Greetings, all,

This seems to be the latest word on the subject, in so far as the
Native American Copper, and its chemical composition are concerned.

_Determining Geologic Sources of Artifact Copper: Source
Characterization Using Trace Element Patterns._ George
(Rip) Rapp, James Allert, Vanda Vitali, Zhichuan Jing, and Eiler
Henrickson. University Press of America, Lantham. 2000. xi
+ 156 pp., 24 figures, 41 tables, 2 appendices, glossary, index,
bibliography. ISBN 0-7618-1688-7.

It took an awful lot of time for our academic establishment to come
thus far... Nobody seems to have been interested in this subject prior
to this research team.

No surprise, really, considering what else is going on in this field
of American archaeology.

Some quotes from the review below,

"[This book] represents a monumental step forward in native copper
sourcing studies.

"... scientific attempts to source native copper using trace-element
analysis have lagged behind...

"Twenty-one native copper artifacts were sourced to seven
fingerprinted deposits in the region."

All the best,

Yuri.

________________


_Determining Geologic Sources of Artifact Copper: Source
Characterization Using Trace Element Patterns._ George
(Rip) Rapp, et al.

Reviewed by Kathy Ehrhardt, Department of Anthropology,
New York University, New York, NY 10003

Compared to work with other archaeological materials,
relatively few archaeometric provenance studies focus on, or
have even dealt with, sourcing native North American artifact
copper. For George Rapp and his team, this small volume
represents the results of large-scale, long-term pioneering
research into the applicability of trace-element analysis by
neutron activation to doing just that. For over a quarter century,
he and his colleagues, based at the Archaeometry Lab,
University of Minnesota, Duluth, have been engaged in
developing standardized methodological procedures and
appropriate analytical protocols for using NAA to link, as
unambiguously as possible through chemical fingerprinting,
individual prehistoric copper artifacts with the particular ore
sources from which the artifact raw material came. To date,
they have amassed an impressive database of well over 1,000
trace element characterizations representing at least seventyfive
potential ore sources from at least five major copper-bearing
regions of North America. They have successfully fingerprinted
seventeen sources. The team has also sampled over 200 native
copper artifacts, and have proposed sources for twenty-one.

As their research unfolded, the group published several "works
in progress" reporting on various aspects of the problem. They
now submit the current monograph as their most thoroughgoing,
comprehensive treatment of the data to date. What they present
here is a concise, substantive, readable chronicle of their efforts
to streamline this specific technique for use on a particular
class of raw material and on the prehistoric material culture
industry associated with it. It represents a monumental step
forward in native copper sourcing studies.

Their research responds directly to longstanding questions
archaeologists have asked concerning the sources of artifact
copper in prehistory. Inquiry has centered on the native copper
deposits of the Lake Superior region. Because of the geological
significance of the deposits and the amount of prehistoric
extraction and production activity that went on there, it has
long been considered the "center" of indigenous copper working
technology. However, throughout prehistory, major copper-using
cultures have been found hundreds of miles from this source.

Also, functional and decorative artifacts made of native copper
have been recovered from burial and domestic contexts at sites
in many parts of the eastern woodlands. These occurrences
have served as important springboards for investigating such
processes as the dynamics of long distance trade/exchange,
technological and symbolic aspects of mortuary ceremonialism,
and continuity in change in ancient metalworking practices.

Archaeologists have been quite successful modeling these
activities by finding patterns in the form, manufacturing style,
and use, as well as the depositional context and distribution of
copper artifacts. However, at the same time, many have
assumed that the copper itself originated in the Lake Superior
region. While some archaeologists have long been aware that
understanding where the artifact copper actually came from
would have enormous implications for validating, adjusting, or
even redrawing these models, scientific attempts to source native
copper using trace-element analysis have lagged behind
investigations centering on other raw materials.

This volume reflects these authors' attempts to remedy
the situation. The thrust of their research here, however, is
methodological and analytical, not interpretive in an
archaeological sense. In the introduction, they provide only a
brief historiographic overview of archaeological investigations
into Great Lakes copper and into the question of copper
sourcing. For this background, they refer the reader to their
previous papers or to the references they cite in the text. They
proceed directly to explaining how provenance studies using
trace-element analysis can contribute to resolving these
questions, and that their research goals center on working out
a methodology with which to do so. Their strategy has involved
locating, sampling, and characterizing accurately as many
geological copper sources (ore bodies, mines, localities) as
possible. Once copper sources were "fingerprinted"
geochemically, characterizations of individual artifacts could
potentially be "matched" to them.

The researchers then introduce the reader to the myriad
of complex geological, methodological, and analytical problems
they faced as they made their way through their research
program. These problems relate to three major aspects of the
research: 1) understanding the geochemical nature and
heterogeneity of the raw material as it occurs in nature and the
potential changes it may have undergone as it was processed,
used and abandoned in prehistory; 2) determining the
appropriateness and limitations of the technique and the
instrumentation as well as establishing optimal sampling and
data collection procedures; and 3) applying the appropriate suite
of statistical methods to achieve the most accurate
characterizations results. They spend much of the rest of the
book discussing these problems in greater depth and explaining
how they handled them.

In Chapters 2 and 3, they set the "material" stage by
providing important geomorphological and geochemical
descriptions of several types of copper deposits across North
America. Although they tested over 75 separate deposits, they
focus on the 17 which were ultimately fingerprinted. Importantly
for provenance studies of native copper, the specific
geochemical conditions under which copper is formed are
reflected in its trace element makeup. As the authors note,
however, understanding and accounting for within-source
variation in trace element distribution is as important (and can
be as problematic) as characterizing between-source variation.

Chapters 4 and 5 cover how the INAA technique works
and how specific sampling and data collection procedures were
ultimately arrived at to ensure optimal irradiation results and
accurate trace-element values. For instance, careful recording
and sampling protocols were established to avoid problems and
errors due to improper material sampling and specimen
preparation. Irradiation parameters (flux, irradiation and decay
times) and measurement protocols had to be worked out and
kept relatively constant for each of the batches irradiated. When
standards were changed at the reactor facility (U. of Wisconsin
Nuclear Reactor) from use of an internal gold standard to a
soil standard (Canadian Reference Soil Standard CCRMPSO4),
inconsistencies in the growing database needed to be
resolved. As a result, after 20 years of refining the technique,
the authors reanalyzed 389 key source and artifact samples.

The next three chapters (6-8) review the data analyses
and results. First, the authors explain how the ten trace-elements
(AG, Cr, Fe, Hg, Sb, Zn, As, Au, La, W) they used in their
analysis were selected from the original 46 measured. They
then walk readers through the analytical procedures used to
classify and separate sources, providing clear and detailed
rationale for each step. Easily decipherable tables and figures
illustrate their arguments. The authors used a multivariate
statistical approach, specifically predictive and descriptive
discriminant analyses, to analyze the data. Seventeen deposits
were represented in the data set. In all but two cases, the
deposits were represented by at least ten samples, collected
as carefully as possible from areas within a defined source.
Their results demonstrated clear geographic distinction
among source groupings, with the seven Lake Superior Region
sources clustering together. Further separations within these
seven deposits were also possible. Separations were based
largely on relative trace-element contents. Particular elements
or elements determined to be discriminating factors in both
classification and separation of sources were identified.

Finally, the researchers turn to sourcing native copper
artifacts (Chapter 9). They use samples from three northeastern
Minnesota prehistoric sites to demonstrate the process, focusing
on the Lake Superior region as the potential source of the raw
material. Twenty-one native copper artifacts were sourced to
seven fingerprinted deposits in the region. Based on the
differences in age of the artifacts, the authors posit that this
information may well lead to new thoughts about locational
change in intraregional exploitation of Great Lakes sources
over time.

The authors conclude by emphasizing that the database as
presented is far from exhaustive. As they readily admit, many
problems, including inter-laboratory comparability of results,
could not be solved herein. However, numerous issues were
indeed resolved, and the methodological and substantive
contributions of this volume far outweigh its shortcomings. The
authors have demonstrated (at least in the cases they presented
here) that discrete geological sources of native copper can be
distinguished reliably through trace-element analysis. In addition,
the trace-element data (presented both in the text and in the
appendices) and the methodology generated in this study provide
researchers with a solid jumping-off place from which to further
test and refine the methodology, expand the database, and
extend native copper sourcing assignments. More importantly,
with this research, Rapp and his colleagues have provided the
opportunity for archaeologists to apply a new line of scientifically
derived evidence to our old, as yet unresolved questions
concerning prehistoric copper exploitation. While the authors
make only limited attempts to do so, interested readers may go
to Mary Ann Levine's work on sourcing native copper in the
northeast by NAA for one good example.

Reference
Levine, Mary Ann. 1996. Native Copper, Hunter-Gatherers, and
Northeastern Prehistory. Unpublished dissertation, Department
of Anthropology, University of Massachusetts, Amherst.

Yuri Kuchinsky in Toronto -=O=- http://www.trends.ca/~yuku

It is a far, far better thing to have a firm anchor in
nonsense than to put out on the troubled seas of
thought -=O=- John K. Galbraith