RT Journal Article
T1 Deformation mechanics in inclined, brittle-ductile transpression zones: Insights from 3D finite element modelling
T2 Mecánica de la deformación en zonas transpresivas frágil-dúctiles inclinadas: perspectiva desde modelización 3D de elementos finitos
A1 Nabavi, Seyed Tohid
A1 Alavi, Seyed Ahmad
A1 Díaz Azpiroz, Manuel
A1 Mohammadi, Soheil
A1 Ghassemi, Mohammad Reza
A1 Fernández, Carlos
A1 Barcos, Leticia
A1 Frehner, Marcel
K1 Oblique convergence
K1 Inclined transpression
K1 Inclined extrusion
K1 Strain partitioning
K1 3D finite-element modelling
AB Most natural examples of transpression zones developed at oblique convergence regime are inherently 3D and have inclined boundaries. A 3D finite element model with an elasto-plastic rheology is used to investigate the structural and mechanical evolution of inclined transpression zones in a rock sequence above a frictional basal detachment. Inelastic constitutive relationships allow permanent strains to develop in response to the applied loads. FE-modelling results show that oblique convergence is accommodated by discrete deformation at the main pre-existing inclined faults (=70º) and by distributed brittle and ductile deformation at active blocks. Oblique contraction at the active blocks resulted mainly in layer-parallel shortening, orthogonal to the model outer boundaries, whereas thickening in the horizontal and vertical directions was accommodated via layer-parallel, fault strike-parallel extension and up-dip extrusion (i.e., inclined extrusion). Lateral extrusion should have compensated the rest and/or volume loss took place. Folding and thickening of the mobile backstop produced a non-cylindrical, asymmetric, bi-vergent anticline where permanent strains developed principally in the steep forelimb. Secondary, conjugate fault zones also accommodate oblique slip and contribute to uplift. Displacement vectors within the transpression zone are rotated counter-clockwise (ca. 20º–30º) with respect to vectors in the fixed backstop. Areas with higher rotation values seem to correlate with those showing higher ellipticity values. The presence of pre-existing faults favored strain partitioning from the onset of deformation. FE-modelling results compared with analytical, natural example, and analogue modelling results show that our mechanical modelling can overall match inclined transpression zones geometry that present different modes of strain partitioning and localization.
PB Elsevier
YR 2020
FD 2020-05-11
LK https://hdl.handle.net/10433/25730
UL https://hdl.handle.net/10433/25730
LA en
NO Seyed Tohid Nabavi, Seyed Ahmad Alavi, Manuel Díaz-Azpiroz, Soheil Mohammadi, Mohammad Reza Ghassemi, Carlos Fernández, Leticia Barcos, Marcel Frehner, Deformation mechanics in inclined, brittle-ductile transpression zones: Insights from 3D finite element modelling, Journal of Structural Geology, Volume 137, 2020, 104082, ISSN 0191-8141, https://doi.org/10.1016/j.jsg.2020.104082
NO financial support from the Spanish Ministry of Science, Innovation and University (projects PGC2018-100914-B-I00 and PGC2018-096534- B-I00)
NO Universidad Pablo de Olavide. Departamento de Sistemas Físicos, Químicos y Naturales
NO Departamento de Ciencias de La Tierra, Universidad de Huelva
NO Faculty of Earth Sciences, Department of Geology, Shahid Beheshti University, Tehran, Iran
NO High Performance Computing Laboratory, School of Civil Engineering, University of Tehran, Tehran, Iran
NO Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
NO Zurich University of Teacher Education (PHZH), Zurich, Switzerland
DS RIO
RD May 9, 2026