Main Central Thrust
The Main Central Thrust is one of the north-dipping and NW—SE strike thrust faults along the Himalaya[1]. Generally speaking, the Main Central Thrust is the ductile shear zone, along which the Great Himalayan Crystalline complex was placed over the Lesser Himalayan Sequence.[2]
Geologic background
The Himalayan orogen is the production of the collision between continents of India and Asia. It is structurally dominated by three north-dipping, fault—bound units stacked by, from north to south, the Southern Tibetan Detachment, the Main Central Thrust, the Main Boundary Thrust and the Main Frontal Thrust[2]. These units, from south to north, are:
(1) The Lesser Himalayan Sequence (LHS), mainly low-grade Proterozoic metasediments to unmetamorphosed rocks, which is bound above by the Main Central Thrust. (2) The Greater Himalayan Crystalline complex (GHC), mainly high-grade gneiss and migmatite, which is bound below and above by the Main Central Thrust and the Southern Tibetan Detachment, respectively (3) The Tethyan Himalayan Sequence (THS), mainly Proterozoic to Eocene sediments. deformed in an Paleogene fold-thrust belt.[4] See figure 2 for the structural relationships between rock units and faults.
Kinematic models
To better understand the position and role of the Main Central Thrust, we should point out the kinematic models of Himalayan Orogen. Generally, there are three kinematic models for the emplacement of the Greater Himalayan Crystalline complex above the Main Central Thrust[5] shown in figure 3.
References
- ↑ Upreti, B. N. "An overview of the stratigraphy and tectonics of the Nepal Himalaya." Journal of Asian Earth Sciences 17.5 (1999): 577-606.
- ↑ 2.0 2.1 Helm, A., and A. Gansser. "Central Himalaya, Geological observations of the Swiss expedition 1936." Mdmoires de la Socidtd Helvdtique des Sciences Naturelles 73.1,245 (1939).
- ↑ Dèzes, Pierre, and Albrecht Steck. "Tectonic and metamorphic evolution of the central Himalayan domain in southeast Zanskar (Kashmir, India)." (1999).
- ↑ Webb, A. Alexander G. "Preliminary balanced palinspastic reconstruction of Cenozoic deformation across the Himachal Himalaya (northwestern India)." Geosphere 9.3 (2013): 572-587.
- ↑ Webb, A. Alexander G., et al. "Cenozoic tectonic history of the Himachal Himalaya (northwestern India) and its constraints on the formation mechanism of the Himalayan orogen." Geosphere 7.4 (2011): 1013-1061.