| Autor: |
Tian, Yuntao, Kohn, Barry P., Phillips, David, Hu, Shengbiao, Gleadow, Andrew J. W., Carter, Andrew |
| Zdroj: |
Tectonics; Oct2016, Vol. 35 Issue 10, p2293-2312, 20p |
| Abstrakt: |
This study presents structural and 40Ar/39Ar geochronological data from the southern part of the Longmen Shan fold-and-thrust belt that forms the eastern margin of the Tibetan Plateau. Investigations focused on hinterland ductile top-to-the-WNW shear deformation, which has been linked previously to late Cenozoic lower crustal flow. Consistent with previous studies, the sense of deformation is mapped as top-to-the-WNW in the Longmen Shan hinterland. The timing of the deformation is constrained by 40Ar/39Ar geochronological data of recrystallized minerals aligned along the shear foliation as Late Cretaceous-earliest Paleogene, thus predating the inferred late Cenozoic crustal flow. This deformation is contemporaneous with SE verging thrusting and loading along the Longmen Shan front, which formed a coeval ~2-3 km thick foredeep sequence along the southwestern margin of the Sichuan Basin. In the context of the regional geology, this tectonic configuration could result from either extrusion of a crustal wedge or back thrust in a duplex. Compared to other orogens, where similar crustal configurations have been reported, it is speculated that the eastern Tibetan Plateau margin acquired thickened crust and highly elevated topography in Late Cretaceous-earliest Paleogene time. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text