A research of geoelectric structure in the western Himalayas and Tibet

Abstract:

We made high-resolution, 2D and 3D geoelectric models for the western Himalayas and Tibet from the NLCG inversion method using 0.01~10000s magnetotellurics(MT) data in 80°E and 81°E from the MT standard array grid spacing of 1°× 1° in Qinghai-Tibetan Plateau which is collected in the project SinoProbe. The areas covered the Karakoram and Altan-Tagh faults, and major terrane boundaries in West Tibet and the Himalayas which mainly show as high conductivity body in models while all the block is low under the depth of about 30~40km. And the depth of 40~90 km present a widely high-conductivity zone which is believed as partial malt in Tibetan Plateau. We do not observed significant evidence of Moho beneath West Tibet. Beneath the Lhasa Terrane and Tethyan Himalayas, we find out a high-resistivity zone in the depth of 90km which we believed it is the evidence of Indian plate subduction here and downwelling of the Indian lithospheric mantle occurred beneath here which is similar to central Tibet. This feature is not stopped by the Karakoram Fault, implying that the Karakoram Fault does not cut through the entire crust.

This research is supported by “the Fundamental Research Funds for the Central Universities".