| Autor: |
Santanu Bose, Shamik Sarkar, Puspendu Saha, Nibir Mandal, Carolina Lithgow-Bertelloni |
| Rok vydání: |
2014 |
| Předmět: |
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| Zdroj: |
Journal of Structural Geology. 67:37-49 |
| ISSN: |
0191-8141 |
| Popis: |
We performed a series of sandbox experiments to investigate the initiation of thrust ramping in tectonic wedges on a mechanically continuous basal decollement. The experiments show that the decollement slope ( β ) is the key factor in controlling the location of thrust initiation with respect to the backstop (i.e. tectonic suture line). For β = 0, the ramping begins right at the backstop, followed by sequential thrusting in the frontal direction, leading to a typical mono-vergent wedge. In contrast, the ramp initiates away from the backstop as β > 0. Under this boundary condition an event of sequential back thrusting takes place prior to the onset of frontal thrust progression. These two-coupled processes eventually give rise to a bi-vergent geometry of the thrust wedge. Using the Drucker-Prager failure criterion in finite element (FE) models, we show the location of stress intensification to render a mechanical basis for the thrust initiation away from the backstop if β > 0. Our physical and FE model results explain why the Main Central Thrust (MCT) is located far away from the Indo-Tibetan plate contact (ITSZ) in the Himalayan fold-and-thrust belts. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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