下地壳管道流与青藏高原地貌特征研究

Characteristics of lower crustal channelflow and geomorphology of the Tibetan Plateau

为研究青藏高原粘性系数及粘性层厚度特征,依据地形高程粘性和厚度不同的管道流原理,研究粘性系数和下地壳流厚度的变化与高程变化之间的关系,并根据青藏高原的不同方位的不同地形变化求解了不同方向管道流的粘度和厚度,得到如下成果:(1)下地壳管道流粘度越大、厚度越小,形成的地面高程变化越陡峭;(2)青藏高原南部印度经喜马拉雅边界到昆仑山地区最大粘性系数约为10^(20)psa,管道流厚度约为25km;(3)青藏高原到青海甘肃剖面下地壳管道流最大粘性系数在10^(20)psa管道流厚度约为40km;(4)青藏高原东南过龙门山地区到四川盆地中部地区下地壳管道流最大粘性系数约为1021psa,管道流厚度约为40km,与青藏高原到青海甘肃地区差异性不大;(5)青藏高原东南到云南地区下地壳管道流最大粘性系数约为1018psa,下地壳管道流厚度约为32km,与四川盆地地区及青海甘肃管道流厚度差异较大.结果表明:青藏高原不同方向管道流的粘度是有差异的,各地区管道流厚度差异也较大,总体呈现西薄东厚的特点。纵观四个剖面结果,青藏高原西南与印度交界处地势最为陡峭管道流厚度最小.不同厚度和粘性系数的下地壳管道流模型对青藏高原地貌构造解释比较合理.本文采用水平管道流对青藏高原的四个剖面解释了青藏高原地形形成的一种可能形成机制。

To study the viscosity coefficient and thickness of the viscous layer on the Tibetan Plateau,the relationship between the change in viscosity coefficient and thickness of a lower crustalflow and the change in elevation has been investigated based on the principle of a pipeline flow with different viscosity and thickness of terrain elevation.The viscosity and thickness of the lower crustalflow in different directions were determined based on the changes in the terrain along different directions on the Tibetan Plateau.The following results were obtained:(1)The greater the viscosity and the smaller the thickness of the lower crustal conduitflow,the steeper the ground elevation change formed;(2)The maximum viscosity coefficient in the region from India to the Kunlun Mountains in the southern Tibetan Plateau through the Himalayan boundary is approximately 10^(20)Pas,and the thickness of the conduitflow is approximately 25 km.(3)The maximum value of the viscosity coeffcient of the lower crustalflow in the region ranging from the Tibetan Plateau to the Qinghai–Gansu section is attained when theflow thickness in this region approaches 40 km(4)The maximum value of the viscosity coeffcient of the lower crustalflow in the region ranging from the Tibetan Plateau to the Qinghai–Gansu section is attained when theflow thickness in this region approaches 40 km.,which does not substantially differ from that of the region ranging from the Tibetan Plateau to the Qinghai–Gansu area.(5)The maximum viscosity coeffcient of the lower crustalflow from the southeast of the Tibetan Plateau to Yunnan is approximately 10^(18) Pas,and the thickness is approximately 32 km,which differs from theflow thickness in the Sichuan Basin and Qinghai–Gansu regions.The results show variations in the viscosity of theflow along different directions on the Tibetan Plateau,in addition to considerable variation in the thickness of the lower crustal channelflow from region to region,with the overall characteristics of thinness in the west and thickness in the east.The results of the four profiles reveal that the channelflow thickness is the steepest at the southwest border of the Tibetan Plateau with India.This paper presents a reasonable interpretation of the geomorphology of the Tibetan Plateau using different thickness and viscosity coefficients of the lower crustal channel flow model.In this paper,a possible mechanism for the formation of the Tibetan Plateau topography is explained using a horizontal pipeflow for four profles of the Tibetan Plateau.