Preparation and Certification of High-Grade Gold Ore Reference Materials (GAu 19-22)

Two types of gold deposit with both good homogeneity and a high-grade of gold were selected to prepare four gold ore reference materials (GAu-19,GAu-20,GAu-21 and GAu-22) by the Institute of Geophysical and Geochemical Exploration (IGGE),China.Seven laboratories participated in the certification programme. Volumetric methods for GAu19-21 and atomic absorption spectrometry for GAu-22 were used for the homogeneity testing,the coefficient of variation being found to be less than 3%.After sample digestion and preconcentration,the samples were analysed by flame atomic absorption spectrometry (AAS),colorimetry,neutron activation analysis (NAA)and volumetric analysis. The certified values for the gold concentration in GAu19-22 are 18.3 μg g -1, 32.3 μg g -1, 53.0 μg g -1 and 5.72 μg g -1,respectively.     

Zinc-rich Pyrite from the TAG Active Mound, the TAG Hydrotherma Field, Mid-Atlantic Ridge

Abstract: Pyrite rich in Zn, up to 3.1 wt%, was found in the TAG active mound of the TAG hydrothermal field, the slow-spreading Mid-Atlantic Ridge at 26°08'N and 44°49'W. The Zn-rich pyrite is characterized by an optical homogeneity, a homogeneous distribution of Zn in the back-scattered electron images, both at a magnification of about 500, a negative correlation between Fe and Zn contents of the pyrite and a rather small unit cell edge (a₀ = 5.4117 ± 0.0008Å), strongly indicating that the detected Zn is present in the pyrite in solid solution. Such Zn concentrations are observed exclusively in dendritic pyrite, suggesting that the Znrich pyrite grew from hydrothermal fluids of a high degree of supersaturation due to quenching on the seafloor.     

图象恢复在工业CT中的应用

对于以影象增强器为检测系统的目标旋转式工业ＣＴ，分析了其图象退化的因素，采用对一维投影数据进行图象恢复的方法来提高ＣＴ图象质量。文中给出图象恢复公式，从计算机模拟和实验图象恢复的结果可看到所用方法提高了图象清晰度。     

一种适合定点使用的DTZ型质子旋进磁力仪

系统地介绍了ＤＴＺ系列质子旋进磁力仪的思路和性能特点，通过台站使用认为，ＤＴＺ系列仪器能满足地磁台观测精度的要求，具有实际使用的价值。     

深井电阻率所处井孔位置与地震关系的研究

对鲁南地区近几年发生的４级（ＭＬ）以上有感地震与深井电阻率所处井孔位置的关系进行了研究，进一步证明了“活断层—应力场效应”是存在的     

新亚欧大陆桥的走向及相关问题探讨

第二亚欧大陆桥已成为国际社会关注的焦点之一，但各国对其走向有着不同的见解和主张。本文概述了第二亚欧大陆桥各种走向的有关问题，并强调对其沿线环境灾害必须重视加以治理。     

DISTRIBUTIONS AND HYDROLOGICAL CHARACTERISTICS OF TROPICAL CYCLONE RAINSTORMS AND FLOODS IN CHINA

I.horoductionPleNorthwestPacificOceanisti1elnostfrequentlyaffeCtedareaoftropicalcyclone(TC).AboLIt36percentTCoftheworldoccurinffosarea[2],andthenumberofTCWhichlandedonChinawiti1n1akimumwindforcescalesoverlOisabout35percentofti1atintheeastemcoastalcoLUitriesofAsia[l].BothrainstormsandfloodsMide,theidriuenceofTCareheaVyinChina,suchastherainfalldePthof2749mm/3datXinliao,Taiwanandpeakdischargeof44,6oOm'/satHuanggo(55,42okn'),YalujiangRjver.Therefore,TCisanimportantfaCtorforflooddisas…     

几种测震学指标的短临前兆异常的初步探讨

本文在国家地震局组织的实用化攻关研究的基础上,按日常预报实践中积累的经验,分析研究了江苏及邻近地区几次地震前缺震曲线、波速比变化、b值时间扫描、累计无震单元数、尾波参数特征和地震活动性时间分维6个指标的短临异常信息,得到以下初步结论:(1)一些测震学指标在中强震发生之前三个月左右出现前兆变化;(2)短临前兆异常的幅度与震级大小的关系不明显;(3)在预测检验过程中,对于多数指标R约为0.5—0.6左右。     

钻井岩心定向或岩石露头定向样品的古地磁数据处理程序

本程序适用的范围很广,包括钻井岩心采样,岩石露头采样.坐标系则包括样品坐标,层面坐标与地理坐标.处理内容则包括逐步退磁结果数据表;退磁曲线;正交矢量图,赤平极射投影及其放大图.     

Pyrite deformation in stratiform lead-zinc deposits of the Canadian Cordillera

Pyrite textures in five stratiform lead-zinc deposits from lower to upper greenschist facies environment of the Canadian Cordillera are described and discussed in terms of deposition/early diagenesis, deformation, metamorphism and hydrothermal alteration processes. Overgrowth is an important process during both diagenesis and deformation. Diagenetic and deformational overgrowths can be distinguished. Diffusive mass transfer, involving pressure solution and oriented overgrowth of pyrite is the main deformation mechanism in pyrite deposits at low metamorphic grades. Although diffusive mass transfer favours fine-grained mineral aggregates, its effect on coarse pyrite grains has also been identified. Ore minerals dissolved by pressure solution may be transported, with the assistance of pore fluids within fractures and grain boundaries, over distances significantly greater than the scale of individual grains to give a range of pressure solution/overgrowth textures. The textural modification of pyritic ores from the early stages of diagnesis, through metamorphism and deformation, to post deformation thermal annealing, has important implications for the distribution of trace elements and isotopic compositions in pyritic ores.