Mt. Taylor from Chaco
As I’ve discussed before, the patterns of use and importation of chipped stone at Chaco are somewhat puzzling. Unlike many other commodities, such as wood, corn, and pottery, which were imported from specific distant locations within the Chacoan sphere of influence in astonishing quantities during the height of Chaco’s regional power, chipped stone seems to have been largely a mundane, utilitarian concern. Throughout all periods of Chaco’s occupation most chipped stone was local. At Chaco’s peak of power and influence between AD 1020 and 1130 there was a slight uptick in imports of stone, particularly a distinctive pink chert from the Narbona Pass area to the west.
As I noted in the earlier post, however, obsidian follows a different pattern from the other imported stones. It is most common not at the height of Chaco’s regional power in the eleventh century but much earlier, in the Basketmaker III period between AD 500 and 750, when it is the most common nonlocal type of chipped stone. This was a time when Chaco may have seen an earlier period of regional importance, although figuring out what was going on at this time is very difficult for several reasons. By the Pueblo I period the amount of obsidian seems to drop precipitously, and it doesn’t start to recover until the very end of Chaco’s period of Pueblo occupation after AD 1120. This pattern puts obsidian decidedly out of phase with most other material culture imports to the canyon, which tend to correlate with the well-known evidence for social complexity and monumental architecture that we associate with the Chaco Phenomenon.
A recent paper by Andrew Duff, Jeremy Moss, Tom Windes, John Kantner, and Steven Shackley tries to put the obsidian evidence on a firmer footing by using geochemical sourcing to identify the source outcrops for a broad sample of obsidian found at Chaco and at various Chacoan outlier communities in the San Juan Basin. As they note, this is the latest chapter in a complicated story. Way back in the 1980s, the Chaco Project did an extensive sourcing study of obsidian found in its excavations in the canyon using X-ray fluorescence (XRF), a non-destructive sourcing technique that was then relatively new in archaeology. Their results, reported by Cathy Cameron in a number of publications, were surprising. They seemed to show that the closest source of obsidian, Mt. Taylor, provided very little of the obsidian found at Chaco (about 4%), while a distant source, Red Hill in Catron County, New Mexico, provided a very high proportion, especially in the assemblages from earlier sites. Also well-represented was obsidian from the Jemez Mountains, the second-closest source, with the proportion of Jemez obsidian increasing over time, a common pattern in the northern Southwest.
This seemed to indicate that there were substantial early ties between Chaco and the Red Hill area, far to the south but still just barely adjacent to some known Chacoan outliers. This result was mentioned in many publications on Chaco over the years, although many people didn’t really seem to know what to think of it. However, it soon began to be questioned. After this initial sourcing study had been done, Tom Windes submitted some samples of obsidian from Pueblo Alto and the Spadefoot Toad site for obsidian hydration dating, which involved a sourcing analysis as an intermediate step in the dating process. These analyses were inconclusive when it came to dating the artifacts (not uncommon in the Southwest, where obsidian hydration has a poor record as a dating technique), but the sourcing portion suggested strongly that the samples that had previously been sourced to Red Hill instead came from Mt. Taylor. Windes mentioned this anomaly in his site reports, as did Cameron in her subsequent publications on the subject, but a full published account didn’t appear until this new study.
The new study also used XRF to do the sourcing analysis, but both analytical techniques and source characterizations have improved considerably since the 1980s, so the results were quite different from the first effort. For some reason this study was unable to do a complete reanalysis of the earlier samples (although it implies that this may be possible in the future), so there was only limited overlap and the focus was mostly on recent samples collected by Windes at Basketmaker III and Pueblo I site in and around Chaco, as well as outlier sites studied by Kantner in the Red Mesa Valley near Mt. Taylor and by Duff at the southern edge of the Colorado Plateau near Red Hill.
The results were not really surprising, in that they have been known in broad outline since Windes submitted his samples for dating and reported on the sourcing anomalies, but it’s nice to see them formalized in a peer-reviewed paper. Basically, this study found that no samples from Chaco came from Red Hill, although a few came from other sources in the same general area, and that the most common source found at Chaco was Mt. Taylor. Over time there was a trend in the Chaco data showing a shift from Mt. Taylor to Jemez sources, accompanied by the well-known trend toward less obsidian in assemblages overall. The sample from the Blue J site near Mt. Taylor, in contrast, showed high proportions of Mt. Taylor obsidian increasing over time, in marked contrast to the Chaco pattern. The southern sites showed assemblages of obsidian almost entirely composed of Red Hill and other nearby sources.
Basically, the overall pattern was a classic distance-decay distribution, where the prevalence of a given source at a given site was mostly predictable by the distance between the source and the site. This is in sharp contrast to the pattern for many other imported goods at Chaco, which are present in high quantities in the source areas and at Chaco but not in between. This suggests strongly that obsidian was not part of any general Chacoan exchange system(s) but was procured by individual communities in accordance with their own needs, mostly using the closest sources. This is in keeping with the general tendency for chipped stone to be a relatively low-priority commodity in these societies.
The paper mentions the decline in overall abundance of obsidian after the Basketmaker III period at Chaco, but doesn’t spend much time discussing it beyond saying this:
The overall decrease in obsidian use noted at Chaco sites may reflect a shift in technological focus away from hunting and a subsequent focus on grinding technology as agriculture becomes the dominant subsistence strategy.
As I’ve noted before, this is almost certainly wrong; the decrease in question occurs at the end of the Basketmaker III period, at which time there is considerable evidence that Southwestern populations were already heavily dependent on agriculture. The decrease in obsidian is still odd, though. One thought I’ve had to explain it is that maybe the obsidian from after this period isn’t actually missing at all, but is at Pueblo Bonito, which had lots of obsidian but was excavated a long time ago using techniques that aren’t really comparable to the modern techniques used by the Chaco Project and later efforts that resulted in the collections being analyzed here. I would suggest that an XRF sourcing analysis of the Bonito obsidian would be interesting. As it is, there’s a huge shift in the proportions of the different sources at Chaco between Basketmaker III and Pueblo I. The earlier samples (dominated by the huge samples from the major villages of Shabik’eschee and 29SJ423) show a predominance of Mt. Taylor obsidian, while the later ones show mostly Jemez sources. The sample size is so much smaller for the later period, however, that I’m skeptical about taking this flip at face value. Including the Bonito assemblage might help to bridge this gap, or at least explain it.
Finally, it’s again noteworthy how unimportant obsidian appears to have been to the Chaco system. Even if the Pueblo Bonito evidence ends up indicating a more important role at Chaco itself, the various outlier communities appear to have used local sources and to have followed their own priorities in acquiring this commodity rather than getting it through any Chaco-controlled or -oriented system. This is one of the ways that Chaco appears to diverge from Mesoamerican societies, despite recent evidence that it may have had more contact with them than was previously believed. Obsidian was hugely important symbolically in Mexico, and control of major sources was a major source of power and wealth for various Mesoamerican polities. In the Southwest, however, nobody seems to have cared that much about controlling major obsidian sources, and obsidian seems to have been distributed as a fairly ordinary commodity without any particular symbolic importance. I think this is one of the strongest pieces of evidence suggesting that whatever influence Mesoamerican societies may have had on Chaco was indirect and mediated by Chacoan elites rather than imposed directly from Mexico, as some have argued.
In any case, while this isn’t really the most exciting paper, it’s still an important one in straightening out a part of Chacoan archaeology that had become pretty confused. Obsidian may not have been all that important at Chaco, but it’s still worth studying in part precisely because of its mundanity.
Duff, Andrew I., Moss, Jeremy M., Windes, Thomas C., Kantner, John, & Shackley, M. Steven (2012). Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence Journal of Archaeological Science, 39 (9), 2995-3007 DOI: 10.1016/j.jas.2012.04.032
Gambler's House 
I’m surprised by the contrast between obsidian in Mexico and in this region. I had always assumed that obsidian was more than symbolically important — that it was more functional than other lithics and this accounted for its importance in Mexico. Thus, I had also assumed this was probably the case everywhere. Stand me corrected. Thanks.
It certainly does have functional advantages (most notably, it holds a very sharp edge), which may well have contributed to its importance in Mexico and other places where it was important symbolically. This only makes the Southwest’s relative indifference to the stuff even more mysterious, of course.
Teofilo, while I was camping on Cedar Mesa with friends, they decided to scramble down to the floor of Mule Canyon. Lacking the energy but curious to watch their progress I spotted a likely rock under a tree. It turned out very comfortable and, as it was very close to the rim, I had a great view not just of them but all the way down canyon. As I was sitting I looked down at the ground at my feet and spotted a flake. I swept away some soil and saw more; many more and of several different types of rock. I realized that not only did I not discover this spot but many others much busier than I made good use of it. I can’t say any of it was obsidian (none were black) but I do remember one striking flake of a rich oxblood color and others of a pale white with tiny spots t
through it. Just one of those moments out there that stuck with me… JB
The recently excavated Basketmaker Period, Lift Site at Chaco showed the same pattern of near exclusive use of Grants Ridge obsidian mentioned here. The limited use of Jemez obsidian at Chaco later in time is indeed a mystery. It may be that the small amount of trade in Jemez obsidian was a result of where it was located and who was there. Most of the Jemez caldera where the best obsidian sources were located was within the “Gallina culture” area. This area during the Chaco Period included many dispersed small homesteads and small fortified villages. In the Gallina, there was a near complete lack of Chacoan Great houses and little apparent interaction with Chaco based on the material culture. Although the proximity of this region places it closer physically to Chaco than other utilized regions such as the the Upper San Juan, and parts of the Chuska slope, its resources including pine beams and obsidian were apparently not cornered by Chaco. Architectural styles between the two areas include a number of sharp contrasts. Unlike the large nearby Chaco outliers like Guadalupe, Gallina sites tended to be small and include basic sets of a round pit-structure and a slightly sub-surface rectangular room that often included the “kiva” features of vent shaft and deflector. At face value the layout suggests Gallina culture may have been more matrilineal than Chaco and that two contrasting social systems may have been in place (where are the gender study people on this one?). The dividing line between Chaco and Gallina is roughly on the present Hwy 550 and includes a “no man’s land” between the two groups. The survey data shows this pattern but needs to be ground truthed due to the fairly common past practice of calling early Navajo sites with Dinetah gray and Jemez Black-on-White, Anasazi.
A brief history of the Gallina/Jemez people shows a gradual movement south through time. The early periods included dense populations of people in the northern parts (generally north and east of Aztec). By the late Pueblo I Period there seems to have been a split developing that was complete by the early Pueblo II Period. At this point in time the large villages of the Navajo Lake area that had included great kivas, Cibola ceramics, duck effigies and other various trappings of Chaco-ness left and presumably joined the population massing at Chaco (except some who condensed around the Chimney rock group up north). Another small but scattered group with a contrasting material culture was left behind. This group preferred life within the upper pinyon/juniper and ponderosa woodland where they built small unit Pueblos that often included towers (Buzzard park in the Carson Forest is a good example). Hunting was probably more important to them than the folks who went to Chaco. This of coarse has landed the Gallina with the hillbilly tag among modern historians. As people gradually drifted south in Pueblo II times, a new center of sorts occurred in the Gallina area where the largest sites included tower ringed mesas and pit-structure villages. At some point there was conflict that targeted these people and they continued their southern movement. Remaining people settled in the Jemez springs areas where several distinctive Gallina type architectural traits continued at places like Ungshagi. The early alliance of Jemez and Navajo saw the widespread use of Jemez obsidian (as well as Perdanal chert from the same area) spread throughout the Dinetah as far as Colorado and Arizona. This distribution pattern is the one that should have been apparent during the Pueblo II period with Chacoan affiliated sites.
I find it interesting that to this day Jemez stands out as one of the Puebloan groups that state positively that they do not have ancestral ties to Chaco Canyon. A split, very likely between the Tewa and Towa that occurred by populations in this area in the 900s may have been along the classic lines Stuart & Gauthier discussed concerning their theory of power and efficiency.
So the lack of evidence for obsidian playing a major role in the Chaco system (or perceived lack of evidence at best) cancels out the monumental discovery of chocolate at Chaco? What does the lack of jade masks say about Chaco? Not sure, but The Duff et al paper stays regional but somehow your discussion ends up in mesoamerica and the tiring conclusion that the Chaco system was regional at best because of the lack of a one to one correlation with the south. Obsidian was a very common commodity in Mexico as well but it’s the eccentric carvings that get the press and elite associated bias.
Whoa there, Don. I didn’t say the obsidian evidence (which has been known for a long time) canceled out the chocolate discovery, and I don’t believe anything of the sort. What I do think it argues against is the sort of super-strong Mexicanism espoused by people like Christy Turner and Dorothy Washburn who see Chaco as the result of an actual influx of Mesoamerican people into the Southwest bearing their own culture, accounting for the Mesoamerican elements found at Chaco. I’m more inclined to a view like Lekson’s, in which Chaco is the result of local elites selectively appropriating aspects of Mesoamerican culture for their own purposes. From that perspective, chocolate is one thing they decided to take and obsidian is one they didn’t.
I think it’s more of an influx of People of the SW into Mesoamerica and returning to Chaco w/ ideas, but why haggle over details……Lekson’s view is reasonable and the best published to date IMO. Given the presence of volcanics (and obsidian) throughout central NM perhaps the luster of obsidian wasn’t quite as impressive to Chacoans as it was to those of the traditional highlands and lowlands of mesoamerica. Chaco eltes knew what they liked and needed, and to heck with everything else.
Don
Josh Barton those red flakes were what I think is called Cedar Mesa Chert and flakes of that stuff are all over Cedar Mesa area sites. When I’m hiking along in that area and spot a few flakes it alwyas makes me slow down and snoop around.
I always thought a key part of the importance of obsidian in Mexico was it’s utilization in war clubs which were an important and I guess somewhat key part of the typical Mexican armament.. Evidently archery was never as advanced or advanced more slowly in Mexico than further north on the Colorado Plateau and even the Plains…… but don’t quote me on that one.
Also I always thought there was a distinct decline in the quality of point as well as the material used after the transition from spears/darts/atlatls to bow and arrow which I though occurred @ BM3 to P1??
Retshen, I have been to a couple of those big P3-P4 sites above Jemez Springs and the quantity of obsidian is amazing. I’m not sure if true glass like quality makes it desirable for flaking and tool manufacture but the stuff looks so much like black glass that I had momentary confusion when I first say it along the lines of “where did all this glass come from….duh.
very nice
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