地质学家重视研究深部（变质）CO_2对古气候的影响

地质学家重视研究深部（变质）ＣＯ２对古气候的影响贾跃明（中国地质矿产信息研究院，北京，１０００３７）近几年来，随着过去全球变化研究的兴起，地质学家越来越重视地质历史时期影响大气ＣＯ２浓度的因素的调查。不少人认为，变质作用和火山活动可能是过去大气中ＣＯ...     

滇西石缸河锡矿床的成因探讨

石缸河锡矿床在空间上，时间上和成因上与志本山花岗岩演化分异晚期形成的浅色细粒白云母花岗岩有着密切联系，属岩浆期后热液矿床。     

现代成矿预测若干理论述评

以成矿理论为支撑的现代成矿预测理论取得了长足的进展，对现代矿产勘查与评价实践工作具有重要的指导意义；据成矿预测理论近年来的进展，结合笔者等的研究工作体会，述评地质异常、矿床的成矿系列、矿床模型和超大型矿床勘查等成矿预测理论。     

不透明矿物所含单个低盐度流体包裹体液相组分SAM/AES实验研究:Ⅰ.原理与方法

针对与矿石矿物共存透明脉石矿物所含流体包裹体并不完全代表成矿流体，红外显微技术及EPMA、SEM等常规表面分析手段无法满足不透明矿石矿物所含单个低盐度流体包裹体研究的实际困难，本文首次成功地应用具同步扫描成象功能、电子束斑空间分辨率较高、信噪比较好的PHI595SAM／AES这一当代高灵敏表面分析技术，按单矿物分选→二次去离子水反复超声清洗→外真空热爆→在金属铟片上压制成样的实验流程对新疆阿尔泰多拉纳萨依金矿床含金黄铁矿所含单个低盐度流体包裹体的液相组成进行了静态定点分析，实验取得了满意结果。     

湖南柿竹园钨多金属矿床成矿机理的实验研究

作者在深入柿竹园钨多金属矿床野外地质工作的基础上，采用矿区燕山期花岗岩和泥盆系灰岩作为试料，在含ｐＨ＝４．０的０．３ＭＮａＣｌ＋０．７ＭＫＦ水溶液的高压釜中持续了１２０小时的交代作用。实验的结果表明了：在４００～７００℃的温度和２５０×１０５～９００×１０５Ｐａ的压力下，形成的交代岩及其钨、锡、钼、铋矿物基本上与矿区的矽卡岩及其矿石矿物共生组合相吻合，揭示了湖南柿竹园矽卡岩型钨多金属矿床成矿的机理     

Characteristics and origin of sediment-hosted disseminated gold deposits: a review

Sediment-hosted disseminated gold (SHDG) deposits comprise a major portion of the gold production and reserves in the US. Although presently known to be common only in western North America, SHDG deposits are a significant source of world gold production. These deposits are characterized by extremely fine-grained disseminated gold, hosted primarily by arsenian pyrite. Other metals show very little enrichment although in addition to As, anomalous concentrations of elements such as Sb, Hg, Tl and Ba are utilized as exploration tools. The host rocks are dominantly silty carbonates, but ore concentrations are also present in siliceous and silicified rocks as well as intrusive rocks. Alteration consists of decarbonatization, silicification (jasperoid formation) and argillization, which are arranged both spatially and temporally in that order. Argillic alteration is zoned from kaolinite-dominated cores to sericite-dominated margins. The deposits commonly exhibit significant structural (faults) and stratigraphic (composition/permeability) controls. Until the last few years, SHDG deposits were considered as near-surface, epithermal type deposits in origin. Because of their fine-grained nature and the lack of macroscopic features such as veins, it has proven quite difficult to extract geochemical data that are clearly related to their genesis. However, fluid inclusion data indicate pressures corresponding to depths of 2–4 km under lithostatic conditions. Temperatures are constrained by fluid inclusions and phase equilibria to near 225°C. Stable isotope data from alteration minerals and fluid inclusions indicate that the ore fluids were dominated by meteoric waters, some of which had clearly exchanged oxygen with wallrocks during their passage through the crust. Although the data vary, most ore fluids probably had δD values near −150‰ and δ¹⁸O values ranging from −10 to +5‰. Sulfur isotope values reported from SHDG deposits span a wide range, from −30 to +20‰ (sulfides) and 0 to >45‰ (sulfates). Ore-related sulfides (pyrite, realgar) fall at the upper end of the range reported for sulfides. The alteration and mineral assemblage indicate the ore fluids were probably near neutral and gold was likely carried as a bisulfide complex. The depositional mechanism(s) probably included mixing, cooling and oxidation. These mechanisms are consistent with the observed alteration features, i.e. quartz precipitation, calcite dissolution and sericite-kaolinite coexistence. It also explains the presence of both siliceous ores containing native Au and sulfide ores containing Au in pyrite. The extreme variations in sulfur isotopes as seen at Post and fluid inclusion data from Carlin may be indicative of some phase separation (‘boiling’), but such relations have not been documented in other deposits and the importance of phase separation to gold deposition appears minimal.     

滇中及邻区前地台大地构造演化与铜成矿作用

通过构造层的划分，探讨滇中及邻区前边台演化与运动特征。认为该地区前地台经历了萌陆壳稳定阶段、原陆壳活动阶段、稳定阶段和地槽阶段。壳体演化与运动是幔交替活动与壳体成熟之间互相联系互相制约的结果。最后总结了钢成矿作用与构造演化的若干关系。     

开发利用地理信息系统(GIS)综合分析地学信息进行矿产预测

众所周知,矿产资源预测是综合地学信息,进行优选靶区的有效手段之一。随着地学工作的深入和勘探技术的发展,已获取了大量的多源地学信息,如地质、地球物理、地球化学和遥感等资料。怎样从这众多的资料中提取有用信息进行综合分析,达到矿产资源预测的目的,一直是地学界探索的课题。过去,应用人工的方法来进行此项工作,不但费力、投资大,而且难以达到预期的效果,方法技术也不利于推广。如今,高速、高质量的计算机已趋于普及,使应用计算机技术高效地处理堆积如山的资料成为可能,尤其是近些年发展起来的地理信息系统(GIS),为综合处理地学资料的矿产资源预测的方法技术,开拓了广阔的前景。地理信息系统是一种计算机系统的应用软件,它集数据库管理和图像分析技术为一体,以空间数据迭加分析为重要特征。地学工作者进行矿产资源预测时,通常是从多源地学资料中提取有用信息,再应用专家知识,结合数学方法,如逻辑运算、贝叶斯(Bayes)规则等,建立预测模型,以模型的推理网格为线索,利用地理信息系统有效的空间分析手段,把各种证据图层综合迭加,最终产生以概率为指标的矿产资源预测图,高概率指示有利的矿产资源远景区,可作为勘探者和决策者进行勘查规划的依据。     

A Study on the Geological—Geochemical Dynamics of Hydrothermal Ore Deposition as Exemplified by the Muping—Rushan Gold Deposit Belt,Eastern Shandong,China

This paper presents a method of establishing a hydrothermal ore-forming reaction system.On the basis of the study of four typical hydrothermal deposits,the following conclusions concerning geochemical dynamic controlling during hydrothermal mineralization have been sions concerning geochemical dynaamic controlling during hydrothermal mineralization have been drawn:(1)The regional tectonic activities control the concentration and dispersion of elements in the ore-forming process in terms of their effects on the thermodynamic nature and conditions of the ore-forming reaction system.(2)During hydrothermal mineralization the activites of ore-bearing faults can be divideb into two stages:the brittle splitting stage and the brittle-tough tensing stage,which would create characteristically different geodynamic conditions for the geochemical thermodynamic ore-forming system.(3)The hydrothermal ore-forming reaaction system is an open dynamic system.At the brittle splitting stage the system was so strongly supersaturated and unequilibrated as to speed up and enhance the crystallization and differentiation of ore-forming fluids.And at the brittle-tough tensing stage,the ore-forming system was in a weak supersaturated state;with decreasing temperature and pressure the crystallization of oreforming material would show down,and it can be regarded as an equilibrated state.(4)In the lates stages of hydrothermal evolution,gold would be concentrated in the residual ore-forming solution.The pulsating fracture activite in this stage led to the crush of pyrite ore and it was then filled with gold-enriched solution,forming high-grage“fissure”gold ore.This ore-forming process could be called the coupling mechanism of ore formation.     

南秦岭沉积岩型金矿成矿潜力与找矿前景分析

南秦岭沉积岩区广泛分布于商丹缝合带与勉略缝合带间的秦岭地块中，并以上古生界泥盆系最为发育。该含矿与岩矿建造中产出多种类型的浸染状金矿床，具有一定的空间分布规律。本文根据各金矿类型地质特征、岩矿与含矿岩系组成、所在区地质背景等方面，分析了它们的成矿潜力和找矿前景。