Chris Beekman, J. Charles Kelley, Peter Jimenez Betts, Vincent Schiavitti, Phil Weigand, others are invited.
1996-present Western and Northwestern Mesoamerican Radiocarbon Database
Chris Beekman, J. Charles Kelley, Peter Jimenez Betts, Vincent Schiavitti, Phil Weigand, others are invited.
Archaeological chronologies in western and northwestern Mesoamerica are generally poorly supported, but it is inaccurate to simply say that we have insufficient dates - the region actually has some 300+ radiocarbon determinations. More relevant is the fact that radiocarbon age determinations are frequently left unpublished, discussed only in conference papers of limited circulation, or are published incorrectly. Very explicit standards exist for reporting age determinations, but these are not always followed. Other problems occur when archaeologists compare uncalibrated (which should not really be conceptualized as dates at all) and calibrated figures. Another problem is the frequent lack of strategy in building a chronology. Too often archaeologists in the region have analyzed a single carbon sample rather than a series of stratigraphically related samples, or have analyzed samples without clear associations to a ceramic phase. A date from a chunk of charcoal may well date that chunk, but it doesn't allow the archaeologist to turn around and apply that date to future finds of specific ceramic types. Alternately, some samples from this region have been assigned to a phase on shaky evidence. When the radiocarbon date comes back from the laboratory looking very different from the expected date, the archaeologist may try to reassign the sample to another phase to explain the problem, which only confuses the issue and the underlying problem - poor selection of samples.
West Mexico was also one of the first regions to attempt to use obsidian hydration dating on a wide scale. Unfortunately, the method turns out to be considerably more complex and variable from location to location than previously assumed, and the few projects that still make use of it must take into account a much wider range of environmental and compositional factors if they hope to use it for dating purposes. Ironically, the focus on this method in the west and northwest has diverted efforts away from more established methods such as radiocarbon dating, and hindered overall attempts at correlating chronological sequences within the region and with the rest of Mesoamerica.
In an effort to deal with these problems, I attempted to gather all published radiocarbon determinations for western and northwestern Mexico, and solicited the cooperation of my colleagues in the region. The intention was to produce a standardized listing of all samples, their contexts, their uncalibrated and calibrated dates, etc. Workers in other regions of Mesoamerica (Teotihuacan, Oaxaca) have compiled data of this sort, and I hope to bring our region more into line with research in those areas. The database exists on paper and is currently being transferred to a format more amenable to the Web. Although this was initially intended as a hardcopy publication with all providers of unpublished data as co-authors, various professional difficulties have led to a probable abandonment of that plan. Only published data will be placed on the web, unless those originally providing information agree to this new format.
A timetable for this particular project does not exist. With my new position at University of Colorado at Denver, perhaps I'll find a student interested in such a project.
Comments to Chris Beekman