地质通报2017，Vol.36Issue(9)：1531-1541,11.
大兴安岭北段龙江盆地光华组碱流岩LA-ICP-MS锆石U-Pb年龄及其地质意义
LA-ICP-MS zircon U-Pb dating and geochemical characteristics of the pantellerite of Guanghua Formation from Longjiang basin in northern Da Hinggan Mountains and their geological implica-tions
摘要
Abstract
In this paper, geochemistry and zircon U-Pb isotope chronology of the pantellerite of Guanghua Formation from Longji-ang basin in northern Da Hinggan Mountains were studied and their petrogenesis and tectonic significance were discussed. The zir-cons from pantellerite of Longjiang basin show oscillatory growth zonation of typical magmatic origin and high Th/U ratios (0.71~2.12),indicating a magmatic origin for the zircons. LA- ICP- MS zircon U- Pb weighted average age is 122.4 ± 1.7Ma (n=19, MSWD=0.77). The pantellerite is characterized by high SiO2 content, high alkali content but low Mg, Ca content. The REE pat-terns are characterized by enrichment of LREEs relative to HREEs and distinct negative Eu anomalies in the chondrite-normalized REE patterns, characterized by right-inclined and"V"-shaped feature. These rocks are depleted in Sr and Ba but enriched in Rb, Th, U, Zr. All these characteristics are similar to features of A-type granites which originated from the partial melting of felsic crust under high temperature and low pressure conditions and the subsequent fractional crystallization of plagioclase and Ti and Fe oxides, thus representing an extensional tectonic environment.关键词
碱流岩/LA-ICP-MS锆石U-Pb年龄/A型花岗岩/地球化学/早白垩世/大兴安岭Key words
pantellerite/LA-ICP-MS zircon U-Pb age/A-type granite/geochemistry/Early Creteaceous/Da Hinggan Mountains分类
天文与地球科学引用本文复制引用
张超,吴新伟,张渝金,郭威,权京玉..大兴安岭北段龙江盆地光华组碱流岩LA-ICP-MS锆石U-Pb年龄及其地质意义[J].地质通报,2017,36(9):1531-1541,11.基金项目
中国地质调查局项目《内蒙古1:5万南燕窝沟等四幅区域地质矿产调查》(编号:12120113053900)、《内蒙古1:5万陶海营子等四幅区域地质矿产调查》(编号:DD20160201-04)、《太平洋构造域北段构造格局、演化历史研究及1:250万构造图编制》(编号:DD20160343-08)和《古亚洲洋构造域东段构造格局、演化历史研究及1:250万构造图编制》(编号:DD20160343-09) （编号:12120113053900）
