碱型地幔流体与富碱热液成矿  

Alkaline mantle fluids and alkali-rich hydrothermal metallogenesis

作　　者：杜乐天[1] 王文广[1] 

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《矿床地质》2009年第5期599-610,共12页Mineral Deposits

摘　　要：碱交代作用是整个热液作用成矿的一个基本机理,包括:①所有的热液作用是碱型地幔流体从对岩石(或岩体或地层)进行碱交代(K、Na的带入)开始的;②提供矿源(靠富K、Na热液的强烈交代作用在热液上升路途中萃取岩石矿质);③形成碱交代岩,使热液由强碱性向酸性([H+]离子浓度增长)演化,以破坏稳定的矿质迁移形式,导致沉淀、卸载、成矿;④碱交代岩是高压高温爆裂岩,角砾和次生孔隙度由此大增,有利于热液和构造再活动,成为金属成矿和油气成藏的有利储矿围岩。文章用新的证据证明此富碱热液来自深部碱型地幔流体(A-HACONS)。通过碱金属地球化学这条纲把热液作用和地幔流体作用串联为深浅一个整体。An important ore-forming regularity concerning the alkaline metasomatism in literature has been long neglected. In the past 30 years, the authors have gradually found out that the alkaline metasomatic process constitutes the crucial ore-forming mechanism, as evidenced by the following facts： ① the whole hydrothermal process starts with the alkaline metasomatism （the introduction of K＋ and Na＋ to the altered rocks）; ② this process provides ore sources by leaching and extracting of ore components from pathway rocks through metasomatism; ③ the process can promote the hydrothennal solution transition from alkaline to acidic by the exhaustion of K＋ and Na＋ in the solution and the destruction of the stable migration forms of ore components, thus resulting in their precipitation; ④ alkaline metasomatic rocks become very porous, which is favorable for the introduction and penetration of ore-forming solution and provides ore and oil- gas traps. New evidence is given in this paper which shows that the metasomatic hydrothermal solution is derived from deep alkali-rich mantle fiuids （A-HACONS flow）.

关 键 词：地质学 碱型地幔流体 碱交代作用 热液成矿 

分 类 号：P611[天文地球—矿床学]