@article{oai:nipr.repo.nii.ac.jp:00002720, author = {オオバ, タカノブ and シライシ, カズユキ and OBA, Takanobu and SHIRAISHI, Kazuyuki}, journal = {Proceedings of the NIPR Symposium on Antarctic Geosciences}, month = {Sep}, note = {P(論文), The stability of amphibole was studied in the presence of syenite composition liquid. The melting relationships of three hornblende clinopyroxene quartz syenites and a hornblende two-pyroxene syenite from the Yamato Mountains were determined in the temperature range of 650-900℃, under a water pressure of 0.05-0.3GPa and oxygen fugacities of the FMQ buffer. Experimental results of hornblende clinopyroxene quartz syenites (Y406 and Y904) and one hornblende two-pyroxene syenite (Y557) at 0.1 GPa show that melting begins between 720℃ and 770℃, and amphiboles disappear between 810℃ and 895℃. With the increasing temperature at 0.1GPa, quartz disappears first, then plagioclase and amphibole in that order. The water saturated solidus temperature of a normative quartz-free hornblende clinopyroxene mela-syenite (Y405) is about 780℃ at 0.1GPa. K-feldspar in this sample disappears at lower temperature than amphibole. In two syenites (Y557 and Y904), solidus and the stability limit line of amphibole intersect at a lower pressure than 0.3GPa. Moreover, all rocks investigated are at least 40% melted at temperatures ∿50℃ above the solidus. The present results suggest that amphibole in these syenites could crystallize at pressures lower than 0.3GPa (∿10km in depth), indicating their emplacements at a relatively shallow crustal level.}, pages = {72--82}, title = {EXPERIMENTAL STUDIES ON SYENITIC ROCKS IN THE YAMATO MOUNTAINS, EAST ANTARCTICA}, volume = {6}, year = {1993} }