Evaluating effects of chemical weathering and surface contamination on the in situ provenance analysis of building stones in the Cuzco region of Peru with portable XRF

► Portable XRF was found to be valid for sourcing igneous stone objects in the Cuzco region of Peru. ► Chemical weathering impacted measured concentrations of lighter but not heavier elements. ► Measurements of some lighter elements were impacted by surface contamination. ► Low impact cleaning only marginally reduces impact of surface contamination on lighter elements.