%0 Journal Article %T 内蒙古小黑山地区二长花岗岩和石英闪长岩的锆石U-Pb年代学、元素地球化学及其地质意义<br>LA-ICP-MS Zircon U-Pb Age of Monzonite Granite-Quartz DioritePluton in Xiaoheishan Area of BeishanOrogenic Beltand Its Geological Significance, Inner Mongolia %A 赵志雄 %A 贾元琴 %A 王金荣 %A 许 海 %A 熊 煜 %A 王新亮 %A 刘 强 %A 高 伟 %A 高 鉴 %A 刘孟合< %A br> %A Zhao Zhixiong %A JiaYuanqin %A Wang Jinrong %A XuHai %A Xiong Yu %A Wang Xinliang %A Liu Qiang %A Gao Wei %A GaoJian %A Liu Meng %J 地球科学(中国地质大学学报) %D 2018 %R 10.3799/dqkx.2018.202 %X 对内蒙古北山地区的小黑山二长花岗岩、石英闪长岩进行了岩石学、地球化学、LA-ICP-MS锆石U-Pb定年研究，以探讨该地区构造演化作用.锆石测年结果显示片麻状二长花岗岩结晶年龄为461.5±1.5 Ma，形成于中奥陶世；片麻状石英闪长岩结晶年龄为436.1±1.5 Ma，形成于早志留世.二长花岗岩具有偏铝质－弱过铝质高钾钙碱性的特征，富集轻稀土(LREEs)、大离子亲石元素(LILEs)Rb、K和不相容元素Th、U，亏损重稀土(HREEs)和高场强元素(HFSEs)Nb、Ta、Ti.石英闪长岩属于偏铝质钙碱性系列，具有相对平缓的富集轻稀土元素的配分形式，轻重稀土分馏较为明显，具有弱的负Eu异常， δ Eu=0.69～0.92；相对亏损Nb、Ta、P、Sr、Ti，富集Rb、K.结合区域地质背景，认为二长花岗岩形成于加厚地壳，构造环境为同碰撞，而石英闪长岩形成于板片碰撞后续火山弧环境，进而认为红柳河－牛圈子－洗肠井代表的古生代洋盆向北俯冲消亡时间介于436.1～461.5 Ma.<br>Petrology, geochemical data and LA-ICP-MS zircon U-Pb dating have been obtained from the Xiaoheishan monzogranite and quartz diorite, with the aim of constraining the tectonic nature of the Beishan area. LA-ICP-MS zircon U-Pb age data indicate that the monzonite granite was formed during Middle Ordovician and the quartz diorite was emplaced during Early Silurian. Furthermore, the monzonite granite belong to high-K cal-alkaline, metaluminous-weakly peraluminous with features of rich SiO2 and Al2O3. They also show strong enrichment in LREEs and Rb, K, Th, U, depletion in HREEs and HFSEs (Nb, Ta, Ti). The quartz diorite belongs to cal-alkaline with metaluminous characteristics. In addition, they invariably exhibit relatively gentle light rare earth elements (LREE) enrichment with flat heavy rare earth elements (HREE) and weak negative Eu anomalies ( δ Eu=0.69-0.92) in the chondrite-normalized REE patterns, depletion of Nb, Ta, P, Sr, Ti and enrichment of Rb, K. Based on the regional geology, the above characteristics reflect that the monzonite granite was formed under the tectonic setting of syn-collision, while the quartz diorite volcanic arc after collisional. This implies that the ocean basin represented by Hongliuhe-Niujuanzi-Xichangjing ophiolite mélange belt disappeared during 436.1-461.5 Ma %K 小黑山 %K 地球化学 %K 锆石U-Pb年龄 %K 构造环境 %K 地质意义 %K 岩石学.< %K br> %K Xiaoheishan %K geochemistry %K zircon U-Pb age %K tectonic setting %K geological significance %K petrology %U http://www.earth-science.net/WebPage/Article.aspx?id=4100