【摘要】 格尔木-额济纳旗地学断面从南到北穿过昆仑、祁连和北山3个构造带;在断面中划分出北昆仑-柴达木、中南祁连、北祁连、北山南部和北山北部5个构造地层地体;以及昆仑中央、北宗务隆、中祁连北缘、宽滩山及石板井-小黄山5条地体边界断裂带。断面内地壳厚度约50～70 km,中南祁连地体地壳厚度最大,显示有山根存在;岩石圈厚度约140～150 km。根据地球卫星及地震反射剖面结果表明:青藏高原为一个单独的岩石圈构造单元;高原的北界地表应在宽滩山断裂带,可能是阿尔金断裂的东延部分。通过应力场模拟计算表明:祁连山的隆升主要是受南北两侧的挤压力所致,祁连山两侧的大陆岩石圈相向运动插入到祁连山之下,使祁连山岩石圈上部抬升及下部缩短加厚,形成增厚的岩石圈根。更多还原

【Abstract】 The Golmud - Ejin geoscience transect traverses the Kunlun, Qilian and Northern Beishan tectonic belts from south to north. In the geoscience transect, five tectostratigraphic terranes, i. e. the Qaidam - North Kunlun, South-central Qilian, North Qilian, Southern Beishan and Northern Beishan terranes, and five terrane boundary faults, i. e. the Central Kunlun fault, North Juniil fault, North boundary fault of Central Qilian, Kuantanshan fault and Skibanjing-Xiao Huangshan boundary fault, may be distinguished. The Moho depth is 50-70 km and reaches a maximum 74 km in the Juhong Tu area south of the Har Lake in the Southern Qilian, indicating the existence of the mountain root there. The thickness of the lithosphere is 140-150 km. The landsat images and continental seismic reflection profiling indicate that the Qinghai -Tibet plateau is an independent lithospheric tectonic unit. The northern boundary of the plateau should be the Kuantanskan fault, which is most likely to the eastward extension of the Altun fault. The stress field model calculation indicates that the uplift of the Qilian Mountains mainly resulted from crustal compression both from the north and south sides. The face-to face movement of the lithospheric blocks on both sides of the Qilian Mountains caused them to plunge beneath the mountains, thus leading to the uplift of the upper part of the lithosphere and the shortening and thickening of the lower part of the lithosphere. So a thickened lithospheric root was formed.更多还原