莱阳市吕格庄石墨矿成矿地质条件及成因研究

Study on metallogenic geological conditions and genesis of Lügezhuanggraphite deposit in Laiyang City

莱阳市吕格庄石墨矿属胶辽隆起区域,位于胶莱盆地西部,含矿地层主要为古元古代滹沱纪荆山群,受后期中生代笔架山花岗岩影响,矿体虽有破坏,但也促进了矿物的富集增大。通过对矿石地球化学特征分析,认为该矿区含矿地质体原岩主要为富碳质和富铝质砂质碎屑岩,以杂砂岩、长石砂岩为主,含有少量黏土矿物、碳酸盐岩;样品中Al_(2)O__(3)/TiO_(2)比值为11~28,平均17,反映了沉积物主要来源于上地壳酸性源区,少量来源于下地壳的中基性源区,原岩沉积环境属于浅海相环境、弱还原—还原环境。后经区域动力变质作用,形成了沉积变质型鳞片状石墨矿床。

The Lügezhuang graphite deposit in Laiyang belongs to the Jiao-liao uplift region,which is located in the western Jiao-Lai Basin.The ore-bearing strata are mainly the Jigingshan Group in the Hutuo Paleo-Proterozoic.Influenced by the Bijiashan granite in the late Mesozoic,the ore body is damaged,but the mineral enrichment is increased.Based on the analysis of the geochemical characteristics of the ore,it is concluded that the protolith of the ore-bearing geological body in this mining area is mainly carbonaceous and aluminum-rich sandy clastic rock,mainly composed of sandstones and feldspar sandstone,with a small amount of clay minerals and carbonate rocks.The ratio of Al_(2)O_(3)/TiO_(2) in the sample ranges from 11 to 28,with an average value of 17,which indicates that the sediments mainly come from the acidic source area of the upper crust,and a small amount of them come from the intermediate-basic source area of the lower crust.The protolithic sedimentary environment belongs to the shallow Marine environment and weak reduction-reduction environment.After the regional dynamic metamorphism,a sedimentary metamorphic flake graphite deposits were formed.