【摘要】 本文综述了我们在青藏高原东缘实施的垂直切过龙门山断裂带宽频带地震探测的研究成果,揭示了研究区复杂的地壳上地幔结构,结果表明松潘—甘孜地块与四川盆地西缘莫霍而深度为58 km与40 km±,在龙门山断裂带下方存在约15 km的莫霍面错断;松潘—甘孜与龙门山断裂带域地壳纵横波速度比V_p/V_s比值远大于1.73,预示着粘性下地壳流或基性/超基性物质的存在。探讨了研究区强烈的盆山之间以及深部不同层圈之间的相互作用,推断四川盆地对青藏高原东缘软流圈驱动的物质东向逃逸阻挡作用可能深达整个上地幔。更多还原

【Abstract】 We summarize results from broadband passive source tele-seismic observation across Longmenshan fault belt on the eastern margin of Tibetan Plateau, and reveal the complex arichtecture of the crust and upper mantle in the studied area. The results demonstrate crustal thickness thins from about 58 km under Songpan-Ganzi to about 40 km under Sichuan Basin, and about 15 km Moho offset beneath Longmenshan fault belt; much larger than 1.73 of the average crustal V_p/V_s beneath Songpan-Ganzi and Longmenshan fault belt suggests the existence of viscous lower crust or mafic/super-mafic materials in their crusts. We make further discussion on the interaction between Tibetan Plateau and its neighboring Sichuan Basin, and among crust,lithosphere and asthenosphere,and infer the Sichuan Basin barrier to the eastward Tibetan Plateau’s flow may reach to the upper mantle.更多还原