本文报道的花岗闪长岩位于内蒙古巴彦呼舒以东10 km 处。大地构造位于中亚造山带中段的锡林浩特晚古生代褶皱带。LA-ICP-MS 锆石 U-Pb 测年获得该岩体的侵位年龄为236．1±3．4Ma。花岗闪长岩 SiO2为66．93％～67．22％，Al2 O3为15．13％～15．53％，K2 O 为2．47％～2．56％，Na2 O 为4．35％～4．46％，A ／CNK 值为0．94～0．95，显示该地区花岗闪长岩属于偏铝质钙碱性岩；亏损高场强元素，Sr 达416．6×10－6～425．7×10－6， Sr／Y值为42～49，显示出高 Sr 低 Y 的典型特征，具有 Adakite（高锶低钇中酸性岩）或者高 Sr 花岗岩的特点。花岗闪长岩的锆石εHf（t）值介于13．3～15．7之间；两阶段模式年龄分别为249～356Ma 和258～422Ma。综合分析表明，花岗闪长岩为西伯利亚板块和华北板块碰撞闭合后，加厚的下地壳部分熔融作用的产物。%The granodiorite of the article reports located in 10km east of Bayanhushu Inner Mongolia.The tectonic position belongs to Late Paleozoic fold belt of Xilinhaote of the middle in central Asian orogenic.The age of this pluton is 236.1 3.4Ma by using LA-ICP-MS U-Pb zircon dating method.In this granodiorite,the content of SiO2 is 66.93% ~67.22%,Al2 O3 is 15.13% ~15.53%,K2 O is 2.47% ~2.56%,Na2 O is 4.35% ~4.46%, and the A /CNK is 0.94 ~0.95,this petrochemistry data indicate that the granodiorite belongs to the Partial aluminum and calc—alkaline series,and depleted in high field strength elements,the content of Sr is (416.6 ~425.7)10 -6 ,Sr/Y is 42 ~49,this geochemical characteristic is the same as high Sr low Y of the adakite or high Sr granite.The εHf(t)values and two staged Hf model age of the granodiorite is 13.3 ~15.7,249 ~356Ma and 258 ~422Ma.Synthetical analyze shows,The granodiorite is the product of the thickening of partial melting of crust after closed by Siberian plate and North China plate.
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