大兴安岭十二站晚古生代后造山花岗岩的特征及其地质意义  

Characteristics and geological implications of the Late Paleozoic post- orogenic Shierzhan granite in the Great Xing' an Range.

作　　者：隋振民[1] 葛文春[2] 徐学纯[2] 张吉衡[2] 

机构地区：[1]吉林农业大学资源与环境学院,长春130118 [2]吉林大学地球科学学院,长春130061

出　　处：《岩石学报》2009年第10期2679-2686,共8页Acta Petrologica Sinica

基　　金：国家自然科学基金(40372038;40325006和40739905)项目资助成果.

摘　　要：东北大兴安岭地区的十二站岩体主要由钾长花岗岩、二长花岗岩组成。钾长花岗岩的锆石LA-ICP-MS U-Ph定年结果为298Ma,属于晚古生代岩浆活动的产物。十二站岩体岩石化学以高钾(4.82%～6.06%)为特征,属于钾玄质系列,富集大离子亲石元素(LREE和Rb、Th、K等)而亏损高场强元素(Nb、Ta、P、Ti等),显示后造山花岗岩的特征,是兴安地块与松嫩地块碰撞拼合后后造山阶段的产物。岩体的Hf同位素将大兴安岭北部兴安地块的地壳增生时间限定在显生宙,而额尔古纳地块地壳增生主要发生在新元古代-显生宙,暗示两地块具有不同的早期地壳演化历史。The Shierzhan intrusion, located in the Great Xing' an Range of northeastern China, is mainly composed of syenogranite and morzogranite. Zircon U-Pb age obtained by LA-ICP-MS analyses from the syenogranite is 298Ma, suggesting that it is the production of Late Paleozoic magmatic activities. Petrochemically, the Shierzhan granite is characterized by high K (K(2) O 4.82% similar to 6.06%), and therefore belongs to shoshonite series. It is enriched in LILE (LREE, Rb, Th, and K) and depleted in HFSE (Nb, Ta, P, and Ti), showing characteristics of post-orogenic granites. It is proposed that this pluton was likely the product of post-orogenic evolution after the collision of Xing' an and Songnen massifs. Zircon Hf isotopic data of the granite suggests that crustal growth of Xing' an mass of in northern Great Xing' an Range occurred in the Phanerozoic, which is much different from that of the Eerguna massif which displays crustal formation age of Neoprotozoic to Phanerozoic. Therefore, the Xing' an and Eerguna massifs have different crustal evolution histories.

关 键 词：大兴安岭地区 晚古生代 造山花岗岩 特征 地质意义 post Late Paleozoic 钾长花岗岩 额尔古纳地块 地壳增生 岩体 显生宙 后造山 高场强元素 二长花岗岩 演化历史 岩石化学 岩浆活动 新元古代 地块碰撞 

分 类 号：P58[天文地球—岩石学]