内蒙古阿右旗卡休他他铁(金、钴)矿床地质地球化学特征  

Geological and geochemical features of Kaxiutata iron (gold, cobalt) deposit in Alxa Right Banner, Inner Mongolia

作　　者：许东青 江思宏[2] 张建华[2] 胡朋[2] 赵永发 王曰诚 赖新荣[2] 

机构地区：[1]庆华集团阿拉善矿业科技有限公司阿右旗铁矿,内蒙古阿拉善737300 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《矿床地质》2006年第3期231-242,共12页Mineral Deposits

基　　金：国家地质调查项目(200310200001_01)的资助

摘　　要：文章较为全面地总结了卡休他他铁(金、钴)矿床的地质特征,并通过元素地球化学分析,探讨了该矿床的成矿作用与形成规律。卡休他他中型铁矿床由南、北2个矿带组成,共圈定24个铁矿体,其中以北矿带的3号矿体规模最大,其长约1300m,厚12.9～57m,斜深近200m。铁矿体的产出严格受辉长岩与震旦系浅变质岩接触带附近的矽卡岩控制。钴矿体在南、北矿带铁矿体和矿体外围的矽卡岩带中均有产出,金矿体则全部产出于北矿带矽卡岩带中,金和钴矿体在空间产出上与绝大多数铁矿体并不一致,它们主要与金属硫化物具有密切的成生关系,因此它们的形成可能晚于磁铁矿。元素地球化学分析结果表明,矿区内南、北矿带总体上是同一期成矿作用的产物,它们的少数成矿元素含量和矿石磁性之间的差别,可能与南矿带曾遭受后期二长岩侵入活动的影响,造成了部分成矿元素(如Au、Cu等)的活化迁移有关。卡休他他铁、金和钴矿的形成可能是同一成矿事件中不同阶段的产物,磁铁矿体属于早期岩浆气液阶段接触交代的产物,而钴和金的富集则可能是稍后的中高温热液阶段的产物。因此,卡休他他铁矿床属于接触交代型或矽卡岩型。The Kaxiutata iron deposit is a medium-size magnetite deposit discovered by No. 6 Geological Party of Gansu Bureau of Geology in Alxa Youqi of Inner Mongolia in 1970s. It is associated with rich gold and cobalt. The deposit is composed of two mineralized zones, i.e., south and north iron ore zones. So far, twenty-four ore bodies have been outlined, and the No. 3 is the largest one, which is 1 300 m long and 12.9 to 57 m wide, with a downdip extension of 200 m. Iron ore bodies all occur within the skam located near the contact zone between the gabbro and the Sinian epi-metamorphic rocks. The cobalt ore bodies occur not only within iron bodies but also in the skarn outside the iron bodies, while the gold ores are found only in the skarn of the north iron ore zone. Spatially, the gold and cobalt ores are not consistent with most iron ones, and are mainly associated with the sul-fides. All these indicate that the gold and cobalt ores were formed later than the iron ores. Chemical analyses of the ores and wall rocks suggest that the south and north iron ore zones were formed by the same ore-forming process. The differences of Au, Cu and Ni contents between these two iron ore zones might have resulted from the late intrusion of monzonite. It is believed that the iron, gold and cobalt ores in Kaxiutata were formed at different stages of the same ore-forming event, and the magnetite ores are products of the contact metasomatism between the magma and the strata, while the enrichment of the gold and cobalt resulted from the subsequent sulfide deposition at the meso-hypothermal stages. The Kaxiutata iron deposit belongs genetically to the contact metasomatism or skarn type.

关 键 词：地质学 铁矿 矽卡岩 矿床地质 卡休他他 阿拉善右旗 内蒙古 

分 类 号：P618.31[天文地球—矿床学]