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新疆东准噶尔卡拉麦里地区早泥盆世火山岩由玄武岩和玄武安山岩组成,采用LA-ICP-MS锆石U-Pb定年方法,获得玄武安山岩错石的U-Pb年龄为404.5± 1.9 Ma,表明喷发时代为早泥盆世.岩石地球化学显示早泥盆世火山岩属岛弧拉斑系列,具相对较高的Mg#值(41.25～55.32)及较低的Nb(1.11×10-6～2A2× 10-6)、Zr (73.9× 10-6～95× 10-6)和∑REE (81.50× 10-6～121.80×10-6)含量.富集大离子亲石元素(LILE:K、Rb、Ba)和轻稀土元素(LREE),而亏损Ta、Nb和Ti高场强元素(HFSE:Ta、Nb、Ti),并显示Eu弱的亏损,这些特征与岛弧火山岩类似,其原始岩浆可能起源于俯冲流体交代的亏损地幔楔的部分熔融.结合区域地质背景,认为早泥盆世火山形成于洋内弧的构造环境,为卡拉麦里古洋盆向北俯冲消减的产物.这是在卡拉麦里地区首次报道的洋内弧火山岩,这一新的发现和认识对研究东准噶尔古生代洋盆演化及区域构造格局均具有重要的意义.“,”The Early Devonian volcanic rocks in the Kalamaili area,East Junggar,mainly consist of basalt and basaltic andesite.This paper presents a set of new LA-ICP-MS zircon geochronology,major and trace element geochemistry for several representative basalt and basaltic andesite in Kalamaili area.By dating of the LA-ICP-MS U-Pb zircons from an andesitic sample yield 404± 1.9 Ma,suggesting that it was formed in Early Devonian.Geochemical analyses suggest that the Early Devonian volcanic rocks have high Mg# (41.25 ～ 55.32) and low Nb (1.11×10-6 ～ 2.42× 10-6),Zr (73.9×10-6～ 95×10-6) and ∑REE (81.50×10-6～ 121.80×10-6) contents,belonging to the tholeiite series.The samples have characteristics of enrichment of LILE (K,Rb,Ba) and LREE,depletion of HFSE (Nb,Ta,Ti) and slightly negative Eu anomalies.These geochemical features indicate they are typical arc volcanic rocks in supper-subduction zone.The primitive magma of the rocks was possibly generated by partial mnelting of a metasomatic mantle source modified by the subducted slab-derived fluid.Combining with the regional geological background we propose that the Early Devonian volcanic rocks formed in an intra-oceanic arc environment,which was the magmatic arc formed by the northward subduction of the Kalamaili oceanic basin in the Early Devonian.Meanwhile the intra-oceanic arc volcanic rocks reported in the Kalamaili area,which have important significance for Paleozoic oceanic basin evolution and regional tectonic framework in East Junggar.