Details of the Abstract
| Title of paper | Another Possibility of the Crustal High Conductivity Zone in the Western Tibetan Plateau |
| List of authors | Gu, J., Jin, S., Dong, H. |
| Affiliation(s) |
1 SGIDI Engineering Consulting (Group) Co., Ltd, Shanghai, China, 2 School of Geophysics and Information Technology, China University of Geosciences, Beijing, China, 3 School of Geophysics and Information Technology, China University of Geosciences, Beijing, China, |
| Summary |
The Tibetan Plateau is known as a natural laboratory for geodynamic research due to its unique surface geometry and tectonic complexity. However, limited previous geophysical surveys in the western Tibet Plateau have left its deep three-dimensional structure poorly understood. To address this, magnetotellurics data from the SinoProbe and INDEPTH-MT projects were used to establish the first crustal-scale three-dimensional electrical structure across the region from the Himalaya to the Qiangtang block, which may provide new insights into the geodynamic characteristics of the western Tibetan Plateau, including its crustal evolution and material transport. The electrical model shows that the mid-upper crust in the study area and the Bangong Lake-Nujiang suture zone are high-resistance structures. In the north-central Qiangtang block, a barrel-shaped high conductor extends from about 20 km depth to near the Moho surface. This high conductor was also observed in the middle crust of the Lhasa block, extending northwards from ~20 km below the Himalayan region to near the Moho surface of the Bangong Lake - Nujiang suture zone. Below the high conductor in the Lhasa’s middle crust, a relatively high resistance body was observed. To further understand the characteristics and origin of these high conductivity zones, the relationship between the conductivity of different minerals/geofluids with temperature, pressure, and water content was used, which were calibrated by petrophysical experiments. Through this analysis, the high conductivity zone in the Qiangtang block was found to represent a highly partial melting zone (i.e., a magma chamber) associated with mantle melt uplift. In contrast, the high conductivity zone in the Lhasa crust may indicate the crystal fractionation of lower crustal melts formed carbonated-silicate melts, suggesting the involvement of CO2 in the evolution of the juvenile Lhasa crust. |
| Session Keyword | 4.0 Tectonics and geodynamics, including magmatism |
| File upload |
4.0_another_possibility_of_th_gu_01.pdf
|