Changes

===Definition of the Main Central Thrust by various criteria===

===Definition of the Main Central Thrust by various criteria===

Despite the above difficulties in defining the Main Central Thrust, the following definitions of the Main Central Thrust have been made by various criteria:<br />

Despite the above difficulties in defining the Main Central Thrust, the following definitions of the Main Central Thrust have been made by various criteria:

(1) by lithologic criterion, the Main Central Thrust is defined as the boundary between the quartzite and phyllite, which belong to the Lesser Himalayan Sequence, and the orthogneiss biotite-rich schist, which belong to the Greater Himalayan Crystalline complex<ref name=":2"/><ref>Daniel, C. G., et al. "Exhumation of the Main Central Thrust from lower crustal depths, eastern Bhutan Himalaya." Journal of Metamorphic Geology 21.4 (2003): 317-334.</ref>.<br />

# by lithologic criterion, the Main Central Thrust is defined as the boundary between the quartzite and phyllite, which belong to the Lesser Himalayan Sequence, and the orthogneiss biotite-rich schist, which belong to the Greater Himalayan Crystalline complex<ref name=":2"/><ref>Daniel, C. G., et al. "Exhumation of the Main Central Thrust from lower crustal depths, eastern Bhutan Himalaya." Journal of Metamorphic Geology 21.4 (2003): 317-334.</ref>.<br />

 

# by metamorphic isograd, the Main Central Thrust follows the [[kyanite]] isograd. Under this criterion, the crystals of kyanite appears upward only within several meters of the lithologic change stated in the above<ref>Le Fort, Patrick. "Himalayas: the collided range. Present knowledge of the continental arc." Am. J. Sci 275.1 (1975): 1-44.</ref>.<br />

(2) by metamorphic isograd, the Main Central Thrust follows the [[kyanite]] isograd. Under this criterion, the crystals of kyanite appears upward only within several meters of the lithologic change stated in the above<ref>Le Fort, Patrick. "Himalayas: the collided range. Present knowledge of the continental arc." Am. J. Sci 275.1 (1975): 1-44.</ref>.<br />

# by the differences in U—Pb detrital zircon ages, 1.87-1.0 Ga zircons have been reported from the Lesser Himalayan Sequence which is bound above by the Main Central Thrust, and 0.8-1.0 Ga zircons have been reported from the Greater Himalayan Sequence which is bound below by the Main Central Thrust<ref>Parrish, Randall R., and V. Hodges. "Isotopic constraints on the age and provenance of the Lesser and Greater Himalayan sequences, Nepalese Himalaya." Geological Society of America Bulletin 108.7 (1996): 904-911.</ref>.<br />

 

# by the Nd isotope composition, different Nd composition (for example, an average Nd value of -21.5 has been reported in the Lesser Himalayan Sequence while an average [[Nd]] value of -16 has been reported in the Greater Himalayan Sequence) marks the Main Central Thrust<ref> Robinson, Delores M., et al. "The kinematic evolution of the Nepalese Himalaya interpreted from Nd isotopes." Earth and Planetary Science Letters 192.4 (2001): 507-521.</ref>.<br />

(3) by the differences in U—Pb detrital zircon ages, 1.87-1.0 Ga zircons have been reported from the Lesser Himalayan Sequence which is bound above by the Main Central Thrust, and 0.8-1.0 Ga zircons have been reported from the Greater Himalayan Sequence which is bound below by the Main Central Thrust<ref>Parrish, Randall R., and V. Hodges. "Isotopic constraints on the age and provenance of the Lesser and Greater Himalayan sequences, Nepalese Himalaya." Geological Society of America Bulletin 108.7 (1996): 904-911.</ref>.<br />

# by strain, the Main Central Thrust is defined as a broad zone which a few kilometers thick. This zone accommodated most of the ductile shear zones and brittle thrust faults between the lowermost part of the Greater Himalayan Crystalline complex and the uppermost part of the Lesser Himalayan Sequence<ref name=":9"/><ref> Searle, M. P., et al. "The structural geometry, metamorphic and magmatic evolution of the Everest massif, High Himalaya of Nepal–South Tibet." Journal of the Geological Society 160.3 (2003): 345-366.</ref>.

 

(4) by the Nd isotope composition, different Nd composition (for example, an average Nd value of -21.5 has been reported in the Lesser Himalayan Sequence while an average [[Nd]] value of -16 has been reported in the Greater Himalayan Sequence) marks the Main Central Thrust<ref> Robinson, Delores M., et al. "The kinematic evolution of the Nepalese Himalaya interpreted from Nd isotopes." Earth and Planetary Science Letters 192.4 (2001): 507-521.</ref>.<br />

 

(5) by strain, the Main Central Thrust is defined as a broad zone which a few kilometers thick. This zone accommodated most of the ductile shear zones and brittle thrust faults between the lowermost part of the Greater Himalayan Crystalline complex and the uppermost part of the Lesser Himalayan Sequence<ref name=":9"/><ref> Searle, M. P., et al. "The structural geometry, metamorphic and magmatic evolution of the Everest massif, High Himalaya of Nepal–South Tibet." Journal of the Geological Society 160.3 (2003): 345-366.</ref>.

==Prospect==

==Prospect==