EGU21-14589
https://doi.org/10.5194/egusphere-egu21-14589
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Strain Analysis of Transfer Faults in Extending Regions: Inferences from Micropolar Theory

Bülent Tokay1 and Erdin Bozkurt1,2
Bülent Tokay and Erdin Bozkurt
  • 1Middle East Technical University, Geological Engineering, Üniversiteler Mahallesi, Dumlupınar Bulvarı, No: 1, 06800, Ankara, Turkey (btokay@metu.edu.tr)
  • 2Center for Global Tectonics & State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, 388 Lumo Road, Hongshan District, Wuhan 430074, Hubei Province, China

Transfer faults are generally identified as transversely oriented discrete faults linking normal fault segments in extensional tectonic settings.  The presence of the transfer faults in fault networks provides displacement transfer between the normal faults. The role and tectonic significance of transfer faults in overall extensional deformation of the upper crust is however not known very well. Micropolar theory extended by J-2 plasticity facilitates evaluation of a deforming medium in which cataclastic flow takes place with respect to each component of deformation. In this study, a series of experiments based on the Micropolar theory are performed, using fault-slip patterns, to better understand interplay among dip angle of normal and transfer faults connecting to each other, angle of linkage, and extensional direction. Synthetic linkage cases are created systematically considering various orientation of both faults sharing common stretching direction.
Our findings reveal that in orthogonal and oblique linkage cases, 3D strain field is mostly observed; a few cases exhibit plane strain. All cases are subjected to simple shearing. In cases of orthogonal linkage, extensional direction is predominantly oblique to the strike of the normal faults. Many of these cases have no block rotation (microrotation) independent from macrorotation. No particular relationship between changing dip amount of faults and direction of extension is observed. In cases of oblique linkage, (sub)orthogonal direction of extension appear in nearly half of experiments, especially those including normal faults dipping less than 60˚. The frequency of non-zero microrotation is seen apparently more than that in orthogonal linkage cases.
The study represents that structural togetherness of the transfer and normal faults essentially can accommodate complete micropolar strain in a region. This further suggests that not only the normal faults but the transfer faults should also be considered as major primary structural elements in extending domains.

How to cite: Tokay, B. and Bozkurt, E.: Strain Analysis of Transfer Faults in Extending Regions: Inferences from Micropolar Theory, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14589, https://doi.org/10.5194/egusphere-egu21-14589, 2021.

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