Shallow system rejuvenation and magma discharge trends at Piton de la Fournaise volcano (La Réunion Island)
Artikel i vetenskaplig tidskrift, 2017

Basaltic magma chambers are often characterized by emptying and refilling cycles that influence their evolution in space and time, and the associated eruptive activity. During April 2007, the largest historical eruption of Piton de la Fournaise (Île de La Réunion, France) drained the shallow plumbing system (>240×106 m3) and resulted in collapse of the 1-km-wide summit crater. Following these major events, Piton de la Fournaise entered a seven-year long period of near-continuous deflation interrupted, in June 2014, by a new phase of significant inflation. By integrating multiple datasets (lava discharge rates, deformation, seismicity, gas flux, gas composition, and lava chemistry), we here show that the progressive migration of magma from a deeper (below sea level) storage zone gradually rejuvenated and pressurized the above-sea-level portion of the magmatic system consisting of a vertically-zoned network of relatively small-volume magma pockets. Continuous inflation provoked four small (<5×106 m3) eruptions from vents located close to the summit cone and culminated, during August–October 2015, with a chemically zoned eruption that erupted 45±15×106 m3 of lava. This two-month-long eruption evolved through (i) an initial phase of waning discharge, associated to the withdrawal of differentiated magma from the shallow system, into (ii) a month-long phase of increasing lava and SO2 fluxes at the effusive vent, coupled with CO2 enrichment of summit fumaroles, and involving emission of less differentiated lavas, to end with, (iii) three short-lived (?2 day-long) pulses in lava and gas flux, coupled with arrival of cumulative olivine at the surface and deflation. The activity observed at Piton de la Fournaise in 2014 and 2015 points to a new model of shallow system rejuvenation and discharge, whereby continuous magma supply causes eruptions from increasingly deeper and larger magma storage zones. Downward depressurization continues until unloading of the deepest, least differentiated magma triggers pulses in lava and gas flux, accompanied by rapid contraction of the volcano edifice, that empties the main shallow reservoir and terminates the cycle. Such an unloading process may characterize the evolution of shallow magmatic systems at other persistently active effusive centers.

effusive paroxysm

effusive trends

unloading

Piton de la Fournaise

shallow plumbing system

Författare

D. Coppola

Universita degli Studi di Torino

A. Di Muro

Institut de Physique du Globe de Paris

A. Peltier

Institut de Physique du Globe de Paris

N. Villeneuve

Institut de Physique du Globe de Paris

V. Ferrazzini

Institut de Physique du Globe de Paris

M. Favalli

Istituto Nazionale di Geofisica e Vulcanologia

P. Bachèlery

Universite Blaise Pascal, Clermont-Ferrand II

L. Gurioli

Universite Blaise Pascal, Clermont-Ferrand II

A. J L Harris

Universite Blaise Pascal, Clermont-Ferrand II

S. Moune

Universite Blaise Pascal, Clermont-Ferrand II

I. Vlastélic

Universite Blaise Pascal, Clermont-Ferrand II

Bo Galle

Chalmers, Rymd- och geovetenskap, Optisk fjärranalys

Santiago Arellano

Chalmers, Rymd- och geovetenskap, Optisk fjärranalys

A. Aiuppa

Istituto Nazionale di Geofisica e Vulcanologia

Universita degli Studi di Palermo

Earth and Planetary Science Letters

0012-821X (ISSN) 1385-013X (eISSN)

Vol. 463 13-24

Ämneskategorier

Geologi

Multidisciplinär geovetenskap

DOI

10.1016/j.epsl.2017.01.024

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Senast uppdaterat

2021-12-30