This paper deals with the experimental studies on the formation of the reworkingtype(rpughly corresponding to S-typ)granites.All the experiments were based on extensive geological investigations into the Napeng granite body of Luoding,Guangdong Province.Thie granite body was formed by reworking and metasomatism of metamorphie rocks which had reached the amphibolite facies,For this reason,the metamorphic rocks consisting mainly of quartz-ica-schists were taken as the starting materials in the experiments.At 1kb and 400°-550℃ the samples of quartz-mica schist reacted with various Na-and K-rich aqueous solutions,resulting in the quartz-albite-biotite and quartz-K-feldspar-biotite assemblages similar to those in the granites.In addition,several initial melting and melting-erystallization experiments on metamorphic rocks and migmatites were performed at 1-2kb and 550°-990℃,Moreover,the equilibrium constants for the reactions were computed at 400°-600℃ ad 1-2kb on the basis of J.D.Frantz's data on the solubility of minerals.Experimental data and thermodynamic calculations indicate that the reworkingtype granites were formed from metamorphic rocks,such as quartz-schist,through reaction with alkali-silicate aquous solutions.
