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1.
《Chemie der Erde / Geochemistry》2022,82(3):125898
Identifying mineralization areas with an acceptable level of reliability is a complex matter demanding the implementation of supervised methods for mapping mineralization exploration aims. In this study, further collecting all available exploratory information and data of the region of study, their good processing and analysis, and then integrating them with an appropriate method, multi-criteria decision-making (MCDM) approaches were utilized to outranking porphyry Cu mineralization areas. This paper describes an acceptable procedure for obtaining evidential layers for recognizing porphyry Cu mineralization, assigning weight to the layers, and combining them. For this aim, first, a data-driven multi-class index overlay (DMIO) approach is applied as it is a proven method with proper results in mineral prospectivity mapping (MPM) to integrate evidential layers (criteria and sub-criteria emanated from geoscience data including geological, geochemical, remote sensing, and geophysical datasets). After that, two recent MCDM models, combined compromise solution (CoCoSo) and multi attributive ideal-real comparative analysis (MAIRCA), were used to prioritize the porphyry Cu potential areas producing MPM. Concentration-area (C–A) fractal method and prediction-area (P–A) plots by considering the areas of occurrence of the known mineralization and normalized density (Nd) as traditional methods were applied for weighting and integration evidential layers and evaluation of the final maps in a data-driven manner. Consequently, verifying the verisimilitude of the MAIRCA prospectivity map (Nd = 3.17) is similar to the DMIO map in delimiting the priority areas. The results of the CoCoSo model (Nd = 2.7) show this methodology was also successfully applied in mapping the porphyry Cu mineralization areas in the study. 相似文献
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《Chemie der Erde / Geochemistry》2021,81(4):125824
This work has evaluated the functionality of various fuzzy-based fusion methods in the mineral potential mapping (MPM), by which a multi-criteria decision-making problem was solved to design a layout for drilling complementary boreholes through a comprehensive analysis of geospatial datasets. The novel methods employed were fuzzy c-means clustering, fuzzy gamma operator, fuzzy inference system (FIS), fuzzy outranking, and fuzzy ordered weighted averaging (FOWA). Kahang porphyry Cu-Mo deposit in the Isfahan province of Iran was chosen as a case study to examine the performance of these fuzzy methods in MPM. Extracted geospatial indicator layers for assessing the potential of porphyry-type mineralization were derived from four criteria, namely geology (rock units and faults), remote sensing (alteration map), geochemistry (Cu, Mo, and factor maps), and geophysics (reduced to the pole and analytical signal of magnetic data). The concentration-area multifractal method was utilized to reclassify each synthesized fuzzy favorability map into five classes. To appraise and compare the efficiency of each employed method, a productivity measure assumed as a cumulative summation of Cu grade multiplied by its thickness above an economical cut-off value of 0.2% was calculated along with each drilling (totally 33 ones). According to fuzzy favorability maps derived from running all fuzzy methods, the FIS and FOWA had the highest efficiency with 80 and 78% of accuracy, respectively. Eventually, taking all fuzzy maps into account led to the delineation of some new favorable zones, whereby further exploratory investigations are envisioned for determining their mining potential. 相似文献
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The central Iranian volcanic-sedimentary belt in Kerman province of Iran that is located within the Urumieh-Dokhtar magmatic arc zone is chosen to integrate diverse evidential layers for mineral potential mapping. The studied area has high potential of mineral occurrences especially porphyry copper, and the prepared potential maps aim to outline new prospect zones for further investigation. Two evidential layers including the downward continued map and the analytic signal of filtered magnetic data are generated to be used as geophysical plausible traces of porphyry copper occurrences. The low values of the resistivity layer acquired from airborne frequency domain electromagnetic data are also used as an electrical criterion in this study. Four remote sensing evidential layers including argillic, phyllic, propylitic, and hydroxyl alterations are extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images in order to map the altered areas associated with porphyry copper deposits. The Enhanced Thematic Mapper Plus (ETM+) images are used as well to prepare iron oxide layer. Since potassic alteration is generally the mainstay of copper ore mineralization, the airborne potassium radiometry data is used to explore both phyllic and potassic alteration. Finally, the geochemical layers of Cu/B/Pb/Zn elements and the main geochemical component responsible for ore mineralization extracted from principal component analysis are included in the integration process to prepare final potential maps. The conventional and the extended version of VIKOR method (as a well-known algorithm in multi-criteria decision making problems) produced two mineral potential maps, and the results were compared with the ones acquired from prevalent methods of the index overlay and fuzzy logic operators of sum and gamma. The final mineral potential maps based upon desired geo-data set indicate adequately matching of high potential zones with previous working and active mines of copper deposits. 相似文献
4.
青海绿梁山铜矿找矿信息的提取与成矿预测 总被引：1，自引：0，他引：1
绿梁山铜矿位于柴达木盆地北缘,属柴北缘成矿带,它是中国西部重要的多金属成矿区带之一。通过对绿梁山铜矿详细的地质调查、水系沉积物测量、高精度磁测扫面和遥感解译等工作,在系统研究其成矿地质条件、地球化学特征、地球物理特征和遥感影像特征的基础上,进一步筛选与矿化有关的异常信息,归纳并提取了地物化遥找矿信息:硅化、黄铁矿化、绿泥石化、绿帘石化、绢云母化等近矿围岩蚀变是寻找铜矿床的间接标志;遥感解译的复合环形构造与遥感蚀变信息叠加区是找矿有利区;在Cu、Au、Bi异常区沿铜矿化向北西存在较多的铜金矿化线索;强磁异常梯度带分布是最显著的深大断裂位置反映;显著的水热蚀变晕也是寻找该类矿床的重要遥感标志。结合以上特征在绿梁山找矿远景区内共圈定出Ⅰ、Ⅱ类靶区共3个。 相似文献
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Application of fractal models to characterization of vertical distribution of geochemical element concentration 总被引：1，自引：0，他引：1
Characterization of the vertical distribution of geochemical element concentration is essential for economic planning in the mining industry. 10 mineralized boreholes and 1 non-mineralized borehole from the Qulong copper deposit, Tibet, western China, were collected to identify the vertical distribution properties of Cu values using fractal models. The vertical distribution of Cu values in mineralized and non-mineralized boreholes shows a positive skewed distribution in the former and multimodal distribution in the latter. The results obtained by the box counting method show that the vertical distributions of Cu values in mineralized and non-mineralized boreholes exhibit self-similarity with box dimensions ranging from 1.28 to 1.37. The box dimensions of mineralized boreholes are greater than that of Cu values in the non-mineralized borehole, indicating that the mineralization makes the distribution of Cu values more irregular. The power-law frequency analysis reveals that Cu values in mineralized boreholes are bifractal. The two portions of the plot define a crossover point at 0.33%, for Cu values less than and greater than 0.33, fractal dimensions range from 0.1 to 0.65, in non-mineralized rocks, and range from 2.71 to 5.79, in the mineralized rocks. Hurst exponents for mineralized boreholes occur at 0.8, which are greater than 0.5, indicating that Qulong copper deposit has a good continuity of mineralization. 相似文献
7.
池沟斑岩型铜钼矿（化）体产于燕山期中酸性岩体内外接触带中,成岩与成矿年龄一致。区内物化探异常及矿化均围绕斑岩体呈（环）带状分布,构成斑岩型-矽卡岩型铜钼矿成矿系列。近年来,池沟地区采用高磁扫面＋CSAMT（可控源音频大地电磁法）＋钻探等组合方法,显示物化探异常特征与池沟出露岩体相吻合,经钻探,在池沟斑岩体接触带深部发现了厚大低品位铜钼矿体。在总结矿区地质特征的基础上,以区内物化探异常特征为依据,认为地表物化探异常与深部矿体位置形态有对应性关系,找矿潜力巨大,具有寻找斑岩型铜矿床的有利条件。 相似文献
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松诺铜矿区位于香格里拉格咱斑岩铜矿带红山-普朗铜多金属成矿亚带中段,矿区剥蚀程度较低,具有寻找斑岩型铜矿的潜力。本次蚀变矿物填图工作采用近红外光谱矿物分析技术,识别出绿泥石、绿帘石、高岭石、云母类、蒙脱石类及伊利石等6类主要蚀变矿物,蚀变类型为青磐岩化、绢英岩化;结合物探、化探异常分布,圈定3处找矿靶区,经对KHT2、KHT3钻孔验证,深部均圈定多层铜矿化体。结果表明,近红外光谱矿物分析技术在斑岩型铜多金属矿床勘查评价中可以较好地划分热液矿化蚀变带,进一步明确斑岩型矿化-蚀变中心,为探矿工程部署提供依据。 相似文献
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研究区存在古元古界辽河群里尔峪组硼富集层.为确定赋存硼矿化地层层位构造蚀变带分布情况,利用地球化学与地球物理测量方法,在已知见硼矿钻孔构造蚀变带进行测量,总结分析硼矿化地球化学与地球物理特征.结合成矿地质条件,建立本区硼矿化地质物化探找矿模式,认为辽河群里尔峪组复背斜和复向斜与本区硼成矿有关.硼矿化分布区物化探特征为：地面磁力测量磁场值呈偏高磁场值分布;中梯激电测量为低视电阻率与偏高视幅频率;电测深反演电阻率反映为低阻线性构造带与偏高激电异常带,在矿化较强烈部位电阻率相对偏低;地球化学异常以硼为主,硼化探异常有明显的浓集中心,同时伴生铅、锌、银复合地球化学异常. 相似文献
10.
《地学前缘(英文版)》2020,11(6):2297-2308
Quantification of a mineral prospectivity mapping (MPM) heavily relies on geological, geophysical and geochemical analysis, which combines various evidence layers into a single map. However, MPM is subject to considerable uncertainty due to lack of understanding of the metallogenesis and limited spatial data samples. In this paper, we provide a framework that addresses how uncertainty in the evidence layers can be quantified and how such uncertainty is propagated to the prediction of mineral potential. More specifically, we use Monte Carlo simulation to jointly quantify uncertainties on all uncertain evidence variables, categorized into geological, geochemical and geophysical. On stochastically simulated sets of the multiple input layers, logistic regression is employed to produce different quantifications of the mineral potential in terms of probability. Uncertainties we address lie in the downscaling of magnetic data to a scale that makes such data comparable with known mineral deposits. Additionally, we deal with the limited spatial sampling of geochemistry that leads to spatial uncertainty. Next, we deal with the conceptual geological uncertainty related to how the spatial extent of the influence of evidential geological features such as faults, granite intrusions and sedimentary formations. Finally, we provide a novel way to interpret the established uncertainty in a risk-return analysis to decide areas with high potential but at the same time low uncertainty on that potential. Our methods are illustrated and compared with traditional deterministic MPM on a real case study of prospecting skarn Fe deposition in southwestern Fujian, China. 相似文献
11.
新疆诺尔特地区化探特征及成矿潜力分析 总被引：2，自引：0，他引：2
新疆阿尔泰诺尔特地区经历了前泥盆纪基底陆壳演化期、上叠盆地发育期、上叠盆地的关闭期和造山后期4个阶段;在地质演化过程中伴随着一系列成矿作用。区域化探资料显示,区内下石炭统中—酸性火山岩出露区以Au、Pb、Zn、Cu为特色的化探综合异常带规模大,强度高,化探异常浓集中心明显,在部分异常区内已经先后发现多处金、铜、多金属矿床、矿点和矿化点。区域构造演化富集了成矿元素,特别是下石炭统红山嘴组火山岩为金、铜、铅、锌矿源层,燕山期岩浆活动对矿源层中的成矿元素进一步富集,并在构造有利部位成矿。本文通过研究区区域成矿条件和区域化探异常特征分析,指出诺尔特地区具有较大的找矿潜力。 相似文献
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Animesh Mandal Arkoprovo Biswas Saurabh Mittal William K. Mohanty Shashi Prakash Sharma Debashish Sengupta Joydip Sen A. K. Bhatt 《Journal of the Geological Society of India》2013,82(6):601-606
Beldih mine at the central part of the South Purulia Shear Zone (SPSZ) has been reported with low grade uranium-bearing formation within quartz-magnetite-apatite host in kaolinized formation. Therefore, the present integrated geophysical study with gravity, magnetic, radiometric, very low frequency electromagnetic (VLF) and gradient resistivity profiling methods around the known mineralized zones aimed at identifying the exact geophysical signatures and lateral extent of these uranium mineralization bands. The closely spaced gravity-magnetic contours over the low to high anomaly transition zones of Bouguer, reduced-to-pole magnetic, and trend surface separated residual gravity-magnetic anomaly maps indicate the possibility of high altered zone(s) along NW-SE direction at the central part of the study area. High current density plots of VLF method and the low resistive zones in gradient resistivity study depict the coincidence with low gravity, moderately high magnetic and low resistivity anomalies at the same locations. Moderate high radioactive zones have also been observed over these locations. This also suggests the existence of radioactive mineralization over this region. Along profile P2, drilled borehole data revealed the presence of uranium mineralization at a depth of ～100 m. The vertical projection of this mineralization band also identified as low gravity, low resistivity and high magnetic anomaly zone. Thus, the application of integrated geophysical techniques supported by geological information successfully recognized the nature of geophysical signatures associated with the uranium mineralization of this region. This enhances the scope of further integrated geophysical investigations in the unexplored regions of SPSZ. 相似文献
15.
荣那铜矿是中铝矿产资源有限公司近年在斑岩型铜矿找矿方面取得的一项重大突破。矿床产于班公湖—怒江缝合带北侧岛弧带中。公司在找矿初期重视基础地质研究,加强对地调和矿调成果的二次解剖,借鉴国内外斑岩铜矿区域分布规律,结合1∶5万磁法异常,明确多龙矿集区重点找矿方向;根据前期勘查成果,结合1∶5万水系沉积物测量成果,确定荣那、拿若为重点验证区。通过总结国外斑岩铜矿蚀变模式、矿化模式和勘查模式,选择有效的激电勘查方法圈定重点验证地段。结合隐伏斑岩体系矿化中心为中低阻、负磁异常、中等极化率,外围发育黄铁矿化壳形成近似环状中高阻、正磁异常、中高极化率异常,最终确定外围正磁、中高极化环形异常系荣那矿床与青磐岩化带有关的黄铁矿化壳引起,负磁、中等极化率异常为矿化中心部位,通过选择合理网度进行钻探验证实现找矿突破。荣那矿床勘查过程中的理论思考,区域-矿田物化探异常的综合分析、有效方法的投入和验证工程的部署充分体现了科学研究与生产的有机结合。 相似文献
16.
Fractal and multi-fractal content area method finds application in a wide variety of geological, geochemical and geophysical fields. In this study, the fractal content-gradient method was used on 1:10,000 scale to delineate geochemical anomalies associated with copper mineralization. Analysis of geochemical data from the Yangla super large Cu-Pb-Zn polymetallic ore district using the fractal content-gradient method, combined with other geological data from this area, indicates that ore-prospecting in the ore district should focus on Cu as the main metal and Pb-Zn and Au as the auxiliary metals. The types of deposits include (in chronological order) re-formed sedimentary exhalative (SEDEX), skarns, porphyries, and hydrothermal vein-type deposits. Three ore-prospecting targets are divided on a S–N basis: (1) the Qulong exploration area, in which the targets are porphyry-type Cu deposits; (2) the Zongya exploration area, where the targets are porphyry-type Cu and hydrothermal vein-type Cu-Pb polymetallic deposits; and (3) the Zarelongma exploration area, characterized mainly skarn-type “Yangla-style” massive sulfide Cu-Pb deposits. Our study demonstrates that the fractal content-gradient method is convenient, simple, rapid, and direct for delineating geochemical anomalies and for outlining potential exploration targets. 相似文献
17.
本文对枞阳县陶家巷工区成矿地质特征,物化探特征,地球化学特征,矿化蚀变特征等进行分析,研究显示区内成矿元素Cu、Pb、Zn等含量高于地壳背景值,断裂构造发育,断裂带内铜矿化、硅化等明显。断层发育,NE向断层发育,多以硅化带形式出现。裂隙发育,具不同程度的硅化高岭土化,局部充填有褐铁矿化脉。陶家巷一高庙山低缓异常带、方家湾地存在重磁同高异常。与已知矿化舍铜破碎带重合。结果表明,陶家巷大刨山铜矿深部及外围、城山岩体与围岩接触带、夏家井、方家湾、五印庵一团山小学和高庙山具有较好的找矿潜力。 相似文献
18.
钦-杭结合带南段庞西垌地区Ag-Au致矿地球化学异常信息识别与提取 总被引：2，自引：1，他引：1
基于分形与多重分形理论的非线性化探数据处理方法及以空间加权主成分分析模型为代表的地学多源信息融合技术,为致矿地球化学异常信息的识别和提取提供了有力的工具。本文以钦-杭结合带南段庞西垌地区1∶5万水系沉积物地球化学数据为例,研究如何综合运用多重分形局部奇异性与空间加权主成分分析这两种地学信息处理方法来识别和提取致矿地球化学异常信息。首先,采用滑动窗口的方法绘制了研究区与银金矿化关系密切的五种地球化学元素Au、Ag、Cu、Pb和Zn的局部奇异性指数图以增强局部弱缓异常信息。然后,在控矿条件分析的基础上,运用北东向断裂构造这一重要控矿要素对Ag-Au成矿作用的影响范围,即距离北东向断裂的距离,作为应变量来构建用于空间加权主成分分析的空间权重系数的计算模型,以此来突显化探样品在控矿地质条件约束下的空间相关性。进而,采用空间加权主成分分析方法来得到Au、Ag、Cu、Pb和Zn多元素奇异性指数值的组合异常(第一主成分因子得分)。结果表明:综合运用多重分形局部奇异性与空间加权主成分分析方法可以有效的识别和提取Ag-Au致矿地球化学异常信息,圈定具有示矿意义的多元素组合异常区。 相似文献
19.
Identifying highly favorable areas related to a particular mineralization type is the main objective of mineral prospectivity modeling (MPM). The northwestern portion of Ahar-Arasbaran porphyry copper belt (AAPCB) is situated within the Urumieh-Dokhtar magmatic belt (UDMB). Because of owning many worthwhile Cu-Mo and Cu-Au porphyry deposits, this area is entitled to incorporate diverse spatial evidence layers for the MPM. In this paper, a hybrid AHP-VIKOR, as an improved knowledge-driven MPM procedure has been proposed for integration of various exploration evidence layers. For this, the AHP is used to calculate important weights of spatial criteria while the VIKOR is applied to outline ultimate prospectivity model. Six effective spatial evidence layers pertaining to the Varzaghan District are selected: (1) multi-elemental geochemical layer of Cu-Mo-Bi-Au; (2) remotely sensed data of argillic, phyllic, and iron oxide alteration layers; and (3) geological and structural layers of Oligo-Miocene intrusions and fault. In addition, a fuzzy prospectivity model (γ?=?0.9) is implemented to assess the AHP-VIKOR approach. Two credible validation methods comprising normalized density index and success rate curve are adapted for quantitative evaluation of predictive models and enhancing the probability of exploration success. The achieved results proved the higher accuracy of the AHP-VIKOR model compared with the fuzzy model in delimiting the favorable areas. 相似文献
20.
内蒙古东乌旗巴润查干陶勒盖地区位于二连-东乌旗成矿带东段,具有良好的成矿地质背景,晚华力西期花岗岩、石英二长斑岩侵入体及各类晚期脉岩伴随北东向断裂构造侵入安格尔音乌拉组地层中,具有十分有利的成矿地质条件。1:5万及1:1万土壤地球化学异常元素主要为Pb、Zn、Cd、Cu等,浓集中心明显,套合较好。1:5万航磁局部异常及1:1万地面高精度磁测异常均与北东向构造岩浆活动密切相关。1:1万地质测量圈定的地表矿化蚀变带与上述物化探异常形态基本一致。通过分析研究区的控矿地质条件及物化探异常特征,认为研究区热液型Pb、Zn多金属矿床具有良好的成矿远景,有进一步工作价值。 相似文献