埃及东南部沙漠地区汉默斯(Hamash)金矿中金从黄铜矿—黄铁矿中的重新运移

在埃及东南部的汉默斯沙漠地区,黄铁矿、黄铜矿和金有的产于石英脉中和花岗岩中,有的则以星散状、浸染状矿体赋存于高度蚀变的变质火山岩剪切带中。这些矿物的形成部分与磁黄铁矿、蓝辉铜矿、锑黝铜矿、辉铜矿、斑铜矿和铜蓝有关。黄钞矿具有两种晶形:(1)含有原生硫化物包裹体的自形—半自形巨型晶体,(2)细晶集合体。黄铜矿具有三种晶形:(1)自形巨型晶体,(2)细晶含微包裹体,(3)它型残余物。硫化物矿物有三个形成阶段,这三个阶段与热液的连续冷却结晶过程有关。在无序的高温热液阶段金以基质存在于早期硫化矿物中,在温度逐渐降低的后期阶段,含金黄铁矿经过重新运移,产生了自然金,显微镜分析结果证明,金和铜在晚期的黄铁矿中相对富集,分析研究过的表层蚀变矿物有:针铁矿、褐铁矿、金以及铁和铜的碳酸盐矿物和硫化物。     

WINDOW FACTOR ANALYSIS:THEORETICAL DERIVATION AND APPLICATION TO FLOW INJECTION ANALYSIS DATA

Window factor analysis(WFA)is a self-modeling method for extracting the concentration profiles ofindividual components from evolutionary processes such as flow injection,chromatography,titrationsand reaction kinetics.The method takes advantage of the fact that each component lies in a specificregion along the evolutionary axis,called the‘window’.Theoretical equations are derived.The methodis used to extract the concentration profiles and spectra of seven bismuth species from data obtained byGemperline and Hamilton,who injected bismuth perchlorate into a flowing stream of hydrochloric acid.     

A NEW RECEPTOR MODEL:A DIRECT TRILINEAR DECOMPOSITION FOLLOWED BY A MATRIX RECONSTRUCTION

In many cases,monitoring data for ambient airborne particles can be organized in the form of a three-way data table with one way for chemical species,one for sampling periods and one for sites.A directtrilinear decomposition followed by a matrix reconstruction(DTDMR)is developed to analyze such adata table as a whole.The three-way data set is composed into three two-way matrices by a direct trilineardecomposition(DTD).The column vectors of each of the matrices are called‘source profiles’,‘emissionpatterns’and‘site coefficients’respectively.Particulate sources are identified by examining both theirsource profiles and emission patterns.After the sources have been identified,emission patterns and sitecoefficients are used to produce a three-way matrix that gives estimates of mass contributions of sourcesto the samples collected at every site in every period.By simulation study,not only has the method beenverified,but a good indicator has been found that shows the number of factors(i.e.sources)in thesystem.Unlike other receptor models,DTDMR does not require source profile data and does not involvetrial-and-error procedures.Since DTDMR identifies sources based on variations in two dimensions,it hasa higher potential to distinguish two sources that have similar chemical compositions.The DTDMRmodel has provided excellent results with simulated data and has been applied in a real world three-waydata set.     

MARS:A TUTORIAL

This tutorial paper presents a simplified view of one of the more recently published multivariatecalibration methods particularly suited to dealing with non-linear data sets.The method is referred toas MARS and stands for multivariate adaptive regression splines.Simple examples are provided toexplain the workings of the method.     

内华达东中部安特勒前陆盆地演化与层序地层学

引言安特勒盆地的密西西比纪沉积岩出露于从爱达荷经东内华达至南内华达的连续区域内。这些岩石为硅质碎屑盆地充填序列,并超覆在晚古生代以碳酸盐沉积为主的北美西部边缘之上。在中内华达的研究区域内(图1),安特勒盆地的大部分地层已被划归为两个单位:(1)Chainman页岩(Spencer,1917;Easton等,1953);(2)Diamond Peak组的砾岩和砂岩(Easton等,1953;Nolan等,1956)。本区安特勒盆地从早密西西比世到早宾夕法尼亚     

澳大利亚特里托里(TERRITORY)北部ARLTUNGE金矿区含金石英脉分布的构造控制

1 绪言在几个世代的石英脉及与其共生的矿化建造中,渐进的脆性—韧性剪切带通常显示一种特有的型式。一组早期的贫金石英脉在剪切带内通常呈雁行状展布。这些石英脉随渐进的形变作用而变形,且被膨胀的石英脉穿切,这种膨胀脉是在剪切事件发生期间较晚期形成的,当时大多数的位移已形成于特有的狭窄裂隙带内。尽管人们通常能够识别上述矿化类型,但却未很好了解其成因和形态约束。本文涉及澳大利亚中部若干后生脉状金矿床,这些矿床是代表从韧性发展到脆性一韧性剪切带中矿化的极好实例。设想通过详细的岩性和构造形态地     

赣东北元古代蛇绿岩Sm—Nd同位素年龄及地质意义

江南古陆东南缘赣东北弋阳—德兴—婺源一线有一条蛇绿岩带,普遍认为它是二个一级大地构造单元的分界线,形成于元古代。推断蛇绿混杂岩是元古代古洋壳俯冲时被挤上来的碎片;也有人认为它是中生代二大古陆之间的缝合线。Sm-Nd矿物等时线给出1034±16Ma(MSWD=1.0)的同位素年龄,它符合元古代缝合带的观点,而不利于中生代缝合带。     

坦桑尼亚和肯尼亚西南部金矿化特征和构造背景

坦桑尼亚和肯尼亚西南部的许多金矿床,都分布在尼安兹绿岩带(27亿年)和乌宾迪系(20亿年)中。这些矿床以块状或浸染状富铁硫化物矿体产在条带状铁建造或凝灰岩层、镁铁质岩层的矿化剪切带以及剪切带控制的石英脉中。其矿化的大部分是后生的,而有些是同生成因的。在尼安兹绿岩带中还有富贱金属的硫化矿床,也是同生成因的。富铁的镁铁质岩是尼安兹绿岩带下部及乌宾迪系中最有利的容矿岩,而条带状铁建造是