Geochemical Anomalies Identified by Multifractal Modeling: Implications for Mineral Exploration in the Ziyoutun Cu-Au District, Jilin Province, China

The Ziyoutun Cu-Au district is located in the Jizhong–Yanbian Metallogenic Belt and possesses excellent prospects. However, the thick regolith and complex tectonic settings present challenges in terms of detecting and decomposition of weak geochemical anomalies. To address this challenge, we initially conducted a comprehensive analysis of 1:10,000-scale soil geochemical data. This analysis included multivariate statistical techniques, such as correlation analysis, R-mode cluster analysis, Q–Q plots and factor analysis. Subsequently, we decomposed the geochemical anomalies, identifying weak anomalies using spectrum-area modeling and local singularity analysis. The results indicate that the assemblage of Au-Cu-Bi-As-Sb represents the mineralization at Ziyoutun. In comparison to conventional methods, spectrumarea modeling and local singularity analysis outperform in terms of identification of anomalies. Ultimately, we considered four specific target areas(AP01, AP02, AP03 and AP04) for future exploration, based on geochemical anomalies and favorable geological factors. Within AP01 and AP02, the geochemical anomalies suggest potential mineralization at depth, whereas in AP03 and AP04 the surface anomalies require additional geological investigation. Consequently, we recommend conducting drilling, following more extensive surface fieldwork, at the first two targets and verifying surface anomalies in the last two targets. We anticipate these findings will significantly enhance future exploration in Ziyoutun.

Adverse Geology Identification Through Mineral Anomaly Analysis During Tunneling:Methodology and Case Study

Accurate and effective identification of adverse geology is crucial for safe and efficient tunnel construction.Current methods of identifying adverse geology depend on the experience of geologists and are prone to misjudgment and omissions.Here,we propose a method for adverse geology identification in tunnels based on mineral anomaly analysis.The method is based on the theory of geoanomaly,and the mineral anomalies are geological markers of the presence of adverse geology.The method uses exploration data analysis(EDA)to calculate mineral anomaly thresholds,then evaluates the mineral anomalies based on the thresholds and identifies adverse geology based on the characteristics of the mineral anomalies.We have established a dynamic expansion process for background samples to achieve the dynamic evaluation of mineral anomalies by adjusting anomaly thresholds.This method has been validated and applied in a tunnel excavated in granite.As shown herein,in the tunnel range of 142+800–142+860,the fault F37 was successfully identified based on an anomalous decrease in the diagenetic minerals plagioclase and hornblende,as well as an anomalous increase in the content of the alteration minerals chlorite,laumonite,and epidote.The proposed method provides a timely warning when a tunnel enters areas affected by adverse geology and identifies whether the tunnel is gradually approaching or moving away from the fault.In addition,the applicability,accuracy,and further improvement of the method are discussed.This method improves our ability to identify adverse geology,from qualitative to quantitative,and can provide reference and guidance for the identification of adverse geology in mining and underground engineering.

Delineation of Potential Mineral Resources RegionBased on Geo-anomaly Unit

The geological anomaly unit method (GAUM) is a new way to delineate and evaluate ore finding targets in line with the “geological anomaly ore finding theory”. Comprehensive ore finding information from geological, geochemical and geophysical data is used for quantitative measurement of the “ore forming geological anomaly unit” in this paper. The main procedures are shown as follows: (1) The geo anomalous events associated with gold mineralization are analyzed in Tongshi gold field; (2) The zonation in the concentrated heavy minerals and the stream sediment elements of ore forming geo anomaly are studied in detail; (3) The deep geological structural framework is deduced by means of the synthetic geological interpretation of gravity and magnetic information; (4) The ore controlling geo anomalies and ore anomalies are chosen as the variables of the favorable ore forming indexes that can be used for the quantitative delineation and evaluation of the potential ore forming regions.

Application of GISto Geo-anomaly-Based Delineation of Mineral Resources

In this paper, the Dongchuan type copper deposits are taken as an example to illustrate the application of GIS to the geo anomaly based delineation of mineral resources. The following eight steps are listed in this paper to delineate the permissive and preferable ore finding areas: (1) the analysis of favorable prospecting index using linear and planar geo anomalies; (2) the analysis of favorable prospecting index using combined anomalies; (3) the construction of a GIS based spatial model for mineral prognosis; (4) the delineation of the permissive ore finding area; (5) the determination of the synthetic anomalies and numerical range for the prediction of the favorable prospecting areas, and the determination of the weights of these two variables; (6) the superimposition of all the selected anomalies and the construction of the superimposition map; (7) the determination of unifying criterion of favorable prospective areas at various levels, and (8) the delineation of favorable prospective areas. Finally, this paper offers a detailed discussion of the results in the forecasting of Dongchuan type copper deposits.

Singularity theories and methods for characterizing mineralization processes and mapping geo-anomalies for mineral deposit prediction

In this paper, we show that geo-anomalies can be delineated for mineral deposit prediction according to singularity theories developed to characterize nonlinear mineralization processes. Associ- ating singularity and geo-anomalies makes it possible to quantitatively study geo-anomalies with modern nonlinear theories and methods. This paper introduces a newly developed singularity analysis of nonlinear mineralization processes and nonlinear methods for characterizing and mapping geo-anomalies for mineral deposit prediction. Mineral deposits, as the products of singular mineralization processes caused by geo-anomalies, can be characterized by means of fractal or multifractal models. It has been shown that singularity can characterize the degree of geo-abnormality, and this has been demonstrated to be useful for mapping anomalies of undiscovered mineral deposits. The study of mineralization and mineral deposits from a nonlinear process point of view is a new but promising research direction. This study emphasizes the relationships between geo-anomalies and singularity, including singular processes resulting in singularity and geo-anomalies, the characterization of singularity and geo-anomalies and the identification of geo-anomalies for mineral deposit prediction. The concepts and methods are demon- strated using a case study of Sn mineral deposit prediction in the Gejiu mineral district in Yunnan, China.

Mineralization and Exploration Perspectives in the Oudiane Elkharoub Zone, Birimian Domain, Reguibat Shield, Mauritania

The Oudiane Elkharoub Zone is one of the major areas of the Reguibat Shield due to its position in the extreme northeast of the Birimian formation (dated between 1.6 and 2.7 Ga) within the Reguibat Shield, coupled with its closeness to with the Archean Domain in the Shield’s southern portion and with the Taoudeni Basin to the east. The results of field mapping, together with chemical (Fire Assay) and XRF (fluorescence spectrometer X-ray) analyses, shows significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies in samples taken from the Oudiane Elkharoub Zone. The results of those analyses will allow us to build a geochemistry maps for the anomalous metal for the study area, understand the relationships between different rock units and the mineralization and the mineralization control and their style, such as structural or lithological control. This context reflects a structural control of the Mineralization according to the conducted analyses and the observation on the field. The mineralization auriferous mainly hosted in quartz vein or quartz-carbonate vein with sulfide (pyrrhotite and pyrite) alteration.

Evidences by Multiscale Analysis and 2D3/4 Models from the Magnetic Anomalies and Iron Mineralization (BIF) over the DJADOM-ETA Area, Southeastern Cameroon

The Magnetic method is one of the best geophysical techniques used to delineate subsurface structures. This study was conducted to investigate the basement faulting and ore mineralization into the overlying geological cover. The GEOSOFT v8.4 software was used to process the data. Upward continuation of the residual magnetic intensity map at various altitudes and the maxima of their horizontal gradient magnetic were used to highlight faults from shallow to deep, as well as, their dips and mineralization zones. The faults with the directions E-W, ESE-WNW and ENE-WSW are identified confirming the result of [1]. This study also reveals that, the layer is affected by faults propagating from the basement upwards into the cover. Our results added additional information to the knowledge of the geological structure and the mineral resources potential in the study area. Based on the 2D3/4 modeling, the Dja Fault (DF) is revealed and highlighted sub-area marked by a magnetite/or hematite dolerite, schist and sandstone blocks, which show strong magnetization. Specifically, in this area, models are made of BIF (bounded iron formation) and BIQ (bounded iron quartzite) as dominant minerals.

Fractal invariable distribution and its application in large-sized and super large-sized mineral deposits

The self-similar is a common phenomena arising in the field of geology. It has been shown that geochemical element data, mineral deposits, and spacial distribution conform to a fractal structure. A fractal distribution requires that the number of objects larger than a specified size have a power-law dependence on size. This paper shows that a number of distributions, including power-function, Pareto, lognormal, and Zipf, display fractal properties under certain conditions and that this may be used as the mathematical basis for developing fractal models for data exhibiting such distributions. The summation method is developed on the basis of fractal models to determine thresholds for Au data in Shandong Province, China. The anomalous area is enclosed by contours which have contour values greater than or equal to threshold （200 × 10^- 9） and contains known large-sized and super large-sized gold mineral deposits.

Geochemical and Geophysical Data Processing Aided by“Multifractal-Spectrum”Filters for GIS-Based Mineral Exploration

A recently developed method, on the bases of “multifractal spectrum” filters for mineral exploration, is introduced in this paper. The “multifractal spectrum” filters, a group of irregularly shaped filters that are constructed on each processed datum, can be used to separate various types of geochemical and geophysical anomalies. The basic model, with an emphasis on the GIS based implementation and the application to the geochemical and geophysical data processing for mineral exploration in southern Nova Scotia, Canada, indicates its advantage in the separation of multiple anomalies from the background.

Gravity and Magnetic Evidence for the Geological Setting of Major Mineral Systems of the Main Metallogenic Belts in South China: A Qualitative Analysis

South China is characterized by large-area multistage magmatism.It boasts a huge number of polymetallic deposits such as W-Sn,Cu-Au,rare earth deposits,thus serving as a"giant granary"of metal mineral resources in China(Lüet al.,2021).

"Three-Component" Digital Prospecting Method: A New Approach for Mineral Resources Quantitative Prediction and Assessment

Three-component' method consists of three close-connected aspects: geological anomaly, diversity of mineralization and mineral deposit spectrum. All these three concepts are not new separately, but it is a new approach to combine these three aspects in one single concept for quantitative mineral resources prediction and assessment and it is also the first time to conduct a more detailed study in each aspect. Investigation and clarification of geological anomalies, diversity of mineralization and spectrum of mineral deposits are realized by digitization and quantification of ore forming controlling factors, ore-existing symbols or marks, characteristics of mineralization and regulation of ore-genesis and laws of distribution. These procedures lead to construction of a 'digital model' for mineral resources prediction and assessment.

Expert System for Statistical Prediction of Mineral Deposits on Middle and Large Scales

The expert system for statistical prediction of mineral deposits on middle and large scales takes the system of scientific exploration theories, criteria and methods proposed by Professor Zhao Pengda as the field expert knowledge. At present the developed system focuses on two aspects: synthetic exploration and quantitative exploration. Among the three basic theories for the prediction of deposits, it highlights the applications of seeking anomaly theory. This system is characteristic in the determination of geological background, the study of geological anomalies and the delineation of geological background, the study of geological anomalies and the delineation of mineralization anomalies. The system combines closely the knowledge base, method base and database .integrates the input and output information of multi - sources and mul-ti - variables , data , graphs and imagine processing system and inquiring system as a whole . So the system can meet in general all kinds of demands in statistical prediction of mineral deposits . Since the statistical prediction of mineral resources is a kind of systematic engineering pro ject , a further study should be carried out on the fields of theoretical exploration and ster eo - exploration on the basis of unceasingly perfecting the above-mentioned fields in order to establish a comprehensive intelligent system for scientific exploration , to provide new methods , new techniques and new ideas for fast prospecting appraisal of mineral resources .

Important Issues of Sustainable Development:Research of Nontraditional Mineral Resources

Nontraditional resources refer to that potential mineral resources are unconsidered and unutilized under actual condition of technique, economic and environment, or some mineral resources are too difficult to find because of geological complexity. There are some signified problems about discovery and exploration of nontraditional mineral resources to be discussed in this paper. It is a very significant project next century, and makes development bases for offspring, which its research and practice the theory of nontraditional mineral resources need interactive combination.

Thermoelectric characteristics of semiconductor minerals in earth's deep crust and their seismogenic significance

Geo-electric anomalies are generated during the process of stress accumulation and release associated with earthquakes.However,the mechanism of these anomalies remains equivocal.Based on the analysis of thermoelectric characteristics of semiconductor minerals of the earth’s deep crust such as graphite,ferrosilicon alloy,magnetite etc.,we perform finite element analysis to evaluate the principles governing the thermoelectric power generated by minerals and rocks.The results show that graphite,ferrosilicon alloy and magnetite all exhibit Seebeck effect and can be superimposed.And the thermo-electric field can be enhanced with the activation temperature increases,the content of thermoelectric minerals increases,the size of aggregates increases,and the spacing of thermoelectric minerals grains decreases.Seismogenic processes would generate a similar thermal gradient.The natural semiconductor minerals in this thermal field show a thermoelectric effect,forming a thermoelectric field that interferes with the background electric field.This study indicates that thermoelectric effect may have an important influence on the formation of geoelectric field.

2.5D Crustal Models Derived from Analytical Polynomial Separation Technique and Spectral Analysis of Gravity Data with Their Probable Gold Mineralization Migrations (Batouri, SE-Cameroon)

Geophysical surveying is crucial in the investigation of mineral resources in poorly exposed areas such as SE-Cameroon, a region known for its gold mineral potential. In this paper, gravity survey is carried out in the Batouri area, SE-Cameroon based on land gravity data from the Centre-south Cameroon. Therefore, an analytical polynomial separation program, based on least-square fitting of a third-degree polynomial surface to the Bouguer anomaly map, was used to separate the regional/residual components in gravity data. This technique permitted to better understand the disposition of the deep and near surface structures responsible of the observed anomalies in the Batouri area. Spectral analysis and 2.5D modelling of two profiles P1 (SW-NE) and P2 (N-S) selected from the residual anomaly map provided depths to basement. These depths constrain the gravity models along the profiles, indicating a variable thickness of the sedimentary infill with an approximate anomaly of -33 mGal. The 2.5D model of the basement shows a gravity body, with a signature suggesting two close and similar masses, which characterize the quartz-bearing formations associated here to granite and gneiss. Our work highlights a main heavy gravity: Gwé-Batouri anomaly, containing the major part of auriferous deposits located along the NE-SW direction. Further, three tectonic sub-basins bounded by normal faults have been highlighted at Guedal, Gwé, and Bélimban, in the south of Guedal-Bélimban depression. They are associated with the extension tectonics, more or less vertical tangential cuts and accidents that have affected the region. A correlation with previous results from tectonic, lithological and gold mineralization activities proves the relevance of the study and the need to intensify geophysical surveying in the area.

Mineralogical and Geochemical Evidence of Fluid-rock Interaction at the Shallow Crustal Level in Koyna Seismogenic Region, Maharashtra, India: Impact and Implications

The Koyna region of Maharashtra located in the western part of the~65 Myr old Deccan traps province,overlying the Neoarchean cratonic granitoid basement of peninsular India,has been experiencing recurring seismicity since 1962 after the impoundment of the Shivajisagar Reservoir behind the Koyna Dam.

Fractionation characteristics of rare earth elements(REEs) linked with secondary Fe, Mn, and Al minerals in soils

Soil secondary minerals are important scavengers of rare earth elements(REEs) in soils and thus affect geochemical behavior and occurrence of REEs. The fractionation of REEs is a common geochemical phenomenon in soils but has received little attention, especially fractionation induced by secondary minerals. In this study, REEs(La to Lu and Y) associated with soil-abundant secondary minerals Fe-, Al-, and Mn-oxides in 196 soil samples were investigated to explore the fractionation and anomalies of REEs related to the minerals. The results show right-inclined chondrite-normalized REE patterns for La–Lu in soils subjected to total soil digestion and partial soil extraction. Light REEs(LREEs) enrichment features were negatively correlated with a Eu anomaly and positively correlated with a Ce anomaly. The fractionation between LREEs and heavy REEs(HREEs) was attributed to the high adsorption affinity of LREEs to secondary minerals and the preferred activation/leaching of HREEs.The substantial fractions of REEs in soils extracted byoxalate and Dithionite-Citrate-Bicarbonate buffer solutions were labile(10 %–30 %), which were similar to the mass fraction of Fe(10 %–20 %). Furthermore, Eu was found to be more mobile than the other REEs in the soils, whereas Ce was less mobile. These results add to our understanding of the distribution and geochemical behavior of REEs in soils, and also help to deduce the conditions of soil formation from REE fractionation.

新疆准噶尔盆地北部黄花沟铀异常点矿化特征及找矿方向

近年准噶尔盆地北缘铀矿勘查取得了较好的找矿成果,相继发现了顶山矿点、卡姆斯特矿产地等。黄花沟异常点的发现为盆地北缘“新地区、新层位、新类型”三新找矿提供了重要线索。文章通过对盆地北缘黄花沟铀异常点的地质调查和系统采样,总结了异常点的铀矿化特征,探讨了矿化成因。研究认为:1)黄花沟异常点矿化主要发育在红砾山背斜核部,吐丝托依拉断裂上盘;2)矿石岩性以细粒岩屑砂岩为主,其次为砾岩,发育褐铁矿化、黏土化蚀变;3)含矿层砂岩成分成熟度较低、结构成熟度中等,为近源冲积扇扇中辫状河道沉积成因;4)黄花沟地区下一步主攻层位为下白垩统吐谷鲁群,主要找矿类型以潜水氧化带型和潜水-层间氧化带型为主。准噶尔盆地北缘下一步找矿工作应重视对隆起与凹陷构造单元的边界及控凹断裂附近、目的层沉积环境与上覆地层具有继承性的位置的查证。

刚果(布)Mpassa-Moubiri铜多金属矿区多源遥感蚀变矿化异常提取

刚果(布)Mpassa-Moubiri矿区铜、铅、锌等矿种找矿前景良好,运用多源遥感数据可提供丰富的找矿地质信息。本文选取Aster、Sentinel-2A、Worldview-2影像,采用主成分分析法分别提取白铅矿化、菱锌矿化、硅化、铁染、蓝铜矿化、孔雀石化等蚀变矿化异常信息,光谱角监督分类方法提取浅表含矿黑土异常信息。运用GIS密度分割挖掘各类蚀变矿化信息空间分布规律,并将其作为评价指标构建层次分析模型,最终圈定异常强度阈值高于0.8、面积17.18 km^(2)的遥感综合异常区域。结果表明:遥感综合异常主要呈北东向展布,富集在碳酸盐岩与碎屑岩接触带的有利成矿部位,与地表调查、化探异常吻合较好,表明多源数据组合能有效提取该矿区蚀变矿化信息,可为后续大比例尺勘查工作部署提供依据。

黄铁矿型(Fe,Mg)O_(2)H晶体到超离子态相变

地球深部的致密含水矿物可能以超离子态形式存在,其物理化学性质须重点考量。前人研究的黄铁矿型FeO_(2)H从有序晶体向超离子态转变时,H离子突破羟基束缚,在固态晶格中自由移动。然而,FeO_(2)H仅在地球深部少量存在,不能代表下地幔的组成。本文的研究体系为包含Mg在内的黄铁矿型(Fe,Mg)O_(2)H,它在下地幔深部的温压条件下通过铁方镁石和水的反应生成。通过第一性原理计算发现,它在高于80 GPa和1750 K时发生超离子态相变。超离子态(Mg,Fe)O_(2)H的转变条件与FeO_(2)H类似,但在低温区具有更高的质子扩散系数,因此更可能导致深部电导率异常。(Fe,Mg)O_(2)H比FeO_(2)H在下地幔的分布更为广泛,其物理、化学特征有助于示踪地球深部的水循环。