Magmatic addition rates differentiate periods of steady-state versus flare-up magmatism in the Central Andean arc

BERTIN, DANIEL; DE SILVA, SHANAKA L.; LINDSAY, JAN M.; CRONIN, SHANE J.; CAFFE, P.J.; CONNOR, CHARLES B.; GROSSE, P.; BAEZ, W.; BUSTOS, EMILCE; CONSTANTINESCU, ROBERT

Communications Earth & Environment

Nature Portfolio

Año: 2023

Cordilleran arcs are built by long periods of steady-state magmatism punctuated by transienthigh-flux magmatic episodes or flare-ups. Such flare-ups, manifested as periods of prodigioussilicic volcanism and magmatism, result from geodynamic perturbations that cause elevatedrates of magma addition to the crust. Questions remain, however, about how magmaticaddition rates quantitatively compare between steady-state and flare-up modes of arcmagmatism, and how long after the major geodynamic perturbation the flare-up begins. Here,we compute new estimates of erupted volumes over the last 35 Myr for the 22.5–29°Ssegment of the Central Andes based on a new volcanic geospatial database. These yieldmagmatic addition rates at least an order of magnitude higher during flare-up compared tosteady-state conditions. A lag time of ~8–12 Myr between ocean ridge subduction (the majorgeodynamic perturbation in the Central Andean arc) and the onset of flare-up conditions isestimated.