Abstract
Localisation of ductile deformation in rocks is commonly found at all scales from crustal shear zones down to grain scale shear bands. Of the various mechanisms for localisation, mechanical anisotropy has received relatively little attention, especially in numerical modelling. Mechanical anisotropy can be due to dislocation creep of minerals (e.g. ice or mica) and/or layering in rocks (e.g. bedding, cleavage). We simulated simple-shear deformation of a locally anisotropic, single-phase power-law rheology material up to shear strain of five. Localisation of shear rate in narrow shear bands occurs, depending on the magnitude of anisotropy and the stress exponent. At high anisotropy values, strain-rate frequency distributions become approximately log-normal with heavy, exponential tails. Localisation due to anisotropy is scale-independent and thus provides a single mechanism for a self-organised hierarchy of shear bands and zones from mm-to km-scales. The numerical simulations are compared with the natural example of the Northern Shear Belt at Cap de Creus, NE Spain.
| Original language | English |
|---|---|
| Pages (from-to) | 81-90 |
| Number of pages | 10 |
| Journal | Journal of Structural Geology |
| Volume | 124 |
| Early online date | 3 Apr 2019 |
| DOIs | |
| Publication status | Published - Jul 2019 |
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Keywords
- Anisotropy
- Self-organisation
- Shear zones
- Strain localisation
- Strain-rate distribution
ASJC Scopus subject areas
- Geology
Cite this
Shear localisation in anisotropic, non-linear viscous materials that develop a CPO : A numerical study. / de Riese, Tamara (Corresponding Author); Evans, Lynn; Gomez-Rivas, Enrique; Griera, Albert; Lebensohn, Ricardo A.; Llorens, Maria Gema; Ran, Hao; Sachau, Till; Weikusat, Ilka; Bons, Paul D.
In: Journal of Structural Geology, Vol. 124, 07.2019, p. 81-90.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Shear localisation in anisotropic, non-linear viscous materials that develop a CPO
T2 - A numerical study
AU - de Riese, Tamara
AU - Evans, Lynn
AU - Gomez-Rivas, Enrique
AU - Griera, Albert
AU - Lebensohn, Ricardo A.
AU - Llorens, Maria Gema
AU - Ran, Hao
AU - Sachau, Till
AU - Weikusat, Ilka
AU - Bons, Paul D.
N1 - HR acknowledges financial support by the China Scholarship Council (CSC; grant nr. 201506400014). EGR acknowledges the support of the Beatriu de Pinós programme of the Government of Catalonia's Secretariat for Universities and Research of the Department of Economy and Knowledge (2016 BP 00208). M.-G.L acknowledges the support of the Juan de la Cierva programme of the Government of Spain’s Ministry for Science, Innovation and Universities.
PY - 2019/7
Y1 - 2019/7
N2 - Localisation of ductile deformation in rocks is commonly found at all scales from crustal shear zones down to grain scale shear bands. Of the various mechanisms for localisation, mechanical anisotropy has received relatively little attention, especially in numerical modelling. Mechanical anisotropy can be due to dislocation creep of minerals (e.g. ice or mica) and/or layering in rocks (e.g. bedding, cleavage). We simulated simple-shear deformation of a locally anisotropic, single-phase power-law rheology material up to shear strain of five. Localisation of shear rate in narrow shear bands occurs, depending on the magnitude of anisotropy and the stress exponent. At high anisotropy values, strain-rate frequency distributions become approximately log-normal with heavy, exponential tails. Localisation due to anisotropy is scale-independent and thus provides a single mechanism for a self-organised hierarchy of shear bands and zones from mm-to km-scales. The numerical simulations are compared with the natural example of the Northern Shear Belt at Cap de Creus, NE Spain.
AB - Localisation of ductile deformation in rocks is commonly found at all scales from crustal shear zones down to grain scale shear bands. Of the various mechanisms for localisation, mechanical anisotropy has received relatively little attention, especially in numerical modelling. Mechanical anisotropy can be due to dislocation creep of minerals (e.g. ice or mica) and/or layering in rocks (e.g. bedding, cleavage). We simulated simple-shear deformation of a locally anisotropic, single-phase power-law rheology material up to shear strain of five. Localisation of shear rate in narrow shear bands occurs, depending on the magnitude of anisotropy and the stress exponent. At high anisotropy values, strain-rate frequency distributions become approximately log-normal with heavy, exponential tails. Localisation due to anisotropy is scale-independent and thus provides a single mechanism for a self-organised hierarchy of shear bands and zones from mm-to km-scales. The numerical simulations are compared with the natural example of the Northern Shear Belt at Cap de Creus, NE Spain.
KW - Anisotropy
KW - Self-organisation
KW - Shear zones
KW - Strain localisation
KW - Strain-rate distribution
UR - http://www.scopus.com/inward/record.url?scp=85064667949&partnerID=8YFLogxK
UR - http://www.mendeley.com/research/shear-localisation-anisotropic-nonlinear-viscous-materials-develop-cpo-numerical-study
U2 - 10.1016/j.jsg.2019.03.006
DO - 10.1016/j.jsg.2019.03.006
M3 - Article
VL - 124
SP - 81
EP - 90
JO - Journal of Structural Geology
JF - Journal of Structural Geology
SN - 0191-8141
ER -