【摘要】 北大别4个麻粒岩和4个TTG片麻岩样品的Sr、Nd同位素分析结果表明,样品普遍具有较高的锶同位素比值(⁸⁷Sr/⁸⁶Sr=0.7066～0.7461),较低的Nd同位素比值(¹⁴³Nd/¹⁴⁴Nd=0.5108～0.5124),表现出明显的壳源特征。结合铅同位素的组成来看,北大别麻粒岩及TTG片麻岩的同位素成分相当于中—下地壳。岩石的物源为古老的地壳,大约在2～3Ga之间。少数样品的同位素特征可能暗示源区有年轻地壳物质的加入。更多还原

【Abstract】 Sr, Nd and Pb isotope analysis of four granulite samples and four gneiss samples from the northern Dabie Orogen were carried out. All the samples have relatively high Sr isotope ratios (87Sr/86Sr=0. 706 - 0. 746) and relatively low Nd isotope ratios (143Nd/144Nd= 0. 5108-0. 5124). These results together with Pb isotopic compositions suggest that the isotopic compositions of granulites and TTG gneisses of the northern Dabie Orogen are equal to those of the middle-lower crust. The TDM values show that these rocks are very old, c. 2-3Ga. The Sr-Nd-Pb isotopic characteristics of some samples imply the addition of younger crustal materials in their sources.更多还原