石英-钨铁矿氧同位素地质温度计及其地质应用研究  

QUARTZ-FERBERITE OXYGEN ISOTOPE GEOTHERMOMETER AND ITS GEOLOGICAL APPLICATIONS

作　　者：丁悌平[1] 刘玉山[1] 万德芳[1] 刘志坚 李金城[1] 张桂兰[1] 

机构地区：[1]中国地质科学院矿床地质研究所

出　　处：《地质学报》1992年第1期48-58,共11页Acta Geologica Sinica

摘　　要：通过实验研究,得出了在350—550℃范围内钨铁矿-水的氧同位素分馏的温度关系。结合已有的石英-水氧同位素分馏方程,求出了石英-钨铁矿氧同位素分馏方程。采用Bigeleison-Mayer函数法,计算了石英-钨铁矿氧同位素分馏的温度关系。得出的结果与上述实验结果很一致。最后作者将得到的校准方程用于5个世界知名的钨矿床,结果表明,用石英-钨铁矿对氧同位素分馏算出的温度范围与其它测温结果十分相近。The quartz-wolframite oxygen isotope geothermometer may become an effective tool for determining the formation temperatures of tungsten deposits. For this reason a method integrating experimental calibration, theoretical calculation and empirical extrapolation has been used in this study in an attempt to establish a relatively reliable quartz-ferberite oxygen isotope geothermometer. Experiments for oxygen isotope exchange between ferberite and water were care ried out and the following equation on oxygen isotope fractionation between ferberite and water against temperature was obtained: 1000lnα_(F_eWO_4-H_2O)=1.04×10~6T^(-2)-2.5 (1) Combining this equation with the equation of Clayton et al. (1972) on oxygen isotope fractionation between quartz and water, a equation on oxygen isotope fractionation between quartz and ferberite was obtained: 1000lnα_(sio_2-FeWO_4)=2.34×10~6T^(-2)-0.4 (2) The Bigeleison-Mayer function method was used to calculate the oxygen isotope fractionation between quartz and ferberite. The theoretical curve obtained agrees with the experimental calibration results quite well in the temperature range of the study. At last the above calibration curve has been used in 5 world famous tungsten deposits to determine their temperatures of formation. The results show that the temperature range for an individual deposit obtained from this quartz-ferberite oxygen isotope geothermometer agrees with that obtained by using the fluid inclusion determination and other isotope geothermometers, From above it is indicated that this quartz-ferberite oxygen isotope geothermometer is reliable.

关 键 词：石英-钨铁矿 温度计 氧 同位素 

分 类 号：P579[天文地球—矿物学]