地质学报2013，Vol.87Issue(3)：330-342,13.
西秦岭江里沟花岗岩体地球化学特征、年代学及地质意义
Geochemical Characteristics and Chronology of the Jiangligou Granitic Pluton in West Qinling and Their Geological Significance
摘要
Abstract
The Jiangligou granitic pluton intruding the Daguanshan Formation outcrops in the northern segment of West Qinling, and consists mainly of monzonitic granite mineralogically containing plagioclase, quartz, potassium feldspar and biotite. The pluton is characterized by typical Himalaya granite features with SiO2 = 71.76%~75.86%, Al2O3 = 11. 67%~14. 84% , MgO = 0. 35%~0. 70%, Sr= 58×10-6 -223×10-6, Y=1.2×10-5~16.1×l0-6, Yb = l. 21×10-6~1. 76×10-6. Rittmann index ranging between 1.42 and 2. 08 is plotted in high K calc-alkaline series in the K2O-SiO2 diagram and A/CNK is 1. 05 — 1. 1, suggesting that the Jiangligou pluton belongs to the peraluminous granites. Primitive mantle normalized trace elements patterns reveal that large ion lithophile elements (LILE ) K, Th, Rb, Ba are enriched, and strength element (HFSE) Nb, P, Ti, Y, Yb are depleted. Total REE content varies greatly with ∑REE = 62X10-6~170×10-6. Chondrite-normalized REE distribution pattern show strong enrichment in LREE and relative depletion in HREE, with obviously Eu negative anomaly (LREE/HREE = 6. 3 ~ 16. 2, (La/Yb)N=4. 9~17. 4, δEu=0. 38~0. 66). LA-ICP-MS isotopic dating show a zircon U-Pb isotopic age of 264.0 + 1. 4 Ma for the Jiangligou granitic pluton, indicating it belongs to middle Permian. Previous studies and this study reveal that the Jiangligou granitic pluton was formed in the thickened crust environment likely affected in distance by subduction and collision resulting from closing process of A' nyemaqen oceanic basin, resulting in compression and extrusion effect in this area. Crust thickening and temperature increasing provide dynamic conditions and magmatic activity space for deep crustal material remelting emplacement in the area.关键词
喜马拉雅型花岗岩/二长花岗岩/岩石地球化学特征/江里沟岩体/西秦岭北段Key words
Himalaya granite/ monzonitic granite/ geochemistry characteristics/ Jiangligou granite/ northern segment of West Qinling引用本文复制引用
孙小攀,徐学义,陈隽璐,高婷,李婷,李现冰,李晓英..西秦岭江里沟花岗岩体地球化学特征、年代学及地质意义[J].地质学报,2013,87(3):330-342,13.基金项目
本文为国家自然科学基金项目(编号 40972150)和中国地质调查局地质调查项目(编号 1212011220649)资助成果. （编号 40972150）
