Material state and tectonic dynamics in the vicinity of the Dinggye region, central part of the Tethys-Himalaya terrane: Insights from the magnetotelluric method

The Tethys-Himalaya terrane in the north of the Himalayan orogenic belt is characterized by pervasive extensional structures such as N–S-trending normal rifts and the North Himalayan Gneiss Dome (NHGD). The Dinggye region is located in the central part of the Tethys-Himalaya terrane. The southern segment of the Xainza-Dinggye rift (XDR) and the Mabja Gneiss Dome are distributed in this region. In this work, we generate a new 3-D electrical resistivity model from an array of magnetotelluric data in the Dinggye region and examine it in addition to other electrical resistivity models to the north and east from previous works. By comparing the geophysical models with available geological and geochemical evidence, we find a clear relationship between the electrical resistivity structure, the presence of gneiss domes, north-south-trending normal rifting, and deep plunging subduction which is related to the source of Helium isotopes (crustal or mantle origin). Overall, the results suggest that the southern migration of lithospheric materials likely contributed to the evolution of the rifts in the Tethys-Himalaya terrane, which also may have been influenced by uplifting and cooling of gneiss domes. The models are consistent with tearing of the Indian lithosphere beneath the Xainza-Dinggye rift and other adjacent rifts. Additionally, the difference in the electrical structure related to the Indian crust along the east-west direction likely results from the exhumation of the continental slab, metamorphism in the Tethys-Himalaya terrane, and southern extrusion of materials in the Lhasa terrane.