河北承德亮甲台超贫钒钛磁铁矿床地质特征及成因

Geological Characteristics and Genesis of Ultra-low Grade Vanadium-titanium Magnetite Deposit in Liangjiatai in Chengde City,Hebei Province

河北承德一带基性—超基性岩中的超贫铁矿石(w(TFe)<20%)资源在河北铁精矿产量中占有重要地位。亮甲台超贫钒钛磁铁矿体产于海西期基性—超基性岩体中,其与辉石角闪岩体有密切的成因联系,有其独特的成矿专属性,由于岩浆结晶分异的不同,造成磁铁矿含量发生变化,在磁性铁含量高的部位易形成矿体。结合矿区地质工作成果,详细讨论了区域成矿地质背景、矿区及矿床地质特征,并与区域类似铁矿床进行了对比分析。研究表明:(1)亮甲台铁矿床成因类型为海西期超基性岩浆晚期结晶分异型铁矿床,成矿条件十分优越;(2)海西期形成的以辉石角闪石为主的超基性岩体,有一定规模和强度的磁异常以及风化产物、岩石中的含磁铁矿物为有利找矿标志。

Ultra-low grade iron ore（ w（ TFe） 20%） in basic-ultrabasic rock in Chengde City takes an important place in the output of magnetite concentrate in Hebei Province. The ultra-low grade vanadium-titanium magnetite deposit in Liangjiatai occurs in basic-ultrabasic rock mass in Hercynian,its metallogenic activity is closely related to the pyroxenite rock mass. The metallogenic property of the deposit is unique,crystallization differentiation of magma causes the variation of magnetite content,the ore-body can be formed easily in the area with high magnetite content. Based on the geological working results of the mining area,the regional metallogenic geological background,geological characteristics of the mining area and the ultra-low grade vanadium-titanium magnetite deposit are analyzed,and the comparative analysis of the above disscussion results and the ones of other deposits in the region is done. The study results indicated that：（1）the genesis type of Liangjiatai ultra-low grade vanadium-titanium magnetite deposit is belongs to the one formed by late ultrabasic magma crystallization differentiation in Hercynian,the metallogenic conditions of the mining area is favorable;（2）the favorable prospecting indicators of the mining area can be summarized as following： the ultrabasic rock mass dominated by pyroxenite in Hercynian,the magnetic anomalies with certain scale and abnormal intensity,magnetite minerals distributed in weathering products and rock mass.