甘肃北山红石山地区马鞍山北花岗岩体的单颗粒锆石U-Pb年龄及地质意义  

The U-Pb age of single-grained zircon from Maanshanbei granite in Hongshishan area of the Beishan orogenic belt, Gansu Province

作　　者：刘明强[1] 王建军[1] 代文军[2] 

机构地区：[1]甘肃省地质调查院,甘肃兰州730000 [2]甘肃省地矿局第三地质矿产勘查院,甘肃兰州730050

出　　处：《岩石矿物学杂志》2006年第6期473-479,共7页Acta Petrologica et Mineralogica

基　　金：中国地质调查局区调项目(200113000057)

摘　　要：在1∶5万红岭等3幅区域地质调查中,岩体的AR、NK/A、A/CNK、δEu值等岩石化学和地球化学特征值表明,马鞍山北岩体属钙碱性系列与高钾钙碱性系列过渡的偏铝质到弱过铝质花岗岩类,具有高锶花岗岩的特点。通过高精度的单颗粒锆石U-Pb同位素测年,获得206Pb/238U表面年龄统计权重平均值为237.8±4·3Ma。这一同位素年龄的获得,说明本区三叠纪应为后造山环境。In the process of 1 ： 50 000 geological survey for Hongling and two other sheets in Hongshishan area of the Beishan orogenic belt, the authors studied AR, NK/A, A/CNK and δEu values of Maanshanbei granite in the Beishan orogenic belt. Petrochemical and geochemical features all indicate that Maanshanbei granite is of the peraluminium to weakly peraluminium type in the transitional zone of calc-alkaline and K-high calc-alkaline series, with characteristics of the Sr-high granite. U-Pb dating of zircon from Maanshanbei granite-diorite yielded an average weighted ^206Pb/^238U age of （237.8 ±4.3） Ma. This isotope age of Maanshanbei granite-diorite is of great significance in studying the tectonic evolution of Hongshishan area in the Beishan orogenic belt, Gansu Province.

关 键 词：甘肃北山 红石山地区 花岗岩 单颗粒锆石U-PB年龄 印支期 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]