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根据阿尔泰—阿尔金地学断面的地震纵、横波资料 ,建立了地壳速度及泊松比结构 .测区的地壳具有明显的三分结构特征 ,其纵波速度自上而下依次为 6 .0～ 6 .3km s、6 .3～ 6 .6km s及 6 .9～ 7.0km s ;阿尔泰南缘的地壳最厚 ,为 5 6km ,准噶尔盆地的地壳最薄 ,为 4 6km ,大部分地区的地壳厚度为 5 0km左右 .准噶尔盆地与天山之间上地幔顶部的纵波速度为 7.7～ 7.8km s ;阿尔泰南缘及塔里木盆地上地幔顶部的纵波速度较高 ,为 7.9～ 8.0km s.测线南部 ,包括东天山及塔里木东缘 ,自地表至 30km深处的地壳纵波速度低 ,泊松比为 0 .2 5 ,表明上地壳主要为石英及花岗质成分 ;而测线北部 (包括阿尔泰及准噶尔盆地 )的中、上地壳则呈现较高的泊松比 (0 .2 6～ 0 .2 7) ,可能为基性地壳的体现 .厚 15～ 30km的下地壳纵波速度 (6 .9～ 7.0km s)较高 ,泊松比为 0 .2 6～ 0 .2 8,可能以镁铁质的麻粒岩成分为主 .位于天山及其南侧地壳中部的低速层 (VP=5 .9km s,σ=0 .2 5 )则可能为晚古生代的构造热事件中的花岗质侵入岩 .
According to the seismic longitudinal and shear wave data of the Altai-Alking geosciences section, the crustal velocity and Poisson’s ratio structure are established.The crust has obvious trisectional structure with the P-wave velocities of 6.0 ~ 6 .3km s, 6.3-6.66km s and 6.9 ~ 7.0km s. The crust is the thickest in the southern margin of Altay with a width of 56 km. The crust in Junggar Basin is the thinnest with a crust thickness of 46 km. The crustal thickness Is about 50 km.The P-wave velocity at the top of the upper mantle between Junggar Basin and Tianshan is 7.7 ~ 7.8 km s.The P-wave velocity at the top of upper mantle in the southern margin of Altay and Tarim Basin is 7.9 ~ 8.0 km s, Including the eastern Tianshan Mountains and the eastern margin of the Tarim. From the surface to the depth of 30 km, the crustal P-wave velocity is low, and the Poisson’s ratio is 0.52, indicating that the upper crust is mainly composed of quartz and granite components. In the northern part of the survey line (including Altay and Junggar The middle and upper crust of the basin show a higher Poisson’s ratio (0.226-0.27), which may be the manifestation of the basic crust. The longitudinal crustal velocity (6.9 ~ 7.0 km s), and the Poisson’s ratio is 0.26 ~ 0.28, probably with mafic granulite Main points located in the middle of the south side of the earth’s crust and Tian low level (VP = 5 .9km s, σ = 0 .2 5) may enter the granitic rocks tectonic events in the late Paleozoic.