Folded fabric tunes rock deformation and failure mode in the upper crust

Abstract The micro-mechanisms of brittle failure affect the bulk mechanical behaviour and permeability of crustal rocks. In low-porosity crystalline rocks, these mechanisms are related to mineralogy and fabric anisotropy, while confining pressure, temperature and strain rates regulate the transition...

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Autores principales:	F. Agliardi, M. R. Dobbs, S. Zanchetta, S. Vinciguerra
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/86799920d5564857a45725dfc57f6dc7
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spelling	oai:doaj.org-article:86799920d5564857a45725dfc57f6dc72021-12-02T11:40:12ZFolded fabric tunes rock deformation and failure mode in the upper crust10.1038/s41598-017-15523-12045-2322https://doaj.org/article/86799920d5564857a45725dfc57f6dc72017-11-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-15523-1https://doaj.org/toc/2045-2322Abstract The micro-mechanisms of brittle failure affect the bulk mechanical behaviour and permeability of crustal rocks. In low-porosity crystalline rocks, these mechanisms are related to mineralogy and fabric anisotropy, while confining pressure, temperature and strain rates regulate the transition from brittle to ductile behaviour. However, the effects of folded anisotropic fabrics, widespread in orogenic settings, on the mechanical behaviour of crustal rocks are largely unknown. Here we explore the deformation and failure behaviour of a representative folded gneiss, by combining the results of triaxial deformation experiments carried out while monitoring microseismicity with microstructural and damage proxies analyses. We show that folded crystalline rocks in upper crustal conditions exhibit dramatic strength heterogeneity and contrasting failure modes at identical confining pressure and room temperature, depending on the geometrical relationships between stress and two different anisotropies associated to the folded rock fabric. These anisotropies modulate the competition among quartz- and mica-dominated microscopic damage processes, resulting in transitional brittle to semi-brittle modes under P and T much lower than expected. This has significant implications on scales relevant to seismicity, energy resources, engineering applications and geohazards.F. AgliardiM. R. DobbsS. ZanchettaS. VinciguerraNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-9 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q F. Agliardi M. R. Dobbs S. Zanchetta S. Vinciguerra Folded fabric tunes rock deformation and failure mode in the upper crust
description	Abstract The micro-mechanisms of brittle failure affect the bulk mechanical behaviour and permeability of crustal rocks. In low-porosity crystalline rocks, these mechanisms are related to mineralogy and fabric anisotropy, while confining pressure, temperature and strain rates regulate the transition from brittle to ductile behaviour. However, the effects of folded anisotropic fabrics, widespread in orogenic settings, on the mechanical behaviour of crustal rocks are largely unknown. Here we explore the deformation and failure behaviour of a representative folded gneiss, by combining the results of triaxial deformation experiments carried out while monitoring microseismicity with microstructural and damage proxies analyses. We show that folded crystalline rocks in upper crustal conditions exhibit dramatic strength heterogeneity and contrasting failure modes at identical confining pressure and room temperature, depending on the geometrical relationships between stress and two different anisotropies associated to the folded rock fabric. These anisotropies modulate the competition among quartz- and mica-dominated microscopic damage processes, resulting in transitional brittle to semi-brittle modes under P and T much lower than expected. This has significant implications on scales relevant to seismicity, energy resources, engineering applications and geohazards.
format	article
author	F. Agliardi M. R. Dobbs S. Zanchetta S. Vinciguerra
author_facet	F. Agliardi M. R. Dobbs S. Zanchetta S. Vinciguerra
author_sort	F. Agliardi
title	Folded fabric tunes rock deformation and failure mode in the upper crust
title_short	Folded fabric tunes rock deformation and failure mode in the upper crust
title_full	Folded fabric tunes rock deformation and failure mode in the upper crust
title_fullStr	Folded fabric tunes rock deformation and failure mode in the upper crust
title_full_unstemmed	Folded fabric tunes rock deformation and failure mode in the upper crust
title_sort	folded fabric tunes rock deformation and failure mode in the upper crust
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/86799920d5564857a45725dfc57f6dc7
work_keys_str_mv	AT fagliardi foldedfabrictunesrockdeformationandfailuremodeintheuppercrust AT mrdobbs foldedfabrictunesrockdeformationandfailuremodeintheuppercrust AT szanchetta foldedfabrictunesrockdeformationandfailuremodeintheuppercrust AT svinciguerra foldedfabrictunesrockdeformationandfailuremodeintheuppercrust
_version_	1718395710797250560

Folded fabric tunes rock deformation and failure mode in the upper crust

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