Archaeological Palynology of Teuchitlán

Conclusion

The research had three main goals: (1) to obtain palynological data to compare to and augment existing palynological data obtained during research on wetland agricultural systems within the study area, (2) to provide an indication of the sort of pollen data that may occur at archaeological sites in the region, and (3) to establish a sampling protocol for additional palaeoethnobotanical research to be conducted in the region. Given the results of the analysis, it is difficult to conclusively resolve any of these goals.

A total of 184 sediment samples for palynological analysis were obtained, satisfying the ambition of obtaining samples from a wide range of structures, features, and chronological contexts. Excavation conducted at the site had emphasized clearing surface vegetation and loose soil from the architectural features, and trenching of the exposed features. Obviously, clearing would only reveal the most recent occupation period, while trenches were, for the most part, fairly shallow, although some were to be excavated more deeply in subsequent excavation seasons. Thus most of the sampled contexts would date to relatively recent occupations of the site, but not exclusively so. A few test pits and trench sections were excavated through some of the features, in some cases, such as in the circle 1 patio, to the underlying bedrock. Therefore, samples from earlier contexts were obtained, including from sediment believed to predate occupation of the site. However, no clear identifications of earlier building episodes were visible at the time samples were collected.

Thus, suitable sediment samples for satisfying the first two goals of the project were collected. However, the pollen content of these samples failed to provide information pertinent to the first goal, and only negative information toward the second. If the pollen samples from the site of Teuchitlán are representative of pollen samples from Guachimonton sites, then this does not bode well for future archaeological palynology at these sites. In spite of using two quite different extraction methods – methods that have proven successful at a variety of other locations, including from within the study area – no archaeological context samples produced pollen concentrations of over 3000 grains per square centimeter. The question is, of course, why this may be so.

Most of the samples collected, and most of the samples analyzed, were obtained from fill (Table 1). It was recognized that the recovery of pollen from this context would be problematic for two reasons. First, transporting and/or mixing or otherwise working with the sediment apparently eliminates most of the pollen the sediment may once have contained. Second, the fill was probably fairly rapidly buried thereby precluding the presence of exposed surfaces upon which pollen could accumulate. Thus it was not too surprising that none of the fill samples contained more than 3000 grains / cubic centimeter, and only one contained more than 1000 grains / cubic centimeter.

Assuming that transport of the material for and the making of the adobe would also eliminate or severely reduce pollen content, the critical factor in whether or not pollen would be present in the adobe was how long it was exposed to pollen deposition while being allowed to dry. The very low concentration values for this material type suggests that burial was fairly rapid, or at least rapid enough to preclude deposition of sufficient quantities of pollen for analysis.

The low concentration values for the original soil was thought a possibility because aeolian soils are often palynologically depauperate. Unfortunately this did prove to be the case.

What did come as a surprise was the very low pollen concentrations for the floor samples. Floors are generally exposed to the air for relatively long periods of time, and routinely have pollen concentration levels sufficient for analysis. Perhaps the low pollen concentration values for the Teuchitlán ballcourt floor samples relate to the way the surface was manufactured, or used, or exposed. At this point in time, it is not possible to determine why these samples contain so little pollen.

Research currently underway at another site in the study area will help to indicate whether or not these results are typical of Guachimonton sites in particular, and habitation or ceremonial sites in general. Shortly after I collected these samples, excavation commenced at the site of Llano Grande (Figure 1), and samples for palynological analysis were obtained and are going to be analyzed. I am unsure of the contexts from which these samples were obtained, or how they are being processed, but it will be interesting to see what sort of results are obtained.

Probably the most important goal of the research was to establish a sampling protocol, first to direct collection of sediment samples for palaeoethnobotanical analysis as excavations continue at Teuchitlán, and second to guide assessment of sampling contexts at other archaeological sites within the study area. Such a protocol would help to ensure that depositional contexts from which sediment samples were collected had similar cultural and natural formation processes. This would help to ensure that variations seen in the pollen, and macrobotanical, assemblages could be related to and help identify variations in site type, feature type, chronological period, and geographic location. Such variations would also provide information in regard to domestic activities associated with processing, storage, and preparation of plant resources and how this may have varied both within and between sites, and across time. If samples being compared witness different formation processes, then variation in their assemblages would also relate to such processes. In some instances these are the sort of data wanted, such as in comparing samples from wetland agricultural systems to habitation / ceremonial sites, but different formation processes makes many intra-site and inter-site comparisons more problematic.

Samples obtained from floors are particularly suitable as floors represent surfaces that are exposed to pollen deposition for extended periods of time while the site is occupied. In addition to airborne pollen, pollen adhering to the surfaces of harvested and collected plants is commonly dispersed onto the floor during the processing or storage of these plants. It is assumed that over time, a basically random sample of this pollen becomes incorporated into the floor itself. Yet, in this study, samples collected from a ballcourt floor or floors failed to yield adequate counts for analysis. Furthermore, excavations conducted at Teuchitlán, or at least excavations that had been conducted up to the time of my arrival, failed to uncover very many floors. However, only very limited excavation had been conducted on the platforms, the most likely location for floors, so floors may yet be discovered. Still, given the apparent lack of floors and the very low pollen concentrations from the floor(s) that was sampled, and the low concentration of pollen from fill context samples, it would seem that collection of samples from any surface that may have been exposed during the site’s occupation is essential.

In sum, this research did not provide the sort of data that was anticipated. Nevertheless, as excavation has continued, so has the collection of sediment samples for palaeoethnobotanical analysis. Given the results of current analysis, the importance of obtaining samples from any surface thought to have been exposed during occupation of the site is being emphasized. Hopefully, analysis of these contexts will prove more rewarding.

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