河北平泉县下金宝金矿床岩体地球化学特征及其与成矿的关系分析

从矿床地球化学特征入手,对下金宝矿体矿石、矿体围岩的常量元素、稀土元素和微量元素特征进行探讨。结果表明:下金宝岩体的花岗斑岩类岩石属于硅酸过饱和类钙碱性过铝质岩石,属于A型花岗岩,且K、Nd、Hf、Th、Rb相对富集,而亏损Ta、Nb、Sr和Ti,说明其岩浆并非单纯来源于上地幔,在岩浆上升过程可能受到了地壳物质的混染;结合下金宝金矿床的控矿因素、蚀变分带特征、岩体地球化学特征、矿石结构构造、围岩蚀变、成矿温度,得出斑岩体是区内成矿的必要因素,下金宝金矿床应是以次火山热液作用为主的斑岩型金矿床。

Geochemical characteristics of ore-bodies in Xiajinbao Au deposit in Pingquan of Hebei and its relationship with mineralization

Starting with the geochemical characteristics of the deposit,this paper conducted research on mac-roelements,REEs and trace elements of ore-bodies and wall rocks of Xiajinbao deposit.The study shows that granite porphyry type rocks in Xiajinbao rock mass are silicate supersaturated,peraluminous and calc-al-kali rocks,which fall into the category of a type granite.Elements like K,Nd,Hf,Th and Rb are relatively enriched while elements like Ta,Nb,Sr and Ti are relatively depleted.It indicates that the magma may not merely derive from the upper mantle and it may be contaminated by crustal materials in the process of the magma ascension.Based on ore-controlling factors,alteration zoning characteristics,geochemical character-istics of rock mass,texture and structure of ores,wall rock alteration,ore-forming temperature of Xiajinbao Au deposit,it is concluded that porphyry rock mass is a necessary factor of the mineralization,and Xiajinbao Au deposit is a porphyry type Au deposit related to subvolcanic hydrothermal processes.