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对秦岭—大别造山带大量Nd同位素资料进行统计,获得了该地区陆壳基底和区域花岗岩类的147Sm/144Nd平均值,分别为0.136和0.108。基于区域资料获得的二阶段亏损地幔模式年龄(T2DM)比用147Sm/144Nd=0.118做参数的计算结果要普遍偏老,两种结果的差异随着模式年龄的偏老明显偏大。本研究获得的该区域地壳147Sm/144Nd组成特征与元素丰度资料之间存在较大差异,结合稀土元素综合对比,表明前人获得的该区域元素丰度资料偏酸性。
A large number of Nd isotopic data from the Qinling-Dabie orogenic belt were collected and the average 147Sm / 144Nd values of continental basement and regional granitoids in this area were obtained, which were 0.136 and 0.108 respectively. Based on the regional data, the calculated T2DM of the second-stage depleted mantle pattern is generally older than the calculated value of 147Sm / 144Nd = 0.118. The difference between the two results is obviously larger with the age of the model. There is a big difference between the 147Sm / 144Nd composition and the elemental abundance data of the crust in this study. Combined with the comprehensive comparison of rare earth elements, it shows that the elemental abundance data obtained in the past are somewhat acidic.