【摘要】 依据地震层析和接收函数的结果获得了天山山脉东段和西段的深部构造的速度图像,探讨了印度板块向北推进和青藏高原隆升对天山山脉造山作用的影响以及天山山脉不同地段的地壳上地幔构造的差异。克拉玛依—库车剖面上清楚地展示出,天山是由高速和低速的地体拼合而成。来自塔里木的高速体向北俯冲到天山达200km以下的深度,而来自准噶尔盆地的高速体则没有明显地向南推进,说明由南向北的推进是很强的,它是造成天山山脉继续隆升的主要动力,从而造就了天山山脉。天山山脉在Moho面以上的部分是中天山北缘断裂和中天山南缘断裂之间的低速体与两侧的高速体拼合成的,其南北宽度约350km,向深度延伸越过200km。塔里木盆地和准噶尔盆地均为高速体的范围,天山山脉东段Moho面以上的地壳部分,南部高速体有向北推进和俯冲的特征,但不明显。夹在两盆地之间的天山主要为低速体,仅在乌鲁木齐和北天山山前断裂以南有残留的高速体,深度不超过30km,这表明天山是由速度不同的地质体挤压而拼合成的。天山延伸到乌鲁木齐以东,向深部的延伸仅仅100km上下。在富蕴—库尔勒剖面上,塔里木板块向北的推进相对于克拉玛依—库车剖面有所减弱。天山西段表现出强烈的造山作用,向东逐步减缓,到达天山的东段,虽然天山深部的构造活动仍然在继续进行,地震活动频繁,可是,活动区域集中在天山底部不过100km上下。说明山根的范围比西部减少了近一半。更多还原

【Abstract】 Deep velocity structures in the east and west Tianshan Mts.are obtained from tomography and receiver functions.This article discusses the effects of the north indentation of the India plate and the uplifting of the Qinghai-Tibet plateau on orogenic processes of the Tianshan Mts.and attempts to explain the difference in crust and upper mantle structure in different segments of the Tianshan Mts.A Karamay-Kuqa profile shows clearly that the Tianshan Mts.are formed from a jig-saw-like puzzle of high and low velocity terrains.The high velocity Tarim terrain was thrust northwards and beneath the Tianshan to a depth of 200 km.In contrast,a southward lower plate displacement of the Junggar high velocity terrain is not evident.These differences indicate that the strong main driving force for uplifting of the Tianshan Mts.came from south to north.The crust of the Tianshan Mts.is composed of a low velocity terrain lying between the north and south marginal faults of the central range and the high velocity terrains that border them.The north-south width of the Tianshan Mts.is about 350 km,and its basement extends to a depth of more than 200 km.In the east segment of Tianshan Mts,the southern high velocity terrain was underthrust northward only slightly.The Tianshan Mts.between the Tarim and Junggar basins is mostly a low velocity terrain.Only to the south of rümqi city and the north Tianshan faults is there a residue of high velocity terrain at a depth of less than 30 km.This indicates that the Tianshan block was constructed by a jig-saw-like puzzle of terrains with different velocities.To the east of Urümqi,the Tianshan Mts.reaches only to a depth of about 100 km.A Fuyun-Kola profile shows a northward underthrusting of the Tarim plate that is less than that in Karamay-Kuqa profile.Therefore,the west Tianshan Mts.shows strong uplift,which is gradually weakened eastward into the east Tianshan Mts.Structural activity continues in the eastern Tianshan with major earthquake activity,but seismic activity only occurs to the depth less than 100 km.Here,the mountain root has only a half of the thickness of the western segment of the Tianshan Mts.The convergence of the strong Tarim and Junggar blocks causes the uplift of the Tianshan Mts.and an eastward flow of lithosphere materials,perhaps having a relationship with the Altun strike-slip fault.Consequently,deep structure and relief exist distinct differences,and the east and west of the Tianshan Mts.in Xinjiang exhibit major differences in both relief and the depths of their lithospheric roots.更多还原