Postclassic Ceramic Database

About the Project

Technical Discusion

Database

 

SPONSORED BY
The National Science Foundation

Kinds of Analysis

In order to identify technological style patterns that reflect Postclassic sociopolitical group-specific identity as manifest in pottery manufacture and exchange patterns of those groups, three kinds of analyses will be conducted to gather stylistic (type-variety classification), technological (petrographic analysis), and chemical compositional data (INAA) of redwares and incensarios (and effigy-face masks) excavated from ritual contexts (e.g., temples, oratorios, and associated C- and L-shaped structures) from the sites included in the project.

These three different analyses are complementary in nature as each provides a different kind of data so as to create a more robust and comprehensive dataset. Because this project seeks to identify manufacturing and exchange patterns of various sociopolitical groups over a large region, one kind of analysis cannot take precedence over another (Blomster et al. 2005; Flannery et al. 2005; Neff et al. 2006; Neff et al. 2006; Sharer et al. 2006; Stoltman et al. 2005). Upon the completion of the stylistic, petrographic, and chemical compositional analyses, these data will be entered into a publicly accessible database so as to facilitate future discussions about the Postclassic period, ceramic classification, and methodology. 

Sampling

      Samples for analysis will be selected using a stratified random sampling methodology to ensure the variability (technological and decorative) within the larger sample is reflected in the sample for further analysis (Cecil 2001; Hinkle et al. 1994:161). When the ceramic collection is too small for stratified random sampling, I (or collaborators when necessary) will select as many samples as possible to represent the variability in the larger collection. From each site in the proposed project, at least 150 redware sherds, 50 incensario sherds, and samples from all available effigy-face molds will be selected for INAA and from those selected, 50 will be used for petrographic analysis. Those chosen for petrographic analysis will represent the paste variability detected during the classification stage of analysis. If possible, clay samples will be collected for petrographic analysis and INAA. 

After basic typological and descriptive data have been gathered and recorded on the pottery from each participating site, 50 sherds and submitted clay samples will be selected for petrographic analysis. The sampling methodology (stratified random sampling) will ensure that the variability of the different wares (redwares and/or incensarios) and clay resources will be broadly represented (Shepard 1956).

Type-Variety Analysis

      The first step of analysis consists of a typological analysis using the type-variety system (Smith et al. 1960). This hierarchical system uses a series of categories—ware, group, type, and variety in descending inclusiveness—to organize levels of variability in archaeological pottery. For purposes of studying stylistic and technological patterns produced by various sociopolitical groups and exchange of that pottery, it is particularly useful to consider pottery at the ware level. Ware definitions are based primarily on paste attributes and surface finish, but also convey information about geographic location, time period, and decoration (Demarest 1986; Rice 1976, 1982). It is at this level that INAA compositional groups in the central Petén lakes region have been identified and associated with different decorative programs and sociopolitical groups (Cecil 2004; Cecil and Neff 2006). Therefore, characteristics at the ware level of redwares and incensarios may inform the archaeologist more about social, political, economic interactions, and technology of manufacture than do types (Cecil 2001; Demarest 1986:54; Rice 1982).

      A stringent and consistent classification based on extant Mesoamerican type-variety definitions is essential for the success of this project. Such a classification will allow comparison of the same wares and types of over 2000 samples. This is particularly important for the redware category because it exhibits general trends, such as the similar red slip of the Mama, Tulum, and Rita Reds, that often may be overlooked because they have been named as different types when actually they may be the same type.          

Petrographic Analysis

     Petrographic analysis of clays and pottery is an essential step of this project that will identify variability of the samples as well as manufacturing recipes and traditions. Petrographic analysis allows for the identification of naturally occurring versus culturally added inclusions to a clay body because of the differences in inclusion size and sorting (shifting of temper ingredients, or levigating of the clay) (Childs 1989; Orton et al. 1993; Williams et al. 1954). Differences in mineral composition and character reflect human behavior and the choices made during pottery manufacture.  When sherds cannot be assigned to a specific typology (described above), petrography can distinguish more subtle technological characteristics that may have been important to the Postclassic Maya, but were not detectable by the archaeologist’s eye (Childs 1989:24; Steponaitis et al. 1988).

      I will conduct point counting of minerals and pores along transects of the thin-section. The non-volumetric area frequency counting method (counting all of the minerals in a given area) will be the same as that previously used (Cecil 2001) in order to ensure comparability. Thin-sections will be made at Spectrum Petrographics and will be analyzed by me at the University of Missouri. Digital images of significant portions of the sherd and clay thin-sections will be captured with a digital camera mounted on a polarized light microscope. The images will then be transferred to the appropriate database page to facilitate data sharing. 

       Although petrography can identify the different minerals and culturally added temper to the clay, petrography cannot determine differences in clay sources and it cannot detect trace and rare earth elements that are often used to distinguish chemical composition groups. Because the determination of different manufacturing traditions is essential to this project INAA will be used to identify the variability in chemical signatures that will indicate differences in clay resources and/or recipes and if Postclassic Maya were transporting their ideologically-laden, ritual pottery or merely their ideology. Thus, by combining the strengths of petrography and INAA, one can obtain results that predict exchange activities because variability informs archaeologists about choices in technology and resources that are essential to understanding the sociopolitical and socioeconomic milieu during the Postclassic period.

INAA

Although petrography can identify the different minerals and culturally added temper to the clay, petrography cannot determine differences in clay sources and it cannot detect trace and rare earth elements that are often used to distinguish chemical composition groups. Because the determination of different manufacturing traditions is essential to this project INAA will be used to identify the variability in chemical signatures that will indicate differences in clay resources and/or recipes and if Postclassic Maya were transporting their ideologically-laden, ritual pottery or merely their ideology. Thus, by combining the strengths of petrography and INAA, one can obtain results that predict exchange activities because variability informs archaeologists about choices in technology and resources that are essential to understanding the sociopolitical and socioeconomic milieu during the Postclassic period.

      A number of analytical techniques (e.g., x-ray fluorescence and inductively coupled plasma mass spectroscopy) can be used to determine the chemical composition of pottery, but none have the ease of sample preparation and fewer errors due to laboratory procedures as INAA. I propose to use INAA because it has been proven to be a very valuable analytical tool for determining distribution patterns of ceramics in Mesoamerica (Bishop 2003; Bishop and Rands 1982; Bishop et al. 1982; Blackman and Bishop 2007; Foias and Bishop 1997; Fry 1979; Harbottle and Sayre 1975; Hodge et al. 1993;  Little et al. 2004; Neff 2003; Neff et al. 1994; Nichols et al. 2002, 2006; Rands et al. 1982; Reents-Budet et al. 1994; Reents-Budet and Bishop 2003; Rice 1987; Sayre et al. 1971; see also Sabloff 1975).

      All samples for INAA will be submitted to the University of Missouri Research Reactor (MURR, Michael D. Glascock, director of the Archaeometry Laboratory), and will be prepared employing standard INAA and MURR procedures (Bishop et al. 1982; Glascock 1992). I will then analyze the thirty-three standard elemental concentrations with several multivariate pattern recognition techniques (e.g., base 10 transformation of the elemental concentrations, principal component analysis, and Mahalanobis distances). The goal of INAA is to distinguish compositionally homogenous groups within the database of analytical samples that may reflect geographically restricted zones. Thus, INAA data will be combined with the typological, stylistic, and petrographic data previously attained to create technological style groups that can infer various sociopolitical and socioeconomic networks during the Postclassic period. These data will allow archaeologists to compare technological and stylistic characteristics of Postclassic Maya redwares and incensarios across the landscape by suggesting the directionality of Maya migrations. This is possible because these data will form chemical compositional groups that will relate to possible zones of production. Finally, chemical analyses will aid in further refining typological classifications.

This is the link to The University of Missouri Research Reactor Center.