Mark Abbott's findings published in Science

Mark Abbott and co-author Alexander Wolfe from the University of Alberta recently published the report "Intensive Pre-Incan Metallurgy Recorded by Lake Sediments from the Bolivian Andes" in the September 26, 2003 issue of Science.

Abstract. The history of pre-Columbian metallurgy in South America is incomplete because looting of metal artifacts has been pervasive. Here, we reconstruct a millennium of metallurgical activity in southern Bolivia using the stratigraphy of metals associated with smelting (Pb, Sb, Bi, Ag, Sn) from lake sediments deposited near the major silver deposit of Cerro Rico de Potosm. Pronounced metal enrichment events coincide with the terminal stages of Tiwanaku culture (1000 to 1200 A.D.) and that of the Inca through early Colonial times (1400 to 1650 A.D.). The earliest of these events suggests that Cerro Rico ores were actively smelted at a large scale in the Late Intermediate Period, providing evidence for a major pre-Incan silver industry.