多玛—德庆—达孜断面壳幔密度结构特征

Density Sructure of Crust and Mantle Beneath Duoma-Deqing-Dazi Profile

利用人机交互重震联合反演的方法研究了多玛-德庆-达孜断面的二维壳幔横向密度结构特征。模拟结果显示，剖面下的地壳内部大部分存在低速层，念青唐古拉山两侧的德庆、羊八井附近存在两条深大正断层，切割并抬升了其下的中地壳低密度层，低密度层整体被向上抬升5～10km，使得念青唐古拉山深部表现为一个地垒构造。念青唐古拉山位于莫霍面由浅变深的缓坡上，向东逐渐变深。软流圈在念青唐古拉山下形状发生变化，表现为“上凸”特征。

On the basis of some existing studies, the authors study the transverse density structure of the crust and mantle beneath the Duoma-Deqing-Dazi profile using gravity-seismic integrated inversion method. The modeling results state that some low-density layers exist beneath most parts of profile. Two deep normal faults exist on both sides of the Nyainqentanghla Mountain and cut off the low-density layer. The low-density layer beneath Nyainqentanghla Mountain was uplifted from 5 to 10 km higher than others. Thus, the density structure beneath Nyainqentanghla Mountain like a horst. From the mountain to Duoma, the depth of Moho is basically even, but from the mountains to Dazi, namely from west to east, Moho beneath the profile is deeper and deeper. By contrast with the depth of Moho, the top of Asthenosphere beneath Nyainqentanghla is protuberant, like a anticline.