滇西南墨江金厂金镍矿床金、镍赋存状态及成矿过程探讨

墨江金厂金镍矿床位于滇西南哀牢山造山带中段,是西南三江地区一个独特的金镍共生矿床。笔者通过野外地矿物主要为针镍矿、辉砷镍矿、锑硫镍矿、黄铁矿等。依据矿(化)脉切割关系、矿石结构构造及矿物共生组合,墨江金厂金镍矿床成岩-成矿期共发育4个世代黄铁矿。沉积变质期以草莓状黄铁矿和胶状黄铁矿为主,热液成矿期可划分为:早阶段石英-针镍矿-辉砷镍矿-锑硫镍矿-黄铁矿;主阶段石英-黄铁矿-毒砂-硫锑铜银矿-自然金;晚阶段方解石-石英-黄铁矿。对矿区赋金镍贯通性矿物黄铁矿进行详细的电子探针分析,结果显示4个世代黄铁矿微量元素有所差异。其中热液主阶段黄铁矿中含有Au、As、Sb、Pb、Zn、Cu、Co、Ni和Te,显示其流体成分复杂。不同阶段黄铁矿Ni含量不同,沉积变质期黄铁矿中Ni含量较低,为0.00%~0.82%,平均0.26%;热液早阶段黄铁矿中Ni含量最高,为0.43%~3.15%,平均1.38%;热液主阶段黄铁矿中Ni含量降低,为0.00%~0.99%,平均0.22%;热液晚阶段黄铁矿中Ni含量最低,为0.00%~0.09%,平均0.03%。研究结果表明墨江金厂金镍矿床中主要含金矿物和含镍矿物形成于热液期,含金矿物形成晚于含镍矿物。Ni在热液流体中的迁移能力与流体温度正相关,温度越高,Ni进入黄铁矿晶格的能力越强。基于上述金、镍成矿过程研究成果,并对比国内外热液镍矿床的地质-地球化学特征,推断墨江金厂金镍矿床是一个受岩浆热液改造的中-低温热液金镍矿床。     

试论动物非矿化组织的保存

动物非矿物化组织在特异埋葬条件下可保存为化石。缺氧和快速埋葬有利于非矿化组织的保存，但不能阻止微生物的破坏作用。无菌环境下可保存软躯体组织，但在构造变动和古气候变迁等因素的影响下会彻底破坏，不可能在地质历史时期长期存在。最稳定的保存形式是与成岩作用有关的保存类型和以碳化有机质薄膜形式的保存类型。与动物非矿化组织保存有关的常见成岩自生矿物有磷酸盐矿物、碳酸盐矿物和黄铁矿等。其中，磷酸盐矿物在成岩作用过程中结晶最早，可以保存动物的微细构造。这些矿物可以矿化交代动物的肉质和角质使其成为矿化实体；也可以呈假形、铸型或铸模等形式保存。布尔吉斯页岩保存类型中，非矿化组织以碳化有机质薄膜或含水的颧硅酸盐矿物两种形式保存。前可能与粘土矿物吸附有机质、阻止酶的降解作用有关，后可能由自生粘土矿物的交代作用造成。     

矿物对金属离子的竞争吸附实验研究

CaCO_3、石英、针铁矿、三水铝矿、高岭土、蒙脱石、水云母等矿物对Ag+、Cu2+、Zn2+、Ni2+、Cd2+、Pb2+和Cr3+金属离子的竞争吸附实验研究表明，在近中性低离子强度溶液中，矿物单位表面积吸附金属离子的大小顺序是：CaCO3＞石英＞水云母＞高岭土＞蒙脱石＞针铁矿＞三水铝矿。这些矿物可分成3组：第一组的矿物有石英、针铁矿和高岭土等1：1层硅酸盐矿物及其他氧化物；第二组为三水铝矿、水镁石和蒙脱石等2:1层硅酸盐矿物；第三组是碳酸盐、硫酸盐、磷酸盐等含氧盐矿物。它们对于金属离子的吸附反应；＞SO－＋Mn+=＞SOM(n-1)+(n=1,2,3）有如下的显平衡常数KM与矿物介电常数ε的关系式：（1）lgk1M=7．813－26.15／ε（2）lgK2M－9．030－26.15／ε（3）lgK3M=11．65－26．15／ε     

Physical and thermal treatment of phosphate ores — An overview

The annual consumption of phosphate rock approached 150 million tons. The marketable phosphate is usually 30% P₂O₅ or higher. The run-of-mine material is mostly of lower grade which needs processing or upgrading. The processing techniques of phosphate ores depend mostly on the type of associated gangue minerals present in the mined rock. In some cases, simple, inexpensive techniques are enough to produce the required grade. For example, crushing and screening is used to get rid of the coarse hard siliceous material, and attrition scrubbing and desliming is used to remove the clayey fine fraction. If silica is the main gangue material, single-stage or double-stage flotation is the conventional mineral processing technique used in this case. If the ore is igneous carbonatitic alkaline or ultra basic phosphate deposit, crushing, grinding, scrubbing, and flotation associated with other steps such as magnetic and/or gravity separation is proved to be successful in upgrading this type of ore. The sedimentary phosphate ores having carbonate-apatite as the main phosphate minerals and containing carbonates (calcite and/or dolomite) represent a challenge in the field of phosphate concentration due to similarity in the physico-chemical properties of surfaces of the ore constituents. Also, if considerable amount of organic matter constitutes the main gangue material, upgrading of the ore becomes difficult. New flotation systems (techniques and reagents) are being developed to treat these challenging phosphate ores. Furthermore, calcination is another solution for upgrading these difficult-to-treat types of ores. However, calcination is indicted with some controversial drawbacks. This overview discusses and summarizes the State-of-the-Art and the existing efforts to overcome these problems and to produce a high-grade phosphate product suitable for fertilizers and other phosphate compounds.     

原生硅酸盐矿物风化产物的研究进展——以云母和长石为例

研究云母和长石等原生硅酸盐矿物的风化速率和风化产物对于深入理解土壤发生过程、营养元素循环以及全球气候变化具有重要的理论意义。本文从自然风化、人工化学风化和生物风化3方面总结了原生硅酸盐矿物风化作用及其产物的特点，重点阐述了微生物参与下的生物风化作用和生物矿化作用及其意义。野外观察和室内实验研究结果表明，微生物可以加速矿物的分解，而且其细胞表面及其产生的胞外多聚糖可以作为次生矿物成核的模板。     

构造地球化学的回顾与展望

较早的构造地球化学研究思想是“经受着变形的岩石可以发生化学变化”( Sorby,1863).经过长期、广泛和深入研究,相继提出了应力矿物、构造变质、构造动力成岩成矿、改造成矿、构造相和构造地球化学等概念和认识,揭示了构造作用在控制岩石形成和变形过程中还影响其中地球化学元素的分布、分异和成矿等,推动了大地构造、区域地质、...     

多种能源矿产的地球物理判识标志及其在协同勘探上的应用

石油、天然气、煤炭和砂岩型铀矿在同一盆地共同富集成藏为多种能源矿产的协同勘探提供了有利条件。地震和测井方法在各个能源矿产的勘探开发中都得到了广泛的应用。多种能源矿产的协同勘探应该利用现有的丰富的油气煤勘探开发资料(地震资料和测井资料)寻找砂岩型铀矿。鄂尔多斯盆地周边西缘逆冲带、天环凹陷、伊盟隆起和晋西挠折带这些砂岩型铀矿的远景区,据资料统计钻探油气井已达300口以上,为砂岩型铀矿勘探积累了丰富的地震和测井资料。     

粘土矿物改性在岩土工程中的应用

１　问题的提出粘土矿物广泛存在于各种地质体中。特殊的晶体结构赋予粘土矿物许多特性。例如吸水性、膨胀性、可塑性、离子交换性和吸附性能等等。粘土的高比表面积使其具有较强的活性。目前矿物学家和材料学家的兴趣主要集中在研究粘土矿物的表面物理化学性质,采用各种方法改变和提高其活性,扩展它的应用范围,提高粘土的附加值。但是,在岩土力学工程中,却要抑制和降低粘土矿物的活性,特别是与水的结合能力。在工程界,凡涉及岩土工程的领域,都有一个灾害防治（包括地质灾害和工程灾害）和软基处理问题,其中重点处理和防治的对象就…     

Silver-Bearing and Associated Minerals in El Zancudo Deposit, Antioquia, Colombia

The occurrence and the chemical compositions of ore minerals (especially the silver‐bearing minerals) and fluid inclusions of the El Zancudo mine in Colombia were investigated in order to analyze the genetic processes of the ore minerals and to examine the genesis of the deposit. The El Zancudo mine is a silver–gold deposit located in the western flank of the Central Cordillera in Antioquia Department. It consists mainly of banded ore veins hosted in greenschist and lesser disseminated ore in porphyritic rocks. The ore deposit is associated with extensive hydrothermally altered zones. The ores from the banded veins contain sphalerite, pyrite, arsenopyrite, galena, Ag‐bearing sulfosalts, Pb‐Sb sulfosalts, and minor chalcopyrite, electrum, and native silver. Electrum is included within sphalerite, pyrite, and arsenopyrite, and is also partially surrounded by pyrite, arsenopyrite, sphalerite, and tetrahedrite. Native silver is present in minor amounts as small grains in contact with Ag‐rich sulfosalts. Silver‐bearing sulfosalts are argentian tetrahedrite–freibergite solid solution, andorite, miargyrite, diaphorite, and owyheeite. Pb‐Sb sulfosalts are bournonite, jamesonite, and boulangerite. Two main crystallization stages are recognized, based on textural relations and mineral assemblages. The first‐stage assemblage includes sphalerite, pyrite, arsenopyrite, galena and electrum. The second stage is divided into two sub‐stages. The first sub‐stage commenced with the deposition and growth of sphalerite, pyrite, and arsenopyrite. These minerals are characterized by compositional growth banding, and seem to have crystallized continuously until the end of the second sub‐stage. Tetrahedrite, Pb‐Cu sulfosalts, Ag‐Sb sulfosalt, and Pb‐Ag‐Sb sulfosalts crystallized from the final part of the first sub‐stage and during the whole second sub‐stage. However, one Pb‐Ag‐Sb sulfosalt, diaphorite, was formed by a retrograde reaction between galena and miargyrite. The minimum and maximum genetic temperatures estimated from the FeS content of sphalerite coexisting with pyrite and the silver content of electrum are 300°C and 420°C, respectively. These estimated genetic temperatures are similar to, but slightly higher than the homogenization temperatures (235–350°C) of primary fluid inclusions in quartz. The presence of muscovite in the altered host rocks and gangue suggest that the pH of the hydrothermal solutions was close to neutral. Most of the sulfosalts in this deposit have previously been attributed as the products of epithermal mineralization. However, El Zancudo can be classified as a xenothermal deposit, in view of the low pressure and high temperature genetic conditions identified in the present study, based on the mineralogy of sulfosalts and the homogenization temperatures of the fluid inclusions.