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An experimental study of the melting of a magmatic mush by heating from a hot basal intrusion

Olivier Roche 1, Jean-Michel Andanson2, Olivier Bachmann3, Christian Huber4, Julien Monteux1

  • Affiliations:  1 Laboratoire Magmas et Volcans, University Clermont Auvergne, CNRS, IRD, OPGC, Clermont-Ferrand, France; 2 Institut de Chimie de Clermont-Ferrand, University Clermont Auvergne, CNRS, Clermont-Ferrand, France; 3 Department of Earth Sciences, ETH, Zurich, Switzerland; 4 Earth, Environmental, and Planetary Sciences, Brown University, USA

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 191

  • Programme No: 3.2.14

  • Theme 3 > Session 2

Abstract

Understanding the dynamics of magmatic mushes is essential to gain insight into the spatial and temporal evolution of volcanic plumbing systems. In this context, we study experimentally the heating of a mush caused by a hot basal intrusion. The experimental apparatus is a 8 cm-high and 15 cm-diameter glass cylinder with basal and top margins consisting of two horizontal metal plates, whose temperatures are controlled to create a vertical thermal gradient, and with outer wall covered with heating pads to prevent heat loss. We use two types of polyethylene glycol (PEG) as analogue materials, whose properties enable us to meet scaling requirements. At initial state, the cylinder mean temperature is set to obtain an analogue mush consisting of solid PEG particles (analogue crystals) in liquid PEG (analogue melt). The increase of temperature of the lower plate simulates a hot basal intrusion, and the response of the analogue mush is recorded with a video camera through a narrow lateral vertical window. At an initial particle concentration of about 50 vol.%, the particles in contact with the lower plate melt, thus generating a basal liquid layer whose thickness increases over time as the melting front migrates upwards. Subsequently, the remaining granular bed collapses into the liquid layer while particle melting continues as a result of the heat flux provided by the basal plate. Our study gives insight into the possible mechanisms for the thermal remobilization of a magmatic mush.