| 唐雷,刘家军,祝新友,邹滔,杨飞,管育春.内蒙古盔甲山岩体岩石地球化学特征及地质意义[J].矿产勘查,2017,8(6):1031-1043 |
| 内蒙古盔甲山岩体岩石地球化学特征及地质意义 |
| Geochemical characteristics and geological implication of Kuijiashan granite pluton, Inner Mongolia |
| 投稿时间：2017-09-13 |
| DOI： |
| 中文关键词: 碱长花岗岩 高分异 锡多金属矿 内蒙古 |
| 英文关键词: alkali feldspar granite, tin polymetallic deposit, high differentiation, Inner Mongolia |
| 基金项目:中国地质调查局国家二级项目内蒙古赤峰有色金属基地综合地质调查(编号:DD20160072)及自然科学基金(编号:41602098)联合资助。 |
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| 中文摘要: |
| 盔甲山岩体位于大兴安岭南段的锡多金属成矿集中区,与区内锡多金属矿床存在成因联系。盔甲山岩体呈长条状岩株产于锡林郭勒杂岩中,岩性为碱长花岗岩,局部发育萤石及天河石。电子探针结果显示其斜长石An<5,Or<1.14,均为钠长石。地球化学研究显示,盔甲山花岗岩具有富硅、过铝质的特征,为高钾钙碱性—钙碱性系列,富挥发性元素,在Rb-Sr-Ba图解中集中于Rb端元附近。花岗岩的稀土元素总量∑REE平均为166.2×10-6,LREE/HREE平均为2.4,负Eu异常强烈,δEu平均值为0.0013,“四分组效应”明显。Zr/Hf和Nb/Ta平均值分别为11.60、9.93,与高分异花岗岩体中矿化花岗岩及正常花岗岩的过渡阶段一致。盔甲山碱长花岗岩的侵入形成于晚侏罗世—早白垩世,和维拉斯托花岗岩具有相近的Hf同位素组成。上述特征显示盔甲山花岗岩与A1型非造山花岗岩一致,推断岩浆主要来源于地壳,代表中生代晚期受太平洋板块俯冲影响,板内伸展环境下的岩浆作用。由于岩体东侧近南北向的巴彦高勒—乌兰尔根断裂和北侧北东向断裂的两次活动,致使盔甲山岩体不断被抬升,因此盔甲山岩体的超分异矿化部位可能已被剥蚀殆尽。 |
| 英文摘要: |
| The Kuijiashan granite pluton is located in the southern area of the Da Hinggan Mountains area, which is one of the most important tin polymetallic belts in China. The tin polymetallic mineralization is closely related to the pluton in this area. The Kuijiashan pluton, which is composed of alkali-feldspar granite partly with fluorite and amazonite, occurs in the Xilingol complex in form of long bar. According to the result of electron microprobe measurement, all of the feldspars in the Kuijiashan granite belong to albite because the An is less than 5 and Or is less than 1.14. The geochemical studies show that the Kuijiashan granite pluton is characterized with high Si, Rb and rich volatile, and belong to peraluminous and high-potassium calc-alkaline to calc-alkaline series. The REE pattern of the granite shows obvious tetrad effect, with ∑REE of 166.2 ×10-6, LREE/HREE of 2.4, and strong negative Eu anomaly. The average values of Zr/Hf and Nb/Ta are 11.60 and 9.93 respectively, which are consistent with the values of the transitional stage between mineralized and non-mineralized granites. The isotopic data indicate that the Kuijiashan pluton intruded in the period of from late Jurassic to early Cretaceous, and show similar Hf isotopic composition with Weilastuo granites. Based on all above-mentioned features, it is concluded that the Kuijiashan granite has the features of A1-type granite, mainly derived from the crust, and is the product of subduction of the Pacific plate in the late Mesozoic. Due to activities of the south-north trending Bayangaole-Wulanergen fracture in the east and the north-east trending fracture in the north, the Kuijiashan pluton was uplifted constantly, which resulted in erosion of the mineralized part in the high-differentiated pluton. |
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