Santander, February 19th-22nd 2008 - Aranzadi

Manufacturing techniques of Oliva pendants at Xochicalco (Morelos, México)
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societies, and artifacts are produced and used
following rules that determine what specific features
each object has. As a result, the use or production
of similar objects, elaborated under the
same rulings, should be characterized by identical
attributes (Ascher 1961: 793, Velázquez
2007:7). Therefore, standardised attributes indicate
the use of a certain tool, made from a determined
material, employed in a specific manner and
under certain conditions, all of which will leave
characteristic and distinguishable traces on the
worked materials, in this case, shells (Binford
1991: 22, Velázquez 2007: 7).
Since 1997, following this uniformity criteria, the
same tools and manners are being reproduced at
the Experimental Archaeology Shell Workshop in
the Templo Mayor Museum with more than 600
experiments (Fig. 5), with similar tools as those
recorded in several historical sources and archaeological
contexts, which were supposedly used by
the various groups in pre-Hispanic México. Such
tools are flakes and blades of obsidian and chert,
grindstones made of basalt, andesite, riolite, limestone,
sandstone, granite, and slate, among others
(Velázquez 2007: 57–58).
Figure 5. Experimental archaeology on shell pieces (drawing by Julio Romero).
Subsequently, the resulting traces of manufacture
were compared with the archaeological material
on three levels: macroscopic, stereoscopic
microscopy (10X, 30X and 63X), as well as
Scanning Electron Microscopy, or SEM (100X,
300X, 600X and 1000X).
All of the archaeological pieces (290) were
checked macroscopically and stereoscopically
and compared with the experimental ones drilled
with flakes (obsidian and chert burins) and abrasives
(sand, volcanic ash, powder of obsidian, and powder
of chert) and reed, obtaining the following results (fig. 6):
1) Seven pendants had conical perforations
without visible striations; they are similar to those
ones drilled with abrasives.
2) Nineteen pendants had circular striations in
the conical perforation, they match with those ones
drilled with flakes.
3) Thirty-one pendants showed regular perforated
edges with lines, they are similar to those
ones drilled with flakes.
4) One-hundred-and-ten pendants had irregular
edges with lines, they are similar to those ones
drilled with flakes.
5) One-hundred-and-eight pieces (inlays, pendants
and recycled pendants) showed parallel striations;
they are similar to those ones cut with flakes.
For the analysis with the SEM, thirty pendants
were chosen based on their good preservation
and the representativeness of their modifications,
four from each context, except two contexts that
had only one piece (Sector A and Sector E). Five
patterns were identified (Fig. 7):
1) Five pieces presented walls that were pierced
by lines measuring approximately 1.3 µm
wide, which united to form greater strokes, similar
to the experimental perforations that had been
made using sand and reed (Fig. 7a-b).
2) Nine pierced pieces showed fine lines measuring
two µm, which resembled perforations
made with obsidian flakes (Fig. 7c-d).
3) Nine pendants showed parallel bands of
two to four µm, which are similar to drill holes made
with chert burins (Fig. 7e-f).
4) Four presented walls that were crossed by
fine lines measuring two µm, which resembled channeled
perforations produced with obsidian flakes.
5) Three recycled pendants and inlays were
also analyzed with Stereoscopic Microscopy and
SEM. They revealed well defined parallel lines
resulting from cuts made with stone tools; but the
MUNIBE Suplemento - Gehigarria 31, 2010
S.C. Aranzadi. Z.E. Donostia/San Sebastián