Archive for September, 2013

Utah Welcome Sign

Utah Welcome Sign

The initial discovery of chemical markers for chocolate on potsherds from Chaco Canyon in 2009 was a hugely significant development in understanding Chaco. The evidence for the presence of chocolate, a Mesoamerican product that couldn’t possibly have been locally grown and is very unlikely to have been gradually traded northward through a series of intermediaries, gave a huge boost to the “Mexicanist” school of thought about Chaco, which holds that many of the unusual aspects of the Chaco system are due to influence from Mesoamerica.

The initial study only involved a few sherds, though, and understanding the exact role of chocolate at Chaco and its implications for Mexican contact needs a much deeper understanding of where and when cacao was present in the ancient Southwest. Thus, soon after the initial discovery further research by a different set of researchers (using somewhat different methods) began to test other pots from Chaco and elsewhere. They did find further evidence that at least some of the famous cylinder jars from Chaco were used in the consumption of chocolate, but they also found traces of cacao in vessels of similar form from the later Classic Hohokam period in southern Arizona, and, most surprisingly, also in vessels from the “small-house sites” at Chaco and elsewhere that are thought to have housed the lower classes of Chacoan society. The previous evidence for chocolate came from distinctive vessels at the “great houses” that are the hallmark of the Chaco system and seem to have been used by elites (though exactly what they used them for remains unclear and controversial). This is exactly the kind of setting where it would be unsurprising to find unusual, exotic things, and indeed the great houses clearly contained many such things in addition to the chocolate. Finding this sort of exotic foodstuff in more mundane pots at the small houses implies that it may have been more widely accessible than previously thought, which has important implications for understanding the nature of the Chaco system.

Well, now things have become even more complicated. The same researchers who did that follow-up study have done another, this time looking at a much earlier period and a different part of the Southwest. They used their same techniques to test for the presence of chocolate in pottery at Alkali Ridge Site 13 in southeastern Utah, a very important early village site dating to the eighth century AD. Site 13 was one of the earliest large villages established in the northern Southwest during the Pueblo I period, and its architecture shows some striking parallels to later Pueblo I villages such as McPhee Village in the Dolores, Colorado area, as well as to some of the early great houses at Chaco and elsewhere that developed even later. The early Pueblo I period in southern Utah is also associated with the introduction of a new type of pottery, San Juan Red Ware, which was widely traded from an apparently rather restricted production area and probably used for ceremonial purposes of some sort. In addition to being a different color from the more common gray and white pottery of the area, San Juan Red Ware also featured a distinctive design system in its decoration, one without obvious local antecedents. Combined with the distinctive architecture, this has led some archaeologists to posit that there was a migration into southern Utah during early Pueblo I from somewhere to the south, bringing these distinctive traits.

In that context, looking for cacao makes sense, as that would be a clear sign of ties to the south and cultural distinctiveness. Dorothy Washburn, who was the lead author on both this and the previous study,  has actually written mainly on design style in ceramics and other handicrafts, focusing on symmetry patterns. Based on the changes she has found in these patterns, she has argued for a very strong Mexicanist interpretation of Chaco, involving actual migration of people from far to the south bringing a distinctive pottery decoration style. She seems to have a similar view about Alkali Ridge, for similar reasons.

In any case, the study found that there was in fact evidence for cacao on several of the vessels found at Site 13, including some (but not all) of the redware ones. The conclusions, understandably, focus on the association between the new ceramic design system and the use of chocolate, but in fact the redware vessels don’t seem to be much more likely to have evidence of chocolate use than the other ones that were tested. It’s quite possible that San Juan Red Ware was associated with consumption of chocolate specifically, but it seems that other types of pottery were also used for chocolate-related purposes.

This is all very interesting, but it’s also confusing and hard to interpret, in a way that the authors of this paper don’t really address. Back when it seemed like chocolate was limited to cylinder vessels at Chaco great houses, that was easy to interpret: chocolate, like many other exotic goods found at these sites, was part of an extensive trading systems for elite goods, probably used for ritual purposes, which the elites of Chaco participated in (and perhaps dominated and directed). Finding it in the Hohokam vessels implied a similar system operating among elites at Classic Hohokam sites, which is consistent with some interpretations of Classic Hohokam society, plus the Hohokam in general show lots of evidence of contact with Mesoamerica in general so the presence of chocolate is much less surprising there than it was at Chaco. Finding it in the small houses at Chaco complicated the story somewhat and implied that the chocolate imported to Chaco wasn’t as restricted as had been thought, but since it was already known to be present at the great houses it’s not too surprising that the contemporaneous small houses had it too.

Alkali Ridge, though, is much earlier and much further north than any of these other sites. Getting chocolate there in significant quantities would have required a pretty elaborate and robust supply chain over a very long distance, much of which was inhabited by societies that are not generally considered to have been capable of this kind of long-distance coordination. Checking some of those intermediate areas (especially the Hohokam region) to see if they too had chocolate this early is necessary to understand the logistics of this.

There’s also the question of time. We now have evidence of chocolate from Utah in the eighth century, New Mexico (and to a lesser extent Colorado and Arizona) in the eleventh, and Arizona in the fourteenth. There are some big gaps there that need to be filled in to determine if these are three snapshots of a long-term and continuous tradition of chocolate consumption in the Southwest (which would have important implications about trade networks and relations with Mexico) or three separate episodes of chocolate being introduced from the south, possibly through population movement (which would have important implications for regional culture history in general). I think the most important place to look for evidence of continuity between Alkali Ridge and Chaco is in the large late Pueblo I villages in southwestern Colorado, especially the Dolores-area ones like McPhee Village. These sites have apparent connections to both earlier villages like Site 13 and later developments at Chaco. If they also reveal evidence for chocolate use, that would be a strong indication of continuity. The most important places to check for continuity between Chaco and the Classic Hohokam would probably be the Pueblo III communities in east-central Arizona, which again show connections in both directions. Both of these sets of sites are among the best-studied in the Southwest and there should be plenty of pots available for these analyses.

Finally, there is a methodological issue here. It’s possible that these tests aren’t actually detecting chocolate at all, but something else. The authors of the recent paper noted this possibility and looked into whether there are any plants native to the Southwest that might have chemical profiles similar to cacao that would throw off the analysis. They didn’t find any, but they note that many plants have not been analyzed in this way and it’s possible there is a different plant that is showing up in these analyses instead. Another possibility is that there is something about their method itself that is leading to false positives. It’s noteworthy that they have been finding much more extensive evidence of chocolate than the team, led by Patricia Crown and Jeffrey Hurst, that did the initial Chaco study found. That team hasn’t published any more about chocolate at Chaco since then, but I hear Crown was able to do some re-excavation in Room 28 at Pueblo Bonito this summer so there may be more from her on this in the future. Ideally I’d like to see a test of both methods on the same vessels to see how they match up.

The ultimate message here is that even important discoveries, like chocolate at Chaco, require many further studies and refinements to interpret properly. We’re nowhere near a full understanding of the true role of chocolate at Chaco or any other site in the prehistoric Southwest, but every study gets us closer.
Washburn DK, Washburn WN, & Shipkova PA (2013). Cacao consumption during the 8th century at Alkali Ridge, southeastern Utah Journal of Archaeological Science, 40, 2007-2013 DOI: 10.1016/j.jas.2012.12.017

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