新疆东天山哈尔里克奥陶纪的构造属性:来自火山岩LA-ICP-MS锆石U-Pb年代学与地球化学的制约
发布时间：2018-12-11 19:22
【摘要】：新疆东天山哈尔里克造山带火山岩为一套酸性—基性岩(流纹岩、英安岩、安山岩、玄武岩)夹火山碎屑岩(凝灰岩)的岩石组合。流纹岩样品的LA-ICP-MS锆石U-Pb定年结果显示,时代为中奥陶世大坪期((468.8±9.1)Ma),代表了该套火山岩的形成年龄。岩石地球化学分析结果显示,该套火山岩SiO_2含量介于49.12%~78.24%,TiO_2介于0.12%~1.00%,Al_2O_3介于11.31%~20.86%;铝饱和指数A/CNK值为0.80~1.31(均值为0.99),里特曼指数σ值为0.19~3.86(均值为1.29),Mg#值为8.87~49.29(均值为31.20);富集大离子亲石元素(LILE)Ba、Rb以及轻稀土元素(∑LREE)La、Ce,亏损高场强元素(HFSE)Nb、Ta、Ti等。微量元素和稀土元素的相关图解与比值以及发育的捕获锆石反映了俯冲带岛弧钙碱性火山岩特征,且存在大陆地壳混染作用。综合区域地质资料分析,在早古生代期间(中奥陶世—早志留世),哈尔里克造山带存在大面积的与岛弧演化有关的加里东期岩浆活动,此期间哈尔里克造山带的构造背景为洋壳俯冲有关的岛弧环境,其形成可能与东准噶尔南部克拉麦里洋向南俯冲作用有关。
[Abstract]:The volcanic rocks of the Hallik orogenic belt in eastern Tianshan, Xinjiang are a set of acid-basic rocks (rhyolite, dacite, andesite, basalt) with volcanic clastic rocks (tuff). The LA-ICP-MS zircon U-Pb dating of rhyolite samples shows that the age is the Daping stage of the Middle Ordovician (468.8 卤9.1) Ma),) representing the formation age of this set of volcanic rocks. The results of petrogeochemical analysis show that the SiO_2 content of the volcanic rocks is between 49.12 and 78.24 and TiO-2 is between 0.12 and 1.00. The number of Al2O3 is between 11.31 and 20.86; The A/CNK value of aluminum saturation index is 0.80 ~ 1.31 (mean = 0.99), the 蟽 value of Ritman index is 0.19 ~ 3.86 (mean = 1.29), and the Mg# value is 8.87 ~ 49.29 (mean = 31.20). The enrichment of large ion lithophile element (LILE) Ba,Rb and light rare earth element (鈭，
本文编号：2373090
[Abstract]:The volcanic rocks of the Hallik orogenic belt in eastern Tianshan, Xinjiang are a set of acid-basic rocks (rhyolite, dacite, andesite, basalt) with volcanic clastic rocks (tuff). The LA-ICP-MS zircon U-Pb dating of rhyolite samples shows that the age is the Daping stage of the Middle Ordovician (468.8 卤9.1) Ma),) representing the formation age of this set of volcanic rocks. The results of petrogeochemical analysis show that the SiO_2 content of the volcanic rocks is between 49.12 and 78.24 and TiO-2 is between 0.12 and 1.00. The number of Al2O3 is between 11.31 and 20.86; The A/CNK value of aluminum saturation index is 0.80 ~ 1.31 (mean = 0.99), the 蟽 value of Ritman index is 0.19 ~ 3.86 (mean = 1.29), and the Mg# value is 8.87 ~ 49.29 (mean = 31.20). The enrichment of large ion lithophile element (LILE) Ba,Rb and light rare earth element (鈭，
本文编号：2373090
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