Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach
<p>Understanding the tectonic evolution and crustal-scale structure of fold-and-thrust belts is crucial for exploring geological resources and evaluating seismic hazards. We conducted a series of two-dimensional finite difference thermomechanical numerical models with a visco–elasto–plastic/br...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-12-01
|
| Series: | Solid Earth |
| Online Access: | https://se.copernicus.org/articles/15/1479/2024/se-15-1479-2024.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1846126736048128000 |
|---|---|
| author | F. Gomar J. B. Ruh M. Najafi F. Sobouti |
| author_facet | F. Gomar J. B. Ruh M. Najafi F. Sobouti |
| author_sort | F. Gomar |
| collection | DOAJ |
| description | <p>Understanding the tectonic evolution and crustal-scale structure of fold-and-thrust belts is crucial for exploring geological resources and evaluating seismic hazards. We conducted a series of two-dimensional finite difference thermomechanical numerical models with a visco–elasto–plastic/brittle rheology to decipher how the interaction between inherited basement faults and salt décollement levels control the deformation process and structural style of the Fars Arc in the Zagros fold-and-thrust belt during tectonic inversion. Numerical experiments with extension and consequent convergence phases indicate that strain accumulation patterns during initial rifting are controlled by the location and geometry of the prescribed faults. During convergence, the inverted basement faults form large-wavelength and foreland-verging fault-propagation anticlines in the sedimentary cover, while the thick salt layer promotes the growth of second-order detachment anticlines accompanied by both fore- and back-limb thrust faults. Experiments without prescribed basement faults result in dispersed brittle/plastic deformation during rifting and convergence and an effective mechanical decoupling along the salt horizon. Overall, reactivated faults can serve as pathways for stress transfer, resulting in the formation of new faults triggering seismic activity. The structural evolution of orogenic belts like the Zagros does not adhere to a fixed pattern; it is shaped by factors such as basement rock properties and inherited fault orientations. Shallow earthquakes predominantly occur along décollement anticlines in the sedimentary cover, while deeper and larger ones are associated with basement faults. We also observe variations in resistance to deformation based on salt rheology and fault geometry, with listric faults minimizing resistance. The degree of basement involvement directly influences the model's resistance to deformation, with greater involvement facilitating easier deformation. Our results, related to the temporal and spatial relationship between thin- and thick-skinned tectonics, can work as analogues for similar orogenic belts worldwide, such as Taiwan, the Pyrenees, the Alps, the Appalachians, and the Kopet Dagh.</p> |
| format | Article |
| id | doaj-art-9adf0c83848f4e1ab85bda08e4b0ec94 |
| institution | Kabale University |
| issn | 1869-9510 1869-9529 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj-art-9adf0c83848f4e1ab85bda08e4b0ec942024-12-12T10:11:12ZengCopernicus PublicationsSolid Earth1869-95101869-95292024-12-01151479150710.5194/se-15-1479-2024Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approachF. Gomar0J. B. Ruh1M. Najafi2F. Sobouti3Department of Earth Sciences, Institute for Advanced Studies in Basic Sciences, Zanjan, 45137-66731, IranInstitute of Marine Sciences, Consejo Superior de Investigaciones Científicas, 08003 Barcelona, SpainGeosciences Barcelona, Consejo Superior de Investigaciones Científicas, GEO3BCN-CSIC, 08028 Barcelona, SpainDepartment of Earth Sciences, Institute for Advanced Studies in Basic Sciences, Zanjan, 45137-66731, Iran<p>Understanding the tectonic evolution and crustal-scale structure of fold-and-thrust belts is crucial for exploring geological resources and evaluating seismic hazards. We conducted a series of two-dimensional finite difference thermomechanical numerical models with a visco–elasto–plastic/brittle rheology to decipher how the interaction between inherited basement faults and salt décollement levels control the deformation process and structural style of the Fars Arc in the Zagros fold-and-thrust belt during tectonic inversion. Numerical experiments with extension and consequent convergence phases indicate that strain accumulation patterns during initial rifting are controlled by the location and geometry of the prescribed faults. During convergence, the inverted basement faults form large-wavelength and foreland-verging fault-propagation anticlines in the sedimentary cover, while the thick salt layer promotes the growth of second-order detachment anticlines accompanied by both fore- and back-limb thrust faults. Experiments without prescribed basement faults result in dispersed brittle/plastic deformation during rifting and convergence and an effective mechanical decoupling along the salt horizon. Overall, reactivated faults can serve as pathways for stress transfer, resulting in the formation of new faults triggering seismic activity. The structural evolution of orogenic belts like the Zagros does not adhere to a fixed pattern; it is shaped by factors such as basement rock properties and inherited fault orientations. Shallow earthquakes predominantly occur along décollement anticlines in the sedimentary cover, while deeper and larger ones are associated with basement faults. We also observe variations in resistance to deformation based on salt rheology and fault geometry, with listric faults minimizing resistance. The degree of basement involvement directly influences the model's resistance to deformation, with greater involvement facilitating easier deformation. Our results, related to the temporal and spatial relationship between thin- and thick-skinned tectonics, can work as analogues for similar orogenic belts worldwide, such as Taiwan, the Pyrenees, the Alps, the Appalachians, and the Kopet Dagh.</p>https://se.copernicus.org/articles/15/1479/2024/se-15-1479-2024.pdf |
| spellingShingle | F. Gomar J. B. Ruh M. Najafi F. Sobouti Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach Solid Earth |
| title | Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach |
| title_full | Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach |
| title_fullStr | Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach |
| title_full_unstemmed | Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach |
| title_short | Importance of basement faulting and salt decoupling for the structural evolution of the Fars Arc (Zagros fold-and-thrust belt): a numerical modeling approach |
| title_sort | importance of basement faulting and salt decoupling for the structural evolution of the fars arc zagros fold and thrust belt a numerical modeling approach |
| url | https://se.copernicus.org/articles/15/1479/2024/se-15-1479-2024.pdf |
| work_keys_str_mv | AT fgomar importanceofbasementfaultingandsaltdecouplingforthestructuralevolutionofthefarsarczagrosfoldandthrustbeltanumericalmodelingapproach AT jbruh importanceofbasementfaultingandsaltdecouplingforthestructuralevolutionofthefarsarczagrosfoldandthrustbeltanumericalmodelingapproach AT mnajafi importanceofbasementfaultingandsaltdecouplingforthestructuralevolutionofthefarsarczagrosfoldandthrustbeltanumericalmodelingapproach AT fsobouti importanceofbasementfaultingandsaltdecouplingforthestructuralevolutionofthefarsarczagrosfoldandthrustbeltanumericalmodelingapproach |