大别山麻粒岩和TTG片麻岩的Sr、Nd、Pb同位素地球化学  

Sr, Nd and Pb Isotope Geochemistry of Granulites and TTG Gneisses from the North Dabie Mountains

作　　者：葛宁洁[1] 李惠玉[1] 秦礼萍[1] 侯振辉[1] 柏林 

机构地区：[1]中国科学技术大学地球与空间科学系,合肥230026 [2]安徽省地质学会,合肥230001

出　　处：《地质学报》2001年第3期379-384,共6页Acta Geologica Sinica

基　　金：国家自然科学基金(编号49673197);"大陆深俯冲和折返过程中壳慢及岩石圈和软流圈之间的相互作用"项目(编号 G1999075503)资助的成果

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(^(87)Sr/^(86)Sr=0.7066～0.7461),较低的Nd同位素比值(^(143)Nd/^(144)Nd=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。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.

关 键 词：麻粒岩 TTG片麻岩 大别山 锶 钕 铅同位素 地球化学 

分 类 号：P597[天文地球—地球化学]