Excavations at the Copper Smelting Site of El Manchon, Guerrero, México

Interim Report

This report summarizes activities carried out during the funding period. We were able to accomplish the majority of the objectives set out in the research proposal (the second season of fieldwork at El Manchon, Guerrero). The principal activity was to map and to complete excavations of the large smelting furnace in Zone 2 and to trench into, and begin horizontal exposures in the structures in Zone 1. We also were able to begin construction of field facilities in the hamlet of El Manchon.

One major effort was to complete excavating the feature we have designated as a smelting furnace located in Zone 2 of the site. This feature is an assemblage consisting of one to two courses of jumbled stones (approximately 3 × 4 m area) at the edge of an arroyo. A large slag accumulation appears immediately to the north of the assemblage. Slag, charcoal, and pieces of copper ore were recovered in excavations to 60 cm below the surface in the furnace during the previous field season. We completed excavating the furnace and produced two detailed maps of it including several cross sections. The assemblage appears to consist of four to five small furnaces that may have been in use simultaneously, and these consist of burned areas, charcoal, slag, and pieces of copper ore. We recovered a significant sample of thick, undiagnostic pottery in these excavations and a number of potsherds that are types also recovered in the habitation area. We were able to collect at least 50 radiocarbon samples from the furnace. We also recovered some 70 to 100 samples of quartz, some of which contain copper ore. The copper ore was closely associated with quartz. We have yet to locate that copper deposit.

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We also trenched up to and through two of the rectangular structures in the habitation area and began horizontal exposure (to 70 cm) of one of them (Structure G). Cultural material is sparse, but we did locate and recover two potsherd caches within one of the structures (Structure G) at 40-50 cm. Soil color changes, charcoal, other organic remains suggest that this is a midden. Pottery types are the same as those recovered in the surface collections. We reached 1 m in two pits in this structure where we identified a stone alignment (.40 m × .30 m) whose orientation does not conform to that of the structure and which could represent an earlier construction phase. We recovered numerous charcoal samples throughout this structure. We also trenched through a second structure in Zone 1, where we recovered very little cultural material. We plan to continue excavating both structures in the next field season. We also began to construct the field station (we made the adobe bricks and built an outhouse) but early rains put a stop to that activity.

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