The Relationship Between Mineralogical Characteristics and Isotopic Composition of Sphalerite,as Exemplified by the Huxu Deposit,China

The relationship between mineralogical characteristics and isotopic composition of sulfides has not received its proper share of attention from geologists, although many references are available concerning the application of sulfur isotopes to geological problems. Located in the vicinity of the contact region between the Yangtze Platform and the South China Caledonian Folding Zone, the Huxu deposit is hosted in a structural zone in quartz-diorite-porphyrite emplaced in Jurassic volcanic rocks. Sphalerite and galena are the principal ore minerals in the deposit. (1) Sphalerite is highly variable in color and this variation can be related to its chemical composition and sulfur isotopic characters. Dark colored sphalerites are poor in Zn and Ni, rich in Pb, Cu, Fe, Ag and Au and have high δ³⁴S values, while the opposite is true for light-colored ones. (2) δ³⁴S of sphalerite is negatively correlated with the contents of Zn and Ni and positively correlated with the contents of Pb, Cu, Ag and Au, with the absolute values of the correlation coefficients being greater than 0.7. The above two characters suggest that the sulfur isotopic composition of sphalerite is controlled not only by the physicochemical conditions under which the mineral was formed, but also by mineralogical characteristics of the host mineral. (3) Apparent correlations exist among the constituent elements in the sphalerite. For example, Zn is negatively correlated with Cu, Pb, Fe, Ag and Au and positively correlated with Ni. (4) Sphalerites of the same color in the same hand specimen always show similar characters with respect to trace element and sulfur isotopes. (5) Two distinct trends of evolution can be recognized between Zn and Cu, Zn and Pb, Zn and Ag and between these elements on one hand and δ³⁴S on the other, reflecting that the ore-forming solutions may have resulted from mixing of fluids of different origins. (6) Pb is uniformly distributed in sphalerite and shows positive correlations with Cu, Fe, Ag and δ³⁴S, suggesting isomorphic substitution in the sphalerite lattice. This project was financially supported by the Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences.     

基于彩色地图的地形三维数据快速采集系统

主要讨论研制基于彩色地图的地形三维数据快速采集系统。它通过对彩色地图图像进行分色、定向、跟踪等处理 ,能自动、快速地获取高精度的地形三维数据。提出了新的分色算法和数据压缩方法 ,分色算法简便、快速 ,有很大的先进性 ,并取得了很好的结果 ,压缩方法有快速、完整地提取等高线特征点的优点。本软件操作简单 ,能自动快速得到高精度的地形三维数据 ,为地图数据库的建立、数字高程模型的生成以及地理信息系统的数据输入提供了良好的数据源     

Experimental abiotic synthesis of methanol in seafloor hydrothermal systems during diking events

The abiotic synthesis of organic compounds in seafloor hydrothermal systems is one mechanism through which the subsurface environment could be supplied with reduced carbon. A flow-through, fixed-bed laboratory reactor vessel, the Catalytic Reactor Vessel (CRV) system, has been developed to investigate mineral–surface promoted organic synthesis at temperatures up to 400°C and pressures up to 30 MPa, conditions relevant to seafloor hydrothermal systems. Here we present evidence that metastable methanol can be directly synthesized from a gas-rich CO₂–H₂–H₂O mixture in the presence of a mineral substrate. Experiments have been performed without a substrate, with quartz, and with a mixture of quartz and magnetite. Temperatures and pressures in the experiments ranged from 200°C to 350°C and from 15 to 18 MPa, respectively. Maximum conversion of 5.8×10⁻⁴% CO₂ to CH₃OH per hour was measured using a mixture of magnetite and quartz in the reactor. After passivation of the stainless steel reactor vessel, experiments demonstrate that methanol is formed at temperatures up to 350°C in the presence of magnetite, and that the formation rate decreases over time. The experiments also show a loss of surface reactivity at 310°C and a regeneration of surface reactivity with increased temperature up to 350°C. Concentrations of CO₂ and H₂ used in the experiments simulate periodic, localized and dynamic conditions occurring within the seafloor during and immediately following magmatic diking events. High concentrations of CO₂ and H₂ may be generated by dike injection accompanied by exsolution of CO₂ and reaction of dissolved H₂O with FeO in the magma to form H₂. The experiments described here examine how the ephemeral formation of an H₂–CO₂-rich vapor phase within seafloor hydrothermal systems may supply reactants for abiotic organic synthesis reactions. These experiments show that the presence of specific minerals can promote the abiotic synthesis of simple organic molecules from common inorganic reactants such H₂O, CO₂ and H₂ under geologically realistic conditions.     

外向式杯[4]芳烃偶氮类新试剂的合成及其与钴(II)显色反应的研究

合成了一种外向式杯 [4 ]芳烃偶氮衍生物新试剂 ,试验了其性质 ,并研究了与钴 (II)的显色反应条件。在乳化剂OP存在下及pH9～ 10的缓冲介质中 ,形成稳定的红色络合物 ,其最大吸收波长为 5 10nm ,摩尔吸光系数为 1.60× 10 4 L·mol- 1 ·cm- 1 ,钴含量在 0～ 2 5 μg/ 2 5mL范围内符合比尔定律。本法灵敏度不太高 ,但选择性较好。     

四川省旅游“五朵金花”的地球化学特征

通过 1∶ 2 0× 10 4区域化探资料的开发 ,研究了九寨沟、黄龙、峨眉山、乐山大佛、青城山和都江堰等四川省著名的旅游胜地的“五朵金花”的地球化学背景和农业必需元素、生态环境和地热的元素异常发育特征 ,从而进一步从地球化学的角度对景区进行了较全面的评价     

区域矿产资源经济综合指标体系的确定与方法选择

区域矿产资源经济综合评价是矿产普查与勘探学科和地质经济学科中十分重要的新分支.本文侧重讨论了区域矿产资源经济综合评价中的评价指标体系的构造、评价指标效果值的确定、综合评价方法和计算机评价系统的建立等问题.     

Fundamental issues in quantitative estimation of mineral resources

Several issues considered to be fundamental in quantitative estimation of mineral resources and selection of mineral targets are addressed. Integration of multiple data sets, either by experts or by statistical methods, has become a common practice in estimation of mineral potential. Several major problems in data integration must be solved to significantly improve mineral resource estimation. Issues related to randomness of mineral endowment, basic statistical tools, exceptionalness of ore, and economic truncation and translation are discussed in the first part of the article. A number of important technical problems in data integration are also identified; they include data compilation, information enhancement, information synthesis, and target selection.     

金县短水准预报效能的研究

本文首次给出了金县台人工地震探测的最新结果。论述了跨断层短水准还可开发利用的前兆信息资源,并利用层次合成模型对金县短水准异常信息作了两个层次合成,使其地震预报效能较传统方法有了较大幅度提高,其前兆信息水平约60％、预报地震成功率达54％、地震报准率达72％,说明前兆异常信息的层次合成是提高单台单项目地震预报效能经济而有效的方法之一。     

不同时相遥感图像光机复合处理提取土地荒漠化信息研究

光机复合处理技术大大简化了常规遥感制图方法的繁琐步骤，它利用不同时相的遥感图像提取出土地荒漠化变化信息，不仅能确定土地是否发生了荒漠化以及荒漠化的强弱程度，而且还能已荒漠化的土地按荒漠化变化程度分为５种荒漠化无变化型，３种荒漠化强型和４种荒漠化减弱型，所生成图像上反映出自然景观带不仅与实地情况完全一致，而且带界精度都能保证在一下像元之内。     

单台多信道信息的层次合成

本文论述了单台单项目前兆信息水平低下的主要原因和提高途径,指出了可以开发利用的信息资源种类。根据系统工程学原理,提出应对异常信息作层次合成,认为进行四个层次的合成是必要的,且可基本满足要求,并给出各层次的具体合成表达式。对全县短水准作了两个层次合成计算,效果十分显著,层次合成是提高单台单项目前兆信息水平的一种经济而有效的方法。