Developments in Ceramic Materials Research

Postclassic Maya Ceramic Advances 21
Figure 8. Plot of cerium and cesium base-10 logged concentrations showing the separation of the three
Snail-Inclusion Paste ware chemical compositional groups. Samples were analyzed by INAA. Ellipses
represent 90% confidence intervals for group membership.
In addition to reaffirming the differences within each ware that were obtained from
mineralogical analyses, INAA is the best method by which to compare clays to pottery in an
attempt to locate resource areas. In this study several clays (white, orange, yellow, and gray in
color) were obtained from around Lake Yaxhá and Lake Petén Itzá 2 in an attempt to infer
local resources used in pottery manufacture. The clays from around Lake Yaxhá plot within
two Clemencia Cream Paste ware macro-groups (ash paste and non-ash paste) (Figure 9).
Four clays demonstrate statistical membership 3 within the non-ash paste ceramic group
suggesting that these clays could have been used to manufacture Clemencia Cream Paste
ware pottery (Table 3).
Clay sample LGC111 consistently plots within the ash group, but because the sherd
sample size for that group is small, statistical membership cannot be determined with any
certainty. In addition to the Clemencia Cream Paste wares, two clay samples (one orange and
one yellow) were collected from private property near the archaeological site of Ch’ich’.
They were projected against the three chemical compositional groups of the Vitzil Orange-
Red ware pottery.
2 All but one of the white clays were sampled by Prudence M. Rice during the Historical Ecology Project. Sample
LGC111 was a non-naturally occurring deposit excavated from Structure 719 at Zacpetén. The red clays were
collected in 2006 by the author from private land between the archaeological sites of Ch’ich’ and Trinidad de
Nosotros. The gray clay samples were collected in 1998 by the boat launch area at the archaeological site of
Zacpetén.
3 The threshold for statistical membership of clay samples within ceramic sherd compositional groups is much
lower than that for creating ceramic sherd compositional groups (typically above 5.000) because the addition
of tempering material to raw clays does changes the chemical composition so much so that there is rarely a
match at the 5.000 level. Therefore, it is common practice at MURR to suggest that clays may represent
sources for pottery manufacture if there is a probability above 0.300.