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首页> 外文期刊>International Journal of Geosciences >Late Cenozoic Tectonic Uplift Producing Mountain Building in Comparison with Mantle Structure in the Alpine-Himalayan Belt
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Late Cenozoic Tectonic Uplift Producing Mountain Building in Comparison with Mantle Structure in the Alpine-Himalayan Belt

机译：高山-喜马拉雅带地幔构造与晚新生代构造隆升造山构造

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摘要

Tectonic uplift producing recent mountain systems has spanned in the Alpine-Himalayan Belt the time interval from Oligocene to Recent (the last 30 - 35 Ma), being divided into two stages. During the first stage, local uplands, usually not higher than middle-elevated mountains, rose and their total area increased. During the second stage (the last 5 - 2 Ma) this process was accompanied by a total uplift of the greater part of the belt. As a result, the rate of vertical movements increased, the recent mountain systems were formed, and the coarse molasses accumulated in the adjacent basins. Uplift of the land surface resulting in formation of mountain topography is an isostatic reaction to decompaction of the upper spheres of the Solid Earth. Three factors of the decompaction are discussed in the paper. These are: I, collisional compression, resulting in deformational thickening of the Earth’s crust (folding, thrusting, etc.); II, partial replacing of the lithosphere mantle by the lower-dense asthenosphere material and, as a result, decompaction of the uppermost mantle; and III, retrograde metamorphism of high-metamorphosed rocks within the lower crust and near the crust-mantle boundary and, as a result, decompaction of these rocks. These processes were initiated or facilitated by the lateral asthenosphere flows. According to the seismic tomography data, the flows spread from the stationary developed zone of the rise of deep mantle material that is expressed in the recent structure as the Ethiopian-Afar super-plume. Reworking the 400 - 700-km deep transition layer of the mantle, the sub-lithosphere flows could be enriched in sources of aqueous fluids. The flows and their fluids initiated factors II and III of the tectonic uplift and caused softening and detachment of the lithosphere, facilitating deformational thickening of the Earth’s crust, i.e., the factor I. The latter produced uplands during the entire Oligocene-Quaternary development of the orogenic belt, while the factors II and III manifested themselves only during the second stage of mountain building. The detailed studies in the Central Tien Shan and the Greater Caucasus showed that the acceleration of uplift at the second stage was caused mainly by the factor II in the Central Tien Shan and the factor III in the Greater Caucasus.
机译：构造活动抬升产生了新近的山脉系统，在新罕布什尔州-喜马拉雅带跨越了从渐新世到新近（最后30-35 Ma）的时间间隔，分为两个阶段。在第一阶段，通常不高于中高海拔山区的当地高地上升，总面积增加。在第二阶段（最后5-2 Ma），该过程伴随着皮带大部分的完全隆起。结果，垂直运动的速率增加，形成了新近的山脉系统，并且在相邻盆地中积累了粗糖蜜。导致形成山地地形的陆地表面隆起是对固体地球上层球体分解的等静压反应。本文讨论了失压缩的三个因素。它们是：I，碰撞压缩，导致地壳变形增厚（褶皱，推力等）; II，用低密度的软流圈材料部分代替岩石圈地幔，结果是最上面的地幔破裂。第三，下地壳内和地壳幔边界附近的高变质岩逆行变质作用，并因此使这些岩石分解。这些过程是由横向软流圈流动引发或促进的。根据地震层析成像数据，流量从深层地幔材料上升的静止发育区域扩散开来，该区域在最近的结构中表示为埃塞俄比亚-阿法尔超级岩浆。重新改造地幔深400至700公里的过渡层，可以在液面上层液流中丰富液流。流动及其流体引发了构造隆升的因子II和III，并导致岩石圈的软化和脱离，从而促进了地壳的变形增厚，即因子I。后者在整个渐新世-第四纪发育期间形成了高地。造山带，而因子II和III仅在造山的第二阶段才表现出来。对中天山和大高加索地区的详细研究表明，第二阶段的隆升加速主要是由中天山的II因子和大高加索的III因子引起的。

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