Application of integrated geoelectrical methods in Marand (Iran) manganese deposit exploration

This paper addresses the application of integrated geoelectrical methods including induced polarization (IP), resistivity (RS), and self-potential (SP) for exploration and evaluation of the Marand (Iran) manganese deposit. The SP method was used for reconnaissance, in which five profiles were designed and surveyed with a reference electrode that was placed in a distance of at least 800 m far from the measurement points. For the conduct of RS and IP, a new array proposed by Ramazi (2005a), named combined resistivity profiling and sounding (CRSP) was used along nine profiles that made it possible to do sounding survey and produce apparent resistivity pseudo-sections. Some anomalies were detected by means of SP surveys along the profiles and some other were located from IP and RS pseudo-sections, and there was good consistency between anomalies detected by IP and RS and SP method. To check the efficiency of CRSP and in comparison with dipole–dipole array, in the location of profile no. 6, a profile with the dipole–dipole array was designed and surveyed. Finally, by integration of the results from the geoelectrical methods, some locations were suggested for borehole drilling. After drilling in those locations, cores were studied and compared with the results obtained from the geoelectrical methods that resulted in confirmation of the geoelectrical findings. The results obtained by the CRSP array have a match better than the drilling results.     

Investigation of a shallow alluvial aquifer using geoelectrical methods: a case from Turkey

Near-surface geophysical methods are commonly used to solve a wide class of geological, engineering and environmental problems. In this study, a geoelectrical survey was performed to investigate an alluvial aquifer. The study area is located in the southwest of the Çubukluda? graben, situated in the south of ?zmir, Turkey. The geophysical studies included the electrical resistivity imaging and self-potential (SP) methods. The resistivity data were acquired along eight profiles in the northern part of the study area by a Wenner-Schlumberger electrode configuration and the data processing was achieved by a tomographic inversion technique. The SP data were collected by gradient technique along 16 profiles. Total field values were calculated for each profile by addition of the successive gradient values, then a total field SP map was obtained. The water-saturated zone in the northern part of the study area was clearly revealed by the electrical resistivity imaging and the SP survey yielded useful information on the subsurface fluid movement.     

辽东白云金矿区深部地质结构的瞬变电磁法探测

白云金矿床位于华北克拉通东北部辽东青城子矿集区,具有深部找矿潜力.为寻找白云金矿区深部及外围矿体,应用大功率瞬变电磁系统开展了白云矿区含矿地层和控矿构造的勘查.野外数据采集采用中心回线和大回线2种装置.大发射磁矩（7.2×106A·m2）和低发射基频（5 Hz）保证了高数据质量和长的有效观测时间,从而加大探测深度.研究区地层主要为大石桥组三段和盖县组.大石桥组三段总体电阻率较低,主要由透辉透闪片岩和含石墨大理岩引起.盖县组主要成分为片岩和变粒岩,属中高电阻率.研究结果表明瞬变电磁法可以有效探测大石桥组三段和盖县组的分布以及其中发育的褶皱和断裂.3条瞬变电磁测线反演结果表明,白云金矿西部受到较大挤压,形成明显的推覆构造,而白云矿床东部褶皱平缓,挤压相对较弱.      

利用多源大功率充电法定位复杂岩溶含水通道的方法

由于地下发育的岩溶形态空间分布存在不均匀性,导致地表地质调查很难确定地下岩溶含水通道的位置;而一般的地球物理方法受地形或地质条件的限制,在对岩溶含水通道进行探测时存在多解性,往往需要几种物探方法综合判断。本文尝试利用大功率充电法对岩溶含水通道进行快速准确的定位,并通过布设多个充电点来验证异常的可靠性;在布设测线的同时布设以充电点为圆心的弧形测线和平行直线测线,分析对比其优缺点;在数据分析之前分别对数据进行正常场改正和Fraser滤波处理。通过利用多源大功率充电法对洛潭水库复杂岩溶含水通道进行探测后发现：该方法可以快速准确地定位测区内岩溶含水通道的位置及走向,其中弧形测线能够更好地控制整个测区岩溶含水通道的走向,经过正常场改正和Fraser滤波处理后的平行直线测线观测结果也能很好地对异常进行定位;而“多源”观测能更好地甄别有效异常。经钻探及示踪法验证,该方法的探测结果是准确可靠的。     

激发极化法在新疆奇台县岩浆岩型石墨矿中的应用

石墨矿相对于围岩物性特征更加独特,主要呈低阻高极化特征。依据石墨的独特物性条件,奇台黄羊山岩浆岩型石墨矿与围岩明显的物性差异,对黄羊山一带石墨矿勘查布设了激发极化法物探测量方法,通过与地质、槽探、钻探等方法的相互验证、补充,取得了重大勘探成果,突破了亿吨级资源储量类别。激发极化法在黄羊山石墨矿勘查边界圈定及深部资源推断中得到了很好的应用。通过对奇台黄羊山石墨矿激电测量的应用与研究,在大面积、埋藏较深的石墨矿勘查中,运用时间域激电及等距对称四极测深装置测得的视极化率(ηs)、通过反演计算取得的视电阻率(ρs)等主要参数,结合石墨矿体的实际产状确定矿体空间位置,以此准确判定矿体分布范围,为下一步地质工作、资源储量预测和工程布设指明方向。     

综合物探在柴达木盆地盐湖深层卤水钾矿勘查中的应用

青海省柴达木盆地是著名的钾肥生产基地,也是中国盐类矿产的主要产地.以往盐类矿产勘查主要针对第四纪浅部盐类矿产,对第四纪深部及古近纪-新近纪卤水钾矿工作程度较低,资源勘查情况不明.由于盐湖区浅部卤水矿化度较高,会对电阻率类方法造成严重的低阻屏蔽效应,从而影响其探测深度,对于应用地球物理方法造成了极大的局限性.为查明该区深部卤水钾矿资源情况,采用对低阻异常敏感、信号强度大、纵横向分辨率高的瞬变电磁法（TEM）,并结合勘探深度较大的大地电磁测深法（MT）对深层卤水钾矿进行探测.勘查结果识别出了相对低阻异常区,经后期钻孔验证,显示探测结果较为可靠,表明TEM、MT两种物探方法应用于盐湖区深层卤水钾矿探测是有效的,揭示了TEM、MT综合物探方法在盐湖区探测深层钾盐资源的良好应用前景.     

物探方法在复兴屯银铅锌多金属矿区构造与成矿机理研究中的应用

复兴屯银铅锌多金属矿是近两年在大兴安岭成矿带中生代陆相火山盆地里首次发现的特大型银铅锌多金属矿床。在矿床普查与勘查期间开展了地面高精度磁测、时间域激发极化法面积性测量、AMT电磁测深等物探方法,发挥了重要指导作用。①通过地面磁异常数据RGIS软件处理解释判定了普查区构造构局;②综合利用地磁异常和视电阻率异常特征,结合地表出露岩性判定了破火山口断陷盆地位置;③利用激电测深判定了断陷盆地形成过程与构造特征及断裂构造的多期次与硫化物沉淀的多期次性;④依据视极化率异常特征,结合地质构造环境判定了场源性质和成矿物质来源;⑤利用AMT电磁测深资料圈定了筒状次火山岩侵入体。本文在上述研究结果和钻探基础上,还研究了该矿床形成机理,给出了一套寻找该类矿床的物探方法应用思路。     

断层破碎带综合地球物理找水模式——以干田坝村探采结合井为例

乌蒙山贫困缺水区水资源严重缺乏,找水需求大、难度大。为确定了ZK12探采结合井位置,本文首先分析了工区找水环境因素的地层时代、含水介质类型、构造背景、水源条件和水动条件等5个条件;其次,对富水特征的含水岩组、蓄水构造和富水地貌进行研究;最后,重点分析地球物理特征找水因素,介绍了视电阻率联合剖面法、大地电磁测深法、瞬变电磁法、激电测深和地球物理测井等“多方法”应用效果,通过视电阻率、视极化率、衰减度、半衰时等“多参数”,确定断层裂隙水的地球物理特征,建立由浅入深的“多层次”地球物理模式。最终,创新性提出了乌蒙山连片贫困缺水区重点村镇的“多方法、多参数、多层次”地球物理找水模式,克服单一物探方法找水的局限性,精准定井位,对地下水勘查起到示范作用。      

利用综合物探方法探测地下水流通道

尽管充电法需要充电点,但对已知进口或出口的浅埋藏地下水流通道,追踪其走向,该法具有简单、直观、快速的优点.自然电位法对隐伏的地下流体表现突出,但干扰异常多,不易分辨.充电法和自然电位法均可对异常进行定性判断,但不能很好确定地下水流通道的空间分布特征.高密度电法可获得近地表较为精细的空间电性分布.对断层控制下形成的地下水流通道,宜采用浅层地震反射法.当场地受限,探测深度大,需要精细探测时,可采用跨孔电磁波透视.但高密度电法、浅层地震反射法、跨孔电磁波透视法不能对异常进行定性判断.结合探测实例,考虑不同的地质条件和探测成本,对如何选择最佳的组合方法来探测地下水流通道,确定异常性质及其空间分布特征进行了探讨.     

综合物探技术在北京山前平原隐伏断层探测中的应用

复杂地质隐伏断层探测是地球物理勘测难点之一。本文介绍了高密度电法、浅层地震反射波法、可控源音频大地电磁测深法在北京山前平原隐伏断层综合探测的应用。在北京山前平原复杂地形条件下,综合物探技术方法对隐伏断层的探测具有可靠和成果直观的特点。     

安徽泥河玢岩铁矿电磁法探测试验

玢岩铁矿是我国重要的铁矿床类型之一,主要产出在富钠质的安山玢岩和闪长玢岩内或接触带中,由于其围岩多为火成岩,给常规的地球物理探测造成诸多影响,很难确定矿体位置及产状,找矿难度较大。电磁法具有勘探深度大、分辨率高等特点,是探测玢岩铁矿可能的重要手段,为评估电磁法在玢岩铁矿探测中的应用效果,作者在物性统计的基础上,结合已知地质资料,构建了玢岩铁矿理论电性模型,通过模型正演及反演,探讨了音频大地电磁、可控源音频大地电磁、瞬变电磁和复电阻率法刻画玢岩铁矿的分辨率和效果。在此基础上,以安徽省泥河铁矿为例,开展了4种电磁法探测试验,获得了泥河铁矿区三维电性结构模型,该模型反映了地层、岩体、构造的基本信息,虽然不能直接指明矿体位置,但是通过圈定闪长玢岩岩体隆起范围,为找矿工作提供了重要线索。试验结果表明,高质量的数据采集、精细的数据处理和有效的反演方式,是电磁法寻找玢岩铁矿重要保障,泥河铁矿的电磁法探测实例可以为长江中下游玢岩铁矿找矿工作提供指导。     

Geoelectrical Schlumberger investigation for characterizing the hydrogeological conditions using GIS in Omalur Taluk,Salem District,Tamil Nadu,India

The increasing demand for freshwater has necessitated the exploration for new sources of groundwater, particularly in hard rock terrain, where groundwater is a vital source of freshwater. A fast, cost effective, and economical way of exploration is to study and analyze geophysical resistivity survey data. The present study area Omalur taluk, Salem District, Tamil Nadu, India, is overlain by Archaean crystalline metamorphic complex. The study area is a characteristic region of unconfined aquifer system. The potential for occurrence of groundwater in the study areas was classified as very good, good, moderate, and poor by interpreting the subsurface geophysical investigations, namely vertical electrical soundings, were carried out to delineate potential water-bearing zones. The studies reveal that the groundwater potential of shallow aquifers is due to weathered zone very low resistivity and very high thickness and the potential of deeper aquifers is determined by fracture zone very low resistivity and very high thickness area. By using conventional GIS method, the spatial distribution maps for different layer (top soil, weathered zone, first fracture zone, and second fracture zone) thicknesses were prepared. The geoelectrical approach was successfully applied in the study area and can be therefore easily adopted for similar environments.     

高密度电法在岩溶路基勘察中的应用

高密度电阻率法勘探以其生产成本低,工作效率高等特点,在工程地质勘察中得到了广泛的应用。高密度电法采取较密集的测点以及多种装置的组合同时测量,可提供丰富的地电信息,有利于数据资料的处理与解释。这里在分析高密度电阻率法所基于的静电场理论的基础上,归纳溶洞、滑坡、断裂等地球物理特征,结合某高速公路的高密度电阻率法勘探资料,给出了不同地电模型的异常分布情况,提出了一些提高探测能力和解释精度的数据处理分析方法。通过实例证明,这些方法的正确性以及在实际应用中的良好效果,充分展现出了高密度电阻率法在当今工程地质勘察中所发挥的重要作用和优越性。     

新疆小热泉子铜矿物探异常特征及找矿效果

通过在小热泉子矿床开展高精度重力、激发极化面积性测量和高密度相位激电测深,对其物探异常特征进行分析解释,推断异常性质.经钻探工程验证,发现矿体与中高剩余重力、高极化率、中低电阻和高(负值)视相位异常对应较好.     

AMT在印尼某铁矿区勘查中的应用

以印尼某铁矿区为例,说明AMT法寻找隐伏铁矿的有效性。配合磁法,利用AMT法的低阻体圈定隐伏磁铁矿,为钻孔设计及矿山开发提供了物探依据,在国际化的商业勘查中取得了良好的勘探效果。     

电成像与浅层地震联合在浅覆盖区隐伏断层探测中的应用

为了避免单一物探方法在地质反演解释中存在的多解性弊端,本文介绍了以电成像法为主、浅层地震反射波法为辅的综合物探方法对隐伏断层进行探测的应用实例,首先,通过电成像法查找断层破碎带的位置走向,然后利用浅层地震反射波法精确查明断层的产状、性质、位置及断距等地质参数,并对两种方法的探测成果进行综合对比分析,推断该隐伏断层为走向近东西向,倾向近南北向的正断层,断层落差约4.2m,其上断点埋深约17.9m。经钻孔验证表明,电成像与浅层地震联合方法在浅覆盖区隐伏断层探测中具有精确、可靠、经济的优势,该方法具有较强的应用价值。     

Electrical methods of detecting contaminated groundwater at the stringfellow waste disposal site,riverside county,California

At the Stringfellow Class I waste-disposal site near Riverside, California, the influence of variations in groundwater chemistry and saturation on electrical measurements made from the surface was tested Spontaneous potential, D C electrical sounding, dipole-dipole resistivity profiles, and mise-a-la-masse measurements were employed to investigate the sub-surface migration of the acidic fluids deposited in this site between 1956 and 1972 Mise-a-la-masse exploration conducted at the downstream edge of the site detected a major anomaly which, on excavation, proved to be the signature of a previously unsuspected leak from the surface disposal ponds on the site Downstream from the site, a dipole-dipole profile and electrical soundings correlate well with electrical conductivity of groundwater obtained from monitoring wells This study demonstrates that geophysical methods may be used to search for and map leaks from toxic chemical waste dumps     

多种物探方法在湘潭城区活断层勘探中的应用

杨梅洲木鱼湖断裂位于湘潭城区,要查明其位置和性质,地球物理勘探干扰因素多,施工条件不好。调查中分别采用天然电场选频法、高密度电阻率法和地质雷达等方法进行勘探,并通过开挖等方式进行验证,3种物探方法各有特点:天然电场选频法仪器轻便、勘探线布置灵活,干扰因素较少,工作效率高,特别是利用其动态信息确定断层平面位置准确;高密度电阻率法勘探结果比较直观,特别是对断层性质的确定形象,但勘探布极的工作量较大,受地形等因素影响较大,在城区很多地方无法正常开展工作;地质雷达勘探成果形象直观,但设备成本高,勘探受地形等因素影响大,勘探深度有限,一般对表层效果较好。     

图形图像处理方法图示航空物探数据的有效性研究

本文在介绍航空物探微机图形图像处理系统的基础上，通过不同地区实测航空物探资料的处理，对用图形图像处理技术处理和图示航空物探数据的有效性进行了探讨。总结出适用于地质填图、突出局部弱异常及与矿化有关的弱信息等不同地质任务的有效方法组合。分析了各种航空物探图示方法的特点，并就如何发挥图形图像处理技术在航空物探资料的解释处理中的作用提出了建议。认为图形图像处理技术是一种图示航空物探数据的有效方法，可以作为等值线图的补充和改进形式推广应用。     

地球物理勘探新方法技术及应用

介绍了物探工作的新仪器设备、处理软件以及一些新方法新技术，列举了物探方法在资源、环境与工程领域中的应用实例。重点在金属矿方面的应用。物探方法技术的长足进步、发展及其应用，在经济与社会的发展中将发挥越来越重要的作用。