the grand scheme of the Crusade, and compared to the brutality that marked the Crusaders’ actions at Antioch and Jerusalem, the siege of Ma’arra may seem like a minor chapter.  There was something distinctive about Ma’arra, however, and it remained a painful memory for both sides quite out of proportion to the short duration of the siege.  The Arab historians recorded that the massacre of the people of Ma’arra after the siege was even worse in total number killed than that at Jerusalem, and some reported that the Crusaders had promised the people of the city safety before treacherously killing them.  According to the chroniclers who accompanied the Crusaders, however, what happened at Ma’arra was even worse than that.  With clear discomfort but remarkable consistency, almost all of the chroniclers recorded that some of the Crusaders had engaged in an activity much less respectable in European eyes than killing Muslims: eating them.

The cannibalism at Ma’arra has long been a difficult issue for historians of the Crusades to understand.  Beginning with the contemporary chroniclers, some of whom were at Ma’arra and apparently witnessed the events personally, they have offered various explanations for the behavior.  In a recent article Jay Rubenstein took a close look at the accounts the chroniclers offered of Ma’arra, and found some interesting patterns.  For one thing, although almost all of the contemporary chroniclers mention the cannibalism, the specifics of their accounts vary considerably.  Some placed it during the siege, while others put it afterward, during the month when the Crusaders were hanging around the city as their leaders argued.  Some attributed it to famine and starvation among the soldiers, who were said to have eaten flesh from dead bodies furtively.  One eyewitness account says that when the leaders of the Crusade found out about this they piled the bodies in a mound and set fire to them to put an end to it.  Others, however, said that the Crusaders ate the flesh of the dead Muslim enemies avidly and publicly, and one even said that some of the Crusaders were so disgusted by the sight that they deserted, blaming the leaders of the Crusade for not providing sufficient supplies and letting things deteriorate to this point.  Some of the chroniclers blamed the cannibalism on an apparently fictitious group of poor Crusaders called “Tafurs.”

Church of the Holy Sepulchre, Jerusalem

Rubenstein makes some interesting connections between all this and various other medieval references to cannibalism, including various episodes of starvation cannibalism during famines in Europe and references to “theatrical” mock-cannibalism involving the ostentatious preparation of dead enemies as if to eat them in view of living enemies, including one instance allegedly during the siege of Antioch and one earlier, in Spain.  He also mentions Biblical references to cannibalism as a punishment for disobeying God, with the context often being siege warfare quite similar to that conducted by the Crusaders, as well as some suggestive references to the possibility that some Crusaders might have resorted to eating each other (or at least come close) during the long, hard months at Antioch.  This is all rather speculative, however, and most of it has one crucial difference with the reports of what happened at Ma’arra, which Rubenstein does acknowledge: in these cases people were generally eating members of their own group, while at Ma’arra all the chronicles are quite clear in saying that the Crusaders only ate the flesh of the Muslim enemy.  This alone suggests that more than simple survival cannibalism is involved here, since there would surely have been plenty of dead Crusaders around to eat and the contempt the Crusaders had for “infidels” makes it odd that they would choose to defile themselves by eating them.  Rubenstein notes this and comes up with an admittedly speculative reconstruction of what happened at Ma’arra in which he proposes that there had been scattered instances of survival cannibalism at Antioch and perhaps earlier but that at Ma’arra, during the siege, some of the starving Crusaders decided to make a virtue of a necessity by ostentatiously eating dead Muslims in full view of the defenders of the city as a form of psychological warfare.  This would presumably have struck fear in the hearts of the Muslims and perhaps led to an easier conquest of the city than had been the case at Antioch.  Upon learning about this, however, the chroniclers, highly uncomfortable with this celebratory cannibalism, finessed their accounts to put the cannibalism after the siege, attribute it to starvation, and make it furtive and discouraged rather than open and aggressive.  Rubenstein puts the celebratory cannibalism in the context of “holy war” and the idea that the Crusaders thought of themselves as tools of God sent to punish the Muslims, which justified anything they did in the course of achieving that aim, regardless of how perverse and taboo it might be under normal circumstances.

This is an interesting interpretation, and it is similar in some ways to the model I have proposed for the outbreak of cannibalism in the Southwest around AD 1150 (about fifty years after the Ma’arra incident) in which I argued that the attackers, whoever they were, may have been motivated by both hunger and the desire to terrify their adversaries.  I ultimately don’t buy it, though.  A careful look at how Rubenstein supports his argument shows that the sources he relies on are not the most likely to be reliable.  The chronicles that put the cannibalism at Ma’arra during the siege rather than after it, as well as those that mention the possibility of earlier cannibalism and various other aspects of Rubenstein’s theory, were mostly written well after the events in question by people who did not witness them.  Most of them did apparently speak to eyewitnesses in preparing their accounts, and in some cases these eyewitnesses may have included some of the cannibals themselves, a fact that Rubenstein leans on heavily in arguing for their validity as sources, but this is a thin reed on which to hang such an elaborate argument.  Looking just at the chronicles written by writers who actually accompanied the Crusade, some of whom were at Ma’arra personally, they generally seem to agree that the cannibalism took place after the siege, when the Crusaders were hanging around Ma’arra and probably still hungry from the months of deprivation and disease at Antioch.  These chroniclers do disagree on some other aspects of the cannibalism, but in general their disagreements are more minor than those between them and some of the later accounts by writers who were not there and relied on secondhand testimony.  The fact that only Muslims were eaten does still require some explanation beyond simple starvation, but a desire to humiliate the enemy, perhaps combined with an aversion to eating people they had known personally in life, could explain it at least as well as an attempt at psychological warfare, which as Rubenstein notes really requires that the cannibalism took place during rather than after the siege.  It may be a better explanation, in fact, in light of the fact that the Arab historians do not mention the cannibalism although they do note the brutality of the siege and massacre.  This suggests either that the Crusaders were unsuccessful in trying to terrorize the Muslims through ostentatious cannibalism or that the cannibalism took place after there were no living Muslims left in Ma’arra to see it.  It could also suggest that the cannibalism was successful in intimidating the defenders, who were then massacred, leaving no one left to tell other Muslims about it, but the fact that the eyewitness chroniclers were in general agreement that the cannibalism took place after the siege makes me think that it’s more likely that there just weren’t any Muslims around.

Sunset at St. Peter's Church, Jaffa

Note the difference here between Rubenstein’s interpretation of the cannibalism at Ma’arra and mine.  This is a context where we have abundant written documentation of the events in question, and yet we have a variety of possible interpretations of what really happened and no way to tell for sure which is closer to the truth.  We must just rely on which fits the evidence best and is the most plausible, a somewhat subjective matter at all times.  This is in contrast to the more “objective” evidence we have of what happened in some contexts in the prehistoric Southwest, such as the time and place that beam CK-168 was cut down.  Note, however, that the information we have about CK-168 is extremely limited compared to what we know about Ma’arra, despite the many conflicting accounts in the chronicles.  These just aren’t comparable levels of knowledge, and this points out the difference between history and archaeology.  Both can tell us stories about the past, but the stories are very different.  Without the written documents about Ma’arra we would likely never know that cannibalism occurred there; unlike in the alleged instance of cannibalism in the prehistoric Southwest, which are based largely (though not entirely) on extensive “processing” of human bones.  The type of cannibalism alleged at Ma’arra consisted largely of the cutting of strips of meat from the fleshy parts of the body, which would likely not have left any marks on the bones and thus no physical evidence visible in the archaeological record.  But because we do have written records we do know about it.  If we had written records of what happened at Cowboy Wash we would presumably understand it better than we do, but the example of Ma’arra shows that we would not necessarily understand exactly what had happened even then.

Archaeology has its advantages, however.  Judging from what people typically write down when they have access to writing, it’s very unlikely that anyone in the Chuskas or at Chaco would have bothered to write down exactly when and where beam CK-168 was cut down even if they could.  Hundreds of thousands of beams were imported to Chaco during its florescence, and it’s unlikely that the specific origin of each of them would have been important enough to anyone to record.  Nevertheless, the analytical techniques available to modern archaeology does allow us to know in some cases when and where individual beams were harvested.  The story of CK-168 and the story of Ma’arra may be very different types of story, known to us in very different ways, but they are both known to us, and knowing both of them enriches our understanding of the past despite the still unanswered and perhaps unanswerable questions the stories raise.  And remember that these two stories happened at the same time; they were literally simultaneous.  Many things were going on in the world in the year 1098, and the stories of most of them are lost forever.  The stories of these two events, however, are not, and we can still tell them today.

Rubenstein, J. (2008). Cannibals and Crusaders French Historical Studies, 31 (4), 525-552 DOI: 10.1215/00161071-2008-005

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The Context for Early Maize at Chaco

Looking East from the Pueblo Alto Trail

In my earlier post about Stephen Hall‘s recent paper reporting on maize pollen at Chaco Canyon dating as early as 2500 BC, I said briefly that this really shouldn’t be surprising to anyone who’s been following this kind of research closely, and also that I would discuss the context for it later.  Basically, the context is that there has been a considerable amount of evidence accumulating in the past twenty years or so firmly placing maize in the Southwest much earlier than most archaeologists had previously thought.  Much of this evidence has been gathered in a recent paper criticizing Jane Hill‘s arguments for the spread of maize having occurred as part of a migration of Uto-Aztecan speakers from Mesoamerica.  The earliest directly dated maize seems to be from the Los Pozos site in the Tucson Basin, with a date range of 2860 to 2470 BC (this represents the calibrated 95% confidence interval, as do all subsequent radiocarbon dates in this post unless noted otherwise).  According to the text of the paper, however, this date has been questioned, and the earliest uncontroversial direct date on maize comes from the aptly named Old Corn site near Zuni, with a range of 2460 to 2060 BC.  Note that the earliest date Hall found at Chaco (2567 to 2332 BC) has an upper bound slightly earlier than this, although the ranges overlap considerably.  Similarly early dates occur at some Tucson Basin sites and at Three Fir Shelter in northern Arizona, although the Three Fir Shelter date has a particularly large confidence interval.  The considerable geographic extent of these early maize dates implies that the initial introduction of maize to the Southwest may well have been quite a bit earlier than the earliest archaeological evidence for it.  It also suggests that at least in most areas, with some possible exceptions such as the Tucson Basin, maize was initially integrated into a hunter-gatherer lifestyle without causing major changes to either the subsistence system or the social structure of the groups adopting it.  This challenges many of the traditional assumptions about the effect of the introduction of agriculture on hunter-gatherer societies, including the idea that farming necessarily leads to an immediate shift to settled village life.  There is little to no evidence in most areas of any such shift for thousands of years after the earliest evidence for maize agriculture, suggesting that the impetus for such a transition (which did indeed happen in almost all parts of the Southwest eventually) must be sought elsewhere.

Una Vida from Petroglyph Area

Okay, so there’s plenty of evidence for agriculture as early as the pollen dates at Chaco in many parts of the Southwest, but Chaco ain’t Tucson.  The high, dry, harsh environment of the central San Juan Basin seems particularly unsuitable for agriculture compared to a lot of the other areas with early evidence for maize.  So surely this is a surprising finding at least for the local area, right?

Actually, no.  Evidence for the early use of maize in the general area of Chaco, though until now not within the canyon itself, has actually been out there for over twenty years, although it doesn’t seem to have gotten much attention in the subsequent literature.  It is described by Alan Simmons in an article from 1986, reporting on research done initially as a cultural resources management (CRM) project in connection with plans for coal mining in the area directly to the east of Chaco.  This project, known as ADAPT I, found many typical Archaic sites in the area, some of which were excavated as mitigation activities because of the expected impacts of mining.  (I believe this mining operation never actually happened, but I don’t know any of the details.)  These Archaic sites were typical for the San Juan Basin, which is to say that they were mostly lithic scatters with few diagnostic artifacts or datable materials, but a few of them ended up being very surprising in having more under the surface than was apparent at first, including possible hearths or ovens, some of which contained maize pollen associated with charcoal that was radiocarbon dated to the Archaic period and one of which even contained maize macrofossils that were directly dated to the late Archaic.  (The dates Simmons relates are apparently uncalibrated and are therefore not directly comparable to the calibrated date ranges given above, but they are comparable to the uncalibrated dates given by Hall for the pollen samples, including at the early end.)

Looking North from New Alto

This very unexpected result led to a new project, known as the Chaco Shelters Project, to try to get more data on the Archaic period in the Chaco area through intensive study of the type of site most likely to contain well-preserved material: rockshelters.  Two shelters were excavated, both outside of the park boundaries, one to the east (Sheep Camp Shelter) and one to the west (Ashislepah Shelter).  Neither provided much in the way of artifacts, which was something of a disappointment, but both showed evidence of Archaic use, and Sheep Camp Shelter contained macrobotanical remains of both maize and squash.  Neither contained maize (or squash) pollen.  Both maize and squash remains were directly dated to the late Archaic.  The squash results were more important, as the resulting dates were at the time the earliest evidence for the presence of squash in the Southwest.  Despite the presence of these direct dates, the earliest dates Simmons had were on charcoal associated with the maize pollen at the ADAPT I sites, and these could potentially be questioned given the known problems with this kind of indirect dating.  Now that Hall has come up with direct dates on the pollen itself which cover roughly the same timespan, however, Simmons’s indirect evidence looks more convincing than it may have at the time.

At the time Simmons was writing, there was much less direct evidence of Archaic agriculture in the Southwest than there is now, and the few reported early dates were problematic and disputed.  He therefore has a substantial and quite useful discussion of the general issue in addition to reporting his specific data.  He clearly comes down on the side advocating a gradual shift from hunting and gathering to agriculture, with maize being initially adopted by hunter-gatherers as part of a preexisting subsistence system and only becoming the primary means of subsistence considerably later.  This view was generally associated with arguments for in situ development of Anasazi culture out of the local Archaic tradition, and was opposed by those who preferred to see agriculture as being introduced later and all at once, perhaps as part of a migration of agriculturalists from the south (a position now maintained by Jane Hill, among some others).  With regard to the Chaco area specifically, Simmons accounts for the differences between the open ADAPT I sites (with maize pollen but little macrobotanical evidence) and Sheep Camp Shelter (maize and squash macrofossils but no pollen) by proposing that maize was initially integrated into a subsistence system involving seasonal mobility, with spring and summer being spent in the ADAPT I area, where the many sand dunes would have fostered the growth of wild plants, and winter being spent in the more protected rockshelters in the canyons to the west.  When maize and squash were added to the seasonal round, they would have been planted on or near the dunes in the spring, harvested in the fall, and taken back to the shelters to provide durable, storable food for the harsh and largely barren winter.  He admits that the shelter evidence, especially, is a bit weak, as it doesn’t really support the idea of extensive winter use of the shelters, but there were apparently many Archaic sites near the shelters that may provide more support for occupation of the general area during the winter.  He therefore concludes that the model he proposes is generally consistent with the data although more research is needed to confirm it.  He mentions Atlatl Cave, in the park and excavated by the Chaco Project, as one possible additional data point in favor of his model.

Pueblo Bonito from Peñasco Blanco

Hall’s new pollen data from within the canyon provides some support for Simmons’s model, especially in backing up the indirect dates with direct ones, but it also suggests some possible modifications to it.  It clearly seems to indicate that the canyon itself as well as the dunes to the east was used to grow corn during the Archaic.  This casts some doubt on Simmons’s proposal of seasonal mobility, at least in the way he frames it.  Growing corn in the canyon would imply occupation of it, perhaps in rockshelters such as Atlatl Cave, during the spring and summer in addition to (or instead of?) during the winter.  That is, Simmons’s seasonal mobility model could perhaps be “condensed” into a similar model of subsistence activities throughout the year, but with year-round residential occupation in the canyon.  People would presumably have still traveled around to gather resources in different areas at different times of year, but this would be “logistical” as opposed to “residential” mobility, with hunting and gathering parties setting out from a more permanent base camp solely to collect resources as opposed to moving the whole group to the location of the resources.  It is of course also possible that Simmons’s model should be modified in some other way, keeping the seasonal mobility but changing the role of the canyon in it, but it’s hard to see where else in the area would have been more suitable for winter occupation.

One of Simmons’s suggestions, that the advent of corn agriculture may have made the Chaco area an easier place to live by providing a fairly reliable food source in a place with limited and unreliable wild food resources, is particularly interesting.  The San Juan Basin is well-known for its considerable Archaic population, which has generally been interpreted as indicating seasonal mobility and specialized adaptations to the region’s sparse resources, but what if that population was actually supported in part by incipient maize (and squash) agriculture?  People often marvel at the apparent barrenness of the Chaco environment and the oddity of the idea that anyone would try to farm there, but this is another way to look at the harshness of the environment.  To put it differently, farming in Chaco is certainly difficult and risky, but can you imagine trying to live there without farming?

Merrill, W., Hard, R., Mabry, J., Fritz, G., Adams, K., Roney, J., & MacWilliams, A. (2009). The diffusion of maize to the southwestern United States and its impact Proceedings of the National Academy of Sciences, 106 (50), 21019-21026 DOI: 10.1073/pnas.0906075106

Simmons, A. (1986). New Evidence for the Early Use of Cultigens in the American Southwest American Antiquity, 51 (1) DOI: 10.2307/280395

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The Invention of Agriculture

Irrigation System, Navajo Indian Irrigation Project, New Mexico

Earlier I mentioned recent research suggesting that the heartland of Mesoamerican agriculture was in western Mexico, which has important implications for the place of that region in Mesoamerica as a whole and in areas, like the Southwest, subject to Mesoamerican influence in prehistory.  The main research I was talking about is contained in two papers published in PNAS (which for some reason seems to be the main journal for this sort of research) about a year ago describing recent work in the Rio Balsas drainage of northern Guerrero (which is not actually very far west of Central Mexico, but apparently falls within West Mexico as a defined cultural area).  One paper discusses new radiocarbon dates associated with botanical evidence for domesticated maize and squash starch grains and phytoliths that implies initial domestication of those two plants sometime around 7000 BC, which is the earliest date for agriculture yet found in Mesoamerica.  The presumed wild ancestors of domesticated maize and squash occur in this area, so the very early dates associated with clearly domesticated varieties (this is apparent from the nature of the starch grains and phytoliths, which differ from wild examples) strongly implies that this is where initial domestication occurred, and that it later spread to the rest of Mesoamerica and beyond.  The other paper describes the archaeological context from which the dates and archaeobotanical specimens were taken, which was a rockshelter with unusually good preservation of undisturbed deposits.  This is important because one of the reasons initial domestication of plants is so hard to pinpoint in the archaeological record is that plant materials are fragile and rarely survive for long periods.  Rockshelters, however, are good places for preservation, and this one was particularly good because it had a long, undisturbed stratigraphic sequence containing charcoal that could be used for radiocarbon dating along with stone tools that could give some cultural and chronological context in addition to providing botanical specimens from the residue adhering to them.

Irrigated Field, Navajo Indian Irrigation Project, New Mexico

So what are the implications of this?  The two PNAS papers don’t say a whole lot about the big picture, but a more recent paper by two Mexican scholars tries to tie this together with other recent research to form some hypotheses about the origin of agriculture and the rise of Mesoamerican civilization.  Their basic argument is that the early inhabitants of West Mexico made extensive use of fire to control their environment, initially for hunting, had the side effect of changing the local flora and encouraging the dominance of fire-resistant grasses such as teosinte, the wild ancestor of maize.  They also argue that teosinte began to grow together with wild beans and squash at this time, which is more speculative.  By around 7000 BC they see local hunter-gatherer groups in West Mexico as having effectively domesticated teosinte (creating maize), squash, and beans, thus creating the milpa system of agriculture that would become one of the hallmarks of Mesoamerican culture from then on.  Once the system was created it spread rapidly along river corridors to other groups in Mesoamerica and beyond, and the basis of the later complex societies that arose in various regions was in place.  From then on agriculture continued to intensify in each region where it had become established, and the plants used were continually bred for more advantageous features for human use.  This part of the paper relies heavily on genetic evidence.  One interesting feature of this theory is that it sees initial domestication of plants as having come well before the adoption of a fully sedentary lifestyle.  In this view the first maize farmers were seasonally mobile, moving to different locations within a relatively small area over the course of a year in order to use different resources, with agricultural plots initially just being one part of a complicated subsistence strategy.  Permanent sedentism only came later, together with more intensive agriculture and a greater reliance on farming to the exclusion of other subsistence practices.

Trucks Carrying Hay from the Navajo Indian Irrigation Project

So how plausible is this?  I find it fairly plausible overall, but I’m very skeptical about a few parts of it.  The most important is the claim that beans were domesticated at the same (very early) time as maize and squash.  Beans are notoriously difficult to find in the archaeological record, since they have so few parts that are likely to survive for any significant length of time under typical conditions, so it’s entirely possible that they were present as early as the maize and squash documented in the PNAS papers (which did mention three starch grains from some sort of legume that could have been but probably wasn’t a type of bean), but the earliest solid evidence for beans specifically comes from much later, in the last few centuries BC, in Oaxaca.  Genetic evidence seems to indicate that domesticated beans descend from a wild type of bean found only in West Mexico, so the later Oaxacan evidence is pretty clearly not tied to initial domestication, but apparently the people who have done that genetic research have concluded that domestication first occurred in a different part of West Mexico from the Rio Balsas area where the early dates for maize and squash were documented by the PNAS papers.  Noteworthy in this context is that the earliest agricultural sites in the Southwest, which are earlier than the early Oaxacan bean dates, have maize and squash in abundance but no sign at all of beans.  This seems to suggest that maize and squash were domesticated first, with beans and the full milpa system only being added at some later point (maybe during the period of increased sedentism and intensification?), but there are so many uncertainties about this subject that it’s best not to leap to conclusions.

General Supply Country Store, Farmington, New Mexico

Finally, there are some implications of this for the Southwest.  Since West Mexico is generally thought to be the main source area of Mesoamerican influence in the Southwest, the idea that agriculture, and possibly other core aspects of Mesoamerican culture, originated there very early on suggests that Mesoamerican influence in the Southwest wouldn’t necessarily consist of “filtered” ideas from the “core” areas of Central Mexico and the more southerly regions.  Instead, the same ideas and technologies may have diffused separately, at different times, both north and south (and east), where they were elaborated in different ways by people starting with their own cultural traditions.  I think this may explain some of the more puzzling aspects of Southwestern-Mesoamerican relations, particularly the way Southwestern societies clearly seem to have adopted various Mesoamerican items and practices but never the entire Mesoamerican cultural system.  In any case, this is an area worthy of much more research than it has received so far.

Piperno, D., Ranere, A., Holst, I., Iriarte, J., & Dickau, R. (2009). Starch grain and phytolith evidence for early ninth millennium B.P. maize from the Central Balsas River Valley, Mexico Proceedings of the National Academy of Sciences, 106 (13), 5019-5024 DOI: 10.1073/pnas.0812525106

Ranere, A., Piperno, D., Holst, I., Dickau, R., & Iriarte, J. (2009). The cultural and chronological context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexico Proceedings of the National Academy of Sciences, 106 (13), 5014-5018 DOI: 10.1073/pnas.0812590106

Zizumbo-Villarreal, D., & Colunga-GarcíaMarín, P. (2010). Origin of agriculture and plant domestication in West Mesoamerica Genetic Resources and Crop Evolution DOI: 10.1007/s10722-009-9521-4

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Chasing Datura

Drugstore, Trinidad, Colorado

When I was discussing the archaeoacoustics of Chaco earlier, I mentioned that I was a little dubious about some of the stuff John Stein and Taft Blackhorse had said about Navajo connections to the Chaco Amphitheater.  They associate it with a ceremonial tradition involving the ritual use of datura.  There’s an immense anthropological literature on Navajo religion, and I have read only a tiny portion of it, but from what I had read I had gotten the impression that the use of hallucinogenic substances in ritual was not characteristic of the Navajos, and I had certainly not seen any reference to ceremonies involving datura specifically.  So I was initially skeptical about this claim, although the origin legend for the ceremony that they described did fit well into the usual pattern for Navajo ceremonies.

Ghost Sign for Drugstore, Durango, Colorado

Looking into this a bit more closely, however, I found an article that sheds some more light on the issue and seems to partly vindicate John and Taft, or at least point in the direction of material vindicating them.  The article, from 1945,  is by Leland Wyman and Betty Thorne, and it mainly talks about suicide (a topic of unfortunately continuing importance on this blog) among the Navajo.  The overall conclusion is that suicide is rare and subject to at least moderate social disapproval.  Of more interest to me, however, is the finding that poisoning is virtually unknown as a method of suicide.  This is despite the presence of various poisonous plants in the Navajo country, the most widespread and well-known of them being datura.  Wyman and Thorne address the puzzling absence of datura as a means of suicide in a way that is very important to my purposes:

Since this plant is employed in medicine, in certain ceremonials, and especially in a form of witchcraft (frenzy witchcraft), perhaps this avoidance arises from a configuration which might be expressed as “avoidance of the misuse of ceremonial appurtenances.” This would be especially cogent if the appurtenances were likewise misused by “witches.” One often hears concerning Datura, “they (the Navaho) are kind of afraid of it,” and this refers to mere handling as well as to more intimate contact.

The references to the use of datura in medicine and witchcraft are footnoted, while the reference to its ceremonial use is not.  The witchcraft note refers to Clyde Kluckhohn’s classic study of Navajo witchcraft, while the medicine note refers to a work (co-authored by Wyman) on Navajo medicinal ethnobotany.  I intend to follow up on these references when I get a chance.  Just from the way they are presented here, however, it seems clear that there is in fact a tradition of ceremonial use of datura, but that it is likely relatively obscure and not well documented, probably because of the generally fearful attitude toward the plant and its association with witchcraft.  It seems there is something to this datura connection after all, and it will be interesting to see where it goes.

Wyman, L., & Thorne, B. (1945). Notes on Navaho Suicide American Anthropologist, 47 (2), 278-288 DOI: 10.1525/aa.1945.47.2.02a00070

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Better Linguistic Evidence for the Spread of Agriculture

Pithouse Sign, Mesa Verde

Since it seems to be Linguistics Week here at Gambler’s House, here’s another post on Jane Hill’s theory that the spread of agriculture into the Southwest was associated with a migration of speakers of Proto-Northern-Uto-Aztecan (PNUA) from somewhere in Mexico.  Previously I discussed an article of hers from 2001 in which she tried to show that a set of vocabulary items related to agriculture could be reconstructed all the way back to Proto-Uto-Aztecan (PUA), which, if true, would strongly support Peter Bellwood’s argument that agriculture was introduced to the Southwest by speakers of Uto-Aztecan languages migrating north from central Mexico.  I found that article unconvincing.  One reason was that, since almost all of the agricultural vocabulary known from Uto-Aztecan languages quite understandably comes from the southern languages of the family, which were spoken by farming groups, reconstructing that vocabulary all the way back to PUA requires the assumption that PNUA is a valid genetic unit combining all the northern languages, because almost all of the agricultural vocabulary known from those languages comes from Hopi, the only one spoken by a people who primarily practiced agriculture in historic times.  Hill’s 2001 article, however, doesn’t provide much evidence to show the reality of PNUA, which significantly weakens her argument, as do the many problems with the correspondences she does identify.

Basketmaker Pithouse, Mesa Verde

The article I’m talking about now, however, is about a related but somewhat different issue.  Published in 2008, it seeks to show that a set of agricultural terms from PNUA was borrowed into Proto-Kiowa-Tanoan (PKT), presumed to have been spoken by the indigenous hunter-gatherers who occupied the Southwest before the posited PNUA migration, and that a separate set of vocabulary referring to local wild plants and animals was also borrowed into PNUA from PKT.  Here, rather than dealing with the very difficult matter of reconstructing proto-language vocabulary, Hill is dealing with loanword studies, which is generally more fruitful (though still difficult and often frustrating).  The theoretical model for how this borrowing would have occurred is straightforward: speakers of PNUA, practicing an agricultural lifestyle somewhere in the Sonoran Desert, migrated above the Mogollon Rim onto the Colorado Plateau, where they found both a different environment and groups of hunter-gatherers who were very familiar with it.  Since agriculture is a much riskier and more difficult endeavor in this area, with its shorter growing season and less predictable weather than in the Sonoran Desert, hunting and gathering would likely have become more important for the PNUA farmers, and they would have eagerly sought out knowledge of local resources from the local people, who may also have been intrigued by the potential of the unfamiliar agricultural practices of the newcomers.  So, the PNUA speakers introduced the PKT speakers to farming, and in turn the PKT speakers introduced the PNUA speakers to plants and animals important on the Plateau but unknown in the desert.  In the process, some words for these things moved between languages as well.  Hill notes that this implies both that the PKT speakers, formerly hunter-gatherers, chose to adopt agriculture rather than being pushed to marginal areas by the PNUA speakers and that contact between the two groups was not necessarily always antagonistic.  Both of these implications are problematic for Bellwood’s theory of the correlations between language distribution and the spread of agriculture, which holds that hunter-gatherers very rarely adopt agriculture when they come into contact with farming groups expanding out of their homelands with large populations but instead are either assimilated by the farmers or pushed into marginal areas unsuitable for farming.  This is somewhat ironic, since Hill actually makes a very good case for these borrowings, which provides considerable support for some version of Bellwood’s general idea that language and agriculture generally spread together.

Reconstructed Basketmaker Pithouse at Lost City Museum, Overton, Nevada

As in the previous paper, Hill is careful in this one to point out all the potential problems with the etymologies and correspondences she posits here.  There are a lot, especially because Kiowa-Tanoan languages are not very well-documented and PKT reconstructions are much more tentative than P(N)UA ones.  In this case, however, I find most of the correspondences pretty convincing.  With contact linguistics like this, there are some inherent advantages over the sort of “pure” historical linguistics Hill was doing in the earlier paper.  The most important is that loanwords are often pretty easy to identify, especially in well-documented language families.  If a term is found in one language but not in any others in its family, but it’s very similar to a term with a similar meaning in a nearby but unrelated language, it’s pretty easy to conclude not only that an episode of borrowing occurred but also which direction the borrowing went.  This is something of an ideal case, of course, and in practice it’s often not quite as clearcut, but it’s still easier to show that a term was likely loaned into a language or subfamily than that a set of vocabulary can be reconstructed back into a proto-language.

Reoccupied Pithouse, Mesa Verde

In this case, it’s the borrowings from PKT into PNUA that are most convincing.  This is mainly because the PNUA forms are not attested elsewhere in Uto-Aztecan but are quite similar in both form and meaning to what can be reconstructed for PKT (which, again, is not all that reliable).  The loans in the other direction are trickier, in part because Kiowa-Tanoan is a small family and comparisons between branches can’t really be done the way they can for Uto-Aztecan, but given the other loans they seem pretty plausible.  Among other things, these loans provide pretty strong support for PNUA as a valid grouping, which in turn strengthens the argument of the 2001 paper, although it’s important to note that the issue in the 2008 paper is actually rather different, and it’s easy to imagine a group of farmers speaking PNUA migrating out of Sonora or southern Arizona without concluding that their ancestors necessarily migrating out of central Mexico speaking PUA.  PUA could also have been spoken by a group of hunter-gatherers in, say, coastal Sinaloa or Nayarit who adopted agriculture after contact with agricultural groups migrating up from further south, perhaps speaking a language related to Purepecha, much as the PKT speakers later adopted it after contact with PNUA speakers.  Nevertheless, the existence of PNUA is important to Hill’s 2001 argument, and the support for it here does strengthen that earlier argument.

Pithouse Ventilation Sign, Mesa Verde

The implications of this loanword evidence for archaeology are interesting.  It definitely supports R. G. Matson’s argument, based on totally different evidence, that the Western Basketmakers spoke a Uto-Aztecan language and migrated into northeastern Arizona and southeastern Arizona from somewhere further south.  In connection with that argument Matson also surmised that the of the Colorado Plateau and that they spoke Keres or a Kiowa-Tanoan language.  As Hill notes in this article, Keres is an isolate and it would be difficult to use it in this kind of study.  Kiowa-Tanoan, while a small family, does have a sufficient number of languages and enough apparent time-depth to be reconstructed into a form usable for comparisons to PNUA.  It is still fiendishly difficult to figure out what language(s) the inhabitants of any ancient site would have spoken, but the integration of linguistic evidence in studies like this has the potential to shed some light on the issue.

Pithouse Ventilation System, Mesa Verde

To tie this back to Chaco, which seems to have been a pretty important regional center during the Basketmaker III period, the evidence from this article suggests that the Eastern Basketmakers of the Chaco area may have spoken PKT, although they may on the other hand have spoken a language ancestral or related to Keres or Zuni (both isolates).  Or perhaps Chaco was inhabited by more than one linguistic group, as many archaeologists have argued for the later period of its more obvious regional dominance.  This evidence does suggest that whoever was living at Chaco at this time probably was not speaking a Uto-Aztecan language, although it doesn’t entirely rule it out.  There is, after all, no way to tell exactly when this episode of PNUA-PKT contact occurred, although if it involved early contact between farmers migrating in and local hunter-gatherers it would presumably have been rather early in the Basketmaker II period.  Importantly, the fact that the loans seem to have gone both ways shows that whatever contact took place involved both groups continuing to exist as social entities of some sort.  This is not evidence for assimilation, in other words, but for peaceful contact between agricultural and hunter-gatherer groups involving the exchange of information that enhanced the subsistence options of both parties.  The archaeological implications of that are difficult to figure out precisely, but it’s a subject worth thinking carefully about.

Hill, J. (2008). Northern Uto‐Aztecan and Kiowa‐Tanoan: Evidence of Contact between the Proto‐Languages? International Journal of American Linguistics, 74 (2), 155-188 DOI: 10.1086/587703

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Bringing It All Back Home

Highly Deteriorated Vertical Intramural Beams at Pueblo Bonito

I’ve been talking about climate change more than about Chaco lately, which is a pretty big shift from the earlier days of this blog.  In part this just reflects the major changes in my life: while before I was living and working at Chaco, now I’m going to school and spending a lot of time learning and thinking about things like climate change.  I’ve also, frankly, been getting a little bored with Chaco and archaeology, so I’m taking a bit of a break from it.  I’ll definitely come back to it at some point, don’t worry, but for now it’s not among my highest priorities.

Spruce Tree House, Mesa Verde

One of the major points I’m trying to make with this blog, however, is that climate change and other environmental challenges today are by no means disconnected from Chaco and the past.  This is true in various ways, some more abstract than others, but a major report just released by the Natural Resources Defense Council and the Rocky Mountain Climate Organization (via Keith Kloor) on threats to national parks from climate change points to one quite concrete connection.

Mesa Verde from Escalante Pueblo

Like many other parks, Chaco is threatened by the effects of global warming, effects that are starting to become apparent in changes to weather patterns and climatic trends.  It’s not listed as one of the parks most at risk, although Bandelier and Mesa Verde are, but the fact sheet for New Mexico does describe Chaco as being subject to the same pressures as other parks in the region.

Light Snowfall on Fajada Butte

The main effects of climate change on these parks are decreased snowpack, the closely related problem of reduced water supplies, increased erosion resulting from heavier and more frequent downpours, and loss of flora and fauna as a result of habitat changes.

Entrenched Arroyo

These are indeed serious problems, and pretty unambiguously linked to global warming, but they are matters of degree, not kind.  Problems of this sort have always been major concerns in the southwest, where water supplies and the vagaries of precipitation are and always have been hugely important to human settlement patterns and decision-making.  The intensification of these processes due to climate change is of major concern, but it’s not very flashy and it’s unlikely to attract much attention in and of itself.  No major catastrophes to grab headlines and focus attention are likely to result from these changes, but they are serious threats nonetheless.  As so often in the southwest, natural disasters are long and slow, subtly and almost imperceptibly changing the landscape until the status quo become untenable and major, often painful, changes suddenly become necessary.

Tributary Drainage in Chaco Canyon

This gives ample opportunity for people to react and to minimize the damage, of course, but it also gives little incentive for them to do so until it’s too late, which is what makes it so pernicious.  Life in arid environments is always lived on the edge, and the margin for error is minimal, so adaptation to a certain environmental context is always very risky, a huge bet on a particular outcome with unknown odds.  There’s a lot more I could say here about gambling as a metaphor for economic and environmental decision-making, but I’ll just leave it at that for now.

Storm Clouds over Fajada Butte

On a lighter note, I was amused to see this in the New Mexico fact sheet:

In some parks, such as Bandelier and Chaco, snow does not linger that long, but with less snow in winter fewer visitors would get to see the parks at their scenic best.

Chaco’s definitely at its scenic best in the winter, but I can say from experience that very few visitors ever see it.  Winter at Chaco is a very quiet time of year.

Fajada Butte Obscured by Falling Snow

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Chimney Rock

Companion Rock and Chimney Rock

I’m in Cortez, Colorado, for the Pecos Conference, an annual gathering focused on southwestern archaeology which moves from place to place.  On my way up here I stopped at Chimney Rock, one of the most interesting of the Chacoan outliers and one that I had not been to before.

Chimney Rock Mesa

The main reason for both those things is Chimney Rock’s location.  It’s the furthest known outlier to the northeast of Chaco, near Pagosa Springs, Colorado, and there are no other outliers very close to it.  The great house is perched in a bizarre position up on top of a high, steep mesa, and further down the mesa ridge there are many smaller sites, most of them having a distinctive architectural style suggesting that they are basically above-ground pithouses (perhaps because on the mesa there wasn’t enough soil to dig into to create regular pithouses).  There are also more typical pithouses, possibly from a slightly earlier period, further down on the banks of the Piedra River.  While the great house is distinctive in being very “Chacoan” in style, more so than many closer outliers, the small sites on the mesa seem to have more similarities to the architecture of the Gallina culture to the south.

The "Parking Lot Site," an Above-Ground Pithouse below Chimney Rock Great House

Because of its odd location and distance from Chaco, Chimney Rock has been the subject of considerable research over the years, and the University of Colorado has just started a major new research project there headed by Steve Lekson that has already gotten quite a bit of press coverage.  The theories about Chimney Rock’s relationship to Chaco itself vary, and aren’t really that different from theories positing various roles of outliers in general.  The main theories about the founding of the Chimney Rock great house (among those who agree that it was founded by Chacoans at all rather than being an indigenous development) fall into two main groups: resource-procurement and astronomical observation.  The resource-procurement theories emphasize Chaco’s need for wood and the possibility that by the time Chimney Rock was founded in the AD 1070s closer sources such as the Chuska Mountains had been largely exhausted.  The astronomical theories, on the other hand, focus on the two large geological features, known as Chimney Rock and Companion Rock, that give the site its name.  Protruding from the mesa, they have a small gap between them when viewed from the great house that appears to align perfectly with the northernmost moonrise at the lunar major standstill, which only occurs every 18.6 years and did in fact occur around the time the great house was first built, and again when it was expanded or renovated in the 1090s.  This theory has been pushed largely by Kim Malville, an astronomer at the University of Colorado, and investigated thoroughly by Ron Sutcliffe, an engineer and surveyor in Pagosa Springs who has also worked at Chaco.

Trail to Chimney Rock Great House

Given my skepticism about the idea of floating beams down the Piedra River to Aztec or Chaco, it may come as no surprise that I much prefer the astronomical explanation.  While it’s certainly possible that some wood used in great houses elsewhere (more likely in the Totah area than in Chaco itself) came from the Chimney Rock area, there has not been any clear evidence yet establishing this, and if they were carried overland rather than floated, as was apparently the case, upstream areas like Chimney Rock wouldn’t have had any particular advantages over other, closer areas with similar vegetation for procurement purposes.  The procurement scenarios make sense on a general level, but when applied to Chimney Rock specifically they leave many questions unanswered.  Why would the great house need to be way up on top of the steep mesa if the point was to harvest trees?  Why weren’t there any other procurement outliers nearby?  And why so far away?

Piedra River Valley from Chimney Rock Mesa

All these questions are easily addressed by the theory that Chimney Rock was a preexisting religious site based on astronomical observations through the gap between the rocks (probably from various locations throughout the local area).  If the Chacoans were aware of this site, they may well have wanted to integrate it into their system, whatever it was, particularly if astronomical knowledge was an important aspect of the ritual authority that allowed them to put the system together in the first place, which it may have been.  While some archaeoastronomy can get a little too speculative for my taste, this Chimney Rock theory seems like one of the most clear-cut and useful examples of the archaeoastronomical approach as applied to Chacoan sites.  And, indeed, it seems that the astronomical theory has been winning out lately in both scholarly and interpretive circles.  Certainly the tour guide I had today talked about it a lot and didn’t mention wood procurement much.

Masonry at Chimney Rock Great House

In any case, it’s a fascinating place, well worth a trip, and hopefully the new research there will soon begin to shed more light on it.  With Lekson in charge, I have no doubt that the findings will, at the very least, be entertainingly described.

Chimney Rock Great House

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Floating Beams?

Doorway at Far View House, Mesa Verde

M. J. Hinton very kindly links to my post on Chacoan timber sources, and mentions another theory that I didn’t talk about in the post:

I’m certain it is not for lack of knowledge that he doesn’t mention that some think Chimney Rock was an outpost for gathering wood that might have been floated as far as Chaco. I don’t know if there is any merit to this idea. However, waterways may explain why wood would come from some areas and not others. In particular, Jemez may not be upstream from Chaco.

Kiva Pilaster at Escalante Pueblo

I am indeed aware of this idea, and I don’t buy it.  I see a variety of possible objections,  some more reasonable than others.

1. Chimney Rock is about twice as far from Chaco as any of the established sources for timber.  I don’t think this is really the strongest objection, since arguments that the Chacoans are unlikely to have done something because it was impractical or inefficient tend to founder on the considerable evidence that the Chacoans did all sorts of things that were impractical and inefficient.  They really seem to have had access to virtually unlimited amounts of labor, and they used it in all sorts of ways that don’t seem to make much logical sense.
2. There’s no clear evidence that any of the wood at Chaco came from Colorado.  While the spruce/fir study I mostly focused on in the last post didn’t look at the La Platas or San Juans as possible sources of timber, the subsequent ponderosa study did, with ambiguous results.  The strontium isotope ratios they found for the Colorado mountains overlapped with those for both the Chuskas and the Hosta Butte/Lobo Mesa area to the south of Chaco (which wasn’t included in the earlier study because it’s too low for spruce or fir).  While they did find some wood with isotope ratios in this range, with the data they had it was impossible to tell if it came from Colorado or from the other areas with similar ratios.
3. There is considerable evidence that at least some of the large primary beams were left to dry for a few years after being harvested, presumably to reduce their weight.  Floating them down a river after this would waterlog them and totally undo any effect of the curing.  This is particularly important since even after being floated the beams would still have to be carried the thirty miles or so from the San Juan River to Chaco.  While I’m generally skeptical about arguments based on practicality, for reasons mentioned above, the evidence for curing makes this one more plausible than most.
4. If the beams were in fact floated, they would presumably end up with a lot of scratches and scuff marks from hitting things in the river.  Floating logs down a river, especially with the technology the Chacoans had available, is not the easiest method of transportation to control.  And yet, the beams found at Chaco are remarkably pristine.  There’s barely a scratch on any beam in the whole canyon.  There aren’t even any axe marks from debarking, which is in striking contrast to beams at other sites such as Mesa Verde.  This suggests an amazing degree of care taken in the transportation of the beams, which is very hard to imagine if they were ever floated down a river.  I think this is probably the most devastating piece of evidence against the flotation theory.

Animas River, Farmington, New Mexico

In addition to the objections above to the specific idea of beams being floated down from Colorado, there are a lot of problems with the more general idea of timber sources being determined by waterways:

1. This idea isn’t actually consistent with beams being floated down from Colorado, since they could only be floated as far as the San Juan River and would then have to be carried the remaining 30 miles to Chaco.  It’s hard to see how an emphasis on waterways as routes for timber transportation could have led to a decision to do this.  Since there is no real evidence that any of the timber did come from Colorado, however, this isn’t necessarily a major problem for the general idea.
2. Most of the drainages in the southern San Juan Basin are intermittent and only flow at certain times of the year, which would have made transportation of beams a matter of careful timing.  Again, the Chacoans certainly had the ability to time things like this well enough, so this isn’t the most devastating objection.
3. Perhaps more importantly, the known sources of timber (established in the strontium isotope studies) are not upstream from Chaco.  The eastern slope of the Chuskas does drain into the Chaco River via a series of eastward-flowing washes, but these washes enter the Chaco a considerable distance downstream from the canyon.  Trees from the Chuskas, therefore, which seems to have been the primary source of timber for the canyon, could not have been floated and would have to have been carried.  The other major source area that has been identified, around Mt. Taylor, is on the other side of the Continental Divide from Chaco and drains in the opposite direction.
4. Furthermore, the Jemez, which doesn’t seem to have been a significant source of timber for the canyon, is upstream from Chaco.  More precisely, while the Jemez Mountains themselves are on the other side of the Continental Divide, they are just barely so, and the Chaco Wash originates right along the Divide near Star Lake, about 20 miles from Cuba.  Since the Chacoans were clearly carrying beams 50 miles from the Chuskas and Mt. Taylor, they could easily have carried them 20 miles from the Jemez to the wash and floated them in the late summer when it flowed high from the monsoon rains.  The fact that they didn’t seems to clearly indicate that waterways were not a factor in the decision-making process related to timber procurement.

Sign in Cuba Pointing to Chaco

I’m not sure where this idea came from originally, but it’s certainly out there and I’ve heard it several times.  It may have started as a way to explain the anomalous location of Chimney Rock, which really is odd in a number of ways, including its combination of considerable distance from Chaco with extensive Chacoan influence.  I think the evidence for an astronomical basis for the foundation of Chimney Rock is a lot more plausible than the idea that it was a lumber camp.  The idea of logs being floated from Chimney Rock to Chaco really doesn’t make much sense, and until any evidence for it surfaces (which I think is pretty unlikely) I’m not inclined to give it much credence.

Sign for Chaco Wash Laundromat (Formerly Pueblo Alto Trading Post)

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Where They Got the Wood

Chaco Wash and Escavada Wash Near Their Confluence

One of the most striking things about the environment of Chaco Canyon today is its vegetation, which is dominated by greasewood and saltbush and features an almost total lack of larger trees on the canyon floor.  There are some cottonwoods and tamarisks in the arroyo of the wash, which were mostly planted in the 1930s by the Civilian Conservation Corps, and on top of the mesas there are quite a few junipers and some piñon pines, but for the most part it’s a shrubby, treeless landscape.

Juniper Trees on the South Mesa Trail

The Chacoan style of architecture, however, features an enormous amount of wood, mostly in the ceilings of rooms but also in the lintels of doorways and vents and in some cases as intramural beams inside the walls.  It has been estimated that about 200,000 beams were used in construction in the canyon.  Because of the arid climate and the strength of the construction, a considerable amount of this wood has survived quite well and can be seen by visitors today.  One of the questions those visitors ask most frequently is where all this wood came from.  It’s a very reasonable question, and one that has resulted in a considerable amount of research that, unusually for Chaco research, has actually come up with some answers.

Intact Roof at Pueblo Bonito

Early excavators, like many modern visitors, generally assumed that the wood must have been local, and that the climate therefore must have been significantly different in Chacoan times from how it is now.  This view persisted as late as the 1960s, when most experts agreed that there had been a substantial forest in the canyon that had since retreated as a result of both human-induced deforestation and natural climate change.  Considerable research since then, however, has demonstrated quite clearly that this is not the case and that the climate in the canyon has been more or less the same for at least the past 5000 years.  Although there have been fluctuations from year to year and decade to decade in rainfall amounts and other climatic variables, the range of variation seen over the past 1000 years is basically the same as that seen in historical records over the past 100 years.  That is, rainfall can vary by a couple of inches or so pretty regularly, but there hasn’t been the sort of rainfall that would support a large forest during any time that would be relevant to the study of the great houses.

Tributary Drainage in Chaco Canyon

It’s likely that there were a few isolated stands of ponderosa pine in the canyon before construction really got going in the 800s, and the famous tree found in the excavations of the west plaza of Pueblo Bonito was presumably a remnant of one of these, but once construction began in earnest these would have been depleted very quickly.  After they were gone, it would have just been the juniper and cottonwood seen today.  These are found frequently as charcoal in hearths, indicating that they were likely widely used as firewood, but structural wood is mostly ponderosa, douglas fir, spruce, fir, aspen, and other large, straight, high-elevation species.

Roof Beams at Pueblo Bonito Showing Core Samples Taken for Dating

Over the past twenty years the Park Service has been conducting a series of studies, collectively known as the Chaco Wood Project, to sample every piece of exposed wood in the canyon and try to use the samples to come up with answers to a variety of questions.  The main purpose has been to create a very accurate and precise chronology using tree-ring dating, which has resulted so far in a substantial reinterpretation of the early history of Pueblo Bonito, but the samples have been used for other sorts of research as well.  Among these is the use of isotope ratios to determine the sources of structural wood.

Partial Roof at Pueblo del Arroyo

The main isotope ratio used in this sort of study is that of Strontium-86 to Strontium-87.  Strontium is a trace element found in all sorts of living things, and it has the useful property of being absorbed while the living thing in question is living but being unaffected by any biological processes after it is absorbed.  As a result, the amount of the various isotopes of strontium in a given organism is determined by the environment in which it grows and then remains constant throughout its lifetime and beyond.

Original Lintels at Chetro Ketl

Since the amounts of both Strontium-86 and Strontium-87 in an organism result from the environment in which it originated but don’t change after that, even if it is moved elsewhere after its death, measuring the ratio of the two in surviving samples of tissue and comparing it to the ratios found in various places where the organism might have originated can potentially reveal with considerable precision the area of origin.  This technique has been applied to samples of structural wood from Chaco with considerable success.

Viga Stubs at Peñasco Blanco

The most successful study of this type looked at spruce and fir (which are generally indistinguishable in this context) from sites in the canyon.  Although nowhere near as common as ponderosa in Chacoan construction, these species are from higher elevations and thus occur in fewer places in the region, which greatly simplifies this type of study since it reduces the number of possible areas of origin that need to be tested.  The study measured the ratios in the samples and compared them to those found at the three nearest areas where these species grow.  These are the Jemez Mountains to the east, the Mt. Taylor area to the southeast, and the Chuska Mountains to the west.  Each of these areas is about 50 miles from Chaco Canyon.

Jemez Electric Pole in Chimayo, New Mexico

The results of the study showed that both the Chuskas and Mt. Taylor were major sources of timber found in Chaco, but that the Jemez was not, despite being just as close.  There is no obvious ecological or economic reason for this, but it is noteworthy that outlying communities showing extensive Chacoan influence are very numerous in the foothills of the Chuskas and Mt. Taylor but totally absent in the Jemez.  Indeed, the east is the direction in which there is the least evidence for any Chacoan influence, and the evidence for any contact at all between Chaco and the areas east of the Rio Puerco is very scanty.  This suggests that the sourcing of timber destined for Chaco was affected more by social factors than by geographic or ecological ones.

Mt. Taylor from the Volcanoes Just West of Albuquerque, New Mexico

A subsequent study using the same methodology looked at possible sources for ponderosa, which is much more abundant in Chacoan construction than spruce and fir but much harder to investigate in this way because of its much more widespread distribution in the region, which is probably the reason for its greater abundance in construction.  Since it grows at lower elevations than spruce or fir, ponderosa is all over the place, and it is very difficult to test a sufficiently wide range of possible sources to come up with definitive results.  The results of this second study, therefore, while consistent with those of the first in indicating the Chuskas and Mt. Taylor, were more tentative than those of the first, and it’s quite possible that there were sources of ponderosa that were not tested in the study.  Still, the basic congruence of the results in the two studies indicates pretty clearly that, whatever additional sources there may have been, the primary sources for structural wood at Chaco were the Chuskas and Mt. Taylor.

Chuska Mountains from Tsin Kletzin

These two areas, but especially the Chuskas, in addition to having numerous outliers and considerable evidence of Chacoan influence, appear to have provided other goods to Chaco, such as pottery and chipping stone, in significant quantities as well.  All of these lines of evidence, therefore, point to a very close connection between Chaco and the Chuskas, and probably to a similarly close connection to the Mt. Taylor area as well.

Intact Roof Beams in Room 6, Pueblo Bonito

There are few questions about Chaco for which there are clear and relatively straightforward answers, but thanks to the application of modern geochemical techniques to archaeological questions this is one for which there are such answers.  In the future, this type of research is likely to become more and more widespread, and so other questions may soon be added to the “answerable” list.  In the meantime, however, the wood question stands as a beacon of hope in a sea of mystery.

Chuska Mountains from Peñasco Blanco

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