Articles | Volume 12, issue 2
https://doi.org/10.5194/se-12-405-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/se-12-405-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Short communication
| 
18 Feb 2021
Short communication |
| 18 Feb 2021
| 18 Feb 2021
Experimental evidence that viscous shear zones generate periodic pore sheets
James Gilgannon
CORRESPONDING AUTHOR
Institute of Geological Sciences, University of Bern, 3012 Bern, Switzerland
Marius Waldvogel
Institute of Geological Sciences, University of Bern, 3012 Bern, Switzerland
Thomas Poulet
CSIRO Mineral Resources, Kensington, WA 6151, Australia
Florian Fusseis
School of Geosciences, The University of Edinburgh, Edinburgh EH9 3JW, UK
Alfons Berger
Institute of Geological Sciences, University of Bern, 3012 Bern, Switzerland
Auke Barnhoorn
Department of Geoscience and Engineering, Delft University of Technology, Delft, the Netherlands
Marco Herwegh
Institute of Geological Sciences, University of Bern, 3012 Bern, Switzerland
Related authors
James Gilgannon and Marco Herwegh
EGUsphere, https://doi.org/10.5194/egusphere-2025-1718, https://doi.org/10.5194/egusphere-2025-1718, 2025
Short summary
Short summary
Carbonate rocks can control how strong the Earth’s crust is in places. They are often described in simple terms as calcite or dolomite, but they are more complicated. At the atomistic level different amounts of elements, like magnesium and calcium, are incorporated at different temperatures and at the microscopic level carbonates can have different internal structures. We review 50 years of experimental data to provide equations that can describe the strength of most kinds of carbonates.
Roberto Emanuele Rizzo, Damien Freitas, James Gilgannon, Sohan Seth, Ian B. Butler, Gina Elizabeth McGill, and Florian Fusseis
Solid Earth, 15, 493–512, https://doi.org/10.5194/se-15-493-2024, https://doi.org/10.5194/se-15-493-2024, 2024
Short summary
Short summary
Here we introduce a new approach for analysing time-resolved 3D X-ray images tracking mineral changes in rocks. Using deep learning, we accurately identify and quantify the evolution of mineral components during reactions. The method demonstrates high precision in quantifying a metamorphic reaction, enabling accurate calculation of mineral growth rates and porosity changes. This showcases artificial intelligence's potential to enhance our understanding of Earth science processes.
Derek D. V. Leung, Florian Fusseis, and Ian B. Butler
EGUsphere, https://doi.org/10.5194/egusphere-2025-3499, https://doi.org/10.5194/egusphere-2025-3499, 2025
This preprint is open for discussion and under review for Solid Earth (SE).
Short summary
Short summary
Curling stones often collide with each other during a game. Over time, these collisions cause damage in the striking bands on the sides of the stones. We determined experimentally how hard these stones collide into one another. We then looked at old curling stones to understand how damage builds up in these rocks. We found that early, fast impacts produce fractures until the striking band is saturated in fractures. Repeated impacts after this stage make fractures grow.
Sandro Truttmann, Tobias Diehl, Marco Herwegh, and Stefan Wiemer
Solid Earth, 16, 641–662, https://doi.org/10.5194/se-16-641-2025, https://doi.org/10.5194/se-16-641-2025, 2025
Short summary
Short summary
Our study investigates the statistical relationship between geological fractures and earthquakes in the southwestern Swiss Alps. We analyze how the fracture size and earthquake rupture are related and find differences in how fractures at different depths rupture seismically. While shallow fractures tend to rupture only partially, deeper fractures are more likely to rupture along their entire length, potentially resulting in larger earthquakes.
James Gilgannon and Marco Herwegh
EGUsphere, https://doi.org/10.5194/egusphere-2025-1718, https://doi.org/10.5194/egusphere-2025-1718, 2025
Short summary
Short summary
Carbonate rocks can control how strong the Earth’s crust is in places. They are often described in simple terms as calcite or dolomite, but they are more complicated. At the atomistic level different amounts of elements, like magnesium and calcium, are incorporated at different temperatures and at the microscopic level carbonates can have different internal structures. We review 50 years of experimental data to provide equations that can describe the strength of most kinds of carbonates.
Natalia Nevskaya, Alfons Berger, Holger Stünitz, Markus Ohl, Oliver Plümper, and Marco Herwegh
EGUsphere, https://doi.org/10.5194/egusphere-2024-3970, https://doi.org/10.5194/egusphere-2024-3970, 2025
Short summary
Short summary
To date, there remains a deficiency in rheological parameters for polymineralic rocks to be used in models for strain localization and seismicity in the Earth's continental middle crust. We calculated grain size and stress sensitivity of experimentally deformed natural, fine-grained, granitoid rocks. Extrapolation of these parameters predicts a switch in the weakest material as a function of grain size and deformation mechanism: from coarse monomineralic quartz to fine polymineralic rocks.
Natalia Nevskaya, Alfons Berger, Holger Stünitz, Weijia Zhan, Markus Ohl, Oliver Plümper, and Marco Herwegh
EGUsphere, https://doi.org/10.5194/egusphere-2024-3968, https://doi.org/10.5194/egusphere-2024-3968, 2025
Short summary
Short summary
Rheology of polymineralic rocks is crucial to unravel the strain and stress distribution in Earth’s middle crust with implications for e.g. seismicity or geothermal systems. Our experimental study of the viscous rheology of natural, fine-grained, granitoid rocks shows that dissolution-precipitation creep and pinning is active in extremely weak narrow zones. Due to the polymineralic character, strain localizes with and without a precursory fracture in zones weaker than monomineralic quartz.
Veronica Peverelli, Alfons Berger, Martin Wille, Thomas Pettke, Benita Putlitz, Andreas Mulch, Edwin Gnos, and Marco Herwegh
Eur. J. Mineral., 36, 879–898, https://doi.org/10.5194/ejm-36-879-2024, https://doi.org/10.5194/ejm-36-879-2024, 2024
Short summary
Short summary
We used U–Pb dating and Pb–Sr–O–H isotopes of hydrothermal epidote to characterize fluid circulation in the Aar Massif (central Swiss Alps). Our data support the hypothesis that Permian fluids exploited syn-rift extensional faults. In the Miocene during the Alpine orogeny, fluid sources were meteoric, sedimentary, and/or metamorphic water. Likely, Miocene shear zones were exploited for fluid circulation, with implications for the Sr isotope budget of the granitoids.
Roberto Emanuele Rizzo, Damien Freitas, James Gilgannon, Sohan Seth, Ian B. Butler, Gina Elizabeth McGill, and Florian Fusseis
Solid Earth, 15, 493–512, https://doi.org/10.5194/se-15-493-2024, https://doi.org/10.5194/se-15-493-2024, 2024
Short summary
Short summary
Here we introduce a new approach for analysing time-resolved 3D X-ray images tracking mineral changes in rocks. Using deep learning, we accurately identify and quantify the evolution of mineral components during reactions. The method demonstrates high precision in quantifying a metamorphic reaction, enabling accurate calculation of mineral growth rates and porosity changes. This showcases artificial intelligence's potential to enhance our understanding of Earth science processes.
Veronica Peverelli, Alfons Berger, Martin Wille, Thomas Pettke, Pierre Lanari, Igor Maria Villa, and Marco Herwegh
Solid Earth, 13, 1803–1821, https://doi.org/10.5194/se-13-1803-2022, https://doi.org/10.5194/se-13-1803-2022, 2022
Short summary
Short summary
This work studies the interplay of epidote dissolution–precipitation and quartz dynamic recrystallization during viscous granular flow in a deforming epidote–quartz vein. Pb and Sr isotope data indicate that epidote dissolution–precipitation is mediated by internal/recycled fluids with an additional external fluid component. Microstructures and geochemical data show that the epidote material is redistributed and chemically homogenized within the deforming vein via a dynamic granular fluid pump.
Berit Schwichtenberg, Florian Fusseis, Ian B. Butler, and Edward Andò
Solid Earth, 13, 41–64, https://doi.org/10.5194/se-13-41-2022, https://doi.org/10.5194/se-13-41-2022, 2022
Short summary
Short summary
Hydraulic rock properties such as porosity and permeability are relevant factors that have an impact on groundwater resources, geological repositories and fossil fuel reservoirs. We investigate the influence of chemical compaction upon the porosity evolution in salt–biotite mixtures and related transport length scales by conducting laboratory experiments in combination with 4-D analysis. Our observations invite a renewed discussion of the effect of sheet silicates on chemical compaction.
Veronica Peverelli, Tanya Ewing, Daniela Rubatto, Martin Wille, Alfons Berger, Igor Maria Villa, Pierre Lanari, Thomas Pettke, and Marco Herwegh
Geochronology, 3, 123–147, https://doi.org/10.5194/gchron-3-123-2021, https://doi.org/10.5194/gchron-3-123-2021, 2021
Short summary
Short summary
This work presents LA-ICP-MS U–Pb geochronology of epidote in hydrothermal veins. The challenges of epidote dating are addressed, and a protocol is proposed allowing us to obtain epidote U–Pb ages with a precision as good as 5 % in addition to the initial Pb isotopic composition of the epidote-forming fluid. Epidote demonstrates its potential to be used as a U–Pb geochronometer and as a fluid tracer, allowing us to reconstruct the timing of hydrothermal activity and the origin of the fluid(s).
Samuel Mock, Christoph von Hagke, Fritz Schlunegger, István Dunkl, and Marco Herwegh
Solid Earth, 11, 1823–1847, https://doi.org/10.5194/se-11-1823-2020, https://doi.org/10.5194/se-11-1823-2020, 2020
Short summary
Short summary
Based on thermochronological data, we infer thrusting along-strike the northern rim of the Central Alps between 12–4 Ma. While the lithology influences the pattern of thrusting at the local scale, we observe that thrusting in the foreland is a long-wavelength feature occurring between Lake Geneva and Salzburg. This coincides with the geometry and dynamics of the attached lithospheric slab at depth. Thus, thrusting in the foreland is at least partly linked to changes in slab dynamics.
Cited articles
Alevizos, S., Poulet, T., and Veveakis, E.: Thermo-poro-mechanics of chemically active creeping faults. 1: Theory and steady state considerations, J. Geophys. Res.-Sol., 119, 4558–4582, https://doi.org/10.1002/2013JB010070, 2014. a, b
Badertscher, N. and Burkhard, M.: Brittle–ductile deformation in the Glarus thrust Lochseiten (LK) calc-mylonite, Terra Nova, 12, 281–288, https://doi.org/10.1046/j.1365-3121.2000.00310.x, 2000. a
Beach, A.: The Interrelations of Fluid Transport, Deformation, Geochemistry and Heat Flow in Early Proterozoic Shear Zones in the Lewisian Complex, Philos. Trans. Royal Soc. A, 280, 569–604, 1976. a
Beall, A., Fagereng, Å., and Ellis, S.: Fracture and Weakening of Jammed Subduction Shear Zones, Leading to the Generation of Slow Slip Events, Geochem. Geophy. Geosy., 20, 4869–4884, https://doi.org/10.1029/2019GC008481, 2019. a
Bürgmann, R.: The geophysics, geology and mechanics of slow fault slip, Earth Planet. Sci. Lett., 495, 112–134, https://doi.org/10.1016/j.epsl.2018.04.062, 2018. a
Carter, K. and Dworkin, S.: Channelized fluid flow through shear zones during fluid-enhanced dynamic recrystallization, Northern Apennines, Italy, Geology, 18, 720–723, https://doi.org/10.1130/0091-7613(1990)018<0720:CFFTSZ>2.3.CO;2, 1990. a
Chen, J., Verberne, B., and Niemeijer, A.: Flow-to-Friction Transition in Simulated Calcite Gouge: Experiments and Microphysical Modelling, J. Geophys. Res.-Sol. Ea., 125, e2020JB019970, https://doi.org/10.1029/2020JB019970, 2020. a, b
Cherukuri, H. and Shawki, T.: An energy-based localization theory: I. Basic framework, Int. J. Plast., 11, 15–40, https://doi.org/10.1016/0749-6419(94)00037-9, 1995. a
Covey-crump, S.: The high temperature static recovery and recrystallization behaviour of cold-worked Carrara marble, J. Struct. Geol., 19, 225–241, https://doi.org/10.1016/S0191-8141(96)00088-0, 1997. a
Delle Piane, C., Burlini, L., Kunze, K., Brack, P., and Burg, J.-P.: Rheology of dolomite: Large strain torsion experiments and natural examples, J. Struct. Geol., 30, 767–776, https://doi.org/10.1016/j.jsg.2008.02.018, 2008. a, b, c, d
Edmond, J. and Paterson, M.: Volume changes during the deformation of rocks at high pressures, Int. J. Rock Mech. Min. Sci., 9, 161–182, https://doi.org/10.1016/0148-9062(72)90019-8, 1972. a
Egholm, D., Knudsen, M., Clark, C., and Lesemann, J.: Modeling the flow of glaciers in steep terrains: The integrated second-order shallow ice approximation (iSOSIA), J. Geophys. Res.-Earth, 116, F02012, https://doi.org/10.1029/2010JF001900, 2011. a
Evans, B.: Creep constitutive laws for rocks with evolving structure, Geol. Soc. Spec. Publ., 245, 329–346, https://doi.org/10.1144/GSL.SP.2005.245.01.16, 2005. a, b
Fossen, H. and Cavalcante, G.: Shear zones – A review, Earth Sci. Rev., 171, 434–455, https://doi.org/10.1016/j.earscirev.2017.05.002, 2017. a
Fressengeas, C. and Molinari, A.: Instability and localization of plastic flow in shear at high strain rates, J. Phys. Chem. Solids, 35, 185–211, https://doi.org/10.1016/0022-5096(87)90035-4, 1987. a, b, c
Gilgannon, J.: se-2020-137_dataset_and_code, BORIS, available at: https://doi.org/10.7892/boris.151266, 2021. a
Gilgannon, J., Fusseis, F., Menegon, L., Regenauer-Lieb, K., and Buckman, J.: Hierarchical creep cavity formation in an ultramylonite and implications for phase mixing, Solid Earth, 8, 1193–1209, https://doi.org/10.5194/se-8-1193-2017, 2017. a
Giuntoli, F., Brovarone, A., and Menegon, L.: Feedback between high-pressure genesis of abiotic methane and strain localization in subducted carbonate rocks, Sci. Rep., 10, 1–15, https://doi.org/10.1038/s41598-020-66640-3, 2020. a, b
Goncalves, P., Poilvet, J.-C., Oliot, E., Trap, P., and Marquer, D.: How does shear zone nucleate? An example from the Suretta nappe (Swiss Eastern Alps), J. Struct. Geol., 86, 166–180, https://doi.org/10.1016/j.jsg.2016.02.015, 2016. a
Guével, A., Rattez, H., Alevizos, S., and Veveakis, M.: Contact phase-field modeling for chemo-mechanical degradation processes. Part I: Theoretical foundations,
arXiv [preprint], arXiv:1906.07755, 18 June 2019. a
Haertel, M., Herwegh, M., and Pettke, T.: Titanium-in-quartz thermometry on synkinematic quartz veins in a retrograde crustal-scale normal fault zone, Tectonophysics, 608, 468–481, https://doi.org/10.1016/j.tecto.2013.08.042, 2013. a
Handy, H., Hirth, G., and Bürgmann, R.: Continental Fault Structure and Rheology from the Frictional-to-Viscous Transition Downward, chap. 6, 139–182, MIT Press, 2007. a
Hansen, L., Zimmerman, M., Dillman, A., and Kohlstedt, D.: Strain localization in olivine aggregates at high temperature: A laboratory comparison of constant-strain-rate and constant-stress boundary conditions, Earth Planet. Sci. Lett., 333–334, 134–145, https://doi.org/10.1016/j.epsl.2012.04.016, 2012. a, b, c, d
Herwegh, M. and Jenni, A.: Granular flow in polymineralic rocks bearing sheet silicates: new evidence from natural examples, Tectonophysics, 332, 309–320, https://doi.org/10.1016/S0040-1951(00)00288-2, 2001. a, b
Herwegh, M. and Kunze, K.: The influence of nano-scale second-phase particles on deformation of fine grained calcite mylonites, J. Struct. Geol., 24, 1463–1478, https://doi.org/10.1016/S0191-8141(01)00144-4, 2002. a, b
Herwegh, M., de Bresser, J., and ter Heege, J.: Combining natural microstructures with composite flow laws: an improved approach for the extrapolation of lab data to nature, J. Struct. Geol., 27, 503–521, https://doi.org/10.1016/j.jsg.2004.10.010, 2005. a
Hobbs, B. and Ord, A.: Structural Geology: The Mechanics of Deforming Metamorphic Rocks, Elsevier, the Netherlands, 2015. a
Hobbs, B., Ord, A., and Teyssier, C.: Earthquakes in the ductile regime?, Pure Appl. Geophys., 124, 309–336, https://doi.org/10.1007/BF00875730, 1986. a
Hobbs, B., Ord, A., and Regenauer-Lieb, K.: The thermodynamics of deformed metamorphic rocks: A review, J. Struct. Geol., 33, 758–818, https://doi.org/10.1016/j.jsg.2011.01.013, 2011. a
Kohlstedt, D. and Holtzman, B.: Shearing Melt Out of the Earth: An Experimentalist's Perspective on the Influence of Deformation on Melt Extraction, Annu. Rev. Earth Planet. Sci., 37, 561–593, https://doi.org/10.1146/annurev.earth.031208.100104, 2009. a
Lopez-Sanchez, M. A. and Llana-Fúnez, S.: A cavitation-seal mechanism for ultramylonite formation in quartzofeldspathic rocks within the semi-brittle field (Vivero fault, NW Spain), Tectonophysics, 745, 132–153, https://doi.org/10.1016/j.tecto.2018.07.026, 2018. a
Mancktelow, N.: How ductile are ductile shear zones?, Geology, 34, 345–348, https://doi.org/10.1130/G22260.1, 2006. a, b
Mancktelow, N., Grujic, D., and Johnson, E.: An SEM study of porosity and grain boundary microstructure in quartz mylonites, Simplon Fault Zone, Central Alps, Contrib. Mineral. Petrol., 131, 71–85, https://doi.org/10.1007/s004100050379, 1998. a
Mariani, E., Brodie, K., and Rutter, E.: Experimental deformation of muscovite shear zones at high temperatures under hydrothermal conditions and the strength of phyllosilicate-bearing faults in nature, J. Struct. Geol., 28, 1569–1587, https://doi.org/10.1016/j.jsg.2006.06.009, 2006. a
Menegon, L., Fusseis, F., Stünitz, H., and Xiao, X.: Creep cavitation bands control porosity and fluid flow in lower crustal shear zones, Geology, 43, 227–230, https://doi.org/10.1130/G36307.1, 2015. a
Neupauer, R. and Powell, K.: A fully-anisotropic Morlet wavelet to identify dominant orientations in a porous medium, Comput. Geosci., 31, 465–471, https://doi.org/10.1016/j.cageo.2004.10.014, 2005. a, b, c, d
Neupauer, R., Powell, K., Qi, X., Lee, D., and Villhauer, D.: Characterization of permeability anisotropy using wavelet analysis, Water Resour. Res., 42, W07419, https://doi.org/10.1029/2005WR004364, 2006. a
Noack, L. and Breuer, D.: Plate tectonics on rocky exoplanets: Influence of initial conditions and mantle rheology, Planet. Space Sci., 98, 41–49, https://doi.org/10.1016/j.pss.2013.06.020, 2014. a
Paterson, M.: Localization in rate-dependent shearing deformation, with application to torsion testing, Tectonophysics, 445, 273–280, https://doi.org/10.1016/j.tecto.2007.08.015, 2007. a, b, c
Peacock, S.: Thermal and metamorphic environment of subduction zone episodic tremor and slip, J. Geophys. Res.-Sol. Ea., 114, B00A07, https://doi.org/10.1029/2008JB005978, 2009. a
Peters, M., Herwegh, M., Paesold, M., Poulet, T., Regenauer-Lieb, K., and Veveakis, M.: Boudinage and folding as an energy instability in ductile deformation, J. Geophys. Res.-Sol. Ea., 121, 3996–4013, https://doi.org/10.1002/2016JB012801, 2016. a
Pieri, M., Kunze, K., Burlini, L., Stretton, I., Olgaard, D., Burg, J.-P., and Wenk, H.-R.: Texture development of calcite by deformation and dynamic recrystallization at 1000K during torsion experiments of marble to large strains, Tectonophysics, 330, 119–140, https://doi.org/10.1016/S0040-1951(00)00225-0, 2001. a
Poirier, J.-P.: Creep of Crystals: High-Temperature Deformation Processes in Metals, Ceramics and Minerals, Cambridge Earth Science Series, Cambridge University Press, Cambridge, UK, https://doi.org/10.1017/CBO9780511564451, 1985. a
Poulet, T., Veveakis, M., Herwegh, M., Buckingham, T., and Regenauer-Lieb, K.: Modeling episodic fluid-release events in the ductile carbonates of the Glarus thrust, Geophys. Res. Lett., 41, 7121–7128, https://doi.org/10.1002/2014GL061715, 2014. a
Précigout, J., Prigent, C., Palasse, L., and Pochon, A.: Water pumping in mantle shear zones, Nat. Commun., 8, 15736, https://doi.org/10.1038/ncomms15736, 2017. a
Précigout, J., Stünitz, H., and Villeneuve, J.: Excess water storage induced by viscous strain localization during high-pressure shear experiment, Sci. Rep., 9, 3463, https://doi.org/10.1038/s41598-019-40020-y, 2019. a
Regenauer-Lieb, K., Yuen, D., and Fusseis, F.: Landslides, Ice Quakes, Earthquakes: A Thermodynamic Approach to Surface Instabilities, 1885–1908, https://doi.org/10.1007/978-3-0346-0138-2_15, 2009. a, b
Regenauer-Lieb, K., Karrech, A., Chua, H., Poulet, T., Veveakis, M., Wellmann, F., Liu, J., Schrank, C., Gaede, O., Trefry, M., Ord, A., Hobbs, B., Metcalfe, G., and Lester, D.: Entropic Bounds for Multi-Scale and Multi-Physics Coupling in Earth Sciences, pp. 323–335, Springer Berlin Heidelberg, Berlin, Heidelberg, https://doi.org/10.1007/978-3-642-40154-1_17, 2014. a, b
Regenauer-Lieb, K., Veveakis, M., Poulet, T., Paesold, M., Rosenbaum, G., Weinberg, R., and Karrech, A.: Multiscale, multiphysics geomechanics for geodynamics applied to buckling instabilities in the middle of the Australian craton, Philos. Mag., 95, 3055–3077, https://doi.org/10.1080/14786435.2015.1066517, 2015. a, b, c
Renner, J. and Evans, B.: Do calcite rocks obey the power-law creep equation?, Geol. Soc. Spec. Publ., 200, 293–307, https://doi.org/10.1144/GSL.SP.2001.200.01.17, 2002. a
Schmid, S. and Handy, M.: Towards a genetic classification of fault rocks – geological usage and tectonophysical implications, chap. 16, 339–361, Academic Press, New York, 1991. a
Selverstone, J., Morteani, G., and Staude, J.-M.: Fluid channelling during ductile shearing: transformation of granodiorite into aluminous schist in the Tauern Window, Eastern Alps, J. Metamorph. Geol., 9, 419–431, https://doi.org/10.1111/j.1525-1314.1991.tb00536.x, 1991. a
Shawki, T.: An Energy Criterion for the Onset of Shear Localization in Thermal Viscoplastic Materials, Part II: Applications and Implications, J. Appl. Mech., 61, 538–547, https://doi.org/10.1115/1.2901493, 1994. a, b
Shigematsu, N., Fujimoto, K., Ohtani, T., and Goto, K.: Ductile fracture of fine-grained plagioclase in the brittle-plastic transition regime: implication for earthquake source nucleation, Earth Planet. Sc. Lett., 222, 1007–1022, https://doi.org/10.1016/j.epsl.2004.04.001, 2004. a
Sibson, R.: Fault rocks and fault mechanisms, J. Geol. Soc., 133, 191–213, https://doi.org/10.1144/gsjgs.133.3.0191, 1977. a
Sibson, R.: Crustal stress, faulting and fluid flow, Geol. Soc. Spec. Publ., 78, 69–84, https://doi.org/10.1144/GSL.SP.1994.078.01.07, 1994. a
Spiess, R., Dibona, R., Rybacki, E., Wirth, R., and Dresen, G.: Depressurized Cavities within High-strain Shear Zones: their Role in the Segregation and Flow of SiO2-rich Melt in Feldspar-dominated Rocks, J. Petrol., 53, 1767–1776, https://doi.org/10.1093/petrology/egs032, 2012.
a, b, c
Tannock, L., Herwegh, M., Berger, A., Liu, J., and Regenauer-Lieb, K.: The effects of a tectonic stress regime change on crustal-scale fluid flow at the Heyuan geothermal fault system, South China, Tectonophysics, 781, 228399, https://doi.org/10.1016/j.tecto.2020.228399, 2020. a
van der Walt, S., Schönberger, J., Nunez-Iglesias, J., Boulogne, F., Warner, J., Yager, N., Gouillart, E., Yu, T., and the scikit-image contributors: scikit-image: image processing in Python, PeerJ, 2, e453, https://doi.org/10.7717/peerj.453, 2014. a
Vauchez, A., Tommasi, A., and Mainprice, D.: Faults (shear zones) in the Earth's mantle, Tectonophysics, 558–559, 1–27, https://doi.org/10.1016/j.tecto.2012.06.006, 2012. a
Verberne, B., Chen, J., Niemeijer, A., de Bresser, J., Pennock, G., Drury, M., and Spiers, C.: Microscale cavitation as a mechanism for nucleating earthquakes at the base of the seismogenic zone, Nat. Commun., 8, 1645, https://doi.org/10.1038/s41467-017-01843-3, 2017. a
Veveakis, E. and Regenauer-Lieb, K.: Review of extremum postulates, Curr. Opin. Chem. Eng., 7, 40–46, https://doi.org/10.1016/j.coche.2014.10.006, 2015. a, b, c
Wang, K. and Tréhu, A.: Invited review paper: Some outstanding issues in the study of great megathrust earthquakes – The Cascadia example, J. Geodyn., 98, 1–18, https://doi.org/10.1016/j.jog.2016.03.010, 2016. a, b
Weinberg, R. and Regenauer-Lieb, K.: Ductile fractures and magma migration from source, Geology, 38, 363–366, https://doi.org/10.1130/G30482.1, 2010. a, b, c
Xiao, X., Evans, B., and Bernabé, Y.: Permeability Evolution During Non-linear Viscous Creep of Calcite Rocks, 2071–2102, Birkhäuser Basel, Basel, https://doi.org/10.1007/978-3-7643-8124-0_3, 2006. a
Závada, P., Schulmann, K., Konopásek, J., Stanislav, U., and Ondrej, L.: Extreme ductility of feldspar aggregates - Melt-enhanced grain boundary sliding and creep failure: Rheological implications for felsic lower crust, J. Geophys. Res. Solid Earth, 112, B10210, https://doi.org/10.1029/2006JB004820, 2007. a
Short summary
Using experiments that simulate deep tectonic interfaces, known as viscous shear zones, we found that these zones spontaneously develop periodic sheets of small pores. The presence of porous layers in deep rocks undergoing tectonic deformation is significant because it requires a change to the current model of how the Earth deforms. Emergent porous layers in viscous rocks will focus mineralising fluids and could lead to the seismic failure of rocks that are never supposed to have this occur.
Using experiments that simulate deep tectonic interfaces, known as viscous shear zones, we found...
