Crustal structure beneath the Abaga area of Xing'an-Mongolia Orogenic Belt using teleseismic receiver functions

The crustal thickness and average crustal V-p/V-s, velocity ratio beneath the region of Abaga volcano are obtained by P wave receiver functions. Primary data are recorded by 38 seismic stations deployed in the Abaga area. We also apply a common conversion point stacking (CCP) approach to investigate the characteristics of Moho. Our results reveal that the local crustal thickness ranges from 35 to 44 km with an average value of 40 km. Thicker crust is found beneath the edge of Ordos basin, while thinner crust is distributed in the Abaga volcano region. The measured crustal V-p/V-s ratio varies from 1. 70 to 1. 87, with an average value of 1. 76. High V-p/V-s ratio is found beneath the Abaga volcanic region, correlating perfectly with the Cenozoic volcanic cluster. CCP stacking results show that Moho discontinuity beneath the study area is relatively flat with some small-scale variations at the suture zones. Thin crustal thickness and high V-p/V-s ratios beneath Cenozoic Abaga volcanic region may imply the underplating by volcanic activity, resulting in the intrusion of a large amount of mafic basalts into the crust.