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黔西南与玄武岩有关的铜矿及其表生成矿过程的实验研究
An Experimental Study on the Minerogenesis of the Copper Deposits Related to the Emeishan Basalt in the Southwestern Guizhou Province, China
【作者】 黄艳;
【导师】 朱笑青;
【作者基本信息】 中国科学院研究生院(地球化学研究所) , 地球化学, 2006, 硕士
【摘要】 铜是我国当前紧缺的金属矿产,所以研究铜矿形成的地质规律、寻找铜的矿产基地是地质工作者一项重要的任务。本文以关岭丙坝和盘县黑牛坪地区峨眉山玄武岩底部与二叠系茅口组灰岩接触界面上赋存的铜矿床(点)为例,开展了成矿的模拟实验研究,论述了黔西南地区这一类型铜矿的成矿地质条件。 1.铜的地球化学特性表明:铜是一种典型的亲硫元素,其外层电子构型为:3d104s1,铜离子(Cu2+)具有较强的极化力,容易被风化淋滤,形成酸根离子,增加铜盐在水中的溶解度,从而使其易于迁移搬运。 2.分布在贵州西南部的峨眉山玄武岩中的铜矿是近年发现的一种新的铜矿类型。通过野外考察和室内岩矿鉴定,按铜矿化的矿物组合及赋存特点,初步划分为:凝灰角砾岩型黄铜矿化和次生氧化、硫化物铜矿化。其中,次生氧化、硫化物铜矿化类型在区域上的分布更为广泛。通过研究,笔者认为这一新型铜矿很可能具有重要的创新性研究意义和找矿价值。 3.通过黔西南地区关岭丙坝和盘县黑牛坪铜矿围岩样品的水-岩相互作用模拟实验,探讨峨眉山玄武岩含铜性及与铜矿形成的关系,并研究了铜元素在成矿流体中迁移搬运的物理化学条件。实验研究结果表明,酸雨和酸性水最容易形成高含量的成矿溶液。 4.通过低温开放体系中纳米级胶体铜的制备实验研究,笔者认为,与金、银等惰性元素不同,制备胶体铜的条件太过苛刻,不能用于地质实验研究。实验结果也表明:纳米铜胶体在没有任何保护剂存在的条件下,在低温开放体系中长期稳定存在不被氧化的可能性不大。 5.铜离子(Cu2+)与不同矿物和岩石之间的吸附实验表明:不同的矿物和岩石对纳米铜的吸附性能不同。 6.通过本次研究工作,笔者探讨了该类型铜矿成矿的机制:在表生条件下,富含Cu的峨眉山玄武岩,在雨水及表生循环水的淋滤下将以硫化物形式存在的Cu活化淋滤出来,然后沿岩层运移至峨眉山玄武岩底部及茅口灰岩上部的有利位置上富集。在铜元素迁移过程中,从铜的硫化矿物被氧化分解丌始,形成铜的硫酸盐配合物迁移,最后氧化形成孔雀石、蓝铜矿、水胆矾等次生矿物。
【Abstract】 At present, copper is a badly insufficient metal resource in our country. Therefore, it is our geologic workers’ important mission to study on the ore-forming mechanism and to prospect for the base of the copper deposits. Taking examples of the Bingba and Heiniuping copper deposits occurring on the contact zone between the base of the Emeishan basalt and limestone of the Middle Permian Maokou Formation in Guizhou province, the paper discussed the geological conditions of basalt-type copper deposits, and some leaching experimental studies of copper in basalt under the Supergene system were carried out:1. Based on the geochemical characters of element copper, it has been revealed that Cu is a kind of sulphophile chemical element. Cu2+ is easily mobilized, transported and precipitated under leaching action, because of its strong polarization.2. The copper deposits in western of Guizhou, which were discovered during the early 2000s, are an new type of copper ore deposits occurring in the Emeishan basalt. On the basis of field investigation, mineral assemblages and occurrence modes of ores, two types of the copper mineralization are identified. One is the tuffaceous breccia chalcopyrite mineralization, and another is the secondary native copper mineralization and sulfide mineralization. Among these two types of copper mineralization, the latter is much wider distributed in the border area. The author’s studies suggest that this new type of copper ore deposits is very likely to be of important significance in the innovative research and prospecting work.3. Weathering-leaching simulating experiments are carried out on samples of wall rock from the Bingham and the Heiniuping copper deposit, southwestern guizhou, with the aim of determining the relationship between coppery of the Emeishan Basalt and the copper deposits, and determining the optimum physical and chemical conditions for the mobilization of copper in solution. The experimental results show that acidic water is most favorable to the formation of ore-forming element-rich solutions. In addition, the results indicate that copper is most easily mobilized from the Emeishan Basalt if fluids contain chlorine.
【Key words】 copper deposit; Emeishan basalt; weathering-leaching simulating experiment; copper colloids; Supergenesis; Rock and mineral absorption; SW Guizhou;
- 【网络出版投稿人】 中国科学院研究生院(地球化学研究所) 【网络出版年期】2006年 12期
- 【分类号】P618.41
- 【被引频次】3
- 【下载频次】259