摘要
一个花岗岩带或复式岩基中各个岩体的^(87)Sr/^(86)Sr和^(87)Rb/^(86)Sr的算术平均值,在等时线图中可获得一条直线。这直线可认为是一种等时线或混合线。如果为混合线,则可认为花岗岩带或复式岩基是混合成因。通常包括因围岩或其它岩浆的加入而发生的岩浆混染作用和成岩前的源岩混合作用;若为等时线,则可据直线的斜率计算出年龄,标示花岗岩的源岩Sr同位素均一化作用的最终时间或岩浆房中岩浆sr同位素均一化的最终时间。
The arithmetic means of the (^(87)Sr/^(86)Sr)and(^(87)Rb/^(86)Sr)ratios of every individual intrusion in a granitic belt or complex in an isochron diagram may distribute along a straight line. The line can be considered as a sort of isochronism or a mixing line, i, e.: areal isochronism or areal mixing line. If it is a mixing line, the granitic belt or complex may be of mixing genesis,the mixing in general may include contamination of magma in coorporation with country rocks or other magma and with source rocks before formation of magma. If the line is isochronism, by means of the slope of the line, an age may be calculated。It shows the time of final homogenization of Sr isotopes in the source rocks of the granites or in magma of the magroatic chamber.
出处
《矿物岩石》
CAS
CSCD
1991年第1期80-85,共6页
Mineralogy and Petrology
关键词
铷
锶
同位素
区域
等时线
混合线
Rb-Sr isotope, areal isochronism, areal mixing line, granitoid
