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滴水泉一带早石炭世火山岩分布于卡拉麦里蛇绿岩带南侧、准噶尔盆地东缘。岩石类型有玄武岩、玄武安山岩、安山岩、安山质角砾熔岩。岩石系列为碱性系列和拉斑玄武岩系列,LA-ICP-MS锆石U-Pb年龄为(336.6±3.7)Ma~(338.3±5.2)Ma,时代为早石炭世。火山岩富集LILE和轻稀土元素((La/Yb)N=3.3~8.5),Nb、Ta略显亏损,I sr值在0.70354~0.70411之间,εNd(t)值为+4.9~+6.6,源区可能是受到俯冲板片脱水流体交代的大陆地幔楔。地球化学特征表明,火山岩形成于板内环境,为后碰撞岩浆活动的产物,暗示准噶尔盆地东缘地区后碰撞岩浆活动至少从早石炭世就已经开始。火山岩中捕获的老锆石指示,准噶尔盆地东部可能存在古老基底。
The Early Permian volcanic rocks are distributed in the south of Kalamaili ophiolite zone and the eastern margin of Junggar Basin. Rock types are basalt, basaltic andesite, andesite, andesite breccia lava. The series of rocks are basic series and tholeiite series. The LA-ICP-MS zircon U-Pb ages are (336.6 ± 3.7) Ma ~ (338.3 ± 5.2) Ma, dating from Early Carboniferous. Volcanic rocks are enriched in LILE and light rare earth elements (La / Yb) N = 3.3-8.5), Nb and Ta are slightly depleted, I sr values are between 0.70354 and 0.70411, εNd (t) values are between + 4.9 and + 6.6, The source zone may be a continental mantle wedge that is subducted by subducting slab dewatered fluids. Geochemical characteristics indicate that volcanic rocks formed in the intraplate environment and are the product of post-collision magmatism, suggesting that post-collision magmatism in the eastern Junggar Basin has started at least from the Early Carboniferous. Old zircons captured in volcanic rocks indicate that an ancient basement may exist in the eastern part of the Junggar Basin.