喇嘛苏铜矿床斑岩体地质地球化学特征及含矿性评价

GEOLOGICAL AND GEOCHEMICAL FEATURES AND EVALUATION OF ORE BEARING POTENTIALITY OF PORPHYRITIC BODIES IN LAMASU COPPER DEPOSIT

矿区内广泛发育以斜长花岗斑岩和花岗闪长斑岩为主的中酸性斑岩体。斑岩的结构特征反映出岩浆浅成侵位成因。研究表明该区斑岩具有相对富硅和富碱高钾的岩石化学特征，属钙碱性系列；具有Ｃｕ、Ａｇ、Ｂｉ等成矿元素高丰度的微量元素地球化学特征和低ΣＲＥＥ与高δＥｕ值的稀土地球化学特征。矿区内铜矿化富集在斑岩体内外接触带，斑岩体深源浅成特点和富碱高钾岩石化学特征于铜矿化富集有利。Ｃｕ、Ａｇ等成矿元素高丰度及其与矿化类型一致性说明成矿与岩浆活动有密切成因关系。

Naturally acid porphyritic rock bodies,mainly plagio granite ones and granodiorite ones are wildly distributed in studied mine area. Structural features of such rock bodies indicate that they are formed of hypabysaal intrusion of magma. Concerning the porphyritic rocks in this area,the study shows that thier petro geochemistry are characteristic of relatively abundance of silicon、alkali and potassium;trace element geochemistry characteristic of having high metallogenic element concentrations of copper、silver、bismuth etc.;REE geochemistry characteristic of having low ΣREE value and high δEu value.Copper mineralization of this area occurs mainly in both sides of the contact zone of rocks.Porphritic rock bodies,a type of hypabyssal rocks from deep magmatic resource charateristic of high contents of alkali and potassium,are advantageous for copper mineralization. That the minerlization types of rocks are consistent with the high values of copper and silver in rocks shows the mineralizationa are closely associated with magmatism.