Fine structures of the crust and upper mantle of the basin-and-range juncture on the northwestern margin of the Qinghai-Tibetan Plateau are first delineated by the deep seismic reflection profile across the juncture z...Fine structures of the crust and upper mantle of the basin-and-range juncture on the northwestern margin of the Qinghai-Tibetan Plateau are first delineated by the deep seismic reflection profile across the juncture zone between the Tarim Basin and the West Kunlun Mountains. Evidence is found for the northward subduction of the northwest marginal lithosphere of the Qinghai-Tibetan Plateau and its collision with Tarim lithosphere beneath the West Kunlun Mountains. The lithosphere image of the face-to-face subduction and collision determines the coupling relationship between the Tarim Basin and the West Kunlun Mountains at the lithosphere scale and reflects the process of continent- continent collision.展开更多
The deep seismic sounding profile across the Tianshan Mountains revealed a two-layer crustal structure in the Tianshan region, namely the lower and upper crusts. Lateral variations of layer velocity and thickness are ...The deep seismic sounding profile across the Tianshan Mountains revealed a two-layer crustal structure in the Tianshan region, namely the lower and upper crusts. Lateral variations of layer velocity and thickness are evidently shown. Low-velocity layers spread discontinuously at the bottom of the upper crust. The Mono depth is 47 km in the Kuytun area and 50 km in the Xayar area. In the Tianshan Mountains, the Moho becomes deeper with the maximum depth of 62 km around the boundary between the southern and northern Tianshan Mountains. The average velocity ranges from 6.1 to 6.3 km/s in the crust and 8.15 km/s at the top of the upper mantle. Two groups of reliable reflective seismic phases of the Moho (Pm1 and Pm2) are recognized on the shot record section of the Kuytun area. A staked and offset region, 20-30 km long, is displayed within a shot-geophone distance of 190-210 km in Pm1 and Pm2. Calculation shows that the Moho is offset by 10 km in the northern Tianshan region, 62 km deep in the south while展开更多
文摘Fine structures of the crust and upper mantle of the basin-and-range juncture on the northwestern margin of the Qinghai-Tibetan Plateau are first delineated by the deep seismic reflection profile across the juncture zone between the Tarim Basin and the West Kunlun Mountains. Evidence is found for the northward subduction of the northwest marginal lithosphere of the Qinghai-Tibetan Plateau and its collision with Tarim lithosphere beneath the West Kunlun Mountains. The lithosphere image of the face-to-face subduction and collision determines the coupling relationship between the Tarim Basin and the West Kunlun Mountains at the lithosphere scale and reflects the process of continent- continent collision.
文摘The deep seismic sounding profile across the Tianshan Mountains revealed a two-layer crustal structure in the Tianshan region, namely the lower and upper crusts. Lateral variations of layer velocity and thickness are evidently shown. Low-velocity layers spread discontinuously at the bottom of the upper crust. The Mono depth is 47 km in the Kuytun area and 50 km in the Xayar area. In the Tianshan Mountains, the Moho becomes deeper with the maximum depth of 62 km around the boundary between the southern and northern Tianshan Mountains. The average velocity ranges from 6.1 to 6.3 km/s in the crust and 8.15 km/s at the top of the upper mantle. Two groups of reliable reflective seismic phases of the Moho (Pm1 and Pm2) are recognized on the shot record section of the Kuytun area. A staked and offset region, 20-30 km long, is displayed within a shot-geophone distance of 190-210 km in Pm1 and Pm2. Calculation shows that the Moho is offset by 10 km in the northern Tianshan region, 62 km deep in the south while
