Diverse strategies for copper production in Chalcolithic Iberia. (December 2022)

• Record Type: Journal Article
• Authors: La Duc, Elizabeth; Montero-Ruiz, Ignacio; Freestone, Ian C.; Fanlo Loras, Javier; Jabalquinto Expósito, Isabel María; Martín de la Cruz, José C.; Pérez-Lambán, Fernando; Picazo Millán, Jesús V.; Martinón-Torres, Marcos
• Is Part Of: Journal of archaeological science. Volume 46(2022)
• Publication Date: 2022-12
• Subjects: Archaeometallurgy -- Chalcolithic -- Iberia -- Copper -- Technical ceramics; Archaeology -- Periodicals; Archaeology -- Research -- Periodicals; 930.1
• DOI: 10.1016/j.jasrep.2022.103683
• Languages: English
• ISSNs: 2352-409X

Abstract

Highlights: We analyze Chalcolithic copper smelting outside the usual research foci of archaeometallurgy in Iberia Slag from Lugar Viejo is typical for Chalcolithic Iberia, but use of organic temper in crucibles is notable Slag from Cueva del Cañaveralejo is earliest fayalitic slag yet found in Iberia; presence of sulfides is also unusual We argue for the need and value of studying regional variability Abstract: Our understanding of early copper metallurgy in the Iberian Peninsula is mostly based on analysis from well-studied regions in the Southeast and Southwest. This paper focuses on two recently recovered Chalcolithic metallurgical assemblages outside these traditional research foci: two slagged crucibles from Lugar Viejo III (Zaragoza) and two large slag cakes from Cueva del Cañaveralejo (Córdoba). Analysis of the compositions and microstructures of the artifacts using optical microscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) suggests they are related to primary copper production, namely smelting in crucible-furnaces under relatively oxidizing conditions, as is standard for this period. The slag layers on crucibles from Lugar Viejo indicate the production of copper with minor amounts of arsenic, also typical for this period. Of special note is the use of organic temper in the crucibles from Lugar Viejo, a practice found at the nearby site of Moncín but rare at other sites in Iberia. However, the slags from Cueva del Cañaveralejo are atypical in their large size (approx. 125 g each), fayalitic composition, unusual efficiency as demonstrated by a low copper content, and lack of arsenic; furthermore, the high sulfur content raises the possibility of the use of sulfidic ores. Results from both sites are compared against published data from well-known sites such as Los Millares, Las Pilas, Almizaraque, and Bauma del Serrat del Pont. The new data from Lugar Viejo and Cueva del Cañaveralejo reinforce the interpretation of metallurgy in the Iberian Peninsula as a low-skilled, conservative technology but also indicate the need for more research into regional variations. (See Supplementary Data 1 for a summary in Spanish).