广西大厂铜坑锡多金属矿床矿石稀土元素特征及其地质意义

铜坑锡多金属矿是广西大厂矿田中具代表性的超大型矿床,由上部的锡多金属矿和下部的锌铜矿组成。区内矿化具有"上锡下铜、近铜远锡"的分带特征和上脉下层的矿体产出规律。文章对区内不同类型矿体的矿石进行系统的稀土元素测试,结果显示不同类型矿石稀土总量具有规律性变化特征,稀土配分模式均表现为轻稀土富集、铕铈不同程度亏损的右倾配分曲线,结果表明上部的锡多金属矿体和下部的锌铜矿具有相同的物质来源。通过对矿区侵入岩稀土元素特征对比研究,表明区内成矿与龙箱盖花岗岩有关,成矿物质是自东向西、由下至上、由近花岗岩到远离花岗岩运移的,矿床成因应属于岩浆热液充填—交代型。     

狮金山铜钼金多金属矿普查及储量评估

从区域地质特征、矿体特征、矿区地质特征和矿石质量等方面,详细地对狮金山铜钼金多金属矿进行了研究,并得出了狮金山铜钼金多金属矿储量的估计值,对青阳县矿山资源的开发利用具有重要意义。     

基于小波能量的钢丝绳断丝损伤信号处理

提出了利用小波能量作为钢丝绳断丝损伤信号处理的1个特征量．根据Parseval能量积分等式从理论上推导了小波变换系数具有能量的量纲,将小波能量引入钢丝绳断丝信号处理中是可行的．通过对信号进行多层离散小波分解建立了小波能量求解的方程式,计算不同频带内钢丝绳断丝损伤信号的能量值,这些频带内的能量统计是在时域波形上进行的,体现了小波分析具有时频分析能力．最后针对不同的断丝损伤情况,分别求解各个频带内的小波能量值,修正了应用于钢丝绳断丝损伤信号处理的小波能量计算公式．试验结果表明小波能量表征断丝信号的1个特征量是有意义的．     

激电法在果卜德地区铜金多金属矿中的应用

本次电法工作配合地质勘探工作,在研究区成矿有利地段,开展激电中梯剖面测量工作,系统采集电物性标本,统计不同岩性的电阻率以及极化率特征,其中孔雀石化花岗闪长岩是引起激电异常的主要岩石,以此为依据圈出7处激电异常,且得到了后期地表工程验证,取得了较好的应用效果,通过对果卜德地区铜金多金属矿中的激电资料进行综合整理和分析,解释了该区激电异常特征,本文为应用激电法寻找铜金多金属矿提供了一个可参考的实例。     

豫西宽坪银多金属矿床地质特征及矿床成因探讨

豫西宽坪银多金属矿床位于华北地台南缘熊耳山变质核杂岩中部,成矿条件优越。矿体赋存于太华群杨寺沟岩组,其形态、规模、产状严格受NNE、NEE向构造蚀变带控制。结合成矿地质背景,研究分析了宽坪银多金属矿地质特征、控矿因素和找矿标志,并对矿床成因进行了探讨,认为矿床成因类型为构造蚀变岩型银多金属矿。对该地区银多金属矿的地质特征和成因研究,有利于拓宽崤山地区银多金属矿找矿思路,为该区及周边实现找矿突破提供借鉴。     

青海东昆仑各玛龙银多金属矿地质特征及找矿远景分析

各玛龙银多金属矿是在东昆仑那更康切银矿周边发现的构造热液型银多金属矿床,运用绿色勘查手段评价,发现了5条含银构造蚀变带、20条矿体。通过对各玛龙银多金属矿地质特征,控矿因素及找矿标志进行综合分析研究,对比那更康切银矿地质特征,认为该矿床具类似那更康切尔大型银多金属矿的找矿前景,为区内下步找矿工作具有重要的借鉴意义。     

关于解决金属矿山巷道整体混凝土衬砌裂缝的几点意见

在破碎、松散的岩层中建造金属矿山巷道,整体混凝土衬砌结构往往出现裂缝,甚至破坏。造成影响生产,延误工期,增加造价等不良现象,这在金属矿山已经有了不少实例。我们所调查的华北、西南、华东等矿山以及某金属矿等混凝土衬砌都有程度不同地出现了裂缝,且进行了各式各样的加固,仅某金属矿,到1964年10月底对衬砌裂缝区段的三分之一的     

广东怀集大坪地区铁铜多金属矿成矿地质特征及成因探讨

阐述了广东怀集大坪地区铁铜多金属矿的地质特征,并对其矿床成因进行了探讨。     

木奇北沟一带金铜多金属矿地质特征

本文通过对木奇北沟一带金铜多金属矿开展普查工作及查阅该地区相关地质资料,对该区地质特征、矿体特征、矿石特征、矿化阶段、围岩蚀变特征等地质特征进行了详细的论述。     

四川省荥经县羊儿窝铁铅多金属矿地质特征及找矿前景浅析

荥经县羊儿窝铁铅多金属矿位于扬子准地台西南缘的上扬子台坳之峨眉山断拱。区域内出露地层为震旦系、寒武系、奥陶系、志留系,其中震旦系为区内含矿层位。通过对矿区地质、物化探异常、矿体特征、矿石矿物特征和围岩蚀变特征进行总结研究,总结矿床成矿规律和找矿标志,分析其找矿潜力。通过物化探测量,在矿区圈定了Cu9、Pb10异常,发现了两条铅锌矿体,矿石矿物主要为黄铁矿、次为方铅矿及闪锌矿,围岩蚀变主要为硅化、碳酸盐化。经过分析,初步判断该矿床属沉积-改造型多金属矿床。对成矿地质背景、矿体特征、矿床成因和找矿标志等进行综合分析,矿区具有较好的找矿前景。     

西准噶尔地区阿尔木强铜矿地质特征及成因分析

阿尔木强铜矿位于新疆西准噶尔盆地西北缘,中亚成矿域巴尔哈什—准噶尔成矿省塔尔巴哈台—谢米斯台成矿带的东端。文章以成矿地质条件、矿床地质特征为基础,通过岩石化学、微量元素及稀土元素的地球化学特征,探讨了矿床的地质特征与成因。研究表明,阿尔木强铜矿形成于中志留世火山岩强烈活动的后期,成矿环境为大洋岛弧构造环境,成矿温度属于中高温,成矿类型为火山岩容矿的构造热液改造型铜矿床。成矿阶段可划分为黄铁矿阶段、金属硫化物阶段、碳酸盐阶段、次生氧化阶段4个成矿阶段。     

新疆小石头泉地区黄草沟银多金属矿地质特征及矿床成因

黄草沟银多金属矿床位于东天山博格达—哈尔里克构造带东段的小石头泉地区。矿体产于下石炭统雅满苏组第二亚组(C_1y~2)火山岩地层中,受断裂构造控制,主要呈脉状;矿石类型以石英脉型为主,金属矿物以辉银矿、黄铜矿、褐铁矿、黄铁矿、闪锌矿为主,非金属矿物以石英、方解石为主;矿区普遍发育硅化、碳酸盐化、绿帘石化等低温蚀变组合。黄草沟银多金属矿床成矿地质特征与浅成低温热液型成矿系统一致,应属于浅成低温热液型银多金属矿床。     

冀东下营坊金矿床黄铁矿原位微量元素地球化学特征及其指示意义

下营坊金矿床为冀东地区一个重要的金矿床,为进一步探讨金矿不同矿化类型之间的关系及其成因。本次在总结下营坊金矿床地质特征基础上,通过LA-ICP-MS微区原位分析,获得下营坊金矿床不同矿化类型矿石中黄铁矿的微量元素含量特征。对比分析发现,从热液型矿化到角砾岩矿化,再到矽卡岩型矿化,其微量元素含量呈连续的规律性变化,结合金矿化与大东山的时空关系,指示下营坊金矿床成因上与大东山杂岩体关系密切,表明它们可能属于同一个岩浆体系在不同物理化学条件下的演化产物。     

云南地区现今应力场特征及成因分析

基于国际开放地震数据库(Global CMT),统计了云南地区1976—2015年期间66组震级(M_w)≥4. 8的震源机制数据。通过TENSOR程序反演震源机制的简化应力张量发现:云南地区应力机制以走滑型(SS)为主,占66. 7%;其次为正断型(NF),占22. 7%,且主要集中分布在云南西北断裂附近。将66组震源机制数据按区域分为4个次级区块分别联合反演,其结果显示:云南西北地区拉张作用显著,最大主应力方向为WNW—ESE和NNW—SSE;云南西南、东北地区以挤压作用为主,最大主应力方向分别为NNE—SSW和NW—SE;云南东南地区板块相对稳定,基本没有中强震发生。以震源机制反演结果为约束,利用有限元数值模拟得到了研究区连续应力场变化特征,即具有顺时针旋转的趋势,其主要原因是喜马拉雅东部构造特殊的下地壳和上地幔物质使得云南地区成为印度板块向北推进的优势通道,进而挤压应力向东南偏转形成旋转的应力场。     

The source of naturally occurring arsenic in a coastal sand aquifer of eastern Australia

The discovery of dissolved arsenic in a coastal aquifer used extensively for human consumption has led to widespread concern for its potential occurrence in other sandy coastal environments in eastern Australia. The development of an aquifer specific geomorphic model (herein) suggests that arsenic is regionally derived from erosion of arsenic-rich stibnite (Sb(2)S(3)) mineralisation present in the hinterland. Fluvial processes have transported the eroded material over time to deposit an aquifer lithology elevated in arsenic. Minor arsenic contribution to groundwater is derived from mineralised bedrock below the unconsolidated aquifer. An association with arsenic and pyrite has been observed in the aquifer in small discrete arsenian pyrite clusters rather than actual acid sulfate soil horizons. This association is likely to influence arsenic distribution in the aquifer, but is not the dominant control on arsenic occurrence. Arsenic association with marine clays is considered a function of their increased adsorptive capacity for arsenic and not solely on the influence of sea level inundation of the aquifer sediments during the Quaternary Period. These findings have implications for, but are not limited to, coastal aquifers. Rather, any aquifer containing sediments derived from mineralised provenances may be at risk of natural arsenic contamination. Groundwater resource surveys should thus incorporate a review of the aquifer source provenance when assessing the likely risk of natural arsenic occurrence in an aquifer.     

Shallow hydraulic fracturing measurements in Korea support tectonic and seismic indicators of regional stress

We have conducted five hydraulic fracturing stress measurement campaigns in Korea, involving 13 test holes ranging in depth from 30 to 250 m, at locations from North Seoul to the southern coast of the peninsula. The measurements reveal consistent crustal stress magnitudes and directions that suggest persistence throughout western and southern Korea. The maximum horizontal stress σ_H is oriented between ENE–WSW and E–W, in accord with plate movement and deformation, and with directions indicated by both focal mechanism solutions from earthquakes inland and offshore as well as borehole breakouts in mainland China close to its eastern coast. With respect to magnitudes, the vertical stress is the overall minimum stress at all tested locations, suggesting a thrust faulting regime within the relatively shallow depths reached by our tests. Typically, such a stress regime becomes one favoring strike-slip at greater depths, as is also indicated by the focal mechanism solutions around Korea.     

Quantification of surface faulting potential in a low to moderate active region: An example from the Southern Rhinegraben area

In low to moderate tectonically active areas, such as intracontinental regions with deep reaching zones of crustal weakness, direct observations of surface faulting offsets are very scarce and the seismic record is often incomplete and small. This complicates the study of a possible surface faulting hazard and requires new analysis concepts. In the case study presented in this paper, the seismic hazard potential of an already defined nuclear power plant site located in such a moderate active region had to be reassessed, and the possible effects of surface faulting had to be quantified.     

东昆仑灶火河西铁多金属矿找矿前景浅析

灶火河西铁多金属矿位于东昆仑中岩浆弧带与祁漫塔格结合带上,该矿床是近些年新发现的一处铁多金属矿,矿体主要赋存于花岗闪长岩与碳酸盐岩的外接触带上,少部分产出于岩体与围岩的内接触带中以及破碎蚀变带中,含矿围岩为古元古界金水口岩群,矿体多呈不规则条带状、透镜状,近北西西展布,受接触带控制明显,少部分矿体受断裂及层间破碎带控制明显,矿石矿物主要为磁铁矿、钛铁矿、黄铁矿、黄铜矿、硫砷铜矿等。笔者通过对灶火河西铁多金属矿成矿特征、矿床成因及物化探资料研究,认为成矿及接触带及断裂构造关系密切,矿床成因类型主要为夕卡岩型或接触交代型,该区具有较好的找矿前景。     

Experimental modeling of segmental shallow tunnels in alluvial affected by normal faults

Faulting is one type of permanent ground displacement and tunnels are at the risk of damage from faulting because of their long lengths. There are few studies that examine the behavior of tunnels intersecting the fault zones although it is of continuing concern for design engineers. Determining the failure mechanism provides critical information for the design of a tunnel, including its segmental lining. The present study conducted a series of centrifuge model tests on segmental tunnels subjected to normal faulting. The results indicated the absence of sudden failure of segmental tunnels under normal faulting and improvement of function in response to an increase in the overburden of the tunnel. The angle of the fault affected tunnel behavior. Despite large displacement faulting, structural damage to the segments was very low because of the adequate geometric functioning of the segments and their joints. The length of the zone affected by faulting in the tunnel decreased as the overburden increased, but the severity of damage increased in response to localization of fault displacement. Sinkhole formation upon the collapse of soil into the tunnel is likely at the ground surface. Special attention must be paid to the effect of sinkholes on at ground structures in the vicinity of the tunnel.     

Role of organic matter in framboidal pyrite oxidation

An experimental system has been set up to investigate the reaction kinetics of framboidal pyrite oxidation in real, reactive acid sulfate soil assemblages. This study was undertaken to determine the degree to which pyrite oxidation rates are reduced by bacteriological reactions and organic matter, which both modify the net reaction mechanisms and compete for available oxygen. The results from these experimental runs not only confirm the role of organic matter in mitigating pyrite oxidation but indicate that at least initially, the acidity produced is consumed or otherwise ameliorated by parallel reactions. Tracking pH or [H+] in both a reactor and in soil does not accurately reflect reaction progress and may not correctly indicate the true level of risk. In comparison, the tracking of pyrite oxidation with the concentration of sulfate in solution is not affected by side reactions or precipitation and is therefore a better indicator for the rate of pyrite destruction.