Authors:	Kiss, Daniel Moulas, Evangelos Kaus, Boris Spang, Arne
Title:	Decompression and fracturing caused by magmatically induced thermal stresses
Online publication date:	13-Jun-2023
Year of first publication:	2023
Language:	english
Abstract:	Studies of host rock deformation around magmatic intrusions usually focus on the development of stresses directly related to the intrusion process. This is done either by considering an inflating region that represents the intruding body, or by considering multiphase deformation. Thermal processes, especially volume changes caused by thermal expansion are typically ignored. We show that thermal stresses around upper crustal magma bodies are likely to be significant and sufficient to create an extensive fracture network around the magma body by brittle yielding. At the same time, cooling induces decompression within the intrusion, which can promote the appearance of a volatile phase. Volatile phases and the development of a fracture network around the inclusion may thus be the processes that control magmatic-hydrothermal alteration around intrusions. This suggests that thermal stresses likely play an important role in the development of magmatic systems. To quantify the magnitude of thermal stresses around cooling intrusions, we present a fully compressible 2D visco-elasto-plastic thermo-mechanical numerical model. We utilize a finite difference staggered grid discretization and a graphics processing unit based pseudo-transient solver. First, we present purely thermo-elastic solutions, then we include the effects of viscous relaxation and plastic yielding. The dominant deformation mechanism in our models is determined in a self-consistent manner, by taking into account stress, pressure, and temperature conditions. Using experimentally determined flow laws, the resulting thermal stresses can be comparable to or even exceed the confining pressure. This suggests that thermal stresses alone could result in the development of a fracture network around magmatic bodies.
DDC:	550 Geowissenschaften 550 Earth sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-9171
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Journal of geophysical research : B, Solid earth 128 3
Pages or article number:	e2022JB025341
Publisher:	Union
Publisher place:	Washington, DC
Issue date:	2023
ISSN:	2169-9313
Publisher DOI:	10.1029/2022JB025341
Appears in collections:	DFG-491381577-H