【作者】 龙永珍；

【导师】 戴塔根； 张启钻；

【作者基本信息】 中南大学 ， 矿产普查与勘探， 2003， 博士

【摘要】 桂西地处东南地洼区赣桂地洼系与滇桂地洼系相接地带，区内褶皱、断裂构造发育。本区铝多金属矿资源十分丰富，主要分布于古大新溶蚀平原的周边地带—平果、靖西、德保、田东等地，按成因类型划分为两种：一种为沉积型铝多金属矿，另一种为岩溶堆积型铝多金属矿。沉积型铝多金属矿：赋存于下二叠统茅口灰岩浸蚀面之上—上二叠统底部合山组地层中，矿体呈层状或似层状，与煤层、黄铁矿密切共生，S含量较高，目前尚未利用；堆积型铝多金属矿：赋存于第四系更新统红土层中，且有埋藏浅、规模大、分布广、矿石质量好的特点，是目前主要利用对象。 原生铝多金属矿中S的含量大大高于堆积矿，其余化学组分在两种铝多金属矿中基本相同：主要为Al₂O₃、Fe₂O₃、SiO₂、TiO₂和H₂O⁺，其次伴生有Ga、V₂O₅、Sc、Nb、Ta、REE等有益组分。 原生铝多金属矿中黄铁矿含量较高，而堆积矿中褐铁矿及针铁矿含量相对较高，其余矿物组分在两种铝多金属矿中基本相同。 在本区德保隆华堆积矿的矿泥中发现一未知矿物，经X射线衍射分析及格林-凯利（Greene-Kelly，1953）方法鉴别，该矿物为贝得石；经蒙脱石—贝得石系系列的蒙脱石群定量法（Jones，1964）测定，该矿物的含量为15.45％。 电感耦合等离子体质谱技术是80年代发展起来的新的分析测试技术，该技术提供了极低的检出限、极宽的动态线性范围（8-11个数量级）、谱线简单、干扰少、分析精度高、分析速度快以及可提供同位素信息等分析特性。本次，建立了一套可行的ICP-MS分析方法，对本区铝多金属矿中的微量元素进行了比较系统的分析。 铝多金属矿中伴生的镓含量较高，主要是以类质同象的形式存在于铝矿物中，与铝成显著的正相关关系。 铝多金属矿中稀土元素含量也较高，以化学分析为基础，结合ICP-MS仪器及矿物学分析表明：稀土主要赋存于硬水铝石矿物中，与铝呈正相关关系；其赋存形式可能是以纳米级的矿物微粒存在于铝矿物的晶格中。沉积型铝多金属矿中稀土元素含量及配分特征与堆积型铝多金属矿稍有不同。 稀土元素地球化学特征:Zr、H长Nb、Ta、Tio:等稳定元素与A12O3之比值特征;B、Be、Sr/Ba、Th月口元素特征;S同位素特征;元素Zr、Cr、Ga三角图解;含矿岩系的重砂组合和标型特征，特别是其中的Zr月扭f比值特征;贵金属元素地球化学特征;含矿岩系剖面特征及分布特征表明: 1、本区沉积型铝多金属矿是以古风化壳（基底茅口灰岩）、大新古陆岩石风化物为主要物质来源，有部分基性火山灰的介入，具有多来源的特征; 2、沉积型铝多金属矿形成于以海相为主的环境; 3、堆积新型铝多金属矿是由沉积铝多金属矿在地洼构造演化中，于表生条件下，经物理、化学风化作用改造而形成的; 4、生物和衍生的有机质的成矿作用遍及各个阶段:如早期风化淋滤作用，搬运阶段的护胶作用:沉积水盆中有机物的吸附、分解及净化作用，同生、成岩阶段在还原环境下形成水铝石与黄铁矿，以及后期表生阶段有机质与黄铁矿的氧化作用使矿石去硅去硫而变成优质铝多金属矿。 本区铝多金属矿的成矿模式可概括为“多阶段、多因素、多来源”的沉积-淋滤富集改造的多因复成矿床。 经高压拜尔法溶出试验及溶出浆液沉降性能试验表明:本区堆积铝多金属矿适应于拜耳法规模生产作业，嫁主要富集于循环母液中，而钦、稀土、错、妮、担等元素在赤泥中加以富集，综合利用前景广阔。更多还原

【Abstract】 Western Guangxi lies in the southeast Diwa zone, between Gong-Gui Diwa system and Dian-Gui Diwa system, where folds and faults war developed very well. In this region, aluminum resources are very rich, Al-polymetal deposits are distributed in the ancient Daxin dissolved plain such as Pingguo, Jingxi, Debao, and Tiandong and so on . According to the genesis of these ore deposits, they can be divided in two types: one type is sedimentary deposit, the other is accumnlated Al-polymetal deposit, the first is occurring on the erosion surface of early Permian Maokou limestone - the bottom of late Permian rocks of Heshang group with coal bed and pyrite deposit together as bedlike or bedway, which is not utilized at present because of the high content of S. The other Al-polymetal deposit is occurring in the red soil bed of Quaternary, featuring shallow buried, wide distribution, high A/S and good quality, which is being mostly utilized at present.The chemistry components have not obvious difference between the two types of Al-polymetal ore except the content of S, both of them consist much of Al2O3, Fe2O3, SiO2, TiO2 , H2O+and some of Ga, V2O5, Sc, Nb, Ta, rare earth elements and so on .They almost consist of the same minerals between the two kinds of Al-polymetal deposit ores except the content of pyrite is relatively high and the limonite and pin-iron ore are relatively low in the sedimentary Al-polymetal ores.In the mud of Debao Longhua Al-polymetal deposit, an unknown mineral is determined as Beidellite using way of XRD and Greene-Kelly, the content of this kind of mineral is 15.45% by way of montmorillonite group quantitative analysis .In 1980’s, a new analytical technique--Inductively coupledplasma mass spectrometry (ICP-MS) was introduced to the marketplace, the success of ICP-MS as analytical techniques stems mainly from the following important capabilities: very low detection limits (10"12), broad dynamic concentration ranges (8-11 orders of magnitude for many elements), simple mass spectra, few spectral interferences, good precision,ability to routinely provide elemental isotopic information, and so on. A sets of feasible ICP-MS analytical technique for trace element in western-Guangxi Al-polymetal ores have been developed in this paper.The content of gallium is relatively high, it distributes in all sorts of Al-polymetal ores almost at all as isomorphism with aluminum, and which has good correlation with aluminum.The content of rare earth elements (REE) are relatively high. It is known that the REE distribute in diaspore crystal lattice as nano- meter mineral matters and prominent positive correlation with AI2O3 by ICP-MS analytical technique based on analytical chemistry and mineralogy analytis. There have some different between sedimentary and accumnlated deposit about the content and distribution pattern of REE too.The geochemistry feature of REE; B, Be, Sr/Ba, Th/U, sulfur isotopes, noble metals, the ratio feature between Zr, Hf, Nb, Ta, TiO2 and Al2O3, the triangle diagrammatize feature of Zr, Cr, Ga, and the ore-bearing profil and distribution features show that:(1) the ore-forming materials of the Al-polymetal deposit mostly origin from Maokou limestones in the paleoweathering crustal basement and Daxin paleocontinental rocks, some from eruption and so on.(2) the deposit Al-polymetals which are marine environmental clastic deposits.(3) the accumnlated Al-polymetals anormaly result from the physical , chemical and biological weathering processes of the primary Al-polymetals under the hydrogenic environment duing the Dewa stage.(4) Organism and the derived materials played roles in different stages of the Al-polymetal metal-logenesis, such as weathering, eluviating, transportation, organic material protected gel, the absorption, resolution and purification of large amount of orgrnic matter in water of sedimentary basin in which syngenetic and diagenetic stages were under reduction and diaspore and pyrite formed. In the supergenetic stage the oxidation of organic mat更多还原