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The Peruvian Altiplano is home to a wide range of potassic and ultrapotassic mafic rocks of Cenozoic age. Occurrences follow magmatic lineaments in both the eastern and western Altiplano as well as the Cusco Vilcanota fault system which are north westerly trending. Intrusions are present as <50 km2 stocks, plugs, necks, dykes, and volcanoes. The Eastern Altiplano hosts sanidine- and orthopyroxene-phlogopite lamproites and olivine minettes, whereas the Western Altiplano hosts leucitites, leucite-bearing tephrites, theralites, diopside trachybasalts and rare olivine trachybasalts. The rocks of the Western Altiplano (1241-837 Ma) are contemporaneous to significantly younger than the Eastern Altiplano (2485-1130 Ma). Intrusions proximal to the Cusco-Vilcanota fault system are Quaternary (2-0 Ma) and are composed of diopside-sanidine-phologopite lamproites, augite minettes, kersantites, and trachybasalts. Geochemical data including major and trace element analysis, Sr-Nd isotopic determinations, as well as a detailed map of the distribution of intrusions across the Altiplano can be found in Carlier et al. (2005).
CARNIER, G., LORAND, J.P., LIÉGEOIS, J.P., FORNARI, M., SOLER, P., CARLOTTO, V. & CÁRDENAS, J., 2005. Potassic-ultrapotassic mafic rocks delineate two lithospheric mantle blocks beneath the southern Peruvian Altiplano. Geology 33:7 pp 601-604