Obsidian sourcing of artifacts from the Late Formative site of La Puntilla in the Southern Nasca Region, Peru

We report X-Ray Fluorescence (XRF) analyses of 88 obsidian artifacts from the Early Horizon (aka Formative Period) site of La Puntilla in the Southern Nasca Region (SNR) of south-central Peru. The sample includes a range of artifact types, including 19 projectile points, 21 bifaces (some likely point fragments), 2 cores, 5 utilized flakes, and 41 unmodified flakes. All 88 items are assigned to Quispisisa, the closest obsidian source to the site and the dominant obsidian source in the SNR, despite other sources, such as Jampatilla, being just 20% further in distance. The lack of source diversity suggests that obsidian trade and acquisition during the Early Horizon (ca. 800 BCE – AD 100), especially the Late Formative phase (300 BCE – AD 100) in the SNR, focused on regulated movement of goods through particular trade corridors connecting the Andean highlands and lowlands. We then contextualize the La Puntilla data in a broader spatio-temporal context by combining all previously published SNR obsidian geochemical data. Results show that obsidian source diversity increases during Intermediate Periods in the SNR, and constricts during Horizons, including the Early Horizon, likely reflecting changes in the organization and control of exchange networks in the Andes.