Skip to Main Content
Book Chapter

Non-linear feedback loops in the rheology of cooling-crystallizing felsic magma and heating-melting felsic rock

By
Jean-Pierre Burg
Jean-Pierre Burg
Geologisches Institut, University of Zurich and ETH-Zentrum, Sonneggstrasse 5, CH-8006 Zürich, Switzerland
Search for other works by this author on:
Jean-Louis Vigneresse
Jean-Louis Vigneresse
CREGU, UMR CNRS 7566 G2R, BP 23, F-54501 Vandoeuvre Cedex, France
Search for other works by this author on:
Published:
January 01, 2002

Abstract

At least six major parameters control the rheology of partially molten systems: melt content, rate of melt production, reaction to strain of the solid component, reaction to strain of the molten component, temperature and chemical composition of the source rocks. We examine their interactions to understand the rheology of partly molten rocks and partly crystallized magmas. In particular, this paper focuses on the rheology in the transitional domains between two pairs of thresholds that bracket a transitional regime between solid state and fluid behaviour during melting and crystallization, respectively. We review related information and point out non-linear effects that develop during heating of melting rocks and cooling of crystallizing magmas. Owing to the non-linear interactions, positive or negative feedback loops accelerate or damp the system. Melt in migmatite experiences shear-softening which, along with strain partitioning, facilitates melt segregation. Conversely, the increasing number of rigid crystals during cooling increases the suspension viscosity (shear hardening), which soon inhibits magma movement. These effects reinforce the asymmetry between solid-to-melt and melt-to-solid transitions. They severely contradict the concept of one rheological critical melt percentage valid for both melting and crystallization transitions. Fabric acquisition competes with nucleation and crystal growth, thus leading to hysteresis of the stress-strain rate curves. Implications for field observations include horizontal magma segregation, magma extraction and successive magma intrusions.

You do not currently have access to this article.

Figures & Tables

Contents

Geological Society, London, Special Publications

Deformation Mechanisms, Rheology and Tectonics: Current Status and Future Perspectives

S. de Meer
S. de Meer
Utrecht University, The Netherlands
Search for other works by this author on:
M. R. Drury
M. R. Drury
Utrecht University, The Netherlands
Search for other works by this author on:
J. H. P. de Bresser
J. H. P. de Bresser
Utrecht University, The Netherlands
Search for other works by this author on:
G. M. Pennock
G. M. Pennock
Utrecht University, The Netherlands
Search for other works by this author on:
Geological Society of London
Volume
200
ISBN electronic:
9781862396081
Publication date:
January 01, 2002

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal