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

Jonathan P Perkins,Kevin M Ward,Susan L Beck,George Zandt,Noah J Finnegan,Shanaka L De Silva

doi:10.1038/ncomms13185

Jonathan P Perkins, Kevin M Ward + Show 4 more

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https://doi.org/10.1038/ncomms13185

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Abstract

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.

Highlights

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
APMB volumes and magma production rates modelled from its topographic signature compare well with independent estimates from Ambient Noise Tomography[15], and our surface uplift rate calculations suggest that magmatic flare-ups can grow topography at rates similar to uplift from lithospheric removal
To constrain the topographic signal associated with the presence of the APMB (Fig. 1, Supplementary Fig. 1), we measure the long wavelength component of the topography in the Central Andes and find that a high-amplitude, kilometre-scale dome spatially coincides with the estimated bounds of the seismically imaged magma body (Fig. 1b and 2a)

Summary

Introduction

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. 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. We attempt to constrain surface uplift rates of the APVC over its lifetime from 11 Ma using the volcanic record as a proxy for magmatic thickening over millionyear long timescales relevant to mantle melt flux[16], and place our findings in the context of the known tectonic and geodynamic evolution of the Central Andes between 20o and 25o S. APMB volumes and magma production rates modelled from its topographic signature compare well with independent estimates from Ambient Noise Tomography[15], and our surface uplift rate calculations suggest that magmatic flare-ups can grow topography at rates similar to uplift from lithospheric removal

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