Obsidian Procurement and Exchange at the Apogee of Empire: Wari Political Economy in Arequipa, Peru

During the Middle Horizon (AD 600-1000), obsidian was transported in greater quantities and distances than ever before identified in the Andes, in part by the expansionary Wari state. Two of the three major obsidian sources used in the south-central Andes are located in the modern department of Arequipa, Peru. Arequipa was a region of intense Wari influence and intrusive presence; however, little is known about regional obsidian use. Portable X-ray fluorescence (pXRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used to analyze 383 obsidian artifacts recovered from 10 archaeological sites in Arequipa. Results highlight diachronic and spatial patterning related to obsidian procurement strategies, state versus bottom-up exchange networks, and local participation within the Wari realm. A wide variety of geological obsidian sources, including nonlocal obsidians originating from Wari's Ayacucho heartland, were used. By the late Middle Horizon, the Wari had consolidated regional resources with the sole use of Alca-1 and Alca-4 bedrock obsidians, the largest-sized and highest-quality sources in the area. We assess related models of obsidian procurement and exchange related to state political economy, long-distance caravan activity, and the role of local ceremonial/waystation centers that facilitated the flow of ideas, goods, and people across Arequipa. Durante el Horizonte Medio (600-1000 dC), la obsidiana fue transportada en cantidades y distancias nunca antes vistas en los Andes Centro Sur, debido en parte, al expansionista estado Wari. Dos de las tres principales fuentes de obsidiana utilizadas estan en Arequipa, Peru, region de intensa influencia Wari. Sin embargo, se sabe poco del uso regional de la obsidiana. Se analizan aqui 383 artefactos de obsidiana recuperados de 10 sitios arqueologicos en Arequipa, utilizando fluorescencia de rayos X portatil (pXRF) y espectrometria de masas con plasma de acoplamiento inductivo por ablacion laser (LA-ICP-MS). Los resultados destacan los patrones diacronicos y espaciales del uso de obsidiana, las redes de intercambio y la participacion local dentro del reino Wari. Tambien indican una amplia variedad de fuentes geologicas de obsidiana, incluyendo algunas no locales, originarias del corazon de Wari en Ayacucho. A fines del Horizonte Medio, Wari habia consolidado el uso exclusivo de obsidianas Alca-1 y Alca-4 (fuentes de mayor tamano y calidad de la zona). Aqui evaluamos modelos de obtencion e intercambio de obsidiana relacionados con la economia politica estatal, la actividad caravanera y el papel de los centros ceremoniales/tambos que facilitaron el flujo de ideas, bienes y personas a traves de Arequipa.