某些岩浆岩成岩温度测定

近年来,作者对一些不同类型岩浆岩(花岗岩、霞石正长岩、流纹岩、凝灰熔岩、玄武岩等)矿物中包裹体进行了研究,总结出鉴定熔融(固化)包裹体的特征,并利用南京大学仪器厂生产的LGHS-1型高温加热台对一些岩浆岩进行了成岩温度测定。加热台测温范围0—1450℃±,20℃加热腔体积为0.8立方厘米,温差20—50℃。利用岩石熔融包裹体均匀化温度,可以作为探讨岩浆岩矿物形成温度的一个手段。

THE DETERMINATION OF FORMATION TEMPERATURE OF THE IGNEOUS ROCKS FROM SOME AREAS

The thermometric investigation of melt ineluions in minerals is one of the effective methods for evaluating the temperature of rock-formation.In this work we take some main types of igneous rocks for determining their formation-temperature.On the basis of research results,the authors established some criteria such as: phase state,refractive index,extinction,morphology of gas phase and the phase change during heating etc.to characterize melt inclusions.The formation-temperatures of rocks were determined by homogenizing method or quenching method.The former has been used on the heating stage LGHS-1 made by ourselves-The heating duration ranges from 2 to 8 hours.The melt inclusions in minerals of the different rocks come to melt at 680-1100℃.The temperature of homo-genization is 980-1140℃ for acidic rocks (granite,adamellite),980-135℃ for volcanic rocks (quartz-keratophyre,lava,microclastic tuff lava),1040-1120℃for alkali rocks (nepheline syenite),and 1120-1450℃for basalts.