地物化综合方法在冀北某区隐伏矿(化)体预测定位中的应用

中深部隐伏矿(化)体是当前地质找矿的重点勘查对象。研究区地层简单,多数为第四系覆盖,在已圈定出的区域化探异常范围内,通过地物化综合方法手段进行勘查,目的是发现并圈定出矿(化)体赋存部位,取得深部找矿的突破。该区位于上黄旗—乌龙沟银多金属成矿带,是冀北地区有色金属矿产的重要聚集区,成矿条件十分有利。本次工作在地表圈出的化探、激电中梯异常范围内,通过激电测深测量以及地质山地工程的揭露,验证了矿(化)体的存在,取得较好的找矿效果。由此表明地物化综合勘查技术对隐伏矿(化)体预测定位是行之有效的。     

激电测量在皖南某矿区寻找隐伏矿脉中的应用

激电测量对于寻找与金属硫化物相关性好的矿(化)体具有效果好、效率高的特点,利用激电中梯剖面测量可以达到快速发现激电异常、圈定极化体的目的,结合对称四极测深工作,能在地表覆盖厚的地区发现和追索矿(化)体以及对矿(化)体深部特征进行解剖,达到寻找隐伏矿脉的目的。     

综合物探方法在东昆仑东段益克郭勒斑岩型钼矿找矿中的应用研究

益克郭勒斑岩型钼矿床是近年来在东昆仑东段新发现的斑岩型矿床,笔者在地质研究的基础上,通过开展1∶10000地面高精度磁法测量,在研究区内圈出3处低磁异常。依据地质勘查成果,结合磁物性特征研究对比分析,认为C1、C2磁异常与成矿斑岩体及斑岩成矿作用有关,C3异常由构造引起;对斑岩型矿床成矿条件较好的C2低磁异常区开展1∶10000激电中梯剖面测量,圈出激电异常带2条;对磁、电异常套合好的地面高精度磁测线进行2.5维反演,结合地质解译,选择成矿有利地段进行深部验证,圈出隐伏钼矿体6条,查明了低磁异常套合的激电异常由斑岩矿及斑岩成矿作用引起,并总结了研究区斑岩型钼矿综合找矿模型;发现了明显的地质、地球物理找矿标志,具有较好找矿前景。     

秘鲁帕加贡铜矿区地球物理异常特征及找矿预测

帕加贡(Pachagon)铜矿位于秘鲁著名的北部斑岩铜矿带上,矿床类型与周边及典型的斑岩铜矿床相似。为了对帕加贡矿区深部进行异常研究,提高找矿效果,采用了高精度磁法和激电测深工作,共圈定4处高磁异常、多处剖面激电异常;通过对物探异常的综合分析、处理和解释,圈定了找矿靶区,进行了找矿预测;同时利用钻探进行验证,发现了铜矿(化)体,取得了良好的找矿效果。     

河南省栾川县老王沟矿区多金属矿物化探异常特征及找矿预测

老王沟矿区位于河南省栾川矿集区的西南部,周边矿权密集,成矿地质条件优越。在区内开展了1∶1万土壤地球化学测量,共圈定了8处综合异常。采用化探剖面、激电中梯和槽探等综合手段进行异常查证,在综合异常TR05内发现了与断裂F4有关的铅矿化体;综合异常TR07和TR08与激电中梯高极化率低阻异常套合较好;综合异常TR07开展了岩石地球化学剖面测量,在断裂构造F7处见Zn、Pb、Mo和W高值异常,经槽探工程验证发现了锌矿体。结合区域成矿地质条件和物化探信息,推测老王沟矿区具有较好的找矿前景。     

高精度磁法测量在青海大格勒沟地区镍钴铁矿勘查中的应用

运用1∶1万高精度磁测方法,对1∶5万区域地质矿产调查中发现的磁异常深部隐伏控矿构造及地质体进行评价。结果表明,高精度磁测既有利于圈定隐伏的控矿构造,也有利于圈定隐伏磁性地质体。1∶1万高精度磁法测量数据解译表明,研究区内存在两种不同特征的磁场区域,分别为北部强磁性磁场区、南部低缓-背景磁场区,在磁场区域圈定出3处磁异常,并对磁异常优选剖面反演推断,结合推测出7条深部隐伏断裂构造,旨在说明区内的深部隐伏控矿构造及形成了正磁异常,显示出深部具有较大的镍钴铁矿成矿潜力,为该区开展地质找矿工作提供较为可靠的地球物理依据。     

综合地球物理方法在坦桑尼亚卢帕金矿田东缘Twiga金矿勘查中的应用

综合地球物理方法对隐伏金属矿产勘查具有良好的指示作用,坦桑尼亚西南部的卢帕金矿田为该国重要的产金区,受限于前期地质勘查程度及第四系覆盖影响,该地区的成矿理论研究有待完善。以卢帕金矿田东缘Twiga金矿区为研究对象,通过在区内找矿有利地段开展地面高精度磁测、激电中梯剖面和EH4连续电导率测深等综合地球物理方法测量工作,得到了较丰富的平面ΔT磁异常、平面视极化率异常、平面和断面视电阻率异常、岩(矿)石物性参数等综合异常信息。以此圈定和标识了隐伏含矿构造体的规模大小,经后期钻孔施工得到了查证,区内预测金金属量3110.63 kg,结合区域成矿背景总结规律,为该地区今后的找矿工作提供地球物理方法经验。     

时间域激发极化法在内蒙古小牛群铜多金属矿的应用

隐伏矿床由于埋藏深度大,地下地质构造特征复杂,因此隐伏矿床的勘查不仅需要地质成矿理论的指导,还需要地球物理技术获得矿体的深部异常信息。本文介绍了激电中梯和激电测深在内蒙古小牛群铜多金属矿区的应用,激电中梯扫面可以快速高效的发现和圈定矿致异常,激电测深可以确定矿体的埋深和空间赋存状态。通过地质资料和钻孔查证,发现本地区中高极化率异常与铜多金属矿有良好的空间对应关系,为进一步在本地区进行铜多金属矿体的勘查提供参考和指导。     

大功率激电测量在冀北温家营—马家沟银多金属矿勘查中的应用

冀北温家营-马家沟银多金属矿区矿(化)体受NWW向断裂构造所控制,与硅化、高岭土化、褐铁矿化、黄铁矿化、方铅矿化、铁锰染关系密切,显示出高极化特征。因地表覆盖厚、深部找矿依据不足,未能很好地评估矿区找矿潜力。本次采用大功率激电中梯测量辅以激电测深对矿区进行了探索,圈定了多处高极化异常体,结合测深断面异常特征,查明了矿(化)体的赋存位置,明确了找矿范围。经钻探深部验证,发现了9条隐伏铅锌矿体及多条铅锌银矿化体,与异常部位对应吻合,表明激发极化法对本区寻找银多金属矿是行之有效的,可为类似矿区开展含硫化物银多金属矿勘查提供很好的借鉴。     

综合物探方法在青海祁连泽里镍钴矿勘查中的应用

祁连泽里地区基性—超基性岩较发育,具有形成岩浆型硫化物镍钴矿(化)体的地质条件。由于研究区地表覆盖较厚,本次工作结合区域地质、物化探特征,在其所圈定的镍钴成矿有利地段开展了以地面高精度磁测和激电中梯为组合方式的综合物探找矿应用研究。利用地面高精度磁测来圈定区内基性—超基性岩分布,研究其磁性特征、异常展布规模并配合激电中梯剖面测量成果,提出一套寻找超基性岩镍钴矿的方法组合。此次成果表明找矿方式效果显著,对同类地质成矿背景的隐伏镍钴多金属矿勘查工作具有一定的参考价值。     

Pollution of montane soil with Cu, Zn, As, Sb, Pb, and nitrate in Kanto, Japan

Soil cores and rainwater were sampled under canopies of Cryptomeria japonica in four montane areas along an atmospheric depositional gradient in Kanto, Japan. Soil cores (30 cm in depth) were divided into 2-cm or 4-cm segments for analysis. Vertical distributions of elemental enrichment ratios in soils were calculated as follows: (X/Al)_i/(X/Al)_BG (where the numerator and denominator are concentration ratios of element-X and Al in the i- and bottom segments of soil cores, respectively). The upper 14-cm soil layer showed higher levels of Cu, Zn, As, Sb, and Pb than the lower (14-30 cm) soil layer. In the four areas, the average enrichment ratios in the upper 6-cm soil layer were as follows: Pb (4.93) ≥ Sb (4.06) ≥ As (3.04) > Zn (1.71) ≥ Cu (1.56). Exogenous elements (kg/ha) accumulated in the upper 14-cm soil layer were as follows: Zn (26.0) > Pb (12.4) > Cu (4.48) ≥ As (3.43) ≥ Sb (0.49). These rank orders were consistent with those of elements in anthropogenic aerosols and polluted (roadside) air, respectively, indicating that air pollutants probably caused enrichment of these elements in the soil surface layer. Approximately half of the total concentrations of As, Sb, and Pb in the upper 14-cm soil layer were derived from exogenous (anthropogenic) sources. Sb showed the highest enrichment factor in anthropogenic aerosols, and shows similar deposition behavior to NO₃⁻, which is a typical acidic air pollutant. There was a strong correlation between Sb and NO₃⁻ concentrations in rainfall (e.g., in the throughfall under C. japonica: [NO₃⁻] = 21.1 [dissolved Sb], r = 0.938, p < 0.0001, n = 182). Using this correlation, total (cumulative) inputs of NO₃⁻ were estimated from the accumulated amounts of exogenous Sb in soils, i.e., 16.7 t/ha at Mt. Kinsyo (most polluted), 8.6 t/ha at Mt. Tsukuba (moderately polluted), and 5.8 t/ha at the Taga mountain system (least polluted). There are no visible ecological effects of these accumulated elements in the Kanto region at present. However, the concentrations of some elements are within a harmful range, according to the Ecological Soil Screening Levels determined by the U.S. Environmental Protection Agency.     

Determination of Co,Cu, Fe,Hg, Mn,Sb, Se and Zn in milk samples

Concentrations of Co, Cu, Fe, Hg, Mn, Sb, Se and Zn in IAEA milk (dry) standard A-11 were re-evaluated with the help of instrumental and radiochemical neutron activation analysis (NAA). The results show reasonably good agreement for Co (5.1 ± 0.55 ng/g) and Zn (34 ± 2.5 μg/g), in relation to the recommended values. For Cu (374 ± 15 ng/g), Fe (2.4 ± 0.34 μg/g) and Mn (250 ± 20 ng/g); the results obtained are lower than the reported values.Cu, Mn, and Zn were cross-checked by atomic absorption spectrophotometry (AAS). The results, Cu = 331 ± 27 ng/g, Mn = 302 ± 62 ng/g, and Zn = 35 ± 1 μg/g, fall within the range of mean values obtained by NAA.For Hg and Se, using instrumental NAA, only upper limits could be indicated; because of the low levels of concentrations of Hg and Se on one hand, and high content of P (9100 μg/g) in A-11 milk standard on the other, NAA coupled with radiochemistry is to be preferred for these two elements.In pooled human milk, in addition to Cu and Mn (radiochemical) and Co, Fe, Sb and Zn (instrumental), Hg and Se could also be determined non-destructively because of the favourable Hg/P and Se/P ratios in this matrix.     

ICP-AES法测定海水中钾、钠、钙、镁、锂、锶、锰

研究了采用等离子体发射光谱法(ICP-AES)测定海水中钾、钠、钙、镁、锂、锶、锰7种元素的方法。此方法标准曲线线性关系好,相对标准偏差3.35%,相对误差5.5%,加标回收率达90%～104.3%,有较高的测定精密度和准确度,干扰小,值得推广应用。     

Total arsenic, lead, cadmium, copper, and zinc in some salt rivers in the northern Andes of Antofagasta, Chile

Lake Velenje is located in one of the most polluted regions in Slovenia, the Salek Valley. The major source of pollution in the valley is the coal-fired thermal power plant in Sostanj (STPP, capacity 775 MW). It has five separate units. All units have electrostatic precipitators for fly ash removal. Unit 4 also has installed a wet flue gas desulfurisation system (FGD system). Total mercury (THg) concentrations were measured in lignite, slag and ash samples from the STPP. In flue gas, different mercury species (THg, MeHg, Hg2+, Hg0) were determined separately for unit 4 and unit 5 which use different flue gas cleaning technology. Mercury and methyl mercury (MeHg) concentrations were also measured in lake water at different depths, in inflow water, outflow water, rain, snow and lake sediments in order to establish the influence of the power plant on the lake. Most mercury emitted from the power plant is in the elemental form. The ratio between oxidised and elemental Hg depends on the flue gas cleaning technology. Mass balance calculations have been performed for the STPP. The results show that the major sources of mercury in Lake Velenje are wet deposition and lake inflows. Total and MeHg concentrations in the water column are very low and can be compared to other non-contaminated freshwater lakes in the world.     

Distribution, speciation, and transport of mercury in stream-sediment, stream-water, and fish collected near abandoned mercury mines in southwestern Alaska, USA

Concentrations of total Hg, Hg (II), and methylmercury were measured in stream-sediment, stream-water, and fish collected downstream from abandoned mercury mines in southwestern Alaska to evaluate environmental effects to surrounding ecosystems. These mines are found in a broad belt covering several tens of thousands of square kilometers, primarily in the Kuskokwim River basin. Mercury ore is dominantly cinnabar (HgS), but elemental mercury (Hg degrees) is present in ore at one mine and near retorts and in streams at several mine sites. Approximately 1400 t of mercury have been produced from the region, which is approximately 99% of all mercury produced from Alaska. These mines are not presently operating because of low prices and low demand for mercury. Stream-sediment samples collected downstream from the mines contain as much as 5500 microg/g Hg. Such high Hg concentrations are related to the abundance of cinnabar, which is highly resistant to physical and chemical weathering, and is visible in streams below mine sites. Although total Hg concentrations in the stream-sediment samples collected near mines are high, Hg speciation data indicate that concentrations of Hg (II) are generally less than 5%, and methylmercury concentrations are less than 1% of the total Hg. Stream waters below the mines are neutral to slightly alkaline (pH 6.8-8.4), which is a result of the insolubility of cinnabar and the lack of acid-generating minerals such as pyrite in the deposits. Unfiltered stream-water samples collected below the mines generally contain 500-2500 ng/l Hg; whereas, corresponding stream-water samples filtered through a 0.45-microm membrane contain less than 50 ng/l Hg. These stream-water results indicate that most of the Hg transported downstream from the mines is as finely-suspended material rather than dissolved Hg. Mercury speciation data show that concentrations of Hg (II) and methylmercury in stream-water samples are typically less than 22 ng/l, and generally less than 5% of the total Hg. Muscle samples of fish collected downstream from mines contain as much as 620 ng/g Hg (wet wt.), of which 90-100% is methylmercury. Although these Hg concentrations are several times higher than that in fish collected from regional baseline sites, the concentration of Hg in fish is below the 1000 ng/g action level for edible fish established by the US Food and Drug Administration (FDA). Salmon contain less than 100 ng/g Hg, which are among the lowest Hg contents observed for fish in the study, and well below the FDA action level.     

Levels of antimony,arsenic, cadmium,copper, lead,mercury, selenium,silver, tin and zinc in bone tissue of industrially exposed workers

The contents of the elements antimony, arsenic, cadmium, copper, lead, mercury, selenium, silver, tin and zinc in bone tissue from autopsy specimens of the femur of workers who had been exposed to a large number of metals in a smeltery and refinery in Northern Sweden as well as of a control group have been quantitatively assayed.The analytical techniques used were atomic absorption spectrophotometry, neutron activation analysis and particle induced X-ray emission analysis (PIXE) in a proton microprobe. Increased levels of lead in the bone tissue of exposed workers compared to a non-exposed control group were observed. The median level of lead in the group of exposed workers exceeded the corresponding value of the control group about 5 times.Using the proton microprobe in the PIXE-mode, concentration profiles of copper, lead and zinc were examined within the Haversian system of the bone samples.     

贵州安顺地区岩腊片区水淹坝岩溶内涝成因分析

水淹坝岩溶内涝是安顺市西秀区发育最大范围的岩溶内涝,严重制约了当地经济发展。本文以岩溶地下水系统为单元,通过开展1:10000水文地质调查、地球物理勘探、水文地质钻探等手段,查明内涝所在区的岩溶发育特征、水文地质条件。在此基础上分析得出,水力坡度小、岩层倾角缓造成地下河管道淤塞;人类工程活动使有水落水洞口堵塞,加之广阔的集雨面积和连续的强降雨是造成水淹坝岩溶内涝的主要原因。通过对水淹坝内涝成因分析,为岩溶内涝灾害综合整治提供参考依据。     

清华大学胜因院景观,北京,中国

<正>景观设计:清华大学建筑学院景观学系Landscape Design:Department of Landscape Architecture at the School of Architecture,Tsinghua University胜因院是清华大学教师住宅群之一,始建于1946年,曾有多位清华大学知名教授居住于此。60多年来,随着周围地势因建设而抬高,这里遂成为低洼地带,每逢暴雨便导致严重内涝。对这一颇具历史文化价值的地区进行改造,须将历史保护、     

Biomonitorization of cadmium, chromium, manganese, nickel and lead in whole blood, urine, axillary hair and saliva in an occupationally exposed population

Heavy metal contamination from occupational origin is a cause for concern because of its potential accumulation in the environment and in living organisms leading to long term toxic effects. This study was aimed to assess Cd, Cr, Mn, Ni and Pb levels in whole blood, urine, axillary hair and saliva from 178 individuals with occupational exposure to heavy metals. Levels of metal compounds were determined by atomic absorption spectrometry. We collected information on occupation, lifestyle habits and food intake by questionnaire. Multiple linear regression analyses for metal ion concentration in whole blood, urine, axillary hair and saliva were adjusted for age, gender, smoking and alcohol consumption, lifetime workplace exposure, residence area and food habits. Overall, blood and urine median concentrations found for the five metals analyzed do not exceed biological exposure indexes, so that they are very similar to a non-occupationally exposed population. Toxicokinetic differences may account for the lack of correlations found for metal levels in hair and saliva with those in blood or urine. For those heavy metals showing higher median levels in blood with respect to hair (Cd, Mn and Pb) indicating lesser hair incorporation from blood, the lifetime working experience was inversely correlated with their hair levels. The longer the lifetime working experience in industrial environments, the higher the Mn and Ni concentration in saliva. Axillary hair and saliva may be used as additional and/or alternative samples to blood or urine for biomonitoring hair Mn, and saliva Ni in subjects with occupational exposure.     

Spaces of resilience,ingenuity, and entrepreneurship in informal work in Ghana

Despite playing an important role in the economies of low-income countries, there is a perception that informal markets are haphazard and disorganized. Using in-depth interviews conducted in Accra, Ghana, this study examines the strategic choices that market women pursue to gain access to and thrive in informal working spaces and ensure long-term survival. The findings reveal that entry into the informal working spaces is contingent on women’s ability to forge and nourish ties with acquaintances, kinsmen and middlemen. Further, the study found that in contrast to the notion of unregulated competition typically associated with street vending, market relations among women traders in informal market spaces are marked by alliances between rival sellers that transcended religious, ethnic, linguistic, and generational divides. As well, a strict code of conduct governs market behaviour, underpinned by an ethos of cooperation and mutual assistance among rival sellers. Furthermore, market women in Accra articulate the rationale behind informal entrepreneurship in ways that align with local and national development agenda. In so doing, the market women lend legitimacy to their trade, demand accountability from local authorities, and oppose repressive practices by the state. We highlight the implications of our findings for city planning and development.