Supergene Copper and the Ancient Mining Landscapes of the Atacama Desert: Refining the Protocol for the Study of Archaeological Copper Minerals through the Case Study of Pukara de Turi

Andean highlands in northern Chile is home to the world’s largest copper ore deposits, which have been exploited for thousands of years by different groups, at varying scales and for differ-ent purposes. In this context is important to develop new protocols to characterize mineralogical variability of archaeological copper ores. A comprehensive and representative methodology in the analysis of minerals, the application of non-destructive analytical techniques, and combining insights from geological, archaeological and local knowledge are key to developing a copper mineral repository of the Atacama Desert area. Geochemical analyses were applied to the study of 568 samples from the archaeological site Pukara de Turi, with different techniques as mi-cro-XRF, XRD, QEMSCAN, Raman spectroscopy and technological studies. This exhaustive anal-ysis allowed recognizing two mineralogical associations: atacamite/brochantite (66.0%) and az-urite/chrysocolla (0.9%), besides gangue minerals (33.1%). The patient study of various minerals allows data to be interpreted more reliably and to trace the likely geological sources of these minerals. Azurite/chrysocolla association appears to belong to the same mineral association found in the Cerro Verde district which is probably the source of these samples. Alternatively, atacamite/brochantite veins have been described in the districts of Chuquicamata and El Abra are located.

Copper minerals. Micro-XRF. Archaeometry.