Large Obsidian Bifaces from a Middle Horizon Ritual Offering in the South-Central Coast of Peru: Provenance and Technology

Abstract This report presents the provenance and technological analysis of two large obsidian bifaces recovered from a Middle Horizon (ca. AD 600–1000) ritual abandonment context at the coastal site of Cerro de Oro in the Cañete Valley, Peru. Portable X-ray fluorescence (pXRF) analysis identifies Quispisisa as the obsidian source, thereby documenting its circulation beyond highland Wari contexts. Technological analysis indicates contrasting trajectories: one biface shows no evidence of use, whereas the other exhibits macro use wear consistent with woodworking. Its location in a residential complex suggests community participation in the acquisition and ritual re-signification of prestigious nonlocal materials.