Geomorphometric database and analysis of Late Oligocene to Holocene composite volcanoes of the Central Andes of Bolivia, Chile and Argentina

Abstract

The Central Andes of South America contains hundreds of composite volcanoes with a wide variety of morphologies and ages, making it a unique region to investigate the spatial, temporal and geomorphological evolution of arc volcanism. We present and analyze a database that includes new spatial, geomorphic and morphometric data, as well as relative and absolute age data, for 645 Late Oligocene to Holocene composite volcanoes and large lava domes of the Central Andes of Bolivia, Chile and Argentina (17.1°–28.1°S). The included volcano edifices show a great morphometric diversity, from small simple cones with volumes ≤1 km³ to complex, long-lived massifs with volumes of up to 300 km³. Quaternary edifices have lifespans mostly between 0.2 and 1.8 Myr, and average growth rates typically between 10 and 80 km³/Myr. The spatial distribution of volcanism highlights the influence of arc-oblique structures and of some first-order, continental and oceanic crustal anomalies. Cumulative bulk volumetric output estimates are of 12,000 km³ for the last ∼11.6 Myr, with an average output rate of 0.86 km³ per km of arc per Myr. Volumetric output peaks are centered at ∼19°, 21.8°, 24.2°, 25.5°, and 26.8°S, each with variable inputs in terms of age and position with respect to the present-day arc. The database offers new opportunities for more detailed analyses of the spatial and/or temporal evolution of volcanism along different segments of the arc and for a variety of regional analyses in combination with geophysical, tectonic or geochemical datasets.