论姑山铁矿床的形成条件

On the basis of geological characteristics the Gushan iron deposit should be assigned to volcano-hydruthermal type with hematite qusrtz as its principal mineral assemblage.Iron concentration of the ore-forming fluid has been estimated from the ratio of hematite to quartz in the ores. By using experimental and thermodynamic data the soinbilities of iron minerals at elevated temperatures and pressures are calculated in the system FeO-Fe2O3-NaCl-HCl-H2O. The effect of T, P, pH, fe2 and total concentration of chlorine on the solubilities of iron minerals are discussed. Thermodynamic calculations based on presumed physicochemical conditions for the ore-forming solutions are in good agreement with geological observation. The calculation shows that iron minerals were deposited at log fo2=-21--25, log(mKCl mbl^ ) =-2,5--3, P=1-0.75 (or 0.5) Kb,T=400-350℃. It is believed that the original fluid was an acid NaCl-bearing solution of magmatic derivation. However, iron in the solution was enriched with falling temperature by dissolving pre-exist iron minerals in the consolidated rocks rather than extracted directly from the magma. Either decreasing temperature (below 400℃) or pressure is capable of depositing iron minerals from the solution, but the ratio of Fe to Si in the ore is dependent mainly upon the pH. The widespread silica vein at later stages is a reflection of decreasing acidity of the solution. Increase in fo2 will also favor the deposition of iron minerals. The hypabyssal occurrence and the existance of the Huangmaqing shale contribute greatly to the formation of hematite.     

风化壳淋积型稀土矿床成矿机理的实验研究

风化壳淋积型稀土矿床是很重要的一种矿床类型。作用采用水析法提取了梧州市区风化壳淋积型稀土矿床中的粘土矿物，并进行了钕和镱的吸附实验研究。实验结果表明，在不同的实验体系中，吸附反应达到平衡的时间是不同的，２％ＨＣ１至少１２ｈ，１％ＨＣ１至少０．１ｈ。影响粘土吸附稀土的物理化学因素有：溶液浓度，溶液酸碱度（ｐＨ值），离子强度，固液比和温度等。在ｐＨ值较低的相同实验条件下，轻稀土的吸附效率要明显高于重稀     

相图的构筑和应用

随着地质工作的不断深入,摆在地质作工者面前的任务是,不仅要确定矿物和岩石的种类、分布和矿床的类型,而且要知道这些矿物、岩石和矿床是在什么样的条件下和怎样形成的.这就要求我们查清形成它们的物理化学条件.相图是研究各种物理化学条件下矿物相变化的一种重要方法,目前,愈来愈多的矿物、岩石和矿床学家正在用这种方法研究岩石和矿床的形成条件. 构筑相图的方法主要有三种.(1)实验方法:这是最基本的方法,但所需设备比较复杂,费用较高,控制条件要求严格,并且实验所需时间也     

中国若干钨矿床相平衡关系

This paper reviews the features of several tungsten ore deposits in southern China, including the Shezhuyuan, Yaogangxian, Xihuashan, Danping, Yiatang and Dajishan mines. The authors think that the formation depth of greisen-type deposits is intermediate between the depths of pegmatite- and porphyry- type deposits. Using phase diagrams of the model system K2O-AhO3-SiO2-H2O-HF, the formation mechanism of greisens has been argued. The variation of mineral assemblages from K-feldspar, muscovite to topaz reflects a gradual increase in acidity. This variation can be used as a criterion to appreciate the depth of mineralization. Equilibria of tungsten minerals in greisen and skarn deposits can be depicted on chemical potential diagrams of the model system CaO-FeO-WO3-CO2-F2O-1. The assemblage wolframite fluorite is shown to have been transformed to scheelite magnetite with decreasing μHP. Depending on CO2 activity in the fluids, there are two distinct phase diagrams.One shows that wolframite is incompatible with calcite, and the other demonstrates that scheelite is incompatible with rhodochrosite. On the phase diagrams of the model system FeO-MnO-WO3-F2S-1, huebnerite is transformed to ferberite with increasing μP1O-1orμF2S-1,During the replacement of wolframite by scheelite, the wolframite residue must have been enriched in Mn.     

梅山铁矿床蚀变矿物组合的相平衡研究

宁芜型铁矿是我国主要铁矿床类型之一,梅山铁矿床又是其中最大和最富的。梅山铁矿的围岩遭受过广泛和复杂的蚀变,它兼有矽卡岩型和斑岩型矿床的蚀变组合特征。研究梅山铁矿床围岩蚀变的相平衡关系,不仅具有实际意义,对进一步研究矽卡岩型、火山岩型和斑岩型矿床的形成机理也具有指导意义。本文试图从梅山铁矿的地质特征出发,结合前人有关的实验资料,解释各种蚀变组合形成的物理化学条件。但前人的实验资料往往是残缺不全的,体系的组分又过于简单,因此,我们又在实验相图的基础上,结合本矿床的具体特征,     

K_2O-Al_2O_3-SiO_2-H_2O体系的相平衡研究

K_2O-Al_2O_3-SiO_2-H_2O体系形成一些主要造岩矿物,如长石、石英和云母等,因此受到有关学者的广泛重视。为了探讨岩石的形成机制,国外许多学者曾研究过该体系矿物的稳定范围。近年来,伊万诺夫、J.W.谢德(Shade)、R.P.温特施(Wintsch)、D.M.伯特(Burt)、H.W.戴(Day)和J.J赫姆利(Hemley)等也先后用热力学方法研究过该体系的相平衡关系。但至今,该体系中某些矿物的相平衡关系仍然有争议,例如,     

四川冕宁稀土矿床脉石矿物的微量及稀土元素地球化学特征

包裹体地球化学研究表明，四川冕宁稀土矿床中存在着岩浆成因的萤石、重晶石和方解石，它们的微量元素地球化学特征与热液成因对应矿物有明显差别：岩浆成因重晶石相对富集亲石元素，贫亲硫元素；无论是岩浆成因重晶石，还是萤石均明显富集挥发分。稀土元素地球化学研究显示，不同成因萤石、重晶石在稀土元素总量、ＬＲＥＥ／ＨＲＥＥ、（Ｌａ／Ｙｂ）Ｎ、δＥｕ及δＣｅ等一系列稀土元素地球化学参数上都存在明显的差异。该项研究还揭示了岩浆成因萤石、重晶石是在相对还原和酸性体系内结晶而成的。     

论四川冕宁稀土矿床的成因

本文从实际出发，以寻求路网的满意养护对策，基于柔性中面网的灰色本质，为此，推导了预测路况ＰＣＩ的多点激励有后效模型ＧＭ，并提出了一个灰色发展系数指标［ａ］，它可从发展机制上保证对策满意性。而后，从满意对策的特点出发，建立了确定路网满意养护对策的灰色非线性优化模型，并给出了简化迭代算法。应用示例表明，该文方法确定的养护对策，不仅满意性得到了初步保证，而且使用效益也有较大程度的提高。     

萤石中流体-熔融包裹体的研究

在四川冕宁稀土矿床霓辉重晶石伟晶岩型矿体早期萤石中笔者发现了大量的流体-熔融包裹体。矿物的光学性质及激光拉曼光谱特征表明,流体-溶融包裹体内晶体矿物为重晶石。萤石中流体-熔融包裹体的“均一化”温度为493.7—502.3℃,其捕获温度更高,这说明主矿物萤石的形成温度很高,笔者认为这类萤石是由富含挥发分,以氟化钙、硫酸钡为主要成分的盐熔体直接结晶而成的,即该类萤石以及与之共生的重晶石具有岩浆成因的特征。