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The electrical resistivity and induced polarization (IP) methods are widely used in geological mapping, prospecting and exploration of mineral deposits, engineering geology, hydrogeology, archaeology, and geotechnical and environmental applications. Historically, these methods have formed the basis of the electrical prospecting technique. In these methods, a DC or low-frequency AC electrical current is introduced into the earth through a grounded transmitter line. The measured quantity is the electric field. However, if the earth’s resistivity or chargeability changes horizontally, this change gives rise to an anomalous magnetic field, which is studied by the magnetometric resistivity (MMR) and magnetic induced polarization (MIP) methods, respectively. Along with advantages, some shortcomings are inherent in the MMR and MIP techniques. Apparently, the main drawback of these methods is that the magnetic fields of both the transmitter line wire and ground electrodes on the surface are several orders of magnitude greater than the anomalous magnetic field response. This introduces a significant “noise” to magnetic-resistivity data. We investigate the potential of using a circular electric dipole (CED) in magnetometric resistivity techniques. It has been found that the application of a CED, instead of a conventional transmitter line, dramatically enhances the signal-to-noise ratio. 相似文献
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《International Geology Review》2012,54(7):609-618
The use of plants as indicators in prospecting for minerals is discussed on a broad scale from the standpoints both of available literature and field experiments. The method of isoline mapping of mineral deposits by means of metal content in ashes of plant parts is detailed,. The author cautions against too broad use of any single species as a “direct” indicator or too heavy reliance on ash content, as some species tend to concentrate certain minerals, regardless of soil composition. Instead, a combination of species as indicators and a combination of factors, such as appearance of leaves, luxuriance of the plant, and color and time of blooms is recommended. The tendency of some minerals to nullify the effect of others–iron counteracting the effect of copper, for instance — is noted, as well as different effects on plants of different salts of the same mineral. In spite of these qualifications and the early, stage of development of this technique, the method has particular merit in areas where the strata overlying the metal-bearing deposits is relatively thick. Analyzing the ash content of leaves of deep-rooted trees is particularly helpful in detecting the presence of an ore mineral in such a situation. — A. Eustus 相似文献
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加权Logistic回归是基于GIS成矿预测的主要方法之一,其模型是不同于线性模型的一种类型。它具有强大的空间分析功能、适用性强、不受任何独立条件的约束、预测结果更可靠,因此在矿产资源评价研究中得到了很多地质学家的青睐。以矿床模型和成矿理论为基础,加权Logistic回归分析模型在成矿预测中的应用主要包括三部分:加权Logistic回归模型的建立及其应用、成矿有利度综合评价、成矿远景区圈定。本文以中国—哈萨克斯坦边境地区扎尔玛—萨吾尔成矿带斑岩型铜矿为例,探讨了基于GIS的加权Logistic回归模型在成矿预测中的应用。 相似文献
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以大型隐伏矿床的发现历史为依据,系统地总结了隐伏矿勘查的经验与策略,并从矿产勘查哲学的角度进行了深入的思考。针对拟寻矿床的地质特征。抓住深部关键的地质因素,查明地球物理和地球化学特征与它们的对应关系,把地球物理和地球化学判据转化成找矿标志,是提高隐伏矿找矿效率的关键。成矿作用的分带现象是一个普遍的规律,对于指导隐伏矿预测和矿床深部勘探具有重要的意义。直接信息是矿产勘查最可靠的信息。直接信息和间接信息并不是以学科划分的,在一定的条件下和一定的研究程度上两者可以转化。以直接信息为先导,实现从区域到局部的转变,使找矿迅速突破。必须充分重视各类方法的应用条件与前提。重视各种直接信息的挖掘与印证,加强各类方法的集成与综合。对于一个重要的成矿区（带）来说,随着地质研究与找矿工作的深入,需要不断地修订和调整勘查准则。矿产勘查投资是一种高风险、高效益的投资,是一项创造性很强的实践．集调查与研究于一体。矿产勘查不以研究“水平”论高低,而以“成败”论英雄;要看勘查的实效,而非理论的高深;要看是否见矿,而非勘查过程的简繁。经验与理论、科学与技术的交叉与融合是通向矿产勘查的成功之路。 相似文献
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Buffer zones in bo\th two-dimensional (2D) and three-dimensional (3D) spaces are commonly used in prospectivity mapping. The method completes a modelling that starts with a real example and progresses to the development of a virtual model. This includes the consideration of lithological or structural contacts at depth, which is a theoretical concept based on extrapolation of data collected in the field, rather than an empirical observation of the feature based on physical samples. This contribution documents an improved buffer analysis method for the study of 3D-space that is implicit (rapid), precise (smooth) and based on triangulated characteristics, which can be used to construct influence domains of geological models. As traditional 2D GIS-based mineral potential mapping is gradually becoming limited with time, mineral potential mapping in three dimensions (3D) is increasingly becoming an important tool in finding concealed economic mineralization. This contribution documents an improved methodology of buffer analysis for prospectivity mapping processing mineralized favourable models rather than describing an advance in the geometry of surface rendering of “geological complexity”. Measures used in this buffer analysis include the: (1) voxelization of geological objects (i.e. assigning numerical values of features on a regular cube in 3D-space); (2) revision of the 3D Euclidean distance transform and the calculation of signed distance field; (3) extracting surfaces from the field; and (4) construction of a buffer-surface based on a “discrete smooth interpolation” (DSI) algorithm. Furthermore, this contribution constructs 3D models using a buffer analysis algorithm and prospectivity mapping introduced here, which is based on real data from the Jiama Cu-polymetallic deposit in Tibet and Daye Fe deposit in the Hubei Province, China. This contribution also presents a comparison between voxel and irregular triangle models, which illustrate that irregular triangle mesh buffer analysis (ITB) can improve modelling techniques for GIS-based 3D mineral potential mapping. The outcome is an increase in the accuracy of prospectivity mapping. 相似文献
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随着近年来取得重要找矿突破的普朗斑岩型铜矿的规模化开采，进一步摸清首采区外围资源潜力任务紧迫。遥感技术尤其是国产卫星资源一号02D星等高光谱卫星成功发射，为我国高海拔艰苦地区快速精准识别与矿化相关的蚀变矿物提供了可能。针对以往对植被覆盖区高光谱矿物识别有效性方法探索不足，本文选取普朗铜矿区为研究，采用资源一号02D高光谱遥感数据，使用比值植被指数划分植被覆盖区及非植被覆盖区。基于实测波谱，分层次构建了植被覆盖区及非植被覆盖区与普朗铜矿矿化密切相关的绢云母、绿泥石、绿帘石蚀变特征矿物波谱曲线，并采用匹配滤波方法开展了蚀变矿物填图示范应用。野外验证表明：该方法可有效探测普朗斑岩型铜矿外围尤其是首采区东侧植被覆盖区绢云母等蚀变特征矿物分布信息，结果显示普朗首采区东侧具有较大找矿潜力。 相似文献
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Landslide risk analysis procedures in this study could evaluate annual landslide risk, and assess the effectiveness of measures. Risk analysis encompassing landslide hazard, vulnerability, and resilience capacity was used to evaluate annual landslide risk. First, landslide spatial, temporal, and area probabilities were joined to estimate annual probability of landslides with an area exceeding a certain threshold in each slope unit. Second, different elements were assigned corresponding values and vulnerabilities to calculate the expected property and life losses. Third, the resilience capacities of communities were calculated based on the scores obtained through community checklists and the weights of items, including “the participation experience of disaster prevention drill,” “real-time monitoring mechanism of community,” “autonomous monitoring of residents,” and “disaster prevention volunteer.” Finally, the annual landslide probabilities, expected losses, and resilience capacities were combined to evaluate annual landslide risk in Shihmen watershed. In addition, annual risks before and after the implementation of measures were compared to determine the benefits of measures, and subsequently benefit–cost analysis was performed. Communities with high benefit–cost ratios included Hualing, Yisheng, Siouluan, and Gaoyi. The watershed as a whole had a benefit–cost ratio far greater than 1, indicating the effectiveness of measures was greater than the investment cost. The results of factor sensitivity analysis revealed changes in vulnerabilities and mortality rates would increase the uncertainty of risk, and that raise in annual interest rates or reduction in life cycle of measures would decrease the benefit–cost ratio. However, these changes did not reverse the cost-effective inference. 相似文献
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随着矿产资源预测的发展,三维矿产资源定量预测评价已经成为矿产勘查领域的热点。然而真正决定矿产预测及矿产勘查成败的核心在于:如何构建恰当的预测变量来反映成矿作用过程。本文以四川拉拉铜矿为例,通过成矿系统分析“源-运-储-保”四大要素总结了该区矿产预测的地质找矿要素。基于三维地质建模技术以及成矿信息定量提取技术,构建了区域找矿要素三维地质信息。以找矿信息量为数学模型,确定了拉拉铜矿成矿有利区划,圈定了4个找矿靶区。本次研究将矿床成矿系统分析(知识驱动)与三维定量分析(数据驱动)相结合,将成矿作用过程及关键因素(源、运、储、保等)转化为可预测的具体空间要素,并使用三维可视化技术进行三维空间重构,该方法为今后的三维定量预测工作提供了有利参考。 相似文献
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为了有效、合理、客观地评价高光谱卫星数据质量, 充分发挥其在矿产及能源普查方面的作用, 进行了一系列研究.围绕最具代表性的3种载荷指标(几何空间分辨率、波谱分辨率及信噪比)的不同尺度, 从均方差异常、直方图异常、数据相关性异常、反射率曲线异常、信噪比参量以及该模拟数据的实际应用(蚀变信息提取和矿物填图)等多角度入手, 系统而全面地分析了模拟星载Hymap高光谱数据针对不同指标与尺度的影像质量效果.研究结果表明, 这3种载荷指标之间相互制约, 并随着空间分辨率和波谱分辨率的提高将降低图像的信噪比.当几何空间分辨率为15 m、波谱分辨率为15~20 nm, 同时信噪比≥350时, 就可以满足常规的矿物填图要求. 相似文献
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A restricted Boltzmann machine can be trained to encode and reconstruct training samples from a training sample population with an unknown complex probability distribution. Small probability samples can be differentiated from the training sample population due to their comparatively larger encoded and reconstructed errors. In mineral potential mapping, mineral potential areas usually take up only a small proportion of the whole mineral exploration region and have specific evidence map patterns. Assume that the whole mineral exploration region is divided into uniform cells and a restricted Boltzmann machine is then trained on all the cells. As a small proportion of the total training cells, mineral potential cells have much larger encoded and reconstructed errors compared to non-mineral potential cells. Based on the encoded and reconstructed errors of the training cells, ASC and ASE are thus defined as two mineral potential indicators for mineral potential mapping with the trained restricted Boltzmann machine. The Altay district in northern Xinjiang in China, which is linked with a complex geological setting, is chosen as a case study area. Restricted Boltzmann machines with 12 visible units and differing hidden units are constructed and trained on 9582 training cells in the study area. The ASC, ASE, posterior probability, and deposit-bearing probability are used to predict the mineral potential of each grid cell in the study area. The AUC (area under the curve), a measure of aggregated classification performance in machine learning, is applied to measure the mineral potential mapping performance of these four mineral potential indicators. The results show that the four mineral potential indicators perform similarly well. Therefore, a restricted Boltzmann machine can be trained to map mineral potentials, and the ASC and ASE are two feasible indicators for the mineral potential mapping with the trained restricted Boltzmann machine. 相似文献
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项目以铜铅锌银为主攻矿种,以层控型、矽卡岩型铜多金属矿等为主攻矿床类型,采用1∶5万地质填图、地面高磁测量、水系沉积物测量和遥感地质解译等为工作方法,基本查明了区内矿产地质背景,共圈定各类异常111个,提交了3处新发现矿产地,建立了铜铅锌矿床的找矿标志及找矿模型,圈定8个成矿远景区和23处找矿靶区。首次在研究区新发现念青唐古拉岩群、蛇纹石化橄榄岩和云英岩-矽卡岩型铜钨矿床及矽卡岩型铋矿床、矽卡岩型铟矿床;首次在念青唐古拉地区厘定来姑组和马里组2个具有重要找矿意义的控矿层位,提出了该地区同生沉积、后期改造的区域成矿模式。为该地区进一步地质调查、矿产勘查规划与开发提供丰硕的基础资料。 相似文献
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《China Geology》2018,1(3):392-401
Through the study of the geological conditions of potash deposits in China from recent years, a new understanding of potash theories has arisen that appropriate Chinese geological features. Important progress and substantial breakthroughs have been gained in the direction and management of potash prospecting: (1) Important breakthroughs in continental potassium prospecting: The “Quaternary gravel type deep potassium rich brine metallogenic model in western Qaidam” ensures Quaternary deep potassium rich brine prospecting will grow new KCl resources by 350 Mt, providing a resource guarantee for meeting the Chinese demand for sylvite. (2) The Marine facies potash prospecting shows good prospects: the determination of the new type of Triassic polyhalite potash ore deposits in Sichuan provide an important scientific basis for the establishment of exploration planning and the selection of exploration target areas for polyhalite minerals in the Sichuan Basin; The “two-storey potash deposits model” in southwestern Yunnan has been confirmed, which indicates prospects for the exploration of potash in the deeper Marine facies in southwestern Yunnan are likely to be successful. The discovery of a high concentration of rich bromite salt and potash salt in the Paleogene of the Kuqa depression and the southwestern Tarim region provides strong support for the likelihood large-scale potash deposits exist in these regions. 相似文献
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望谟县包树地区成矿地质条件优越,已有资料显示,存在寻找萤石等重要矿产的潜力。为了推进区内萤石矿的找矿工作,为下一步找矿提供找矿靶区,本文通过大比例尺地质填图、剖面测量、槽探、物探、钻探等手段,在区内发现了两套构造蚀变体(SBT),圈定了13个萤石矿体。初步查明了这些矿体的分布范围、赋存状态、规模、数量及其变化规律,估算了潜在资源。结合对区内萤石矿成矿地质条件和成矿规律的分析,圈定了望谟打岩萤石矿找矿远景区、望谟新屯萤石矿找矿远景区及望谟石屯萤石矿找矿远景区三处成矿远景区。应用固体矿产预测方法,建立预测模型对这些远景区的萤石矿资源进行预测,得出:望谟打岩萤石矿找矿远景区存在潜在萤石矿资源,具有较大的资源潜力;望谟新屯萤石矿找矿远景区存在潜在萤石矿资源,具有较大的资源潜力;望谟石屯萤石矿找矿远景区,成矿概率为≤01,具有成矿的基本条件,资源潜力较小。 相似文献
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浅析黔西北水东—五指山地区铅锌矿控矿因素、成矿规律及找矿方向 总被引：1，自引：0，他引：1
黔西北水东—五指山地区铅锌矿位于扬子陆块西南缘,紫云—垭都北西向构造旁侧,是黔西北铅锌成矿带的一个组成部份,通过该地区矿产资源远景调查及矿产评价成果展现了较好的找矿前景,发现了中型矿床5个,并在攻深找盲取得了突破性进展。笔者通过区域控矿因素、成矿地质背景分析,结合工作成果及认识,模拟类比在相似地质条件,指出找矿方向,认为区内成矿地质条件优越,找矿前景好,具备寻找大型、超大型矿床的潜力。 相似文献
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利用遥感技术可以经济、有效地获取地质找矿信息。基于多光谱遥感数据的蚀变信息提取已在地质填图和找矿工作中广泛应用,近几年,中国高分五号（GF-5）高光谱数据以其较高的光谱分辨率为地表蚀变矿物的精细化识别提供了基础数据。文章结合Landsat-8 OLI多光谱和GF-5高光谱数据,对内蒙古苏莫查干敖包萤石矿及周边开展蚀变信息提取,分析有利成矿区域,并进行野外验证,进一步发掘外围矿产资源潜力并探究遥感地质勘查的可信度。笔者基于Landsat-8多光谱数据,利用主成分分析方法提取了铁染、羟基类蚀变,并对其异常等级进行了划分;基于GF-5高光谱数据运用最小噪声分离（MNF）算法、纯净像元指数（PPI）算法、混合调制匹配滤波（MTMF）填图方法,在研究区内提取出白云母、绿泥石、高岭石、磁赤铁矿和褐铁矿5种矿物。将两者蚀变信息提取结果叠加,笔者发现苏莫查干敖包萤石矿区及外围存在热液蚀变特征,具备金属成矿潜力,野外验证发现研究区除萤石外,还伴生有铅锌多金属矿。因此,笔者认为多光谱和高光谱遥感数据结合的蚀变信息提取在地质矿产资源勘查领域具有一定应用潜力。 相似文献