三元长石地质温度计及其在我国粤西花岗岩中的应用  

Ternary-feldspar geothermometry and its application in studyof granitoids in West Guangdong

作　　者：王联魁[1] 沙连堃[1] 徐文新[1] 邓高强[1] 

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640

出　　处：《华南地质与矿产》2003年第4期1-9,共9页Geology and Mineral Resources of South China

摘　　要：根据Greenetal(1986)提出的三元长石温压计公式,以长石三元固溶体和矿物相平衡为基础,通过热力学推导,建立了联立方程法和迭代法两种计算三元长石温度的方法。根据联立求解可获得TAb-Or、TOr-An、TAb-An三个温度值,迭代法求解可获得TAb、TOr、TAn三个温度值。因此,一个样品可计算出6个温度数据。选择粤西地区有代表性的18个花岗岩体,按混合岩建造→深熔花岗岩建造→岩浆建造南岭系列花岗岩→岩浆建造长江系列花岗岩的顺序,进行三元长石法的温度计算,所得到的相应各建造和系列花岗岩的上限温度为755℃→766℃→865℃→970℃;下限温度为664℃→665℃→775℃→814℃,亦即上下限温度都逐渐升高,其规律性与地质和地球化学研究结果完全一致,体现了三元长石地质温度计的可靠性和准确性。On the base of the ternary feldspar geothermometry proposed by Green et al.(1986),the theory of ternary-feldspar solid solution and phase equilibration,the authors established two methods of calculating the forming temperature of ternary-feldspar through thermodynamic calculation.With simultaneous equation method and iterative method of ternary-feldspar geothermometry,one sample can be calculated to get six temperature data(T_(Ab-Or),T_(Ab-An),T_(Or-An),T_(Ab),T_(Or)and　T_(An)).Calculations show that the forming temperatures of 18 granitic bodies from West Guangdong range from 664℃ to 755℃(migmatitic granitoids),665℃ to 766℃(anatectic granitoids),775℃to 865℃(Naling Series granitoids)and 814℃ to 970℃(Yangtze River Series granitoids),indicating an increasing trend of forming temperatures from migmatitic granitoids to anatectic granitoids to Naling Series granitoids to Yangtze River Series granitoids,which is consistent with the results of geological and geochemical study,proving that the ternary-feldspar geothermometry is valid and exact.

关 键 词：长石地质温度计 花岗岩 粤西 热力学推导 联立方程法 迭代法 

分 类 号：P578.94[天文地球—矿物学] P588.12[天文地球—地质学]