Sedimentary and crustal velocity structure of central and southern Mongolia from joint inversion of Rayleigh wave phase velocity, ellipticity and teleseismic P waveform

A high-resolution 3-D shear wave velocity model of the crust beneath central and southern Mongolia was established to understand suture zone and regional tectonics. The model was derived by a joint inversion of Rayleigh wave phase velocities and ellipticities and stacked teleseismic P waveforms. The surface and body wave measurements were made, respectively, from ambient noise and teleseismic data recorded by Central and Southern Mongolia Array. There are significant differences in Rayleigh wave phase velocities, Rayleigh wave ellipticities, sediment basement depths, Moho depths, average crustal shear wave velocity between two sides of the Mongolia-Okhotsk Suture and the Main Mongolian Lineament, suggesting that these two sutures are crustal faults at least. In the Middle Gobi Belt, Middle Gobi volcano and Bus-Obo volcano are interconnected in the crust, and there is a large low-velocity layer in the lower crust, which implies the magma chamber of the two intraplate volcanoes exists there. Furtherly it is speculated that the magma chamber is related with underplating by mantle convection beneath Hangay Dome.