Petrology and Geochemistry of Schists, Gneisses and Leuco-granites in the East-northern Part of the Hida Metamorphic Belt, Central Japan.

1.(I)Bernas‘method that powder sample was decomposed with hydrofluoric acid in a sealed Teflon vessel was a little modified to make a clean solution easily.(Ii)A simple method by atomic absorption spectrometry without adding large amounts of other elements for suppressing the interference of coexisting elements was investigated for the determination of major elements in silicates.2..In the Tateyama-gawa of the upper Hayatsuki-gawa area，two discordant temperatures，610-650℃and 700-780℃from different sample were estimated by cordierite-garnet and garnet-biotite geothermometry。The metamorphic temperature of 700-780°C might correspond to an earlier stage of metamorphism characterized by spinel，corundum，Mg-rich garnet and others；the metamorphism of 610-650°C might have been caused by migmatization related to the leuco-granites and be characterized by andalusite and cordierite.3。The metamorphic grade increases from staurolite-kyanite zone of the amphibolite facies in the Kurobe-gawa area to the transition zone of the amphibolite-granulite facies in the Tateyama-gawa.With the increase of the metamorphic grade，chemical change is as follows：&lt；SiO_2&gt；decreases，&lt；Na_2O&gt；，&lt；K_2O&gt；，MgO，MnO and&lt；TiO_2&gt；increase，and&lt；Al_2O_3&gt；，FeO and CaO remain hardly unchanged.4。The results of chemical analyses of leuco-granites in calcareous，pelitic and basic gneisses indicates that the migmatites in the calcareous and plitic gneisses are formed in situ more easily than those in the basic gniesses。

1. (i) Bernas' method that powder sample was decomposed with hydrofluoric acid in a sealed Teflon vessel was a little modified to make a clean solution easily.(ii) A simple method by atomic absorption spectrometry without adding large amounts of other elements for suppressing the interference of coexisting elements was investigated for the determination of major elements in silicates.2. In the Tateyama-gawa of the upper Hayatsuki-gawa area, two discordant temperatures, 610-650゜C and 700-780゜C from different sample were estimated by cordierite-garnet and garnet-biotite geothermometry. The metamorphic temperature of 700-780゜C might correspond to an earlier stage of metamorphism characterized by spinel, corundum, Mg-rich garnet and others; the metamorphism of 610-650゜C might have been caused by migmatization related to the leuco-granites and be characterized by andalusite and cordierite.3. The metamorphic grade increases from staurolite-kyanite zone of the amphibolite facies in the Kurobe-gawa area to the transition zone of the amphibolite-granulite facies in the Tateyama-gawa. With the increase of the metamorphic grade, chemical change is as follows: <SiO_2> decreases, <Na_2O> , <K_2O> , MgO, MnO and <TiO_2> increase, and <Al_2O_3> , FeO and CaO remain hardly unchanged.4. The results of chemical analyses of leuco-granites in calcareous, pelitic and basic gneisses indicates that the migmatites in the calcareous and plitic gneisses are formed in situ more easily than those in the basic gniesses.