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利用新疆及邻区 2万多条Pn射线的走时资料 ,采用层析成像的方法反演该地区上地幔顶部的Pn速度结构 .主要结果是 :①新疆地区平均Pn速度为 8 2km s ,高于中国大陆地区的平均值 (8 0km s) ,速度变化量从 - 0 3km s到 0 2km s.②准噶尔盆地是明显的高Pn速度区 ,高速区与地貌形状吻合较好 ,最大值达 8 4km s;塔里木盆地整体上呈现高速异常 .二者都可能与盆地是稳定地块、构造活动和变形较弱有关 .③在盆地与山脉的交接带即主要的构造活动带 ,存在较低的Pn速度 ,可达 7 9km s.④塔里木南缘中部存在一显著的低速区 ,可能与岩浆活动和构造活动较强有关 .⑤上地幔顶部波速各向异性整体上盆地中心较弱 ,边缘地带较强 .新疆南部波速的各向异性可能是因印度板块对欧亚大陆的碰撞使地幔物质向北蠕动的结果 .
Using the travel time data of more than 20,000 Pn rays in Xinjiang and its adjacent areas, the tomographic imaging method is used to invert the Pn velocity structure at the top of the upper mantle in the area. The main results are as follows: ① The average Pn velocity in Xinjiang is 82 km, The average value of the Chinese mainland (80km s) varies from - 0 3km s to 0 2km s. ② The Junggar Basin is a distinctly high Pn velocity region, which coincides well with the topography, with a maximum of 84km s, and the Tarim Basin as a whole shows high-speed anomalies, both of which may be related to the stable block, tectonic activity and weak deformation in the basin.③In the main tectonic belt at the junction of the basin and the mountains, there is a low Pn velocity , Up to 7 9 km s.④ There is a significant low-velocity zone in the central part of the southern margin of Tarim which may be related to the magmatic activity and tectonic activity.⑤ The upper anisotropy of the upper mantle is generally weak in the center of the basin and strong in the periphery. The anisotropy of wave velocity in southern Xinjiang may be the result of creeping of the mantle material northward due to the collision of the Indian plate with the Eurasian continent.