In this contribution Ezzo adds detailed (human) bone
chemistry analyses to the extensive archaeological data sets available
for Grasshopper Pueblo, a 14th century masonry pueblo site that was the
subject of University of Arizona field schools for three decades (1963-1992).
Located in east-central Arizona, on the Fort Apache Indian Reservation,
Grasshopper Pueblo lies on the Mogollon Rim, in a transition zone between
the Colorado Plateau to the north and the Basin-and-Range province to the
south. In this area the northern Evergreen Woodlands grade into the biota
of the Sonoran Desert, rendering the landscape diverse and the resource
EzzoŪs ultimate goal is to investigate human adaptation and social organization at Grasshopper Pueblo. To achieve this, he determines the degree to which dietary variation is structured by biological (age, sex, cranial deformation), social (grave furniture), spatial, and temporal parameters. A number of additional topics are considered, including ecological questions about environmental change and possible depletion of game, diet in relationship to stress, and nutrition. Ezzo is also concerned with social issues, including the relationship of social structure to subsistence change and the emergence of inequality. For analytical purposes, Ezzo combines all pre-AD 1330 remains into an early grouping, with the post-AD 1330 series comprising the later sample. Thus, Establishment (AD 1275-1300) and Expansion (AD 1300-1330) materials are considered together, as are the Dispersion (AD 1330??) and Abandonment (??1400) remains.
A major strength of this work lies in the bone chemistry analyses. Ezzo employs both trace elements and stable isotopes, expending considerable effort in an appropriately critical evaluation of elemental models for paleodietary inference. After enjoying an initial popularity during the 1970s and early 1980s, multi-element approaches have undergone careful review and the reality of post-depositional change has been recognized.
To increase the number of burials that can be assigned to the early and late temporal divisions, Ezzo supplements stratigraphic information with relative dating through fluoride analysis. At total of 141 remains were tested, including 18 with known stratigraphic associations. The fluoride technique performed well among the žknownsÓ and was therefore used to assign the remaining individuals to the early (Total N = 163) and late (Total N = 67) samples selected for further elemental study.
To minimize the effect of diagenesis, a complicated three stage cleaning procedure was followed, including soaking in hydroxylamine hydrochloride and acetic acid to remove metallic oxides and diagenetic carbonates. A vacuum chamber was also employed to draw air out of microscopic pore spaces and thus enhance the efficiency of an acid wash. The samples were then dried, ashed, and the following elements measured, using Inductively Coupled Plasma Emission Spectroscopy: Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, Sr, and Zn. To test the effectiveness of the washes, 24 individuals were sampled a second time, with ICP results generated after the initial water cleaning procedure. This test indicated that carbonates and oxides had been successfully removed by the washes, as indicated by a reduction of Ba, Mg, Sr, and Ca/P. The constancy of Al and Fe was attributed to physical contamination by clay inclusions, which were only partially removed.
Further statistical study of element concentrations, including principal components analysis and a correlation matrix of elemental concentrations indicated that Ba showed little evidence of diagenesis. Sr concentrations, however, were positively associated with F, suggesting a diagenetic component. A strong positive correlation between Sr and Ba argues, however, that the biogenic signal had not been completely lost. Ezzo concludes that of the elements tested here, only Ba and Sr are useful in paleodietary reconstructions. He offers a compelling argument against the use of Zn, erroneously thought by some other workers to reflect meat consumption.
A stratified random sampling procedure was employed to select 54 individuals for stable carbon and nitrogen isotope analyses. Ezzo concludes that his collagen quality is acceptable since its dry weight is always over 5%. He does not report C:N ratios, another standard means for evaluating contamination (Ambrose 1993). The results reported here reflect collagen values only. Ezzo notes, however, that a subsequent investigation of 11 apatite samples, using the technique and theoretical orientation of Krueger (Krueger and Sullivan 1984), strengthens his conclusions. The fact that *13C values based on bone apatite represent a better estimate of total diet than those of collagen has only recently been appreciated.
Of the variables examined by Ezzo, sex, space, and time appear to structure elemental and isotopic variability at Grasshopper Pueblo. Male diets change very little over time, with late phase men slightly more dependent upon C4 plants than their earlier counterparts. The dietary shift for females, however, is marked. The early female diet contained many collected plant resources and relatively little meat when compared to males. In the more recent samples, however, diets were quite similar for both sexes with women moving from wild resources to maize consumption. Spatial variation in paleodietary signals suggests that decision-making concerning access to food resources occurred at the household level.
The most disappointing feature of this monograph is the lack of attention to volume production. Effective copy editing could have corrected EzzoŪs occasional convoluted and thus unclear sentence structure and eliminated unnecessary redundancy. An example of the former is EzzoŪs opening statement in Chapter 1, which should be a crisp exposition of his goals. žThis study examines the probability of significant dietary change through time and dietary variability across space and in terms of several social and biological variables at Grasshopper Pueblo, and considers how these behavioral developments inform on aspects of human adaptation and social organization at the puebloÓ (Ezzo 1993:1). Redundancy is also plentiful: ž...an inference that has been previously discussed a number of timesÓ (Ezzo 1993: 55). Even more grating are the failures to proof-read. For example, on page 27 appears the following. žIn their comparison of these three regions, Graves, Longacre, and Holbrook (1982) note the general lack of increased social complexity despite population gtion process is destructive, special care had to - be taken to inflict as little damage to each specimen a possible. If the femora of an individual baly damaged, nonexistent, or in such pristine conditio that I did notation and a shift from horticulture to agriculture.Ó This is the most extreme of several such lapses. Even more distracting are the many typographical errors, which divert the readerŪs attention from the volumeŪs important messages. A partial list includes žflourideÓ (p. 33), žanicent dietÓ (p. 39), žtendendcyÓ (p. 77), žDiseprsionÓ (p. 77), žfiaxtionÓ (p. 94), žsietÓ (p. 94), žAdvacnedÓ (p. 95), žMagensiumÓ (p. 96), žmalnutirtionÓ (p. 99), and žmeansurementsÓ (p. 100). The bibliography is replete with mistakes and varied styles. There are at least three different ways in which the University of Cambridge Press is referenced, for example.
In sum, this volume is important to our knowledge of paleodietary inferences from bone chemistry. EzzoŪs discussion of multi-element approaches and post-depositional change is especially acute. Southwestern archaeologists and bioarchaeologists will also find the dietary inferences enlightening, especially those relating to temporal changes by sex and by household. If more attention had been paid to aspects of volume production, the monograph would be even more effective.
Ambrose, S.H. 1993. Isotopic Analysis of Paleodiets: Methodological and Interpretive Considerations. In M.K. Sanford (ed.), Investigations of Ancient Human Tissue: Chemical Analyses in Anthropology, 59-130. Gordon and Breach, Langhorne, Pennsylvania.
Krueger, H.W. & C.H. Sullivan. 1984. Models for carbon isotope fractionation between diet and bone. In J.E. Turnlund & P.E. Johnson (eds.), Stable Isotopes in Nutrition, 205-222. American Chemical Society Symposium Series 258, Washington, DC.