Surface uplift in the Central Andes driven by growth of the Altiplano Puna Magma Body

Title of Publication: 
Surface uplift in the Central Andes driven by growth of the Altiplano Puna Magma Body
Perkins, Jonathan P., Ward, Kevin M., de Silva, Shanaka L., Zandt, George, Beck, Susan L. and Finnegan, Noah J.
Publication Info: 
Nature Communications 7, Article number: 13185 (2016) doi:10.1038/ncomms13185

The Altiplano-Puna Magma Body (APMB) in the Central Andes is the largest imaged magma reservoir on Earth, and is located within the second highest orogenic plateau on Earth, the Altiplano-Puna. Although the APMB is a first-order geologic feature similar to the Sierra Nevada batholith, its role in the surface uplift history of the Central Andes remains uncertain. Here we show that a long-wavelength topographic dome overlies the seismically measured extent of the APMB, and gravity data suggest that the uplift is isostatically compensated. Isostatic modelling of the magmatic contribution to dome growth yields melt volumes comparable to those estimated from tomography, and suggests that the APMB growth rate exceeds the peak Cretaceous magmatic flare-up in the Sierran batholith. Our analysis reveals that magmatic addition may provide a contribution to surface uplift on par with lithospheric removal, and illustrates that surface topography may help constrain the magnitude of pluton-scale melt production.

Full article

(a) The approximate extent of the Altiplano-Puna Volcanic Complex (APVC; dashed yellow line) is seen. Caldera locations are denoted by black circles. (b) Shows the locations of basement outcrops (grey shaded areas), the 2.9 km s−1 velocity contour that roughly defines the extent of the APMB (solid black line) and the −400 mGal Bouguer gravity anomaly of Prezzi et al.3 (dashed black line) overlain on the long wavelength topography. Longitudinal and latitudinal cross section lines for Figs 2 and 3 are shown in yellow.