Crossing the Borders: New Methods and Techniques in the Study of Archaeological Materials from the Caribbean

Metal Objects and Indigenous Values / 39
texts elsewhere in the Caribbean and are commonly called guanín (Bray 1993, 1997;
Oliver 2000; Siegel and Severin 1993; Szaszdi Nagy 1984; Whitehead 1990). Microscopic
observations indicate that they were cut out of a thin sheet, the edges being
subsequently polished to remove sharpness. Although some remnant casting porosity
is visible on the surface of the objects, it is likely that the original metal sheet
was subject to hammering after casting. The small < 1 mm perforation used for
threading was not punched or drilled but cut, as suggested by repeated shallow cut
marks in several directions. The sheets also exhibit some simple repoussé decoration,
normally in the form of shallow grooves parallel to the edges (Figure 3.2b).
These manufacturing details in conjunction with their excavated context make it
likely that these sheets were used as pendants, perhaps forming part of a necklace
in burial 57, where all four sheets and the ornithomorphic pendant were found.
Macroscopic studies of the ornithomorphic pendant have made stylistic links with
examples found in Colombia (Oliver 2000).
Ternary alloys with such high levels of copper are not known to occur naturally
in the Caribbean, and there is no ethnohistorical or archaeological evidence for
prehispanic ternary alloy production in the Caribbean. Therefore it appears likely
that these ternary alloys found at El Chorro de Maíta were not produced locally but
were imported from continental South America, where guanín objects are commonly
found (Bray 1997; La Niece and Meeks 2000).
Tubes
Metal tubes, rolled from flat sheets < 0.4 mm thick, were found in association with
17 skeletons in the cemetery. In the majority of cases the tubes were found individually
with different skeletons, however in burial 25, five tubes were found in
association near the left knee of the skeleton. Complete tubes are approximately
30 mm in length and are tapered with a diameter ranging from 3 mm to 2 mm
at each end (Figure 3.2c). ED- XRF surface analyses consistently showed these
tubes to be made of brass. SEM- EDS data on cross sections of five specimens confirmed
this. They were all found to be copper- based alloys containing high zinc
contents (15.6–26.1 wt percent) with smaller amounts of lead (≤ 1.7 percent), iron
(≤ 0.4 percent), nickel (≤ 0.7 percent) with occasional traces of tin (≤ 0.7 percent)
and silver. The high zinc content of these brasses is particularly distinctive,
as such high levels could only be produced using the process of crucible cementation,
before zinc sublimation techniques were introduced in the eighteenth century.
Previous analyses of brass artifacts from the German town of Nuremberg, a
major European metal production center during the late fifteenth century, repeatedly
showed brasses with a high zinc content in association with relatively high
nickel (> 0.2 wt percent) and a virtual absence of arsenic (< 0.05 wt percent)
(Mitchener et al. 1987). This metal composition is entirely consistent with the brass
tubes found at El Chorro de Maíta. The zinc content of the tubes found in El
You are reading copyrighted material published by the University of Alabama Press.
Any posting, copying, or distributing of this work beyond fair use as defined under U.S. Copyright law is illegal and
injures the author and publisher. For permission to reuse this work, contact the University of Alabama Press.