The pressure estimated by amphibole geobarometer in syenite and granil

我们试图估算含角闪正长岩和花岗岩在水压0.05~0.34 GPaFMQ缓冲液中氧逸度在600GPaC-930GPaC范围内的压力。角闪石的稳定极限曲线使其P-T斜率由低压时的正值变为高压时的负值，并在两个压力点与正长岩和花岗岩固相线相交。我们认为，大和山脉正长岩中的角闪石可能在小于0.3 Gpa(深度：-10公里)的压力下结晶，可能是在一个浅的地壳岩浆室中。Hammarstrom和Zen(1986,1992)提出了钙碱性深成岩体的结晶压力与角闪石的总铝含量之间的经验关联式。然而，在目前的实验中，闪石在固相线附近的化学成分没有变化。我们报道了角闪石中的辉石含量随着温度的升高而增加。如果将角闪石与不同温度下合成的角闪石进行比较，角闪石地球压力计具有相当大的不确定性。我们尝试了钠、铝、镁和铁在角闪石和辉石之间的分配。

We attempt to estimate the pressure of amphibole-bearing syenites and granitic rocks in the range 600ﾟC -930ﾟC under a water pressure from 0.05GPa to 0.34GPa and oxygen fugacitied of the FMQ buffer. The stability limit curve of amphibole changes its P-T slope from positive at low pressure to negative at high pressure, and it intersects with a solidus of syenite and granite at two pressure points. We suggest that amphibole in syenite from the Yamato Mountains could have crystallized at pressres less than 0.3GPa (depth : -10 km), probably in a shallow crustal magma chamber.Hammarstrom and Zen (1986, 1992) proposed an empirical correlation between the estimated pressures of crystallization of calc-alkaline plutons and the total Al content of horublende. However, in the present experiments, the chemical composition of amphibole near solidus does not change. We reported that the pargasite content in amphibole increases with increasing temperature. If we compared with amphiboles synthesized at different temperatures, amphibole geobarometer is considerable uncertainty. We attempt the partitioning of Na, Al, Mg and Fe between amphibole and pyroxene.