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Line 31: − + − − (1) the lithology and stratigraphy have not been completely investigated and understood<br /> − − (2) the metamorphic grades across the Main Central Thrust shear zone are continuously changing, thus any one particular [[isograd]] is not reliable for determining the location of the Main Central Thrust<br /> + +
→Various definitions of the Main Central Thrust
Although the general definition of the Main Central Thrust has been given, it is not enough due to the complication and difficulties in defining the Main Central Thrust.<br />
Although the general definition of the Main Central Thrust has been given, it is not enough due to the complication and difficulties in defining the Main Central Thrust.<br />
For long, many researchers have defined the Main Central Thrust by different criteria, including by lithology different between the hanging wall and the footwall, by metamorphic grade change from the hangingwall to the footwall, by the different U—Pb detrital [[zircon]] ages, by the different Nd isotope compositions, by the different strain, etc. Some of these criteria has also been combined. However, none of these criteria can be reliable if they are used independently<ref name=":9">Searle, Michael P., et al. "Defining the Himalayan main central thrust in Nepal."Journal of the Geological Society 165.2 (2008): 523-534.</ref>. Meanwhile, these criteria cannot all be satisfied neither<ref name=":10">Yin, An. "Cenozoic tectonic evolution of the Himalayan orogen as constrained by along-strike variation of structural geometry, exhumation history, and foreland sedimentation." Earth-Science Reviews 76.1 (2006): 1-131.</ref>. The most dominating problems are:<br />
For long, many researchers have defined the Main Central Thrust by different criteria, including by lithology different between the hanging wall and the footwall, by metamorphic grade change from the hangingwall to the footwall, by the different U—Pb detrital [[zircon]] ages, by the different Nd isotope compositions, by the different strain, etc. Some of these criteria has also been combined. However, none of these criteria can be reliable if they are used independently<ref name=":9">Searle, M. P., R. D. Law, L. Godin, K. P. Larson, M. J. Streule, J. M. Cottle & M. J. Jessup, 2008, Defining the Himalayan main central thrust in Nepal: Journal of the Geological Society, vol. 165.2, pp. 523-534.</ref>. Meanwhile, these criteria cannot all be satisfied neither<ref name=":10">Yin, A., 2006, Cenozoic tectonic evolution of the Himalayan orogen as constrained by along-strike variation of structural geometry, exhumation history, and foreland sedimentation: Earth-Science Reviews, vol. 76.1, pp. 1-131.</ref>. The most dominating problems are:
# the lithology and stratigraphy have not been completely investigated and understood<br />
# the metamorphic grades across the Main Central Thrust shear zone are continuously changing, thus any one particular [[isograd]] is not reliable for determining the location of the Main Central Thrust<br />
===Definition of the Main Central Thrust by various criteria===
===Definition of the Main Central Thrust by various criteria===