Crustal Structure of the Northeastern Tibetan Plateau from the Southern Tarim Basin to the Sichuan Basin, China

Structure of the crust and mantle down to 700 km depth beneath the East Qaidam basin and Qilian Shan from P and S receiver functions

“…• N a Moho depth of 55-60 km is obtained by Wang et al (2013) Fig. 1 and Cui et al 1995;Gao et al 1995) which crosses the Qilian Shan about 200 km to the WNW of this study, maximum Moho depths of 75-80 km were obtained beneath the south Qilian Shan.…”

“…A comparison between Moho depths obtained from this study and those from the wide-angle reflection/refraction profile from the Tarim basin via the Qaidam basin to the Sichuan basin (B in Fig. 1 and Wang et al 2013) shows that at the point of intersection at about 36…”

“…The S receiver function image is along the same profile but extends about an extra 1.5 • both to the south and north. The dashed white lines mark the locations of previously completed seismic profiles including the INDEPTH IV profile (A, Zhao et al 2011), the Tarim basin -Qaidam basin -Sichuan basin profile (B, Wang et al 2013), the Golmud -Ejin Qi profile (C, Cui et al 1995;Gao et al 1995) and a short profile crossing the North Kunlun Thrust in the southeast corner of the Qaidam basin (D, Shi et al 2009). the Tibetan plateau mainly to the south over the past 20 yr and thus have provided images beneath the plateau down to about 700 km depth (e.g. Kosarev et al 1999;Kind et al 2002;Vergne et al 2002;Wittlinger et al 2004Wittlinger et al , 2009Nábělek et al 2009;Shi et al 2009;Zhao et al 2010Zhao et al , 2011.…”

Partially melted, mica-bearing crust in Central Tibet

“…Some of this evidence is geographically localized—such as observations of low electrical resistivity in the middle to lower crust [e.g., Unsworth et al ., ; Bai et al ., ] and strong P to S conversion bright spots on active‐source wide‐angle reflection data that have been cited as indicating midcrustal melt or fluids [e.g., Makovsky and Klemperer , ; Makovsky et al ., ]. Localized seismological evidence that points to a midcrustal low‐velocity layer derives from surface wave dispersion, receiver function, and wide‐angle reflection studies [e.g., Kind et al ., ; Cotte et al ., ; Rapine et al ., ; Mechie et al ., ; Jiang et al ., ; Xu et al ., ; Caldwell et al ., ; Guo et al ., ; Li et al ., ; Wang et al ., ; Xu et al ., ]. Other evidence, more broadly distributed across Tibet, includes the absence of middle to lower crustal earthquakes [e.g., Chu et al ., ; Sloan et al ., ], extensive Cenozoic volcanism [e.g., Chung et al ., ], satellite magnetic anomalies consistent with a raised Curie isotherm [ Alsdorf and Nelson , ], strong crustal attenuation [e.g., Xie , ; Rai et al ., ; Levshin et al ., ], pervasive slow speeds in seismological models of the middle crust [e.g., Villaseñor et al ., ; Shapiro and Ritzwoller , ; Yao et al ., ; Acton et al ., ; Yao et al ., ; Jiang et al ., ; Yang et al ., ], and strong midcrustal radial anisotropy [e.g., Shapiro et al ., ; Duret et al ., ; Huang et al ., ; Xie et al ., ].…”

Continental dynamics of Eastern China: Insights from tectonic history and receiver function analysis

“…The P-wave velocities in the lower crust of the Dabie-Sulu orogenic belt range from 6.7 to 7.1 km/s, with an average of 6.9 km/s (Gao et al, 1999), which is lower than that of the global average P-wave velocity (7.14 km/s) (Rudnick and Fountain, 1995). The above results exclude the possibility that the lower crust has mafic/ultramafic composition in this area Chen et al, 2010;Stratford and Thybo, 2011;Zhang et al, 2012c;Wang et al, 2013c).…”