摘要
从构造热演化的角度研究了青藏高原的形成模式,对形成机制中的两种主要假说:双地壳模型和叠瓦状模型进行了热模拟.在模拟时考虑了逆冲断层、均衡地壳抬升和沉积覆盖层对温度场的影响.结果表明,双地壳模型的热演化结果和实际观测资料明显不符;叠瓦状模型的结果在藏南地区能够较好地符合地球物理观测资料和解释地质构造运动.除较高的放射性元素含量外,断层的摩擦剪切热和沉积盖层热折射伴随地体的抬升侵蚀是喜马拉雅两条花岗岩带和反转的高温变质岩带的主要成因,并和现今上地壳水热活动有密切的关系.
Thermal consequences of tectonic processes are investigated by numerical techniques. Comparison of predicted thermal structures of a tectonic model with geological and geophysical observations can test the validity of the tectonic model. Two major tectonic models on the formation of the Tibetan plateau, the double crust thrust model and the imbricated thrust fault model, are studied. Thermal effects of thrust faulting, isostatic denudation and sedimentary cover are included in the modeling, The results indicate that the double crust thrusting model would produce a thermal process in contradiction to the observation; while the imbricated thrust model can explain geological and geophysical observations in southern Tibet. Frictional/shear heating on faults, thermal refraction of sedimentary layers, and thermal effects of isostatic denudation, in addition to high radio elements content, are found important for the formation of two belts of leucogranites and inverted meamorphism in southern Tibet, and they are also related to modern hydrothermal activity there.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1992年第6期710-720,共11页
Chinese Journal of Geophysics
基金
国家自然科学基金
关键词
青藏高原
构造
热演化
地壳
Tibetan plateau, Thermotectonics, Finite element method, Thermal modeling.
