VMS型铅锌矿成矿流体研究进展

热液(水)系统铅锌矿成矿流体的研究,是矿床地球化学研究的重要课题之一。正确识别系统中流体包裹体特征,成矿流体来源、迁移及金属沉淀机制,是深刻理解热液铅锌矿形成演化的关键。文章系统总结了与VMS型铅锌矿成矿流体有关的流体包裹体岩相学特征、成分测试技术与方法、成矿流体形成与演化。以VMS型矿床的典型成矿模式为主线,分别讨论了成矿流体载体矿物的选择、流体包裹体均一温度和盐度、LA-ICP-MS的应用、流体包裹体成分及同位素成分分析,并给出了VMS型铅锌矿成矿流体研究方面今后的发展趋势。     

黄沙坪多金属矿床流体地球化学研究进展

黄沙坪铅锌矿床是南岭钨锡钼铋铅锌多金属成矿带的一个典型矿床,是湘南地区最大的铅锌多金属矿床。通过对该矿床前人研究资料的收集和整理,对矿床流体地球化学研究中的重要进展进行归纳总结。矿床不同矿物中发育六类包裹体,分别为纯气相、纯液相、富气相气液两相、富液相气液两相、含CO_2三相、含子矿物三相包裹体。按照矽卡岩不同矿化类型成矿流体呈现矽卡岩阶段分异作用和硫化物阶段混合作用为主的演化特征;是典型的还原性矽卡岩型铜多金属矿床。     

油气成藏期研究综述

油气藏的形成过程受众多因素控制,研究油气成藏的途径有多种,但油气成藏期是研究油气油藏重要途径之一.本文主要阐述的是通过流体包裹体系统分析法、 有机包裹体岩相学特征、 自生矿物定年等方法对油气成藏期次进行研究.     

赣中铅锌矿地质特征与成矿物质分析

赣中某矿田是一个以锡、铅、锌为主的大型矿田。各类矿床以岩体为中心,呈"晕圈式"分布,从内到外由高温矿种过渡为低温矿种。文章探讨了区域内锌矿床的矿体特征、矿物组成、稀土元素特征、同位素地球化学特征和流体包裹体特征,分析了锌矿的地质地球化学特征、成矿流体来源以及成矿机制。     

漳平市横坑口矿区萤石矿地质特征及其矿床成因分析

通过对矿区开展地质勘查工作,在深部控制了萤石矿体的规模、产状、形态和空间位置。矿区萤石矿体主要产于F2构造破碎带内,矿体形态、产状受断裂构造所控制。矿石类型主要有萤石型、石英—萤石型、角砾岩—萤石型,多呈网脉状、角砾状、块状矿石构造。文章根据矿体产出特点及围岩蚀变特征,结合国内类似矿床的成矿地质特征,认为矿床成因类型为中—低温热液裂隙充填型。     

贵州省务川田坝重晶石-萤石矿床地质特征及成因探讨

本文研究务川田坝重晶石-萤石矿床地质特征,认为务川田坝重晶石-萤石矿床受奥陶系下统红花园地层和北北西向发育的张性裂隙双重控矿,初步探讨了该矿床成因和成矿模式,并提出了找矿建议。     

伊通盆地伊丹凸起双阳组成藏期研究

为了确定伊丹凸起主要目的层双阳组的成藏期次,本文利用伊69井双阳组流体包裹体测试结果,在埋藏史热史恢复的基础上,根据化学动力学理论恢复双阳组的生烃史,从烃源岩生烃史以及包裹体均一温度等方面,对伊丹凸起双阳组成藏期加以判断,为下一步勘探部署提供依据。     

葛山坞矿区萤石矿地质特征及成矿特点

详细阐明葛山坞萤石矿的成矿地质条件（地层、构造、岩浆岩）。描述了矿体的数量、分布、形态、厚度、产状等地质特征。对矿床的控制因素及成因进行了初步探索。认为矿床成因类型属于中低温热液充填型矿床。     

试述福建武夷山翁坑萤石矿地质特征

武夷山翁坑萤石矿位于武夷山市岗谷乡黄尾村境内,2001年福建省核工业二九四大队通过地质调查发现矿体,现在已经投入开发利用。该萤石矿属岩浆期后中—低温热液充填型脉状小型矿床,其成矿地质特征在闽北丰富的萤石资源中具有一定的代表性。     

试述福建武夷山翁坑萤石矿地质特征

武夷山翁坑萤石矿位于武夷山市岗谷乡黄尾村境内,2001年福建省核工业二九四大队通过地质调查发现矿体,现在已经投入开发利用.该萤石矿属岩浆期后中—低温热液充填型脉状小型矿床,其成矿地质特征在闽北丰富的萤石资源中具有一定的代表性.     

Workfare,welfare, agency,and well-being

Workfare programs are state-instituted programs that require able-bodied persons with children of school age who wish to claim welfare payments to participate in job training programs, and, eventually, to enter the work force. The philosophy of workfare is based on the value of work and the goal of self-determination. However, as a mandatory program for welfare recipients, workfare requires of those recipients certain duties which, according to those who challenge workfare, interfere with the freedom to choose what one will do with one's life. Whether some form of workfare will be adopted as part of our national welfare system remains to be seen. What the debate about such a program suggests is that welfare, in itself, by ignoring the necessity of security and education for full human agency, neither satisfies basic needs nor prepares its recipients for any life other than that of dependency. With all its difficulties workfare nevertheless presents an alternative to welfare that, at least in theory, more closely identifies its purpose with the values of our society.     

Externalities, Indivisibility, Nonreplicability, and Agglomeration

In this paper we argue that the impact of external scale economies and diseconomies on city size is not nearly as clear-cut as it is tacitly believed in urban economics. Similarly, city-size distortions are not caused by externalities alone. Indivisibility and nonreplicability, which prevent establishing the “right” number of cities, may represent a source for city-size distortions which can be stronger than the standard resource misallocation resulting from external scale economies and diseconomies. It follows that a direct population dispersion policy is not just an inferior substitute to Pigouvian taxes and subsidies but rather a useful complement.     

Mean, median, mode

Summary This note is an attempt to avoid doing the same search for the third time. It happened twice in my life that I wished to prove that the median is located between mean and mode for certain B -distributions: first in 1953, next in 1976. For arbitrary distributions the result is sometimes referred to as F echner's theorem. Of course it does not hold in general. In order to prove the result for particular distributions one can often use an elegant theorem of T imerding . There is a nice relationship with the standardized third central moment.