宁夏中卫香山地区铁矿床地质特征及成因探讨

Discussion on geological characteristics and genesis of the iron deposits in Xiangshan area,Zhongwei,Ningxia

为了研究宁夏中卫香山地区铁矿床的成因及成矿规律,对宁夏中卫香山地区典型铁矿床（点）成矿地质背景、矿床地球化学等方面进行了分析与探讨.结果表明：中卫香山地区铁矿体呈似层状、透镜状,主要沿层间断裂破碎带分布,具有明显的层控特征.矿石矿物主要为赤铁矿和褐铁矿为主,局部见有黄铁矿.香山群硅质岩w（SiO2）为71.74%~92.45%,w（Al2O3）/[w（Al2O3）＋w（Fe2O3）]比值显示大部分样品与大陆边缘硅质岩数据接近.稀土元素PAAS标准化图解表现为平坦型,具有轻微的正铕异常;微量元素在北美页岩标准化图解上变化较大,可能与陆源物质的加入有关.矿床经历了同生沉积期和次生淋滤富集期,含矿溶液沿破碎带及节理渗透时,置换了岩石中含铁的碳酸盐成分成矿,成矿元素在表生氧化条件下淋滤富集.

In order to study the genesis and ore-forming rule of ore deposits in Xiangshan area,Zhongwei,Ningxia,geological background and geochemistry and genesis are analyzed and discussed for the typical iron ore deposits.The results show that the iron deposits body distributes mainly along the fractured zone between the rock layers with obvious features of strata bound,bedded and lenticular like.Ore minerals are mainly hematite and limonite,locally pyrite.Siliceous rocks w（SiO2） is 71.74% to 92.45%,w（Al2O3）/[w（Al2O3）＋w（Fe2O3）] is close to the continental margin cherts data in most samples.PAAS standardized graphic performance for rare earth elements are flat with slight positive Eu anomaly;trace elements in the North American shale-normalized diagram indicates a big change,which may be related to be joined the addition of terrigenous matter.The deposits experienced the syndepositional period and leaching of secondary enrichment period.The ore-bearing solution replaced the carbonate components while it infiltrated into rocks through the fracture zones and joints,and then,the ore-forming elements enriched in the supergene oxidizing conditions.