山东省齐河-禹城地区矽卡岩型铁矿磁铁矿元素地球化学特征及其对成矿作用的指示意义

Geochemical Characteristics of Magnetite Elements and Its Indication of Mineralization of Skarn Type Iron Deposit in Qihe-Yucheng Area in Shandong Province

山东省齐河-禹城地区在黄河北厚覆盖区,有明显的航磁异常和重力异常,通过系统的地质勘探工作,在深部揭露了多处铁矿床,为系统掌握研究区磁铁矿成因机制,服务于基础地质和矿产资源调查,利用EMPA对磁铁矿进行主量元素分析,以确定其成因及成矿环境特征。其中TiO2-Al2O3-MgO和(Ca+Al+Mn)-(Ti+V)成因判别图解表明,磁铁矿属于岩浆热液-矽卡岩型成因类型;FeO(全铁)与SiO2,Al2O3,MgO元素的线性变化关系指示Fe在碱性环境富集成矿;结合V2O3,Cr2O3,TiO2,Ga2O3,SnO2等氧化物对成矿环境温度和氧逸度的指示意义,综合分析认为,成矿作用主要发生在岩浆结晶分异晚期,成矿环境具有高氧逸度、低温、偏碱性的特点。

Qihe-Yucheng area in Shandong Province is in the deep coverage area in north of the Yellow River.There are obvious aeromagnetic and gravity anomalies.Through systematic geological exploration,several iron deposits have been found in the deep part in study area.In order to know genetic mechanism of iron deposit,serve basic geology and mineral resource survey,by using EMPA,major elements analysis has been carried out in order to determine its origin and ore-forming environment.As showed by magnetite genetic classification diagrams of TiO 2-Al 2O 3-MgO and(Ca+Al+Mn)-(Ti+V),magnetite belongs to magmatic hydrothermal and skarn genetic type.The relationship between FeO(total iron)and SiO 2,Al 2O 3,MgO is linear.It is implied that iron mineralization is in an alkaline environment.Combining with indication significance of V 2O 3,Cr 2O 3,TiO 2,Ga 2O 3 and SnO 2 to the degree of temperature and oxygen fugacity in the ore forming environment,it is regarded that mineralization mainly occurred in the late stage of magmatic crystallization differentiation.The metallogenic environment is characterized by high oxygen fugacity,low temperature and partial alkalinity.