地质学报2011，Vol.85Issue(5)：821-833,13.DOI:CNKI:11-1951/P.20110512.0910.016
宁芜盆地花岗岩类的锆石U-Pb年龄、同位素特征及其意义
Zircon U-Pb Ages and Isotopic Characteristics of the Granitoids in the Ningwu Basin, China, and their Significance
摘要
Abstract
Granitic intrusions in the Ningwu basin, outcropping sporadically, consist mainly of quartz monzonite and granite. Few works have been done on these granitic intrusions. This paper presents a detail study of some granitic intrusions by means of LA-ICPMS zircon dating, Lu-Hf zircon isotope, and Sr-Nd isotope analyses. The U-Pb zircon ages for five granitic intrutions are 128.0±1.7 Ma for Niujishan pluton, 126.4 ±1.3 Ma for Huoli pluton, 129.8±1.6 Ma for Gushan pluton (sampling from drill core in the Gushan iron deposit,), 130. 1 ± 1.5 Ma for Xiaoshishan pluton, and 128. 3±1.8Ma for Niangniangshan pluton.These date indicate that the granitic intrusions emplaced in 126～130Ma, suggesting that they were the products of magmatic activity in early Cretaceous. The ages are similar to those of the Gushan and Niangniangshan Formations volcanic rocks and slightly younger than the mineralization ages of the porphyrite iron deposits in the Ningwu basin. The Nd-Sr isotope results suggest that the granitic intrusions derived from the metasomatic mantle, compositionally closing to the EMI, which has relationship with the subduction of the Pacific Plate. The Lu-Hf isotope results imply that the granitic plutons have genetic and evolutional relationship with the mineralized diorites or porphyry diorites. The granitic plutons in the Ningwu basin formed in an extensional geodynamic setting, and were products of the lithospheric thinning in eastern China.关键词
LA-ICP MS U-Pb定年/锆石/同位素/花岗岩类/宁芜盆地Key words
LA-MC-ICP MS dating/ zircon/ isotope/ granitoids/ Ningwu basin引用本文复制引用
袁峰,周涛发,范裕,张乐骏,马良,钱兵..宁芜盆地花岗岩类的锆石U-Pb年龄、同位素特征及其意义[J].地质学报,2011,85(5):821-833,13.基金项目
本文为国家自然科学基金项目(40830426,40803015)、国家"深部探测技术与实验研究专项计划"专题(编号:SinoProbe-03-02-05)、国土资源部公益性行业科研专项项目课题(编号:201011047 07)、中国地质调查局地质调查工作项目(编号1212011121115)及新世纪优秀人才支持计划项H(NCET-10-0324)、安徽省地质勘查专项费项目(2005-51.2007-1,2009-g-22,2009-13)资助的成果. （40830426,40803015）
