Department of Earth and Planetary Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
Department of Geosciences, The University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85712, USA.
Nat Commun. 2016 Oct 25;7:13185. 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.
安第斯山脉中部的高原普纳火成岩体（APMB）是地球上最大的成像岩浆储层，位于地球上第二高的造山高原——高原普纳。尽管 APMB 是类似于内华达山脉岩基的一级地质特征，但它在安第斯山脉中部地表隆升历史中的作用仍不确定。在这里，我们表明，一个长波长地形穹顶覆盖了地震测量的 APMB 范围，并且重力数据表明隆起是等静压补偿的。对穹顶生长的岩浆贡献的等静压建模产生的熔体体积与从层析成像估计的体积相当，并表明 APMB 的生长速率超过了内华达山脉岩基中白垩纪岩浆喷发的峰值。我们的分析表明，岩浆的加入可能对地表隆升的贡献与岩石圈的去除相当，并说明了地表地形可能有助于限制岩基规模熔体产量的大小。
