新疆阿尔泰薄克土巴依铁锰矿地质特征及成矿作用  

Geological Characteristics and Metallogenesis of the Boketubayi Iron-Manganese Deposit in Altay,Xinjiang

作　　者：郭旭吉 李彦[2] 孔令湖[3] 郑佳浩[4] 孙东芊[2] 

机构地区：[1]新疆维吾尔自治区有色地质勘查局706队,新疆阿勒泰836500 [2]河北省地矿局探矿技术研究院,河北三河065201 [3]国土资源实物地质资料中心,河北三河065201 [4]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《现代地质》2015年第6期1309-1318,共10页Geoscience

基　　金：国家科技支撑计划项目(2011BAB06B03-02)

摘　　要：新疆薄克土巴依铁锰矿床赋存于下泥盆统康布铁堡组变质火山-沉积岩系中。本研究利用流体包裹体显微测温、氢和氧同位素以及年代学数据,探讨该矿床的成矿流体性质及来源、成矿时代和成矿作用。结果表明,矿体呈层状,与地层产状一致,矿石具有块状、条带状、条纹状、细脉状和浸染状构造,矿化具有喷流沉积特征。成矿流体属中温(集中在200~320℃)、低盐度(1.05%~4.49%)、中低密度的Na_2O-H_2O体系。重晶石的δD值为-129‰^-116‰,δ^(18)O值变化于10.4‰~11.6‰,δ^(18)OH_2O值为5.7‰~10.3‰,表明成矿流体来自深循环的海水与岩浆水的混合。矿体围岩变质安山岩的锆石LA-ICP-MS U-Pb年龄为(398.8±1.3)Ma,限定成矿时代在399 Ma左右,即为早泥盆世成矿。The Boketubayi iron-manganese deposit is hosted in metavolcanic-sedimentary sequence of the Lower Devonian Kangbutiebao Formation. Fluid inclusion microthermometry,H-O isotopes,and geochronological dating have been carried out to investigate the nature and source of ore-forming fluids,mineralization age,and oreforming mechanism of this deposit. Geological features of the deposit indicate that the ore body was layered,which is consistent with formation occurrence. In addition,massive,banded,striped,thin veins,and disseminated ores were observed in this study,suggesting the mineralization has exhalative-sedimentary characteristics.Fluid inclusions belong to medium-temperature（ cluster between 200 and 320 ℃）,low salinity（ 1. 05% to4. 49%）,and low-to medium-density Na_2O-H_2O system. Stable isotope analysis of barite yielded δD values of- 129‰ to- 116‰,δ^（18）O_（SMOW） values of 10. 4‰ to 11. 6‰,and δ^（18）OH_2O values of 5. 7‰ to 10. 3‰,respectively,indicating ore-forming fluids derived from the mixing of deep circulation seawater and magmatic water.The LA-ICP-MS zircon U-Pb dating yielded an age of（ 398. 8 ± 1. 3） Ma for ore-hosted metamorphic andesite,which indicates the ore forming age of Boketubayi deposit is around 399 Ma in Early Devonian.

关 键 词：铁锰矿床 地质特征 成矿作用 薄克土巴依 新疆阿尔泰 

分 类 号：P618.3[天文地球—矿床学]