共查询到20条相似文献，搜索用时 15 毫秒
1.
Integrated surface electrical resistivity and electromagnetic (EM) surveys were conducted in a hard-rock terrain of Southwestern
Nigeria in the vicinity of active oxidation sewage treatment ponds. The aim was to detect soil contamination due to the spread
of sewage effluent, locate possible leachate plumes and conductive lithologic layers, and access the risk of groundwater pollution
in the vicinity of the sewage-ponds. Dipole–dipole resistivity profiling and very low frequency (VLF) data were acquired at
10-m intervals along five 200-m long east-west geophysical traverses. Resistivity sections obtained revealed four subsurface
geologic layers comprised of lateritic clay, clayey sand/sand, weathered/fractured bedrock, and competent bedrock. A distinct
low resistivity zone corresponding to the contamination plume (labeled B) was delineated from all the resistivity sections.
This low zone extends into the weathered bedrock and possibly suggests contamination of this layer. The filtered real component
of the processed VLF data detected three distinct anomaly zones that are representative of fractured zones filled with conductive
fluids and/or lithologic boundaries that possibly serve as conduits for the movement of contaminated effluents. The results
obtained from the two methods suggest possible contamination of the subsurface soil layers and groundwater in the vicinity
of the sewage-ponds. The existence of this contaminated plume poses a serious threat to the ecosystem and health of the people
living in the vicinity of the sewage-ponds. 相似文献
2.
The distribution and concentration of metals and metalloids in the floodplain of the Clark Fork River of western Montana, USA, are mainly controlled by post-depositional diagenetic mechanisms of metal fractionation. Due to the influx of wastes into the river's headwaters from mining processes around the turn of the century, extensive amounts of contaminated material were deposited onto the floodplain. Tailings were deposited as widespread overbank deposits and point bars adjacent to abandoned channels, and are characterized by orange and gray mottled sediment, which is devoid of vegetation and covered by a blue metal sulfate precipitate during dry periods. Examination of stratigraphic profiles of floodplain sediment indicates three periods of deposition: 1) pre-mining, represented by coarse sand and organic overbank deposits under reducing conditions; 2) syn-mining, characterized by transition sediments and tailings deposits under oxidizing conditions; and, 3) post-mining, distinguished by grass-bound topsoil.Sites were established where sediments and water throughout the stratigraphic section were collected and analyzed. Chemical analyses indicate enriched concentrations of cadmium, copper, manganese, and zinc in sediments and porewater, and arsenic in groundwater, in areas contaminated by tailings deposits. Vertical trends in concentrations of metals show that they are distributed based on apportionment of metal phases between reducing-oxidizing environments and pH fluctuations. 相似文献
3.
Abstract. Magnetotelluric (MT) surveys were carried out around the Muine volcano, Hokkaido, Japan, where it is expected that the heat and metal source forming the polymetallic Ag-Pb-Zn-Cu-In Toyoha deposit is present at depth. Measurements were performed at 20 sites, 18 of which were located along a WSW-ENE profile traversing the north ridge of Mt. Muine. A resistivity model obtained from 2D inversion of the MT data shows subsurface specific conductive and resistive features. Conductive layers are present at the surface of Mt. Muine. The low resistivity is probably due to the clay-rich rocks associated with the hydrothermal alteration. A high resistivity layer, which corresponds to the pre-Tertiary Usubetsu Formation, crops out east of Mt. Muine and dips westward. At the west foot of Mt. Muine, relatively high resistive layers are widely exposed. The resistivity increases with depth and exceeds 1000 ohm-m. This fact indicates that this region is not influenced by the recent hydrothermal activity. An extremely conductive zone about 3–6 km wide and 6–9 km thick exists at a depth of 2 km below Mt. Muine. This zone mostly corresponds to an elastic wave attenuation zone detected by a seismic survey. It is interpreted as a large hydrothermal reservoir or melted magma, which is a heat source of the hydrothermal system in this area. 相似文献
4.
Sustainable mineral resources management: from regional mineral resources exploration to spatial contamination risk assessment of mining 总被引：3，自引：0，他引：3
Wide-spread environmental contamination associated with historic mining in Europe has triggered social responses to improve
related environmental legislation, the environmental assessment and management methods for the mining industry. Mining has
some unique features such as natural background contamination associated with mineral deposits, industrial activities and
contamination in the three-dimensional subsurface space, problem of long-term remediation after mine closure, problem of secondary
contaminated areas around mine sites, land use conflicts and abandoned mines. These problems require special tools to address
the complexity of the environmental problems of mining-related contamination. The objective of this paper is to show how regional
mineral resources mapping has developed into the spatial contamination risk assessment of mining and how geological knowledge
can be transferred to environmental assessment of mines. The paper provides a state-of-the-art review of the spatial mine
inventory, hazard, impact and risk assessment and ranking methods developed by national and international efforts in Europe.
It is concluded that geological knowledge on mineral resources exploration is essential and should be used for the environmental
contamination assessment of mines. Also, sufficient methodological experience, knowledge and documented results are available,
but harmonisation of these methods is still required for the efficient spatial environmental assessment of mine contamination. 相似文献
5.
Mohamed Metwaly Mohamed Ahmed Khalil El-Said Al-Sayed Abeer El-Kenawy 《Arabian Journal of Geosciences》2013,6(9):3527-3533
This study provides an evaluation of the subsurface oil contaminant flow in an oil production field at the Wadi Feiran fan, along the Gulf of Suez, Egypt. The 2D electrical resistivity tomography technique has been applied along four profiles surrounding the spill location of oil dump site. Theoretical soil resistivity response versus fluid resistivity for different cation exchange capacity values has been studied. Then, a physical model for the current situation of flowing the oil over the groundwater (sea invaded water) of saturated fluvial sediments has been introduced. It was supposed that the crude oil has higher resistivity values and turned to be conductive far away from the oil spill source under the effect of microbial biodegradation. Such conditions of contaminated distribution and its resistivity values have been considered during the inversion and interpretation of the acquired data sets. The processed 2D resistivity profiles reveal that oil plumes are accumulated in the seawater invasion direction, whereas it has low signatures along the profiles parallel to the shore line. 相似文献
6.
Mound springs provide the primary discharge mechanism for waters of the western margin of the Great Artesian Basin (GAB), Australia. Though these springs are an important resource in an arid environment, their hydraulics as they discharge from shale are poorly defined. The springs can include extensive spring tails (groundwater-dependent wetlands) and hundreds of springs in a given spring complex. Electrical resistivity imaging (ERI) was used to evaluate spring subsurface hydraulic-connectivity characteristics at three spring complexes discharging through the Bulldog Shale. The results demonstrate that fresher GAB water appears as resistors in the subsurface at these sites, which are characterized by high-salinity conditions in the shallow subsurface. Using an empirical method developed for this work, the ERI data indicate that the spring complexes have multiple subsurface connections that are not always easily observed at the surface. The connections are focused along structural deformation in the shale allowing fluids to migrate through the confining unit. The ERI data suggest the carbonate deposits that the springs generate are deposited on top of the confining unit, not precipitated in the conduit. The data also suggest that spring-tail ecosystems are not the result of a single discharge point, but include secondary discharge points along the tail. 相似文献
7.
This research is an attempt to accomplish a 3-D resistivity imaging survey, which was carried out near a water well contaminated with hydrocarbon materials in Karbala governorate. Two-dimensional resistivity imaging measurements were collected along four parallel profiles, using a Wenner array with electrode spacing of 1 m. The RES3DINV program was used to invert the apparent resistivity data. The results displayed a resistivity distribution of the subsurface in a three-dimensional volume. Thus, both the horizontal and vertical extents of the contaminated zone were displayed. This technique revealed a low resistivity zone at depth ranges from 3 to 6 m in the investigation area, but the seepage starts at depth ranges between 2 and 3 m and continues down depth (may be to the groundwater level). This low resistivity zone is the most likely location for a subsurface seepage of contaminated water. It is clear that the sufficient measurement points along 2-D lines in a small area can increase the 3-D imaging resolution, and nearly real 3-D imaging can be achieved, when the size of subsurface anomaly compared with the electrode spacing (a) of the Wenner array is taken into consideration. 相似文献
8.
黔东镇远地区早寒武世清虚洞组潮坪风暴沉积特征及古地理意义 总被引：2，自引：2，他引：0
东镇远地区早寒武世（相当于2008国际地层年表中的寒武纪第二世）清虚洞组发现类型丰富、特征典型的风暴沉积标志。侵蚀底面、粗粒滞留沉积、粒序层、波状层理、韵律层理等沉积组构明显,而丘状层理不发育。通过对金盆剖面和溜沙关剖面详细的野外观察及室内分析,识别出三种类型的风暴沉积序列。研究区风暴沉积的背景沉积为灰色纹层状灰岩,见波状层理、鸟眼构造等,指示潮坪环境。综合分析得出,镇远地区的风暴沉积属于潮坪风暴沉积。这丰富了湘西黔东地区早寒武世清虚洞组风暴沉积的类型。风暴沉积的发现也为研究区早寒武世位于赤道附近的低纬度区域提供了间接的证据。 相似文献
9.
黑牛洞矿床中的石榴石有三个期次:早期的石榴石呈顺片理拉长的条带,中期的石榴石呈颗粒碎块发育,硫化物常沿早期和中期的石榴石的裂隙和颗粒边缘填充,晚期石榴石呈完整细粒变晶产出。本文测得晚期石榴石的Sm-Nd年龄为101±26M a(初始143Nd/144Nd=0.511765±0.000025),其可能代表黑牛洞矿床最后一期中高级变质作用的时代,与形成富矿体的脆韧性变形作用同期。 相似文献
10.
Abstract: The gold content in siliceous deposits formed from geothermal waters at the Hatchobaru geothermal power station in central Kyushu, Japan, was determined by inductively coupled plasma quadrupole mass spectrometry (ICP–MS). It ranges from 1.3 to 4.6 mg/kg. The highest gold content was obtained from the siliceous deposit formed from acidic waters. In this siliceous deposit, hydrous iron(III) oxide of amorphous state is a major constituent, suggesting that hydrous iron(III) oxide might play an important role when gold is concentrated into siliceous deposits formed from acidic and iron-rich geothermal waters. 相似文献
11.
推荐系统算法是大数据挖掘的重要技术之一。根据钦杭成矿带南段文地幅1∶5万地质矿产调查所获得的数据,研究选取中型银金矿床、小型银金矿床(点)、确证无银金矿床、未评价区域(针对银金矿床)、中型铅锌矿床、小型铅锌矿床(点)、确证无铅锌矿床、未评价区域(针对铅锌矿床)作为待预测的能动项,选取加里东期混合岩、燕山早期侵入岩、燕山晚期侵入岩、北东向断裂、北西向断裂以及Au、Ag、Pb、Zn元素作为因素项,运用基于内容的推荐系统算法,构建能动项-因素项的效用矩阵,计算已知矿床(点)与其他未评价区域之间的相似度,进而预测银金矿床和铅锌矿床潜在的找矿区域。实验结果表明,推荐系统算法能够较好地挖掘与成矿有关的信息,快速抓取出与某类矿床(点)相似的潜在成矿区域。对于银金矿床,相似度较高的区域主要分布在已知矿点周围以及北东向断裂的两侧,少量分布于叠加断裂附近。对于铅锌矿床,中型铅锌矿床的结果显示出较高的区分度,高值区基本涵盖了所有已知的铅锌矿点,小型铅锌矿床的结果更加集中。除已知矿点外,还有几处高值区可作为重点的找矿靶区。 相似文献
12.
马达加斯加Antanisoa石墨矿床成因分析 总被引：1，自引：0，他引：1
马达加斯加是世界优质大鳞片石墨矿重要产地之一,随着大鳞片石墨在诸多新兴领域发挥着越来越大的作用,对马达加斯加石墨矿床的研究显得越来越重要。矿床成因研究对石墨矿床的找矿勘查具有指导作用,然而目前关于马达加斯加石墨矿床的研究程度较低,人们普遍认为马达加斯加的石墨矿床是沉积变质成因。文章将Antanisoa石墨矿床作为研究对象,通过对矿区内石墨片岩的岩相学研究以及矿物化学特征研究,发现沉积变质成因的说法并不妥当。野外地质调查和岩相学研究显示出较多与流体充填有关的现象,矿物化学特征表明石墨片岩中与石墨共生的云母为金云母,浅色电气石为镁电气石。结合前人对马达加斯加岛地质背景研究结果与认识,认为马达加斯加Antanisoa石墨矿床更有可能与幔源流体充填有关,有待进一步研究。 相似文献
13.
华北克拉通北缘是中国重要的金成矿带之一,分布着数十个大中型金矿床,但这些矿床的形成时代及成因类型尚存争议。位于内蒙古赤峰市境内的金厂沟梁是该带最为重要的大型金矿床,其与二道沟和长皋沟金矿床围绕130～122Ma的西对面沟岩体分布。该矿床矿体呈脉状产出,矿脉多赋存在太古代变质岩中,少量产于安山玢岩中,在矿区南部可见矿脉被粗面安山岩切穿,指示成矿发生在安山玢岩之后,粗面安山岩之前。两套岩浆岩的锆石LA-ICP-MS U-Pb定年结果揭示,岩浆结晶年龄分别为129.4±0.9Ma和124.0±0.5Ma,限定金厂沟梁金矿床成矿作用发生在129～124Ma之间,与西对面沟岩体侵位年龄一致,暗示两者具有成因关系,也反映矿床形成于早白垩世中国东部大规模岩石圈减薄的陆内伸展环境。 相似文献
14.
芬兰科密铬铁矿床是欧洲规模最大的铬铁矿床。对该矿床的地质背景、矿床特征、矿床成因及找矿标志进行了总结。结果表明,该矿床与古元古代层状超镁铁质杂岩体具有密切的时空分布关系,杂岩体内的铬铁矿床具典型的层状堆积特征,矿层延伸稳定。由于Cr/Fe值较低,该矿床矿石品位在世界同类矿床中属偏低水平。同位素年代学证据表明,其形成于古元古代早期(2.44 Ga),是由卡累利阿造山作用诱发多期次岩浆侵入活动并与新太古代基底岩层发生混染作用形成的。科密铬铁矿床属于层状铬铁矿床,其地质特征与中国目前已发现的豆荚状或似层状铬铁矿床存在一定区别。 相似文献
15.
Geophysical surveys were carried out in an arsenic contaminated area, in the Ron Phibun District in southern Thailand. Here, tin and associated minerals, i.e. arsenopyrite and pyrite, have been extracted from granites and natural processes and the mining activities led to arsenic contamination in the environment. Electrical resistivity and self-potential (SP) were used to define the distribution of arsenic contamination in the groundwater. Resistivities of 25–100 Ωm and a positive SP anomaly of 66.0 mV were observed in an area where the arsenic content in auger water at 3.5–5.0 m depths was high, 0.5–5.0 mg/l. Integrated interpretation of resistivity, seismic refraction, GPR and gravity data gave a clear image of subsurface shallow structures (< 30 m depths). There was a good correlation between the resistivity and the gravity data. A subsurface rise was found, which possibly acts as a naturally buried dam, separating a high-contaminated area from a low contaminated area. 相似文献
16.
17.
合峪萤石矿矿集区是河南省萤石矿田相对最集中的地段。近年来,多个地勘单位对周边十多个萤石矿权在进行勘查,共提交CaF2矿物量1000万吨以上。本文从该区萤石矿的成矿地质背景、赋矿岩性特征、成矿构造特征分析入手,详细论述不同方向的构造对萤石矿体的控矿作用。研究认为NW向断裂为区域的主要控矿构造及容矿构造,占区域萤石矿资源量的80%,其次是NE向断裂在马丢矿区形成了规模巨大的萤石矿床,并对萤石矿体沿走向、倾向的赋存特征、矿石质量特征进行论述,指出断裂构造破碎带和合峪花岗岩基的出露区及其内外断裂构造破碎带中硅化、绢英岩化和玉髓化等蚀变特征是找矿的直接标志。通过对比鱼池岭钼矿床的矿床特征,初步总结了萤石矿成矿地质背景,为在该区开展萤石矿找矿指明靶区和方向。 相似文献
18.
可可塔勒铅锌矿床位于阿尔泰山南缘麦兹盆地,是新疆目前发现的最大的铅锌矿床之一。在该矿区部署了2条二维测线,开展了大回线源瞬变电磁数据采集和处理,试图根据所观测的电磁异常圈定深部矿体。对异常解释的钻探验证结果显示,反演结果的低阻异常与实际矿体对应很好,电阻率的空间分布特征与矿体在深部的延伸与地层倾向一致,为该矿区资源潜力评价提供了依据,也是在其它矿区开展类似深部勘探的借鉴。 相似文献
19.
张家口北部已发现的铅锌银多金属矿床在成因上多与浅成中酸性侵入岩关系密切。张家口南部中上元古界碳酸盐岩地层分布广泛,目前已在其中发现了梁家沟、火石沟、常庄子等多处铅锌银多金属矿床(点)。赋矿围岩以蓟县纪高于庄组、雾迷山组白云岩为主。与张家口北部已发现的多金属矿床相比,赋存于白云岩中的多金属矿床在矿区范围内浅成中酸性侵入岩体不发育。此外,在矿体形态、矿石组构、矿床地球化学等方面均与已发现的与浅成酸性岩体有关的多金属矿床存在较大差异。文章以梁家沟多金属矿床为例,在矿床和矿石宏观地质特征的基础上,结合矿石Pb、S、Rb、Sr等同位素测试结果,认为成矿物质来源以白云岩围岩和下覆地层为主,矿床的形成与区内大规模逆冲推覆构造有关,矿床成因属密西西比河谷型(MVT)矿床。 相似文献
20.
广东省大宝山矿床是南岭成矿带唯一的大型铜多金属矿床，此次研究在矿区中南部发现了细脉浸染状铜矿的新类型。为确定其是否为斑岩型铜矿的成因类型，本文在梳理南岭成矿带铜成矿条件和成矿规律的基础上，查明了矿区中南部英安斑岩的蚀变和铜矿化特征。综合研究认为南岭成矿带早侏罗世中酸性斑岩的小岩体较多，叠加多期断裂构造和碳酸盐岩建造，非常有利于铜多金属成矿物质的运移、富集。大宝山英安斑岩发育黑云母化、钾长石化、青磐岩化、绢英岩化、泥化等蚀变类型，铜矿化与绢英岩化、绿泥石化关系密切。大宝山铜矿中的英安斑岩沿逆冲推覆构造侵位并呈岩墙状产出，冷却过程中受区域构造应力产生了一组平行裂隙，岩浆房去气作用排出的热液沿裂隙蚀变围岩并充填成矿。大宝山斑岩型铜矿取得的找矿勘查成果表明，“全位成矿，缺位找矿”理念可以有效指导靶区圈定和老矿山外围（深部）找矿勘查，早侏罗世的南岭具有形成较大规模斑岩型铜矿的条件。 相似文献