Geochronology and Geochemistry of the Alkaline Granite Porphyry and Diabase Dikes in Huanglongpu Area of Shaanxi Province: Petrogenesis and Implications for Tectonic Environment

• 责任者：Zhao Haijie (MLR Key Laboratory of Metallogeny and Mineral Assessment ; Institute of Mineral Resources ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Mao Jingwen
• 刊名：Geology in China
• 出版年：2010
• 卷期：37(1)
• 关键词：花岗斑岩 ; granite porphyry ; 辉绿岩 ; diabase ; 铀—铅计时 ; U-Pb dating ; 陕西 ; Shaanxi Province
• 页码：p.12-27
• 图表：13 illus., 5 tables, 61 refs.
• 分类号：0801
• issnNo：ISSN1000-3657
• isbnNo：CN11-1167/P

///Granite porphyry and diabase dikes are outcropped sporadically in irregular shapes in Huanglongpu area, Shaanxi Province. Its rocks are characterized by weakly inclined REE patterns with strong depleted Eu, enrichment of Th, U, Zr, Hf elements and depletion of large ion lithophile elements such as Ba, K, Sr, and high field strength element Ta. Its geochemical signatures and Pb isotopic compositions are similar to Mo-bearing granitoids in East Qingling region, implying that it was produced by partial melting of the lower crust and subjected to fractional crystallization during its evolution. SHRIMP zircon U-Pb dating was conducted for both granite porphyry and diabase, and yielded (131±1)Ma (MSWD=1. 5, n=13)and (129±2) Ma (MSWD=0. 71, n=12)of weighted mean ages respectively. They are considered to be the products of lithospheric extensional environment of intraplate in Early Cretaceous age.