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大兴安岭北部阿龙山—满归地区新近发现一套花岗岩类,岩石类型为正长花岗岩、二长花岗岩、石英正长岩,发育片麻状构造。主要分布于前寒武纪结晶基底区,内部见有前寒武纪变质表壳岩包体;岩石化学特征上显示较好的同源性,属于轻稀土富集型,微量元素以较高的大离子亲石元素(如Rb、Sr、Th等)和较低的过渡族元素(如Cr、Ni、Co、Cs等)含量为特征;成因类型属于I型花岗岩,形成于火山弧及同碰撞的构造背景。单颗粒锆石U-Pb年龄为654±46Ma,应为兴凯期产物。兴凯期花岗岩类的确定对于区域构造的重新认识有重要的意义。
Recently, a group of granites have been discovered in Aolongshan-Mangui area, northern Da Hinggan Mountains. The rocks are of the type of orthoclase granite, monzogranite and quartz syenite, and the development of gneiss structure. Mainly distributed in the Precambrian crystalline basement area, there are pre-Cambrian metamorphic crustal rock inclusions; petrochemical characteristics showed good homology, belonging to light rare earth enrichment type, trace elements with higher Large ion lithophile elements (such as Rb, Sr, Th, etc.) and lower transitional elements (such as Cr, Ni, Co, Cs, etc.) content characteristics; genetic type belongs to I-type granite, formed in the volcanic arc and collisions Tectonic background. Single-zircon U-Pb age of 654 ± 46Ma, should Xing Kai product. The determination of Xingkai granites is of great significance for the re-understanding of regional structure.