Authors:	Moulas, Evangelos Kaus, Boris Jamtveit, Bjørn
Title:	Dynamic pressure variations in the lower crust caused by localized fluid-induced weakening
Online publication date:	30-Nov-2022
Year of first publication:	2022
Language:	english
Abstract:	Metamorphism of dry, lower crust within orogens is often localized in shear zones composed of mechanically weaker rocks. Several field-based studies suggest shear zone development is preceded by brittle faults which provide the fluid pathways required for metamorphism and weakening. However, a unifying model which couples long-term geological deformation to fluid migration and metamorphic reactions does not exist. Here, we present a visco-elasto-plastic model where the most pertinent features observed in transformed lower crust emerge from basic mechanical principles during the deformation of a coherent rock volume with associated fluid introduction. These include a strikingly dynamic and heterogeneous pressure distribution in the reacting and deforming rock volumes. Lower crustal pressure variations may reach 1 GPa at the same depth. This will have first order effects on the pattern of fluid migration in the lower crust, and may explain the apparent discrepancies between the relevant tectonic settings and petrologically-inferred burial depths.
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-8437
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Communications earth & environment 3
Pages or article number:	157
Publisher:	Springer Nature
Publisher place:	London
Issue date:	2022
ISSN:	2662-4435
Publisher DOI:	10.1038/s43247-022-00478-7
Appears in collections:	DFG-491381577-G