Reconstructing two millennia of copper and silver metallurgy in the Lake Titicaca region (Bolivia/Peru) using trace metals and lead isotopic composition

Stéphane Guédron (1, 2) , Julie Tolu (3) , Christophe Delaere (4, 5) , Pierre Sabatier (6) , Julien Barre (7) , Carlos Heredia (2) , Elodie Brisset (1, 2, 8) , Sylvain Campillo (1) , Richard Bindler (9) , Sherilyn C. Fritz (10) , Paul A. Baker (11) , David Amouroux (7)

1 ISTerre - Institut des Sciences de la Terre
2 UMSA - Universidad Mayor de San Andrés
3 ETH Zürich - Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich]
4 OCMA - Oxford Centre for Maritime Archaeology (OCMA), University of Oxford
5 ULB - Université libre de Bruxelles
6 EDYTEM - Environnements, Dynamiques et Territoires de Montagne
7 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
8 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
9 Umeå University
10 Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln
11 Division of Earth and Ocean Sciences [Durham]

Copper, silver, and gold exploitation has been a foundation of economic and socio-cultural development of Andean societies, at least for the last three millennia. The main centers of pre-colonial metallurgy are well-known from archaeological artifacts, but temporal gaps inherent in this record handicap a finer understanding of the modalities of ore exploitation by succeeding civilizations. A continuous record over time of trace metals emitted during ore smelting operations make lake sediments excellent candidates to fill those gaps.Two millennia of metallurgy were reconstructed from atmospherically derived metals together with lead (Pb) isotope ratios in two dated sediment cores from Lake Titicaca. The first evidence for metallurgy is found during the apogee of the Tiwanaku state (AD 800 to 1150), with a higher copper (Cu) accumulation that can be attributed to the smelting of local Cu ores, based on Pb isotopic fingerprinting. During the Late Intermediate Period (AD 1150 to 1450), recorded peaks in metal deposition that persisted for ∼ twenty years show that mining activities were intensive but discontinuous. Pb isotope ratios suggest diversified extractive activities, mainly located in the southern part of the central Altiplano. Finally, the most intense mining epoch began during the Inca Empire (ca. AD 1500) and lasted until the end of the Colonial Period (AD 1830), with unprecedented metal deposition over this interval.Pb isotope fingerprinting shows that mining operations occurred mainly in the Lake Titicaca and Potosi areas and were responsible for metal emissions recorded in the entire Altiplano, as evidenced by other studies.

Mots clés: Central Andes mining; Lake Titicaca sediment; Copper; Silver; Lead isotopes

Domaines: Sciences de l'environnement

Stéphane Guédron, Julie Tolu, Christophe Delaere, Pierre Sabatier, Julien Barre, et al.. Reconstructing two millennia of copper and silver metallurgy in the Lake Titicaca region (Bolivia/Peru) using trace metals and lead isotopic composition. Anthropocene, 2021, 34, pp.100288. ⟨10.1016/j.ancene.2021.100288⟩. ⟨hal-03177464⟩