The Paint on the Pots

Hachured Potsherds at Casamero Pueblo

When I was working at Chaco, people would ask me a lot of questions. I usually knew the answers, but when I didn’t I was quite upfront about saying so. I would often try to find out the answers to questions that had stumped me, but I didn’t always succeed, and many of those questions are the ones that I remember best, even now.

One of those questions had to do with the black-on-white pottery that is a hallmark of Chaco. A guy once asked me what they had used as a fixative to get the paint to adhere to the pottery, and I didn’t know. I didn’t really make much of an effort to find out then, as I didn’t really have any idea where to look. Recently, though, I’ve read two papers that shed interesting light on this question. Understanding them, though, requires some background on Pueblo pottery in general.

Hachured Potsherd at Pueblo Alto

Basically, there are three main types of paint that were used in the prehistoric Pueblo Southwest. Two of these were in use during the period when Chaco was occupied: mineral and carbon. (The third, lead glaze, wasn’t used until later.) Both were used to produce a black color. Other colors were occasionally produced by a variety of means, but for this period black was the overwhelmingly dominant color of painted ceramics. It’s generally possible for experienced archaeologists to tell mineral and carbon paint apart by sight. Although they both tend to look black on a well-fired pot, there are various subtle differences between the two.

Carbon paint is basically just plant material, usually Rocky Mountain beeweed or tansy mustard, boiled down into an extract and applied to the pot. Mineral paint is made of ground iron-rich minerals, usually hematite, mixed with either water or an organic extract similar to those used alone as carbon paint, and sometimes with clay as well. Both types have been used both in prehistory and among the modern Pueblos. However, there were some marked patterns to usage of the different types of paint both geographically and temporally. Overall, the trend was of increasing use of carbon rather than mineral paint over time, spreading from west to east. Chaco ceramics at the height of the Chaco phenomenon in the eleventh century AD were overwhelmingly mineral-painted, while Chuska and Mesa Verde ceramics, while very similar in decoration and imported to Chaco in large numbers, were generally carbon-painted. Around AD 1100 there was a marked shift, and even Chaco pottery began to be primarily carbon-painted. By the 1200s use of mineral paint only continued in areas on the eastern and southern fringes of the Pueblo world. Distinguishing between carbon and mineral paint is thus quite useful for making inferences about culture history during this period. (In subsequent periods things became much more complicated with extensive long-distance migration and the introduction of glaze paints.)

Sherd with Checkered Pattern, Kin Klizhin

Both of the papers I mentioned above are about using more formal means than visual criteria to tell mineral and carbon paint apart. One, by Joe Stewart and Karen Adams, used a scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDS) system to differentiate the two based on the amount of iron detected in the pigment. The other, by Robert Speakman and Hector Neff, used laser ablaction-inductively coupled plasma-mass spectrometry (LA-ICP-MS), a simpler and potentially less expensive method to distinguish between the two types of paint based on the concentrations of various elements. Both found that the methods they used came up with similar results to traditional visual methods, and were superior for certain sherds with unusual mixes of characteristics that made them visually ambiguous. Speakman and Neff also found a surprising amount of variety in elemental composition even within the “carbon” and “mineral” groups, suggesting that there were multiple “recipes” used to mix paint in prehistory, not just the two broad categories. This isn’t all that surprising given that this is clearly the case in modern times based on ethnographic data, but it’s still interesting.

That’s all well and good, but one thing that occurred to me in reading these papers was that it’s not at all clear why there would be multiple paint recipes, since they all ended up with pretty much the same result and some were definitely more complicated than others. This is particularly the case when considering mineral paint, since in many cases it appears that it was actually mixed with the plant concoctions that were in other places used independently as carbon paint. If boiling down beeweed produced a perfectly suitable black paint, why bother adding hematite? This might well explain why the trend over time was from mineral to carbon paint, but it’s still unclear why mineral paint originated in the first place. It does not appear to have predated carbon paint overall, at least at Chaco, where both carbon and mineral types are present as early as Basketmaker III.

Hachured Potsherds at Kin Ya’a

The lack of obvious functional reasons for preferring mineral to carbon paint suggests that the choice may have been more a matter of cultural tradition, which is interesting and implies that some sort of cultural differentiation may have been present quite early in the prehistory of the northern Southwest. This isn’t really surprising, as there is plenty of other evidence for this, but teasing out the implications of all these different lines of evidence pointing to differentiation in material culture is a task that archaeologists have only recently begun to take on. It should be interesting to see what more we have to learn from these differences.

Speakman, RJ, & Neff, H (2002). Evaluation of Painted Pottery from the Mesa Verde Region Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) American Antiquity, 67, 137-144 DOI: 10.2307/2694882

Stewart, JD, & Adams, KR (1999). Evaluating Visual Criteria for Identifying Carbon- and Iron-Based Pottery Paints from the Four Corners Region Using SEM-EDS American Antiquity, 64, 675-696 DOI: 10.2307/2694212

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Lessons from Bolivia

Visitor Center and Fajada Butte from Una Vida

I often read articles on the archaeology of other parts of the world to gain a better understanding of the context for Chaco. The areas I focus on for this are primarily those that had interesting things going on contemporaneous with the Chacoan era, but I also look to some extent on archaeological phenomena in other places that are comparable to the Chaco Phenomenon itself to see if there are any lessons for understanding Chaco to be drawn from them.

Recently I’ve been reading a bit about the archaeology of Tiwanaku, Bolivia, which falls into both categories. The period of Tiwanaku’s florescence overlaps with Chaco’s to some extent, although it falls most earlier, but more importantly the history of research there has some intriguing parallels to the history of Chacoan studies and may hold some useful lessons. My account of Tiwanaku here is drawn mainly from John Janusek’s 2004 review article, as well as some other papers by Janusek and others who seem to share his general perspective.

Tiwanaku itself is a major site located on the Bolivian altiplano near Lake Titicaca. It is in a very stark and desolate-seeming location, which makes its monumental architecture seem incongruous (sound familiar?). Early explorers noted that the site pre-dated the Inka empire, and some considered it the oldest site in the whole Andean region. Archaeological investigations in the early twentieth century showed that the latter characterization was definitely not accurate, but they also found little evidence of domestic occupation, and the idea arose that Tiwanaku was a vacant ceremonial center and pilgrimage destination, which some interpreted as the center for a religious movement that was spread by the expansionary state centered at the site of Wari further north in Peru.

Starting in the 1950s, however, a new archaeological program sponsored by the nationalist government of Bolivia and led by Carlos Ponce Sanginés conducted extensive excavations at the site and concluded instead that Tiwanaku was the urban capital of an expansionist state, which rivaled Wari and eventually even conquered it. By the 1980s researchers from the US were invited to work in the area as well, and their research has generally supported this reconstruction of Tiwanaku rather than the “vacant ceremonial center” hypothesis, although the idea that Tiwanaku actually conquered Wari didn’t hold up. Janusek is part of this research tradition, which is why the fact that my information on the site comes mainly from him is important. There are apparently still other archaeologists who still hold to the older interpretation, but there don’t seem to be many.

Anyone who is familiar with the history of research at Chaco should see the similarities here. One important difference, of course, is that the early research at Chaco assumed that it was a residential rather than a ceremonial center. It was not until the work of the Chaco Project in the 1970s that it began to seem like the great houses in the canyon were something other than “pueblos” in the traditional sense. While the idea of Chaco as a vacant ceremonial center was never universal, and it arose rather recently in the history of Chacoan research, it has been quite influential in recent years. Recent research, such as that of Chip Wills, Steve Plog, and Steve Lekson, has been moving away from this idea, however, and back to the idea of a substantial population in the canyon. In parallel with Tiwanaku, however, many of these recent interpretations have seen Chaco as more of a complex, hierarchical society than a set of autonomous, egalitarian villages. This makes the monumental architecture that is a hallmark of the Chaco Phenomenon seem like more of an expression of hierarchical than spiritual ideals.

One important lesson of Tiwanaku, however, is that these are not necessarily mutually exclusive. The monumental architecture and art at the main site and other sites considered to be regional centers of the same polity (“outliers” in Chacoan terminology?) is generally interpreted as reflecting a religious ideology that supported the hierarchical structure of the Tiwanaku state. This is hardly unusual in early states, of course, but the fact that Tiwanaku was not originally considered to be such a state makes it more relevant to the case of Chaco, which is in the same situation.

Another important similarity between the two systems is in the presence of astronomical alignments in the monumental buildings, and the resultant implication that astronomical observation and the maintenance of a calendar were important elements in the societal system. Tiwanaku was apparently the first society in the region to show this astronomical focus, and Janusek, in a paper on Tiwanaku religion, links this explicitly to its success as a state. In that paper he argues that the changes in monumental construction at Tiwanaku proper were linked to changes in the religious ideology of the site, which over time came to incorporate diverse regional traditions as well as cosmic cycles into a complex, syncretic religion that supported and justified the spiritual and material power of the Tiwanaku elites. As Janusek concludes:

Tiwanaku’s long rise to power in the Andean altiplano was predicated on the integration of diverse local ritual cults and various symbolic dimensions of the natural environment into a reasonably coherent, supremely elegant and powerfully predictive religion. The shifting physicality of Tiwanaku’s religious monuments attests the construction and ongoing transformation of an urban landscape that not only visually expressed the altiplano’s ‘natural’ forces and cycles, but, via recurring construction and ritual, simultaneously shaped new social practices and Tiwanaku’s ever-increasing political influence and productive coordination, intensification and expansion. Tiwanaku was an imperfect and potentially volatile integration of religious cults, productive enterprises and societies. The material objectification of a seductive religious ideology that infused the monumental centre with numinous natural forces and simultaneously projected those forces across distant Andean realms helped drive Tiwanaku’s very worldly imperial mission.

I haven’t seen this same argument applied explicitly to Chaco, but I think it may apply there as well. The part about incorporating diverse cultural traditions seems to match pretty closely with the well-known diversity of material culture at Chaco, with different sites within the canyon, and even different parts of some of the larger sites, showing ties to different parts of the region. I don’t know of any pre-Chacoan sites in the Southwest that show obvious astronomical alignments the way Chaco does, so it seems probable that the Chacoans were the first to figure out these alignments, and they may have also been the first to develop the rigorous calendrical knowledge that such mastery of astronomy implies. I hadn’t really thought about that as a source of Chacoan power before reading about Tiwanaku, but it certainly makes sense. This is a good example of the way reading about these far-flung places has practical advantages for understanding Chaco.

Janusek, John W. (2004). Tiwanaku and Its Precursors: Recent Research and Emerging Perspectives Journal of Archaeological Research, 12 (2), 121-183 DOI: 10.1023/B:JARE.0000023711.96664.1b

Janusek, John W. (2006). The Changing ‘nature’ of Tiwanaku Religion and the Rise of an Andean State World Archaeology, 38 (3), 469-492 DOI: 10.1080/00438240600813541

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