This dataset accompanies planned publication 'Lava-ice interactions at late Pleistocene trachyte-basaltic andesite fissure eruptions, Quetrupillán Volcanic Complex (39°30′ S, 71°43′ W), southern Chile', as well as planned future publications on this volcanic complex. The Ar/Ar data and the Pb, Sr, and Nd data are for basalt and trachyte lava flows at Quetrupillán volcano. The Ar geochronology and isotope geochemistry will aid in the understanding of the timing of eruptive activity and glacial damming of lava flows, and magma source compositions studied in the planned publications. Samples were collected from Quetrupillán volcano by Dave McGarvie (Univ. of Lancaster, UK) and Isla Simmons (Univ. of Edinburgh, UK), who sent them to the USGS Denver for analysis. The analyses were performed from March 2021 to Feb 2023.