中文摘要：

青藏高原东北缘是研究高原隆升和演化的理想场所，其岩石圈结构记录了高原向外扩展的岩石圈变形行为和演化过程，本研究利用一条跨青藏高原东北缘的宽频带观测剖面（红原—景泰剖面）和部分甘肃、青海区域台网的远震体波波形资料，通过S波接收函数方法获得了青藏高原东北缘的岩石圈—软流圈边界（LAB）图像。结果表明：1）松潘—甘孜地体东北部和西秦岭造山带下方的岩石圈较薄，略向北加厚，其LAB深度为110—130km，昆仑断层下方无明显岩石圈错断，推测松潘—甘孜地块与西秦岭造山带的岩石圈可能具有亲缘性；2）祁连地块下方的岩石圈厚度为135—150km，其中祁连造山带东缘的LAB震相不聚焦，反映复杂的造山带型岩石圈属性；3）阿拉善地块下方岩石圈略向南加厚，LAB深度为130～150km，呈向祁连造山带下方汇聚的趋势，但尚未通过海原断裂带；4）鄂尔多斯地块下方的岩石圈较厚，LAB深度为160～170km，反映其稳定的克拉通型岩石圈属性。

英文摘要：

The northeastern （NE） Tibetan Plateau is an ideal place for the studY of plateau uplift and evolution. Its lithosphere records the process of the lithospheric deformation transforming from the Tibet to the stable Alashan and Ordos blocks. Here, using the dense passive-source seismic profile across the NE Tibet and the regional seismic networks of Gansu and Qinghai Provinces, we isolate S receiver functions from the teleseismic S and SKS wave data and resolve the spatial distribution of the lithosphere-asthenosphere boundary （LAB） across the NE Tibetan Plateau. Our observations demonstrate that： 1） Beneath the northeastern Songpan-Ganzi terrane and the ,i West Qinling orogenic belt, ,the LAB lies at 110~ 130 km which dips at a shallow angle to the northeast, and none lithospheric offset is observed beneath the East Kunlun fault. The smooth LAB may indicate an intact lithosphere between these two blocks; 2 ） The lithospheric thickness is 135 - 150 km beneath the Qilian block, and the LAB phases are dispersive beneath the Qilian orogenic belt, in the western part of the Qilian block. The dispersive LAB phases may imply a complex tectonic lithosphere ; 3） The LAB of the Alashan block lies at 130 -150 km, which seems to converging beneath the Qilian block, but dose not across the Haiyuan fault, yet; 4） The lithospheric thickness of the Ordos block is 160- 170 km, which imply a thick and rigid eraton lithosphere.