【摘要】 <正> 花岗岩形成的实验研究,四十年代以来大多集中于熔融实验,交代、改造、花岗岩化作用方面的模拟实验甚少。本文在广东罗定那蓬交代改造型花岗岩的地质、岩石学研究基础上,对其形成过程进行了初步实验研究。更多还原

【Abstract】 This paper deals with the experimental studies on the formation of the reworking-type (roughly corresponding to S-type) granites. All the experiments were based on extensive geological investigations into the Napeng granite body of Luoding, Guangdong Province. This granite body was formed by reworking and metasomatism of me-tamorphic rocks which had reached the amphibolite fades. For this reason, the metamorphie rocks consisting mainly of quartz-mica-schists were taken as the starting ma-terials in the experiments. At 1 kb and 400°550℃ the samples of quartz-mica-schist reacted with various Na-and K-rich aqueous solutions, resulting in the quartz-albite-bio-tite and quartz-K-feldspar-biotite assemblages similar to those in the granites. In addition, several initial melting and melting-crystallization experiments on metamorphie rocks and migmatites were performed at 1-2kb and 550°-900℃. Moreover, the equilibrium constants for the reactions were computed at 400°-600℃ and 1-2 kb on the basis of J. D. Frantz’s data on the solubility of minerals.Experimental data and thermodynamic calculations indicate that the reworking-type granites were formed from metamorphie rocks, such as quartz-mica-schist, through reaction with alkali-silicate aqueous solutions.更多还原