新疆阿尔泰造山带南缘克朗盆地康布铁堡组流纹岩U-Pb年龄和地球化学特征

LA-ICP MS Zircon U-Pb Geochronology and Geochemical Study of Rhyolite at Kangbutiebaio Formationin the Southern margin of Altay Orogenic Belt

阿尔泰造山带南缘分布着大量晚古生代康布铁堡组火山岩,是多个铁、铜、铅锌矿的赋矿围岩。通过LAICP-MS锆石U-Pb测年获得阿尔泰南缘克朗火山-沉积盆地内流纹岩年龄为（392.4±2.4）Ma,表明阿尔泰南缘克朗盆地康布铁堡组火山岩主要形成于晚古生代中泥盆世早期,具高硅（SiO2含量72%-78%）、高碱（总碱含量3%-7%）特征。Nb/Ta比值为8.8-10.1,可能为大陆地壳部分熔融产物。结合区域地质分析,认为它们可能产于与俯冲消减作用有关的陆缘岛弧的大地构造环境中。

The Late Paleozoic volcanic rocks of Kangbutiebao Formation widely distributed in Southern margin of Altay orogenic belt, which are wall rocks of lots of iron,copper,lead and zinc ore deposits.LA-ICP MS U-Pb zircon analyses from rhyolite of Kangbutiebao FM.in Kelang basin yield wegihted m206Pb/238U ages of（392.4 ± 2.4） Ma,which showing volcanic rocks formed in the early part of the late Paleozoic. The Geochemical features to rhyolite with high silicon（SiO2content 72% to 78%）;high alkali（total alkali content in the range of 3% to 7%）;Nb/Ta ratios range from 8.8 to 10.1,which showed that the may be the volcanic rocks are products of partial melting of the continental crust,combining the regional geological analysis they should form in subduction-related continental margin island arc geological environment.