西准噶尔阿尔木强地区奥陶纪布鲁克其组火山岩地质特征和锆石U-Pb年代学及构造意义  

Geological Characteristics and Zircon U-Pb Chronology of Volcanic Rocks of Ordovician Bulukeqi Formation and Its Tectonic Significance in Almuqiang Area,West Junggar

作　　者：邸晓辰 杨晨 Di Xiaochen;YangChen(Xinjiang Geological Survey Institute,Urumqi,Xinjiang,830000,China)

机构地区：[1]新疆维吾尔自治区地质调查院,新疆乌鲁木齐830000

出　　处：《新疆地质》2022年第2期184-190,共7页Xinjiang Geology

摘　　要：新疆西准噶尔阿尔木强地区发育有较丰富的古生代火山岩序列,对构建该地区古生代构造演化格局具重要科学意义。布鲁克其组火山岩主要为一套中基性火山岩,据LA-ICP-MS锆石原位U-Pb测年结果,锆石U-Pb年龄为(468±49)Ma,时代为中奥陶世。地球化学特征表明,布鲁克其组火山岩富集大离子亲石元素Ba,U,相对亏损Nb,Ta等元素,具富铝特征,属钙碱性系列岩石。该组火山岩轻稀土相对富集、重稀土相对平坦,与俯冲带火山岩富铝特征一致,具典型岛弧火山岩特征,总体构造背景与俯冲造山作用有关。Paleozoic volcanic piles are well developed in the Almuqiang area of West Junggar,which are of great sig-nificance for reconstructing the tectonic framework and geodynamic evolution in the Paleozoic.The volcanic rocks of the Bulukeqi Formation mainly consist of a set of intermediate to basic volcanic lavas.LA-ICP-MS in situ zircon U-Pb dating results reveal that they are formed in the Middle Ordovician,with zircon age at 468±49 Ma.The volcanic rocks are enriched in aluminum and belong to the calc-alkaine series with remarked enriched large ion lithosphile elements(such as Ba and U)and depleted HFSE elements,including Nb and Ta.The relatively enriched LREE and flat HREE pat-terns are consistent with aluminum rich characteristics of volcanic rocks in subduction zone,which are typical of those volcanic rocks in continental arcs.The overall tectonic setting is related to subduction orogeny.

关 键 词：西准噶尔 布鲁克其组 中奥陶世 地球化学 锆石U-PB年龄 

分 类 号：P534.42[天文地球—古生物学与地层学] P588.14[天文地球—地质学]