Geochemistry and Geological Significance of Late Triassic Yanzhiba Pluton from the
详细信息
- 责任者：Luo Jincheng (State Key Laboratory of Continental Dynamics ; Department of Geology ; Northwest University ; Xi’an 710069 ; China) ; Lai Shaocong
- 刊名：Geological Review
- 出版年：2010
- 卷期：56(6)
- 关键词：黑云母花岗岩 ; biotite granite ; 岩石地球化学 ; lithogeochemistry ; 秦岭 ; Qinling Mountains
- 页码：p.792-800
- 图表：8 illus., 2 tables, 36 refs.
- 分类号：0801
- issnNo：ISSN0371-5736
- isbnNo：CN11-1952/P
摘要
The Late Triassic Yanzhiba Pluton located in the Northern margin of the Mianxian—Lüeyang Suture, central China. This paper presented the data of occurrence, petrography, zircon U-Pb chronology and geochemistry ,and genesis of the pluton. The pluton mainly consisted by biotite granite. Zircon LA-ICP-MS U-Pb dating for the biotite granite yields a weighted mean age of 200±4 Ma. They have high SiO2 (70.09%～73.35%), alkalis (Na2O +K2O=7.49%～8.59%), Rb, Th, U, K contents and high CaO/Na2O ratios (>0.3), their A/CNK=1.01～1.08 ,σ=2.07～2.62, depletion of Nb, Ta, Ba, Sr, P and Ti. The ∑REE ranges from 129.98×10-6 to 189.97×10-6, slight enrichment of LREE (LREE/HREE=8.00～10.73, (La/Yb)N=8.62～15.68), and significant negative Eu anomalies (δEu =0.41～0.50). In combination with regional geological settings, the authors suggest that the biotite was formed by partial melting of metasedimentary crust, which was induced by fluids from the lower crust or mantle lithosphere.