• A high-resolution (0.4°×0.4°) shear-wave velocity model of the middle-upper crust beneath the Gerze area in northern Tibet is constructed from ambient noise tomography with data from 42 new seismic stations and HI-CLIMB stations, providing new constraints on regional tectonic evolution. • The study identifies significant velocity contrasts across the 84°E-84.5°E tectonic boundary. East of 84.0°E, low velocities (3.0–3.3 km/s) dominate due to the superposition of Mesozoic and Cenozoic tectonic activities, while west of 84.0°E, high velocities (>3.5 km/s) dominate, suggesting a stable, unmodified crustal environment. • The Duolong ore district subsurface is characterized by high velocities at depths of 10–40 km, suggesting that mineralizing materials originate from deep crustal sources. The deep structure likely underwent cooling and consolidation due to Cenozoic uplift, which preserved ore bodies and high-velocity structures, especially in the stable crustal environment west of 84.0°E. To reveal the deep crustal structure of the Gerze region in western Tibet and the ore-forming mechanism of the Duolong ore district, this study combines newly deployed 42 broadband seismic stations with data from HI-CLIMB stations, using the ambient noise tomography to construct a high-resolution shear wave velocity model for depths of 0–40 km. Shallow low velocities are distributed near the Bangong Co-Nujiang suture zone, ranging from 2.8 to 3.2 km/s, consistent with tectonic features of the remnant Tethys Ocean suture zone. Below the South Qiangtang Terrane, , there are discontinuous low-velocity bodies at depths of 0–20 km, and low-velocity bodies at depths of 20–35 km correspond to the low-velocity, high-conductivity layer distributed among the large-scale Tibetan Plateau. A significant east–west difference in velocity structure is observed below 25 km, near 84°E-84.5°E. The eastern region is characterized by low-velocities (3.0–3.3 km/s), while the western part is dominated by high-velocities (3.6–3.8 km/s). The lower velocity structure east of 84°E and the exposure of Cenozoic potassium-rich volcanic rocks at the surface imply on the influence of Cenozoic tectonic uplift, while the higher velocities west of 84°E indicate a stable, unmodified crustal structure. The metallogenic background of the Duolong ore district is closely related to the subduction of the Bangong Co-Nujiang Ocean plate and magmatic activities. The high-velocity beneath the mining area is likely indicative of traces of magma upwelling, and the stable crustal environment west of 84.0°E is conducive to the preservation of mineral bodies and high-velocity structures. This study provides deep geophysical constraints for regional tectonic evolution and the metallogenic mechanism of the Duolong ore district.
Tan et al. (Fri,) studied this question.