Abstract
AbstractWe present new high‐resolution Pn velocity and anisotropy models beneath Mongolia and the adjacent regions by inverting 169,406 Pn arrivals. The data are selected from 786 permanent stations and 106 portable seismographs recently deployed in Mongolia and China's Inner Mongolia. The availability of new data acquired has allowed us to explore the uppermost mantle structures in great detail in this region, and the 2° × 2° model resolution is capable of distinguishing small‐scale geological features. Pn average velocity is 8.18 km/s, substantially faster than the global average. Distinct contrast in the velocity of the uppermost mantle is observed between the central part and two ends of the Baikal Rift, with the presence of higher velocities under the Central Baikal Rift, indicating strong variation of lithospheric thinning across the entire Baikal Rift. Low velocity beneath the Hangay Dome implies partial melting of mantle reflected by asthenospheric upwelling. Azimuthal anisotropy in the upper and lower mantle lid is measured by grouping the travel time data into two phases by epicenter distance. The obvious depth dependence of Pn anisotropy beneath the Hentey Mountains suggests different origins of fabrics. The lower anisotropy may origin from asthenospheric flow, while the shallower fabric may exhibit the preserved lattice preferred orientation anisotropy in the uppermost mantle. Meanwhile, depth‐dependent anisotropic structures and significantly low velocity are found beneath Tien Shan, most possibly suggesting that the lithospheric mantle thinning is experienced by either delamination or local asthenospheric upwelling.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.