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
potential varied.
Ezzoís 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 ìknownsî 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 Ezzoís occasional convoluted and thus unclear sentence structure
and eliminated unnecessary redundancy. An example of the former is Ezzoís
opening statement in Chapter 1, which should be a crisp exposition of his
goals. ìThis 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 puebloî (Ezzo 1993:1). Redundancy is also plentiful:
ì...an inference that has been previously discussed a number of timesî
(Ezzo 1993: 55). Even more grating are the failures to proof-read. For
example, on page 27 appears the following. ìIn 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.î This is the most extreme of several such lapses. Even
more distracting are the many typographical errors, which divert the readerís
attention from the volumeís important messages. A partial list includes
ìflourideî (p. 33), ìanicent dietî (p. 39), ìtendendcyî (p. 77), ìDiseprsionî
(p. 77), ìfiaxtionî (p. 94), ìsietî (p. 94), ìAdvacnedî (p. 95), ìMagensiumî
(p. 96), ìmalnutirtionî (p. 99), and ìmeansurementsî (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. Ezzoís 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.
References
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.