An Unexplored Realm in the Heartland of the Southern Gulf ... - Famsi

output value for each location. Because kriging is most appropriate when spatially
correlated distance and directional data are known, it is used frequently in soil science
studies (McBratney and Webster 1986; Oliver 1990).
Surfer computational software version 8.01 was used to illustrate the soil
chemical data. A point-type, linear variogram model was constructed with the slope and
anisotropy or directional measurement equal to 1, and the angle equal to zero. The linear
error variance was set at one. The data for K, Mn, and P in Plazas I and II were then
plotted on standard xyz grids that were produced by the known points and a probability
model of the unknown points.
A series of recent Mesoamerican ethnoarchaeological studies have been
conducted in efforts to relate observed human activity patterns with soil chemical data
(Barba 1986; Barba and Ortiz 1992; Fernández et al. 2002; Middleton 2004; Middleton
and Price 1996; Wells and Urban 2002). These studies demonstrate a correspondence
between high levels of P with food consumption and the discard of other organic
substances. Conversely, low levels of phosphorus were detected near cooking areas, such
as hearths and ovens. High levels of Mn have also been related to food preparation and
consumption areas and its spatial patterning is similar to that of phosphorus. Manganese
has additionally been associated with pyrolusite (manganese dioxide, MnO2), a black
pigment used in various types of craft production (Wells et al. 2000). Wood ash,
charcoal, and burned earth from fireplaces, hearths, and ovens produce elevated levels of
K in the soil (Wells et al. 2007). In contrast, residues of this element were low in areas of
food consumption (Middleton and Price 1996).
166