LA-ICP-MS Zircon U-Pb Age and Geochemistry of the Early Permian Halinudeng Granite in Northern Alxa Area, Western Inner Mongolia

详细信息   

• 责任者：Shi Xingjun (China University of Geosciences ; Beijing 100083 ; China) ; Tong Ying
• 刊名：Geological Bulletin of China
• 出版年：2012
• 卷期：31(5)
• 关键词：花岗闪长岩 ; granodiorites ; 黑云母花岗岩 ; biotite granite ; 内蒙古 ; Inner Mongolia
• 页码：p.662-670
• 图表：4 illus., 2 tables, 44 refs.
• 分类号：0801
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

摘要

The Halinudeng pluton is located in the northern margin of Alxa area.LA-ICP-MS U-Pb dating of zircons from the pluton yields an age of 284.0±1.8 Ma, indicating that the formation of this pluton is Permian instead of Silurian as previous considered. The main rock types of the pluton include biotite-plagioclase granites and biotite monzogranites,with high SiO₂（67%～72%）, CaO（2.2%～4.4%） and Al₂O₃（14.5%～17.2%）. Geochemical characteristics indicate that they are metaluminous-weakly peraluminous（A/CNK=0.90～1.07） and calc-alkaline to high-K calc-alkaline rocks（Na₂O=3.7%～4.3%, K₂O=2.1%～2.9%）, assuming characteristics of I-type granite. The rocks have lower REE contents（35.2×10^-6～130.6×10^-6） with relative enrichment of LREE and positive Eu anomaly（δEu=1.04～1.90）. The primitive mantle normalized trace element patterns are characterized by the enrichment of the LILE（K, Rb, Ba, Sr） and depletion of the HFSE（Ta, Nb, P, Yb, Y）, showing the features of arc granites.