Dorothy Hosler

Copper Sources, Metal Production, and Metals Trade in Late Postclassic Mesoamerica

Copper ore sources exploited during the Late Postclassic Period (1300 to 1521 CE) were located by means of lead isotope analyses of copper ores from 15 deposits in West Mexico, Oaxaca, and Veracruz and of 171 copper artifacts from nine Mesoamerican archaeological sites in West Mexico and in southern, central, and northeastern Mesoamerica. West Mexican ores provided copper metal for most artifacts from the west Mexican settlements of Atoyac and Urichu, as well as for some artifacts from Aztec towns, Huastec centers, a Maya site, and settlements in Oaxaca and Chiapas. West Mexico was not marginal to Mesoamerican events, but played the primary role in the production and distribution of copper metal and bronze artifacts, one of Mesoamericas key exotic goods.

The Huastec Region: A Second Locus for the Production of Bronze Alloys in Ancient Mesoamerica

Chemical analyses of 51 metal artifacts, one ingot, and two pieces of intermediate processed material from two Late Post Classic archeological sites in the Huastec area of Eastern Mesoamerica point to a second production locus for copper-arsenic-tin alloys, copper-arsenic-tin artifacts, and probably copper-tin and copper-arsenic bronze artifacts. Earlier evidence had indicated that these bronze alloys were produced exclusively in West Mexico. West Mexico was the region where metallurgy first developed in Mesoamerica, although major elements of that technology had been introduced from the metallurgies of Central and South America. The bronze working component of Huastec metallurgy was transmitted from the metalworking regions of West Mexico, most likely through market systems that distributed Aztec goods.

America’s First Polymer Scientists: Rubber Processing, Use and Transport in Mesoamerica

Ancient Mesoamericans were making rubber by at least 1600 B.C, mixing latex from Castilla elastica trees with juice from Ipomoea alba (morning glory) vines. The combination of ethnographic, archaeological and mechanical data presented in this text illustrate that ancient Mesoamericans had fully developed this process, and consciously tailored the mechanical properties of rubber to suit requirements of specific applications by altering the ratio of latex to I. alba juice. Our data focus on rubber balls, sandal soles, and rubber bands for hafting and joining. Elasticity, the mechanical property that defines the ability of a rubber ball to bounce, is maximized with a 1:1 volume ratio of latex to I. alba juice. Rubber with high wear resistance, vital to the life and functionality of a sandal sole, can be created by mixing C. elastica latex with 25 percent I. alba juice by volume. Unprocessed C. elastica latex, without I. alba juice, is the material best suited for joining applications, such as adhesives or hafting bands, where strength and ability to absorb shock is of the greatest importance. Tribute data from sixteenth-century codices substantiate that rubber was processed for specific applications within the Aztec empire—rubber and latex goods were processed and constructed in the C. elastica-bearing regions, and then shipped to the capital for use or further distribution.

Mesoamerican Metallurgy: the Perspective from the West

In Mesoamerica metallurgy developed relatively late, after state level societies had merged in several regions. Our data indicate that metallurgy was introduced from the south, along the Pacific coast, from Northern South America and also from Colombia and Lower Center America. The first evidence comes from western Mexico a region rich in ore mineral resources. That evidence dates to about 700C.E. Within a few hundred years, metalworkers in the region were using bronze, (copper-arsenic, and copper-tin) and copper-silver metal sheet. Mesoamerica constitutes an unambiguous case of technology transfer, and the most interesting aspect of this situation is what Mesoamerican peoples did with metal—a totally new material during the 900 year period before the Spanish invasion. They were interested in those properties—sound, color and reflectivity—unique to it. The object they made, display items, sheet metal beastplates, crowns and objects that sounded, bells, made these choices clear. Other technical option were available, especially given their use of and facility with bronze, (copper-tin and copper-arsenic) so that the Mesoamerican case provides a clear example of the ways in which social exigencies can shape and determine technological outcomes.

A MAZAPA PHASE COPPER FIGURINE FROM ATETELCO, TEOTIHUACAN: DATA AND SPECULATIONS

Abstract Excavations of the Mazapan phase at the Atetelco complex at Teotihuacan by Ruben Cabrera and colleagues produced a small human copper figurine. Studies of Mesoamerican metallurgy have indicated that metallurgy was introduced to western Mexico around a.d. 700 from Colombia, and Ecuador. This particular figurine is a remarkable find. The dates (a.d. 800–900) precede those of copper artifacts in the central Highlands. The manufacturing method (an open-backed casting) is rare in Mesoamerica but common in Colombia and Panama. Open-backed cast figurines that do appear in Mesoamerica come from the Cenote of Sacrifice, are made from copper-gold alloys, and were imported from lower Central America or Colombia. The Atetelco figurine is made from a copper-arsenic alloy. Copper-arsenic alloy objects are common in western Mexico (after a.d. 1150) and Ecuador and northern Peru (after about a.d. 300). The major question concerning the Atetelco figurine is whether it was fashioned in Ecuador or Colombia and imported, or whether it was produced in western Mexico. Our study of artifact chemistry, fabrication methods, and provenience indicate that the weight of the evidence points to western Mexico. We suggest that this fabrication technique (lost-wax castings of open-backed human figurines), while introduced from Colombia and lower Central America, never became a major component of the Mesoamerican metallurgical tradition.

The development of ancient Mesoamerican metallurgy

Over the last twenty years, there has been a discernable increase in the number of scholars who have focused their research on metal production, working and use in antiquity, a field of study which has come to be known as archaeometallurgy. Materials scientists and conservators have worked primarily in the laboratory while archaeologists have conducted fieldwork geared to the study of metal technology in a cultural context with laboratory analysis as one portion of the interpretive program.