• 责任者：Zhou Yun (State Key Laboratory of lsotope Geochemistry ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Liang Xinquan
• 刊名：Geotectonica et Metallogenia
• 出版年：2013
• 卷期：37(3)
• 关键词：A型花岗岩 ; A-type granite ; 湖南 ; Hunan Province
• 页码：p.511-529
• 图表：11 illus., 5 tables, 95 refs.
• 分类号：0801
• issnNo：ISSN1001-1552
• isbnNo：CN44-1595/P

     The Xitian granites are located in the bordering area of Hunan province and Jiangxi province, which is an important part of the Nanling granite belt closely related to tin-tungsten polymetallic deposits. Zircon LA-ICP-MS U-Pb dating of the Longshang fine-grained granite yields an age of 151.7±1.2 Ma, which is the same as previous reported SHRIMP U-Pb ages, indicating the Xitian granites was emplaced in Yanshanian. The granites are characterized by high contents of silicon （SiO2=73.44%-78.45%）, potassium （K20/Na20=l.00-253.77）, aluminum （Al2O3=11.20%- 13.90%）, low in calcium （CaO=0.25%-2.22%） and magnesium （MgO=0.05%-0.42%）, metaluminous to strongly peraluminous （A/CNK=0.90-3.44）. The granites show strong depletion of Sr, Ba, P, Ti, Nb and Eu （εEu=0.004-0.076）, enrichment of Th, Ta, Hf, Rb and LREE. The major and trace element concentrations of the fine-grained granite in Longshang of the Xitian area show that the granite is of A-type. The low eNd（t） （--7.30----8.87） and two stage Nd modal ages ranging from 1.56 Ga to 1.69 Ga suggest that the magma may have derived mainly from partial melting of the old crustal materials. The formation of the Xitian granites may be related to the extension caused by the subduction of palaeo-Pacific plate. The Xitian granites as typical tin-bearing rocks are promising for Tin exploration.