Archaeological Palynology of Teuchitlán

Lab Strategies

Sixteen samples were either judgmentally or randomly selected for laboratory processing. Samples were selected such that the circle 1 patio, the ballcourt, and both the circle 2 pyramid and two of the circle 2 platforms were represented. The samples processed included all three ballcourt floor samples plus one randomly selected trench wall sample; the two ’original soil’ samples; two randomly selected pyramid 2 trench wall (face) samples, and one randomly selected rise/tread sample; two randomly selected platform 3 pinch samples and one randomly selected platform 1 trench wall sample; and four randomly selected samples from the circle 1 patio test pit.

Given the very low pollen concentration values that resulted, it was decided to re-process eight of the samples using a different method to see if this would enhance pollen concentration. For the second technique, the three ballcourt floor samples, the two ’original soil’ samples, and three randomly selected samples were processed.

Extraction

Method One
Tablets containing a known quantity of Lycopodium spores were added prior to processing so concentration values could be calculated. The amount of sediment processed was 5 cubic centimeters per sample. The laboratory procedure involves deflocculation in acid and lye solutions; swirl flotation and screening to separate the lighter and smaller materials of the sample (including pollen) from the heavier and coarser materials; the reduction of inorganic materials using concentrated hydrofluoric acid; acetolysis to reduce the organic fraction, with further reduction of the organic fraction by using bleaching and lye solutions. The resulting polleniferous extract was rinsed in 100% ethanol and stored in glycerol in 1 dram vials.

Method Two
The main difference between the first and second methods involves the use of heavy liquid separation in the latter (cf. (Barr, n.d.), (Schoenwetter, 1996)). As with method one, tablets containing a known quantity of Lycopodium spores were added prior to processing so concentration values could be calculated. The amount of sediment processed was 30 cubic centimeters per sample. The laboratory procedure involves deflocculation in dilute hydrochloric acid; swirl flotation and screening to separate the lighter and smaller materials of the sample (including pollen) from the heavier and coarser materials; the reduction of inorganic materials using concentrated hydrofluoric acid; heavy liquid separation in a zinc bromide solution at 2.0 specific gravity to further reduce extraneous material; and reduction of the organic fraction using bleaching and lye solutions. The resulting polleniferous extract was rinsed in 100% ethanol and stored in glycerol in 1 dram vials. Samples that were processed a second time are designated by (M2) in Table 1.

Counting

Slides were prepared for counting by homogenizing the material in the vial, extracting one or two drops, and placing them on a microscope slide; if necessary, additional glycerol was added to use as a mounting medium. The pollen sample was stained using basic fucsin in an alcohol solution. The slide was then observed through a Zeiss light microscope at magnifications ranging from 200X for pollen counting to 1260X for more difficult identifications. Identifications of pollen types were facilitated through use of the Arizona State University Archaeological Pollen Laboratory comparative reference collection, plus the pollen identification key provided by Kapp (1969), as well as pollen descriptions, drawings and/or photographs provided in Erdtman (1952), González Quintero (1969; 1986), Heusser (1971), Sanchez (1980), Sánchez Martínez (1982), Sánchez-Martínez and Xelhuantzi-López (1990), Montúfar (1985), Moore et al., (1991), and Montúfar López (1995). The abundance and types of pollen grains observed were recorded until at least 200 identifiable pollen grains, excluding unknowns, or a complete slide, or at least 100 Lycopodium spores, had been counted (Table 1). Two hundred grain counts are believed generally suitable for ascertaining the range of frequency values for the most common taxa present (Martin, 1963).

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