再论偏岭石与变高岭石的区别——评《天然烧变高岭石中水铝英石的发现》一文

《矿物学报》１９９５年第４期发表了何宏平的“天然烧变高岭石中水铝英石发现”一文。该文用核磁共振谱中－７９．０×１０－６附近的谱峰，认为该信号来自水铝英石，而不是来自Ａｌ－Ｓｉ尖晶石。这种说法较合理，因刘长龄早就阐明偏岭石在成岩阶段由水铝英石变来。但是我们不同意“天然煤烧变高岭石经后期水化作用变成水铝英石”的观点，而主张“水铝英石是沼泽相原生沉积的；在成岩作用中转变为偏岭石不是煤烧的，有一些理化性质与变高岭石的不同”     

南极乔治王岛菲尔德斯半岛湖泊堆积物的物相组成特征及其环境意义

本文根据南极乔治王岛菲尔德斯半岛燕鸥湖、西湖和基太克湖三个堆积剖面物相组成与丰度的资料，讨论其物相组成特征、物质来源及其环境意义。研究结果表明，湖泊堆积物主要来自该岛广泛分布的火山岩。在南极地区干冷环境条件下，源区母岩所经受的风化作用以物理风化为主，化学风化微弱。高岭石、方解石丰度与年龄关系曲线在湖积层与冰碛层之间的陡削变化表明，相应的环境变化是突变式的，可能与这两种堆积物搬运方式的不同和冰碛物的保护作用有关。     

矿床工业指标的制定与管理解析

１９９４－０４以后，国务院规定矿床工业指标由矿产储量审批机构统一下达，从历史的经验和现实的管理来看都是十分重要的。本文介绍了矿床工业指标制定与管理的原则，程序和方法，以及湖南省储委的５点经验，并提出了加强这一工作的建议。     

福建梅仙丁家山铅锌（银）矿床磁异常特征及其找矿意义

着重论述了丁家山铅锌（银）矿床的地质地球物理特征，磁法找矿的特殊作用，总结了建筑梅仙式矿床的物化探异常标导。     

乌拉山金矿钾长石的标型性及其与金矿化关系

在对乌拉山石英－钾长石脉型这一国内外尚不多见的新类型金矿床的野外观察和室内镜下研究的基础上，通过选择性地对其主要矿物钾长石进行电子探针分析，Ｘ射线粉晶衍射分析，红２外吸收光谱测定及可见光吸收光谱分析，系统详尽地了钾长石的产状，形态，化学成分，结构态及可见光吸收光谱特征，提取了作为找寻石英－钾长石脉型金矿床的重要矿物学标志，并进一步探讨了钾长石与金矿化的关系。     

Classification of mineral deposits into types using mineralogy with a probabilistic neural network

In order to determine whether it is desirable to quantify mineral-deposit models further, a test of the ability of a probabilistic neural network to classify deposits into types based on mineralogy was conducted. Presence or absence of ore and alteration mineralogy in well-typed deposits were used to train the network. To reduce the number of minerals considered, the analyzed data were restricted to minerals present in at least 20% of at least one deposit type. An advantage of this restriction is that single or rare occurrences of minerals did not dominate the results. Probabilistic neural networks can provide mathematically sound confidence measures based on Bayes theorem and are relatively insensitive to outliers. Founded on Parzen density estimation, they require no assumptions about distributions of random variables used for classification, even handling multimodal distributions. They train quickly and work as well as, or better than, multiple-layer feedforward networks. Tests were performed with a probabilistic neural network employing a Gaussian kernel and separate sigma weights for each class and each variable. The training set was reduced to the presence or absence of 58 reported minerals in eight deposit types. The training set included: 49 Cyprus massive sulfide deposits; 200 kuroko massive sulfide deposits; 59 Comstock epithermal vein gold districts; 17 quartzalunite epithermal gold deposits; 25 Creede epithermal gold deposits; 28 sedimentary-exhalative zinc-lead deposits; 28 Sado epithermal vein gold deposits; and 100 porphyry copper deposits. The most common training problem was the error of classifying about 27% of Cyprus-type deposits in the training set as kuroko. In independent tests with deposits not used in the training set, 88% of 224 kuroko massive sulfide deposits were classed correctly, 92% of 25 porphyry copper deposits, 78% of 9 Comstock epithermal gold-silver districts, and 83% of six quartzalunite epithermal gold deposits were classed correctly. Across all deposit types, 88% of deposits in the validation dataset were correctly classed. Misclassifications were most common if a deposit was characterized by only a few minerals, e.g., pyrite, chalcopyrite,and sphalerite. The success rate jumped to 98% correctly classed deposits when just two rock types were added. Such a high success rate of the probabilistic neural network suggests that not only should this preliminary test be expanded to include other deposit types, but that other deposit features should be added     

Geochemistry of shallow sediments in Guaymas Basin, gulf of California: hydrothermal gas and oil migration and effects of mineralogy

Offset of prograde hydrothermal alterations by retrograde reactions is evident in sediments from a piston core (PC6, 8 m long) from the Guaymas Basin, Gulf of California. Geochemical and mineralogical analyses of sediments and pore fluids show superimposed geochemical signals that indicate currently active reactions are modifying previously formed secondary solids. Hydrothermal barite was formed in a previously active flow channel between 150 and 250 cm depth. Hydrothermal gypsum is presently dissolving at depths > 780 cm, below which hydrothermal fluid flow is channeled by a secondary dolomite layer. Thermal stress of organic matter generates hydrothermal gas and petroleum having wide ranges of compositions and maturities. A significant amount of hydrothermally generated oil has been transported laterally through a porous debris flow (approx. 240 cm subbottom), overwhelming the indigenous bituminous matter. Water soluble petroleum constituents have disseminated throughout the cored sediments. From 400 to 700 cm depth the immature organic matter continues to experience thermally-enhanced diagenesis, and an even higher thermal stress has occurred at the bottom of the core. Enhanced bacterial degradation of organic matter has led to depletion of pore water sulfate and enrichment of ammonium (NH₄⁺) in both pore fluid and sediment, resulting in formation of NH₄⁺ bearing secondary clay minerals at depths below 780 cm.     

基性、超基性岩及矿产研究概述 庆祝地矿部西安地质矿产研究所建所30周年

主要介绍我所30年来,在基性、超基性岩及有关矿产研究方面的基本概况、取得的进展及今后一些展望。其中所列进展主要包括:岩浆矿床学、岩石及成因学、岩浆建造学及矿床评价和预测等四个方面的研究。     

长江口细颗粒沉积物的矿物特征和沉积分异

作者系用双目显微镜、偏光显微镜、电子显微镜、X 衍射仪等方法对长江口细颗粒沉积物中的轻矿物、重矿物、粘土矿物进行了定量估算和分析研究,进而阐述细颗粒沉积物的矿物特征、沉积特征及其粘土矿物的沉积分异作用。     

鄂尔多斯盆地盐池-定边地区水化学场分布特征及形成机理

鄂东南矿集区殷祖岩体南部的刘家垄矿区，勘探线和钻孔显示刘家垄铜矿体主要倾向南、南西，受到毛铺-两剑桥东西断裂带的构造控制.矿体主要集中在石英闪长岩体与志留系碎屑岩接触交代部位，在岩体内侧赋存成矿.矿化类型主要有黄铜矿化石英闪长岩和含黄铜矿石英脉.围岩主要为钾化石英闪长岩和角岩化的粉砂岩.通过对比区域上的成矿类型，刘家垄脉状铜矿与斑岩型有关，即斜长石和石英为造岩矿物，可见绿泥石、方解石等蚀变矿物.矿化主要发生在夕卡岩化石英闪长岩带.通过总结成矿规律，认为有利的勘探区段在断裂构造发育、岩体与碎屑岩接触部位的岩体一侧.