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通过对高喜马拉雅块状黑云斜长片麻岩进行高温高压实验-T = 770-1028℃, P = 1.0-1.4 GPa, 无外加自由水), 初步研究了脱水熔融过程和熔体结构; 模拟了高喜马拉雅淡色花岗岩的形成. 实验结果表明: （1) 即便在初熔状态下-熔融程度<5%), 熔体也主要以熔体薄膜的形式分布于矿物的相边界上, 熔体的连通性不仅取决于熔体结构, 还受到熔融程度的控制; （2) “脱水熔融” 实际包含了亚固相脱水作用、流体迁移、含水和缺水熔融等一系列子过程; （3) 实验产生出过铝的花岗质熔体, 其成分与高喜马拉雅淡色花岗岩成分相似, 残留相矿物组合为Pl + Qz + Gat + Bio + Opx ± Cpx + Ilm（Rut) ± （Kfs), 化学成分为中偏基性, 可与在喜马拉雅地区发现的麻粒岩对比. 实验证实黑云斜长片麻岩是喜马拉雅淡色花岗岩的源岩之一, 脱水熔融是形成高喜马拉雅淡色花岗岩和下地壳麻粒岩的重要方式, 并为确定源区的温压条件提供了实验约束.
The dehydration melting process and the melt structure were studied preliminarily by simulating the high-temperature and high-pressure gneiss in the high Himalayan plagioclase gneiss (T = 770-1028 ℃, P = 1.0-1.4 GPa, without external free water) The formation of high-Himalayan pastel granite.The experimental results show that: (1) The melt is mainly distributed in the form of a melt film on the phase boundary of the mineral even in the incipient melting state - the degree of fusion is less than 5% The connectivity is not only dependent on the melt structure, but also controlled by the degree of melting. (2) “Dehydration and melting” actually includes a series of sub-processes such as subsolidate dehydration, fluid migration, water-containing and water- The results show that the composition of Al-based granite melt is similar to that of high-Himalayan pastel granite. The residual phase assemblage is Pl + Qz + Gat + Bio + Opx ± Cpx + Ilm (Rut) And can be compared with the granulites found in the Himalayas.It is proved that the biotite plagioclase gneiss is one of the source rocks of the Himalayan pale granite and the dehydration and melting is the formation of the high Himalayan pale granite and the lower crust granulite Heavy Manner, and provide experimental constraints to determine the temperature and pressure of the source region.