Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Concentration variance decay during magma mixing: a volcanic chronometer

Full text
Author(s):
Perugini, Diego [1] ; De Campos, Cristina P. [2, 3] ; Petrelli, Maurizio [1] ; Dingwell, Donald B. [2]
Total Authors: 4
Affiliation:
[1] Univ Perugia, Dept Phys & Geol, I-06100 Perugia - Italy
[2] Univ Munich, Dept Earth & Environm Sci, D-80333 Munich - Germany
[3] Univ Sao Paulo, Dept Mineral & Geotecton, BR-05508080 Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: SCIENTIFIC REPORTS; v. 5, SEP 21 2015.
Web of Science Citations: 16
Abstract

The mixing of magmas is a common phenomenon in explosive eruptions. Concentration variance is a useful metric of this process and its decay (CVD) with time is an inevitable consequence during the progress of magma mixing. In order to calibrate this petrological/volcanological clock we have performed a time-series of high temperature experiments of magma mixing. The results of these experiments demonstrate that compositional variance decays exponentially with time. With this calibration the CVD rate (CVD-R) becomes a new geochronometer for the time lapse from initiation of mixing to eruption. The resultant novel technique is fully independent of the typically unknown advective history of mixing - a notorious uncertainty which plagues the application of many diffusional analyses of magmatic history. Using the calibrated CVD-R technique we have obtained mingling-to-eruption times for three explosive volcanic eruptions from Campi Flegrei (Italy) in the range of tens of minutes. These in turn imply ascent velocities of 5-8 meters per second. We anticipate the routine application of the CVD-R geochronometer to the eruptive products of active volcanoes in future in order to constrain typical ``mixing to eruption{''} time lapses such that monitoring activities can be targeted at relevant timescales and signals during volcanic unrest. (AU)

FAPESP's process: 09/50493-8 - Crustal and lithospheric mantle models under the Paraná and Chaco-Paraná basins by merging satellite gravity gradiometry, terrestrial gravimetry and geomagnetic and electromagnetic soundings
Grantee:Icaro Vitorello
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 15/11850-0 - 8th Hutton Symposium on Granites and Related Rocks
Grantee:Valdecir de Assis Janasi
Support Opportunities: Organization Grants - Scientific Meeting