Zircon U-Pb Age and Sr, Nd, Hf Isotope Geochemistry of Jingde Pluton in Eastern Jiangnan Orogen, South China
详细信息
- 责任者：Zhou Jie (State Key Laboratory for Mineral Deposits Research ; School of Earth Sciences and Engineering ; Nanjing University ; Nanjing 210093 ; China) ; Jiang Yaohui
- 刊名：Geology in China
- 出版年：2013
- 卷期：40(5)
- 关键词：花岗闪长岩 ; granodiorites ; 二长花岗岩 ; monzogranite ; 铀—铅计时 ; U-Pb dating ; 同位素地球化学 ; isotope geochemistry ; 安徽 ; Anhui Province
- 页码：p.1379-1391
- 图表：9 illus., 3 tables, 57 refs.
- 分类号：0801
- issnNo：ISSN1000-3657
- isbnNo：CN11-1167/P
摘要
Jingde pluton is one of the Mesozoic plutons in eastern Jiangnan orogen of northeast Yangzte Block. New LA-ICPMS zircon U-Pb dating for one granodiorite yielded an emplacement age of(141.0±1.0) Ma. The pluton is composed of monzogranite and granodiorite. New petrographical and petrochemical data show that the pluton is intermediate-somewhat acid(SiO2 =66.01%~70.87%), and has high content of Al2 O3(Al2 O3 =14.91%~ 16.24%) and rich alkali(K2 O+Na2 O = 6.64%~8.01%), with K2 O/Na2 O value ranging from 0.78 to 1.04. The pluton has relatively low content of MgO, TFe2 O3 and P2 O5(MgO = 0.68%~1.06%, TFe2 O3 =2.0%~3.34%, P2 O5 = 0.10%~0.14%). As for trace elements, the pluton is enriched in Sr(189×10-6~452×10-6) with high Sr/Y ratios(23~66) and also enriched in light rare earth elements(LREE)((La/Yb)N = 13 ~ 58), but somewhat depleted in Nb, Ta, P, Ti, Y, Yb, with slightly negligible to positive Eu anomalies(δEu =0.81 ~1.18), similar to the geochemical characteristics of Mesozoic adakitoid in eastern China. Jingde pluton has relatively high Nd isotopes(εNd(t)=-6.28~-7.32), high εHf(t) values(-6.5~-1.1) and younger tDM2 model ages(1.4~1.5Ga), with mafic microgranular enclaves(MMEs), suggesting the importance of mantle material in the magma source. The mafic magmas ascended and heated the lower crust, triggering the partial melting of the lower crust to form the Jingde pluton, with the input of mantle-derived materials.
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