Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models
The salt layer is critical for the structural deformation in the salt-bearing fold-and-thrust system, which not only acts as the efficient décollement layer but also flows to form salt tectonics. Kuqa Depression has a well-preserved thin-skinned fold-and-thrust system with the salt layer as the déco...
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doaj-a2ae911a422d402fac3218f6dd790cd72021-08-24T10:47:17ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632021-08-01910.3389/feart.2021.655173655173Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element ModelsChangsheng Li0Changsheng Li1Changsheng Li2Hongwei Yin3Zhenyun Wu4Zhenyun Wu5Peng Zhou6Wei Wang7Rong Ren8Shuwei Guan9Xiangyun Li10Haoyu Luo11Dong Jia12State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, ChinaSchool of Earth Sciences, East China University of Technology, Nanchang, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, ChinaState Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, ChinaSchool of Earth Sciences, East China University of Technology, Nanchang, ChinaResource Exploration Office, Tarim Oilfield Branch Company, PetroChina, Korla, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, ChinaPetroChina Research Institute of Petroleum Exploration and Development, Beijing, ChinaPetroChina Research Institute of Petroleum Exploration and Development, Beijing, ChinaResearch Institute of Petroleum Exploration and Development, Tarim Oilfield Branch Company, PetroChina, Korla, ChinaResearch Institute of Petroleum Exploration and Development, Tarim Oilfield Branch Company, PetroChina, Korla, ChinaSchool of Earth Sciences and Engineering, Nanjing University, Nanjing, ChinaThe salt layer is critical for the structural deformation in the salt-bearing fold-and-thrust system, which not only acts as the efficient décollement layer but also flows to form salt tectonics. Kuqa Depression has a well-preserved thin-skinned fold-and-thrust system with the salt layer as the décollement. To investigate the effects of salt thickness on the structural deformation in the Kuqa Depression, three discrete element models with different salt thicknesses were constructed. The experiment without salt was controlled by several basal décollement dominant faults, forming several imbricate sheets. The experiments with salt developed the decoupled deformation with the salt layer as the upper décollement (subsalt, intrasalt, and suprasalt), significantly similar to the Kuqa Depression along the northern margin of Tarim Basin. Basal décollement dominant imbricated thrusts formed at the subsalt units, while the monoclinal structure formed at the suprasalt units. The decoupled deformation was also observed in the tectonic deformation graphics, distortional strain fields, and max shear stress fields. However, the salt layer was thickened in the thick salt model, and the salt thickness of the thin salt model varied slightly because the thin salt weakened the flowability of the salt. The lower max shear stress zone was easily formed in the distribution region of salt under the action of compression stress, which is conducive to the flow convergence of salt and the crumpled deformation of interlayer in salt. The results are well consistent with the natural characteristics of structural deformation in the Kuqa Depression. Our modeling result concerns the structural characteristics and evolution of salt-related structures and the effects of salt thickness on the structural deformation in the compressional stress field, which might be helpful for the investigations of salt-related structures in other salt-bearing fold-and-thrust belts.https://www.frontiersin.org/articles/10.3389/feart.2021.655173/fullsalt-related structuressalt thicknessKuqa DepressionDEMstrain-stress |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Changsheng Li Changsheng Li Changsheng Li Hongwei Yin Zhenyun Wu Zhenyun Wu Peng Zhou Wei Wang Rong Ren Shuwei Guan Xiangyun Li Haoyu Luo Dong Jia |
spellingShingle |
Changsheng Li Changsheng Li Changsheng Li Hongwei Yin Zhenyun Wu Zhenyun Wu Peng Zhou Wei Wang Rong Ren Shuwei Guan Xiangyun Li Haoyu Luo Dong Jia Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models Frontiers in Earth Science salt-related structures salt thickness Kuqa Depression DEM strain-stress |
author_facet |
Changsheng Li Changsheng Li Changsheng Li Hongwei Yin Zhenyun Wu Zhenyun Wu Peng Zhou Wei Wang Rong Ren Shuwei Guan Xiangyun Li Haoyu Luo Dong Jia |
author_sort |
Changsheng Li |
title |
Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models |
title_short |
Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models |
title_full |
Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models |
title_fullStr |
Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models |
title_full_unstemmed |
Effects of Salt Thickness on the Structural Deformation of Foreland Fold-and-Thrust Belt in the Kuqa Depression, Tarim Basin: Insights From Discrete Element Models |
title_sort |
effects of salt thickness on the structural deformation of foreland fold-and-thrust belt in the kuqa depression, tarim basin: insights from discrete element models |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Earth Science |
issn |
2296-6463 |
publishDate |
2021-08-01 |
description |
The salt layer is critical for the structural deformation in the salt-bearing fold-and-thrust system, which not only acts as the efficient décollement layer but also flows to form salt tectonics. Kuqa Depression has a well-preserved thin-skinned fold-and-thrust system with the salt layer as the décollement. To investigate the effects of salt thickness on the structural deformation in the Kuqa Depression, three discrete element models with different salt thicknesses were constructed. The experiment without salt was controlled by several basal décollement dominant faults, forming several imbricate sheets. The experiments with salt developed the decoupled deformation with the salt layer as the upper décollement (subsalt, intrasalt, and suprasalt), significantly similar to the Kuqa Depression along the northern margin of Tarim Basin. Basal décollement dominant imbricated thrusts formed at the subsalt units, while the monoclinal structure formed at the suprasalt units. The decoupled deformation was also observed in the tectonic deformation graphics, distortional strain fields, and max shear stress fields. However, the salt layer was thickened in the thick salt model, and the salt thickness of the thin salt model varied slightly because the thin salt weakened the flowability of the salt. The lower max shear stress zone was easily formed in the distribution region of salt under the action of compression stress, which is conducive to the flow convergence of salt and the crumpled deformation of interlayer in salt. The results are well consistent with the natural characteristics of structural deformation in the Kuqa Depression. Our modeling result concerns the structural characteristics and evolution of salt-related structures and the effects of salt thickness on the structural deformation in the compressional stress field, which might be helpful for the investigations of salt-related structures in other salt-bearing fold-and-thrust belts. |
topic |
salt-related structures salt thickness Kuqa Depression DEM strain-stress |
url |
https://www.frontiersin.org/articles/10.3389/feart.2021.655173/full |
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