Newly recovered xenoliths from the modern backarc region in southern Peru were collected to investigate the metasomatic history of the northern Altiplano lithosphere and improve constraints on the formation of recent potassic magmatism in the region. The xenoliths described here were collected from a Quaternary latite lava flow near Huarocondo, Peru and include calcite-bearing phlogopite-orthopyroxenites, harzburgites, a wehrlite, and a phlogopite schist. Xenoliths were analyzed for C and O stable isotope ratios of calcite, H stable isotope ratios of phlogopite, and Sr isotope ratios of calcite, silicates, and phlogopite separates. Mineral chemical analyses where performed on orthopyroxenite and harzburgite xenoliths via electron microbrobe, and bulk rock trace element analyses of all xenoliths were performed via ICPMS. New bulk rock major and trace element analyses of four Quaternary lavas flows belonging to the Rumicolca Formation are also presented. For a detailed discussion of the research motivation, geologic background, analytical techniques, and interpretations, please refer to the related publication.

This dataset is associated with the following publication: Hiett, C., D. Newell, and J. Shervais. Metasomatism and Melting of Cordilleran Lithosphere Resulting From Sediment Relamination During Shallow Subduction. Geochemistry, Geophysics, Geosystems (G3). American Geophysical Union, Washington, DC, USA, 26(7): e2025GC012300, (2025).