内蒙古东乌珠穆沁旗冈干哈尔地区中生代岩浆岩特征及时代浅析

Simple Analysis on Characteristics and Age of Magmatic Rock in the Mesozoic Era in Ganganhar District,East Ujimqin Banner,Inner Mongolia

研究区古生代大地构造位置处于西伯利亚板块(Ⅳ)的额尔古纳造山系(Ⅳ1),次级构造单元为二连-朝不楞-加格达奇造山带(Ⅳ13),中生代大地构造划分属大兴安岭中生代岩浆岩带(Ⅴ1)。区域深大断裂控制了大兴安岭火山-岩浆岩带的分布,并形成与岩浆热液有关的斑岩型、接触交代型和热液型铅、锌、银、金、铜、铁等多金属矿床。本文对该地区中生代岩浆岩特征进行了系统研究。研究区侵入岩发育不好,露头以花岗岩类为主,多呈面积较小的岩株。根据侵入体与围岩的接触关系、同位素年龄等资料可将研究区内侵入岩划分为晚泥盆世花岗岩;晚石炭世花岗岩类。研究区火山活动强烈,根据火山岩产生的层位特点、岩性组成、同位素年龄等资料,研究区内火山岩为晚石炭世-早二叠世火山活动,构成了相应时代地层单元的主体。

The Paleozoic geotectonics position of the research area is located in Erguna orogenic system(Ⅳ1) of Siberia plate(Ⅳ), the secondary building unit is Eren-Chaobuleng-Jagdaqi orogenic belt(Ⅳ13), the the Mesozoic Era geotectonics is belong to the Mesozoic Era magmatic rock belt of Greater Khingan( Ⅴ1). The distribution of volcanic-magmatic belt in Greater Khingan is controlled by regional deep fractures, therefore, the following types are formed that related with the magmatic hydrothermal fluids, they are the porphyritic type, the contact metasomatism, the hydrothermal type lead, zinc, silver, gold, copper, iron and the other polymetallic deposits. The characteristics of the Mesozoic Era magmatic rock in this area are researched systematically. The intrusive rock in the research area is developed not good, the outcrop is dominated by granitic, most of them are small rock stocks. According to the contact relationship between intrusive body and surrounding rock, the isotopic age and the other data, the intrusive body in the research ares can be divided into late Devonian granite, late Carboniferous granites. The volcanic activity is strong in the research area, according to the horizon features, lithologic composition, isotopic age and so on caused by volcanic rock;the volcanic rock in research area is late Carboniferous-early Permian volcanic activity, which constitutes the body of stratigraphic unit in corresponding age.