Happy solstice, everyone. To mark the occasion I figured I’d say a bit about archaeoastronomy, which is an important topic at Chaco that I don’t discuss very often. The various alignments identified at the great houses in the canyon have become quite famous through the work of the Solstice Project to document them, and while I don’t think all of their proposed alignments are necessarily real, there is enough evidence by now to suggest that at least some of them are. Cardinal direction alignments are the most obvious, and the least likely to be coincidental (in my view), and these are found at a few of the sites at Chaco, particularly Pueblo Bonito, Pueblo Alto, and Tsin Kletzin. Interestingly, these three are all in the center of the canyon (“Downtown Chaco”), and the line running due north-south from Pueblo Alto to Tsin Kletzin runs between Pueblo Bonito and Chetro Ketl through the “Chaco Amphitheater.” This all suggests some pretty extensive planning, but it’s interesting that the other parts of the canyon don’t seem to have been part of it. I find the Solstice Project’s proposed alignments at many of the other sites in the canyon a lot more dubious, especially since so many of them are allegedly to the minor lunar standstill. It seems more plausible that there would be solstice alignments in the canyon, and there do indeed seem to be some “viewing points” from which solstice sunrises are marked by prominent features on the horizon, but the only solstice-aligned building proposed by the Solstice Project is Aztec West, which isn’t even at Chaco, although it’s clearly Chacoan in style.
Steve Lekson has proposed that one possible reason for the variety of alignments in Chacoan great houses is conflict between factions within Chacoan society. The way he sees it, solstice alignments were the regional tradition, and cardinal alignments were a new idea at Chaco, perhaps threatening to the old order in the way that many new developments at Chaco were. Indeed, alignment to the southeast was a common architectural practice in pre-Chaco communities, and this may well have had something to do with the solstices, although as far as I know none of these buildings have been demonstrated to have precise solstitial alignments. I’m not so sure that cardinal direction alignments were not present in the region before Chaco, however, and I’m also unsure of whether differences in building orientation really represent ideology the way Lekson proposes. I’m more inclined to wonder if they may instead reflect different ethnic or regional origins for different groups. In either case, though, the factionalism idea is interesting, and quite compatible with what we know of later Pueblo societies. In Lekson’s version, the solstice alignment of Aztec reflects the founding of that center by the solstitial faction at Chaco, while the cardinal faction went elsewhere, maybe to Paquimé, which has a strong cardinal alignment. I’m not sure how much of that I buy, but it’s worth thinking about.