Distribution Of Mineral Deposits Research Articles

The multifractal nature of worldclass orogenic gold systems in greenstone belts: A multiscale approach and case study at the Córrego do Sítio deposit, Rio das Velhas greenstone belt, Brazil

Understanding the controls on the spatial distribution of mineral deposits is crucial for prospecting new occurrences. Various geological processes operate together at microscopic to macroscopic scales, generating mineral systems responsible for significant accumulations of economic minerals. This characteristic of functioning at various scales, accompanied by repetition of features over space during mineralization, indicates that these processes are self-similar, meaning they exhibit fractal geometry. Previous research has demonstrated that the combined action of processes involved in mineralization in such critical, nonlinear systems, produces objects with multifractal characteristics. Therefore, the spatial distribution of mineral deposits should be studied using appropriate methods for better understanding of their controls. In this context, this study investigated the multiscale geometric characteristics of worldclass orogenic gold systems in Archean greenstone belts using fractal and multifractal analyses. First, at the macroscopic-scale, regional-scale features were considered in the major greenstone belt provinces with orogenic gold deposits worldwide, namely: Abitibi (Canada), Norseman–Wiluna (Australia), Rio das Velhas (Brazil), and Central Lapland (Finland). Next, at an intermediate scale, local-scale features were examined in detail within the context of the Córrego do Sítio Lineament. Finally, at the microscopic scale, the focus was on the Córrego do Sítio orogenic gold deposit—a key deposit in the Rio das Velhas greenstone belt. Fractal dimensions of the spatial distributions of mineral deposits, magnetic lineaments, and their intersections were investigated at the macroscopic to local scales, as well as the spatial distribution of ore minerals at the microscopic scale, using the box-counting method. Maps of fractal dimensions of magnetic lineaments were generated and compared with the spatial distribution and tonnage of orogenic gold deposits at the regional scale. The same features were analyzed using the method of multifractal moments. The results at the three scales were analyzed and synthesized to identify meaningful patterns for understanding these orogenic gold systems. With regard to fractality, the orogenic gold deposits in all the investigated provinces exhibited unique spatial distributions at different scales, namely: less than 2–4 km, from 2 to 4 km to 10–30 km, and more than 10–30 km. The analysis of magnetic lineaments yielded a correlation between gradients of fractal dimensions and gold tonnages in the orogenic gold deposits. The multifractal analyses indicate multifractal geometries extending from the microscopic to the macroscopic scale. The calculated multifractal indices of Δα (singularity variation), τ“(1) (multifractality index), and Δf(α) (multifractal spectrum variation) showed direct relationships with endowment of orogenic gold in the studied provinces, as well as with differences in mineralization styles in thin sections. The findings demonstrate the effectiveness of the analyses used for improved characterization of the studied mineral systems; they also allow comparing similar systems at different scales and locations and they can be used to study other mineral systems with similar geological controls.

Correlation between fractal characteristics of fault structures and metallogenic density in the Nanling area, South China

As fault structures exert a significant effect on metallogenic processes and mineralization, their proper characterization can assist in the determination of target areas for exploration. In this study, we apply the fractal theory on the interpretation of remote sensing images of the Nanling area, South China, to determine the relationship between fault structures and regional mineralization. Our results show that the fractal dimension (D) of fault structures in the Nanling area is 1.72, which is much higher than the regional average (1.35) for southern China. This difference reflects a strong geological tectonic activity in this region. Besides, we find that well-developed faults have a complex spatial distribution, and therefore this region is characterized by favorable metallogenic conditions with good prospecting prospects. Our results indicate the presence of a close relationship between the fractal dimension (D) and the spatial distribution of mineral deposits. Specifically, a higher D value generally corresponds to a dense distribution of ore deposits. Finally, based on regional structural and metallogenic characteristics as well as spatial coupling relationships, two target mineralization areas are identified as potential candidates for further exploration.

Influence of Natural, Climatic, and Industrial Factors on Air and Water Quality in The Kemerovo Region (Kuzbass, Russia)

Geographical and climatic features of the Kemerovo region (Kuzbass, Russia) determined the modern geological and geomorphological structure of the territory, as well as a characteristic pattern in the distribution of mineral deposits. The purpose of this work was to study the geomorphological and hydrological features of the Kemerovo region. Atmospheric circulation, relief, and vegetation are the climate's main factors. The combination of these factors forms the climatic characteristics of the region. Soils in open areas (meadows, hayfields) occupy a small area and have high economic and ecological value. Most of the forest is not affected by economic activities. The exception is disturbances in the territories affected by logging and mining enterprises, which especially affect the air and water quality in the region. All the obtained results of the assessment of the geomorphological and hydrological condition of the Kemerovo region should be used when planning further experiments on the stages of technical and biological reclamation of disturbed lands of mining enterprises to restore vegetation cover and the primary state of soils.

Mineral and raw material self-sufficiency of Ukraine: a geographical mensuration

For a more objective assessment of Ukraine’s resource self-sufficiency, monitoring of its natural resource environment, in particular, subsoil, is used, which is in importmant factor in insuring economic stability and security of the state. A component of this scientific and practical issue is the expansion and deepening of the systemic manifestations of the placement of geochemical resources on the territory of Ukraine with the help of economic-geographical zoning schemes and the table of chemical elements, which are considered as fundamental methodological levers. The authors of the article analyzed the most significant generalizing works of Ukrainian and foreign specialists devoted to mineral resources of Ukraine. The purpose of the study is to adapt the Periodic table of chemical elements by D. I. Mendeleev for the systematization of ideas and cartographic modeling regarding the distribution of mineral deposits in the section of economic and geographical areas of Ukraine. The positioning and realization of the purpose serves as the evidence base of mineral-raw material self-sufficiency of Ukraine, it is evidence of the mineral-raw material and economic-geographic strengthening of the role of D. I. Mendeleev’s table. The objective idea of mineral and self-sufficiency of Ukraine, its inclusion in the top groups of the states most provided with the most valuable types of minerals is strengthened and the high level of availability of mineral resources in Ukraine in terms of its economic and geographical areas and regions is confirmed. At the same time, a number of mineral deposits in modern socio-economic conditions are preserved and not used. For the first time a cartographic interpretation of the periodic table of chemical elements (D.I. Mendeleev’s table) is given, which is reinforced by data on the distribution of mineral resources and minerals in terms of economic and geographical regions and areas of Ukraine. There are 33 chemical elements extracted from more than 100 mineral deposits. The information on geochemical raw materials available in Ukraine is systematized by three items (elements of rock-forming minerals → rock-forming minerals → main deposits), which update the cartograms and map diagrams placed on the diagram. The provisions and conclusions of the article testify to the mineral self-sufficiency of Ukraine and can act as a lever for developing strategies for socio-economic development of the regions of Ukraine. D.I. Mendeleev’s table and its mineral content are positioned as an objective factor in the specialization of Ukraine and the international geographical division of labor. It is noted that the main advantages of the Periodic table of chemical elements, including its structure, logic, objec- tivity, system in relation to the economic and geographical regions of Ukraine are considered as an element of monitoring the mineral component of natural resources of the country, the lever of further development of exploratory geology and geomorphology. The highlighted issues revealed a high density of interdisciplinary connections of the subject-object plane of research (geography, geology, cartography, chemistry, geochemistry, economics, regional studies, zoning), and the presented material can be introduced into the latest programs of reformed education in Ukraine.

Crustal Structures of the Qimantagh Metallogenic Belt in the Northern Tibetan Plateau from Magnetotelluric Data and Their Correlation to the Distribution of Mineral Deposits

Crustal structure and fluid or melt originating in the deep crust and mantle are critical in regional magmatic mineral systems. However, the crustal structure and the processes that entrain and focus fluids from a deep-source region to a metallogenic belt remain relatively undisclosed. We present a magnetotelluric (MT) study of the eastern Qimantagh Metallogenic Belt (QMB) in the northern Tibetan Plateau. Data from 33 MT stations in two sections and 7 dispersed stations are acquired using a surface electromagnetic prospecting (SEP) system in frequency band ranges from 320 Hz to 0.00034 Hz. Data are converted by Bostick conversion and two-dimensional (2D) nonlinear conjugate gradient inversion. Our MT results reveal the geoelectrical crustal structure of the QMB, which consists of a southern low-resistivity domain that reflects the Kumukuri rift, a high-resistivity middle domain that represents the southern QMB in the central Kunlun belt, and a northern low-resistivity domain that covers the northern QMB and southwestern Qaidam block. We present a comprehensive tectonic and geophysical model of QMB based on the MT interpretation and geological analysis. We infer the high-resistivity domain as a reflection of a rigid crust and detached lithospheric mantle, this belt separate the QMB into northern and southern QMB. Most of the mineral deposits are found in the northern low-resistivity domain of QMB. Our study and findings provide an understanding of the tectonic evolution of the northern Tibetan Plateau, the crustal structure that controls the temporal and spatial distribution of magmatic rocks, and the geological signature associated with mineral deposits.

Дмитрий Васильевич Рундквист – сотрудник ВСЕГЕИ (1954-1984)

Dmitry Vasilievich Rundqvist (1930-2022) is an outstanding Soviet and Russian geologist, mineralogist and metallogenist, Doctor of Geological and Mineralogical Sciences, Professor, President of the Russian Mineralogical Society (1987-2015), Academician of the Russian Academy of Sciences, full member of the Academy of Mining Sciences. He made an important contribution to theoretical geology and metallogeny: he investigated the processes of mineral and ore formation, and analyzed the most general trends in the evolution of mineral formation in geological history. He is credited with developing the structural-material principles for separating, classifying and establishing the ore content of geological formations, and creating a series of specialized metallogenic maps that reflect the main regularities in the distribution of mineral deposits and a quantitative assessment of the predicted resources of promising regions of the USSR. The formation of D.V. Rundqvist as a prominent metallogenist was held at the All-Union Scientific Research Geological Institute (VSEGEI), where he worked for 30 years, rose from junior researcher to deputy director for science. The period of work of D.V. Rundqvist in VSEGEI is dedicated to this essay.

Spread Of Laterite Nickel Based on Drill Data at PT Manunggal Sarana Surya Pratama, Southeast Sulawesi Province

Modeling of nickel laterite resources is intended to determine the distribution of resources represented in the form of block models. The results of resource modeling indicate the shape and distribution of mineral deposits which can facilitate the mining process and can predict mining boundaries referring to the results of resource modeling. The purpose of this study was to determine the thickness of the saprolite zone layer and the distribution direction of nickel laterite based on drill point data. The data used in the laterite nickel resource modeling are exploration drill data, drill coordinates, and exploration grade classification. Data processing and analysis methods apply block modeling and the variogram method to determine the distribution direction of nickel resources. Based on the results of the cross-section profiles in Section 1 to Section 7, the average thickness of saprolite is 6,605 m, and the block model layer of saprolite which shows high levels of red color (Ni 1.9 - so on) is the most in the north, pink color (Ni 1.5-1.89) is in the north direction before the Ni 1.9 level above, the green color (Ni 1.3-1.49) is in the east and south.

Fractal Structure Characteristics and Prospecting Direction of Dispersed Metals in the Eastern Guizhou Pb–Zn Metallogenic Belt, SW China

The eastern Guizhou Pb–Zn metallogenic belt (EGMB) is an important source of Pb–Zn resources and other critical minerals (including dispersed metals, such as Ge, Cd and Ga) in China. In order to ensure the continuous resource supply of Pb–Zn and associated dispersed metals, it is urgent to explore the direction of further prospecting for them. Fractal theory can realize the fractal structure characterization of fault structures and the spatial distribution of mineral deposits, which is helpful for mineral exploration. However, the fault fractal research and prospecting application are still seldom covered in the EGMB. We used fractal theory to determine fine-scale fractal structure characteristics of fault structures and ore deposits in the EGMB, and Fry analysis to delineate favorable metallogenic areas. The results show that within a scale range of 3.670–58.716 km, the integrated faults capacity dimension (CPD) is 1.5095, the information dimension (IND) is 1.5391, and the correlation dimension (CRD) is 1.5436, indicating fault structures with high maturity, which are conducive to the migration and accumulation of ore-forming fluids. The multi-fractal spectrum width and height are 0.3203 and 1.5355, respectively, implying a significant metallogenic potential. The spatial distribution fractal dimensions (SDD) of Pb–Zn specifically and metal deposits in general are 1.0193 and 1.0709, respectively; the quantity distribution fractal dimensions (QDD) are 1.4225 and 1.4716, respectively, and the density distribution fractal dimensions (DDD) are 1.422 and 1.472, respectively, indicating strong clustering. Hence, the favorable metallogenic regions can be divided into four grades, among which grade I region is continuously distributed in space and has the greatest prospecting potential.

Aeromagnetic data of the Kelâat M'Gouna inlier (Jbel Saghro, Eastern Anti-Atlas, Morocco): Geotectonic and mining implications

The Kelâat M'Gouna inlier (KM'G) is located in the Eastern Anti-Atlas of Morocco, north of the West African Craton (WAC). It offers outcrops of great lithological diversity and has a polycyclic tectonic history. Its bedrock bears traces of the Pan-African orogeny, and its Adoudou-Cambrian cover was affected by the Hercynian orogeny. Therefore, the KM'G inlier is a privileged geological region for a geo-structural study to evaluate its mining potential. In this study, high-resolution aeromagnetic and surface geological data were used to map the structural architecture of the inlier and determine its relationship to the spatial distribution of mineral deposits and showings. Several filters and operators such as Reduction to Pole (RTP), Upward Continuation (UC), Centre for Exploration Targeting (CET) and Tilt Derivative (TDR) were applied to the aeromagnetic data to reveal important magnetic signatures such as magnetic lineaments/domains in the study area. The TDR and UC subdivided the area into two magnetic morpho-structural domains: to the north, a domain dominated by negative anomalies (labeled NMA1, NMA2 and NMA3), which coincide with the Sidi Flah fault and the Azlag and Ibantarn granites; to the south, a domain dominated by positive anomalies (labeled PMA4 and PMA6) which are deeply rooted. CET and TDR have been applied to map structural complexity and depth estimation. Four main magnetic lineament trends were deduced (NE-SW, Sub E-W, NW-SE, and Sub N–S) with variable depths ranging from 45 to 2120 m. A thorough structural scheme was developed based on the CET and TDR outputs and surface geological data. This scheme shows that the main deposits and mineral occurrences are known from the KM’G geological map are in areas with high magnetic lineament density values. Thus, several potential mineralization zones in the study area have been delineated. These results should guide the exploration of possible metal deposits in the KM’G inlier.

Regional magnetic and gravity structures and distribution of mineral deposits in Central Iran: Implications for mineral exploration

Regional-scale magnetic and gravity data have been enhanced to identify major structures and distinguish geophysical blocks in order to evaluate the distribution of major mineral deposits and prospects in Central Iran. Major structures and coherent magnetic blocks have been defined from magnetic data enhanced using a combination of upward continuation and edge enhancement filters. Broad-scale regional structural architecture and coherent density blocks have been defined from gravity data enhanced using the tilt angle. Crustal thickness was calculated from Bouguer gravity data. Integration of the structures, magnetic, density and depth characteristics derived from the complementary geophysical techniques have been used to correlate and interpret the regional distribution of mineral deposits and occurrences to assist future exploration. Porphyry Cu deposits in the Kerman metallogenic zone are shown to be closely associated with major structures in high magnetic and gravity blocks that are coincident with the Tertiary volcanic units, and in areas where the crustal zone was interpreted to be more than 50 km thick. Pb–Zn deposits in Central Iranian Microcontinent are shown to be spatially associated with major structures, predominantly outside of the high magnetic response blocks, and commonly overlay the low gravity and thick crustal zones. In the north of the study area, one group of Fe deposits display a close correlation to blocks with both a high magnetic and high gravity response. Along strike to the southeast, a second group cluster is seen in an area with a moderate magnetic and a low gravity response.

The Piuquencillo fault system: a long-lived, Andean-transverse fault system and its relationship with magmatic and hydrothermal activity

Abstract. Lithospheric-scale fault systems control the large-scale permeability in the Earth's crust and lithospheric mantle, and its proper recognition is fundamental to understand the geometry and distribution of mineral deposits, volcanic and plutonic complexes and geothermal systems. However, their manifestations at the current surface can be very subtle, as in many cases they are oriented oblique to the current continental margin and to the axis of the magmatic arc; be partially obliterated by younger, arc-parallel faults; and also be covered by volcanic and sedimentary deposits, through which the fault might propagate vertically. The Piuquencillo fault system (PFS) is a proposed lithospheric-scale fault system, located in the Main Cordillera of central Chile. Here, we present the results of the first detailed field study of the PFS, based on structural data collected at 82 structural stations distributed across all the western Main Cordillera. The first published U–Pb zircon ages for the La Obra batholith, which is bounded to the south by the PFS but also affected by younger reactivations of it, were obtained. They yielded 20.79 ± 0.13 Ma (granodiorite) and 20.69 ± 0.07 Ma (monzogranite). Statistical analysis of fault-plane data shows that the presence of the PFS is reflected on a strong preferred NW to WNW strike, with variable dip directions, evident from the analysis of the total fault-plane population and also from individual segments of the PFS. In some segments, the presence of major NE- to ENE-striking faults which intersect the PFS is also reflected in the preferred orientation of fault planes. Preferred orientations of hydrothermal veins, breccias and dikes show that both the PFS and some ENE-striking faults were capable of channelling hydrothermal fluids and magma. Kinematic and dynamic analysis of fault-plane data reveals that most of the PFS was reactivated with sinistral ± reverse kinematics during the Neogene, under a strike-slip to transpressive regime with E- to ENE-trending shortening direction (σ1). Detailed kinematic and dynamic analyses were completed for various segments of the PFS and also for the different rock units affected by it. This study supports the concept that the PFS is a lithospheric-scale fault system, which strongly controlled deformation and the flow of magmas and hydrothermal fluids during the Neogene. The PFS forms part of a larger, margin-transverse structure, the Maipo deformation zone, a continental-scale discontinuity which cut across the entire Chilean continental margin and has been active at least since the Jurassic.

World mineral deposits in the table of periodic chemical elements

The distribution of mineral deposits and the distribution of chemical elements on the globe are characterized by heterogeneity. A wide range of publications of domestic and foreign specialists - geologists, geographers, geochemists, economists - were dedicated to mineral resources of the world, mineral deposits. During processing the material the comparative-geographical, cartographic (analysis of minerals maps, mineral resources in the context of continents and regions of the world, cartographic interpretation of Mendeleev periodical table), monographic (analysis of fundamental works of leading domestic and foreign geologists and resource scientists, geologists and geologists, and geologists and geologists) directories, multi-volume editions devoted to geology and mineral resources of individual countries and regions of the world) methods, systematic approach, and GIS technologies - all these were used for received data processing and systematization. Explored mineral deposits (current and potential) form on the planet both individual local deposits and geochemical zones – areas where economically valuable chemical elements and their compounds are concentrated, which are diverse in genesis, stocks, and possibilities of exploitation. The largest of the latter is the Appalachians in the US - the Western Hemisphere, the Highveld in South Africa, Khibiny and the Ural Mountains inRussia - the Eastern Hemisphere. The leading countries in which most geochemical resources are extracted from the subsoil are the United States (65% of the total elements of Mendeleev periodical table), Russia (48%), China (38%), Canada (38%), South Africa (30%), Australia, (27%), Kazakhstan (19%), India (14%), Mexico (13%). The ideas about the level of provision of mineral resources and minerals in individual countries and territories of the world were systematized. The Mendeleev periodical table and its mineral and raw content were presented as an objective factor in the international geographical distribution of labor. The illuminated issues are confirmed high density of interdisciplinary links (geology, geography, chemistry, geochemistry, ecology, economics, regional studies, zoning).

Lithospheric structure of the southern Amazonian Craton from multiple-frequency seismic tomography: Preliminary insights on tectonic and metallogenic implications

We present a P-wave structure for the sub-continental lithospheric mantle (SCLM) beneath the southern segment of the Amazonian Craton (Central Brazil Shield – CBS) using multiple-frequency tomography. Our model includes 469 seismic events recorded between 2009 and 2017 through 314 seismic stations distributed over South America. From these events, we obtained 20507 P and 12329 PKIKP cross-correlation delays in six frequency bands centered at 0.03, 0.06, 0.13, 0.25, 0.5 and 1 Hz. Despite the limited and heterogeneous resolution throughout the CBS, because of the difficulty in the installation of seismographic stations in areas of dense coverage of tropical forest, our tests show reasonable resolution for lithospheric domains with dimensions greater than 390 × 390 km in most of the study area. We recognized a good correlation between the P-wave anomalies and the tectonic domains defined previously based on geochronology and geological data. The surface projection of these anomalies and their margins are associated with clusters of important Au, Cu–Au and IOCG deposits, as well as diamond-bearing kimberlite intrusions, allowing relating deep structures with shallow features and showing a province-scale control in the distribution of mineral deposits and occurrences in the southern Amazonian craton.

Three-Dimensional Mineral Potential Mapping for Reducing Multiplicity and Uncertainty: Kaerqueka Polymetallic Deposit, QingHai Province, China

This study focuses on the selection of a method combining simulations of mineralizing processes with three-dimensional (3D) mapping to quantitatively predict locations of concealed mineralization and to reduce uncertainty and multiplicity. The simulation of ore-forming processes for concealed mineralization requires the assessment of a region’s structural geology, ages of lithological units, degree of metamorphism, and role of magmatism in the genesis of mineralization. The evolution of various factors affecting the development of geological processes in space and time is discussed, including the assessment of models combining regional deformation-magmatic activity-mineralized hydrothermal fluid based on empirical knowledge. Given that metallogeny is a study of the genesis and regional distribution of mineral deposits and emphasizes their spatial and temporal relationships, this paper uses empirical knowledge to predict the locations of concealed mineral deposits. Furthermore, the analysis of 3D geological modeling of concealed orebodies is a process that contributes to understanding the metallogenesis of mineral deposits. In this study of the Kaerqueka skarn and porphyritic deposits, geological, geographic, remote sensing and geochemical data collected from this region are processed using computer modeling techniques available in the Surpac software to establish a digital representation of the mineral field. The “block mapping modeling” theory, geostatistical methods, simulations of ore-forming processes, and 3D mapping methods are then combined to predict the locations of the most promising areas for concealed mineral deposits around the Kaerqueka deposit. This research introduces a new method for predicting and evaluating the locations of concealed orebodies by reducing multiplicity and uncertainty.

Mineral deposits of northeastern Algeria (southern Medjerda mounts and diapiric zone): regional-scale structural controls, spatial distribution, and importance of geophysical lineaments

The Southern of Medjerda mounts and the diapiric zone in the northeast of Algeria host a significant hydrothermal Pb-Zn-Fe-Ba (±Cu, ±F, ±Sr, ±Au, ±Ag) ore deposits and showings. The integration of geophysical data (ground gravity and aeromagnetic datasets) was undertaken in order to clarify and define the litho-structural control of the mineralization. These geophysical surveys allowed the identification of several prominent geophysical features. Some of these features correspond to lithological contacts; others reflect tectonic trough zones, Triassic salt diapirs, sedimentary basins, anticlines, and faults. The preferential (primary) trend of structural features within the study area is NE–SW and NW–SE. Integrated interpretation of geological and regional geophysical data helped the identification of the main factors controlling the distribution of mineral deposits within the study area. Most of the mineral deposits are likely to be found along or near major NE–SW/NW–SE deep lineaments. These major deeper lineaments have probably controlled the kinematic evolution of geological structures, sedimentary basins, and the ascension of the Triassic rocks during the lower Cretaceous. They seem to play a significant role providing favorable pathways for the migration and ascent of mineralized fluids to depositional sites along smaller faults into the sedimentary cover or at contact between Triassic salt outcrops and lower Cretaceous carbonate rocks.

Fractal dimension and its translation into a model of gold spatial proxy

Unraveling the spatial distribution of mineral deposits is an essential part of exploration and important for developing a better understanding of ore-forming processes. In this study, gold assay results (in g/t) of twelve boreholes completed from Mysore Block and eleven boreholes completed from Nabhapur North Block, Central Lode System, Gadag Gold Field (GGF), India, were analyzed using fractal analysis. Both the fractal correlation integral and rescaled range analysis were used to measure the fractal dimension from the gold-concentration values. The fractal dimension values obtained from the fractal correlation integral were used to better constrain the possible auriferous fluid-flow pathways, whilst results obtained from the rescaled range analysis were used to describe the behavior of auriferous veins across the boreholes. The fractal dimension values were found to vary from 0.014 to 3.0, with the higher values taken to indicate the presence of well-developed interconnected fault-fracture networks representing steep permeable fluid-flow pathways. The lower fractal dimension values were taken to indicate unfavorable fluid-flow pathways. In other words, higher-grade gold ores were deposited along the structures represented by steep fractal gradients. Hurst exponent (H) values obtained from the rescaled range analysis were found to vary from 0.50 to 0.96, satisfying the condition 0.5 < H < 1. In summation, the mineralized veins displaying fractal behavior are persistent across the boreholes from both the Mysore and Nabhapur gold deposits, which suggests these deposits are targets for gold exploration.

Macro-scale ore-controlling faults revealed by micro-geochemical anomalies

Whereas the mechanism of fluid flow, and thus structural control, linked with mineral deposit formation is quite understood, the specific structures that likely provided controls on mineralization at certain geographic scales are not readily known for a given region unless it is well-explored. This contributes uncertainty in mineral prospectivity analysis in poorly-explored regions (or greenfields). Here, because the spatial distribution of mineral deposits has been postulated to be fractals (i.e., the patterns of these features are self-similar across a range of spatial scales), we show for the first time that micro-geochemical anomalies (as proxies of micro-scale patterns of ore minerals), from few discrete parts of the Sossego iron-oxide copper-gold (IOCG) deposit in the Carajás Mineral Province (CMP) of Brazil, exhibit trends of macro-scale faults that are known to have controlled IOCG mineralization in the CMP. The methodology described here, which led to this novel finding, would help towards detecting mineral exploration targets as well as help towards understanding structural controls on mineralization in greenfields.

Application of Zipf’s law to estimate undiscovered Gold endowment in the Quadrilátero Ferrífero Province, Brazil

Ore-forming processes act as self-organizing critical systems. These systems exist in an unbalanced nature, such that energy-release can occur as a scale-invariant power-law behavior when a certain threshold is exceeded. In ore-forming systems, the energy released from multiple transient pulses of over-pressured fluid appears to follow a power-law, since the distribution of mineral deposits in mature provinces have been shown to obey Zipf's law. Zipf's law represents a statistical relationship between the size and rank of a discrete phenomenon. In this work, we present the application of Zipf's law in estimating the undiscovered gold endowment of the Quadrilatero Ferrifero Province in Brazil. In addition, we conducted several statistical tests to validate the application of Zipf's law and discussed its limitations regarding smaller deposits. The Kolmogorov-Smirnov's minimum distance was presented as an alternative to defining the lower boundary of the Zipf's law's domain, rather than using an economic cut-off. Our results estimate the maturity of the Quadrilatero Ferrifero Province to be 65%, with potential for the discovery of at least 749 t of gold, comprising 28 deposits larger than 8 t (totaling 519 t), and 2 deposits larger than 40 t (totaling 122 t).

Prostorové rozložení ložisek nerostných surovin těžených artisanální těžbou v oblasti východoafrických velkých jezer

The East African Great Lakes Region is an area rich in rare mineral resources and thus represents a great economic potential. Mineral mining in Great Lakes Region is proceeding in a specific way which is known as artisanal and small-scale mining. This mining with no mechanization is mostly expanding in developing countries. In these areas mining represents one of the main sources of income for the local population and creates one of the main pillars of economic development. This paper presents the artisanal and small-scale mining and spatial distribution of mineral deposits in Burundi, Kenya, Rwanda, Tanzania and Uganda where rare minerals are extracted. The aim of this article is to introduce artisanal and small-scale mining to Central Europe discussion where this topic is relatively neglected. Minerals which are extracted by artisanal and small-scale mining are used in electro-technical industry, i.e. mobile phones, computers, tablets, automobiles, aircrafts and other technical products manufacturing, the extracted minerals become significant and direct part of our everyday life.

Crustal architecture and its controls on mineralisation in the North China Craton

Knowledge of the history of the Earth’s continents and the genesis of mineral deposits is poorly understood on a crustal-scale. This contribution combines geological and zircon Hf-isotopic data collected from igneous rocks associated with mineralisation to gain a better understanding of the nature of the growth of, and mineral genesis in the North China Craton. The new zircon U–Pb dates reported here are 2587 ± 62 Ma for syenogranite at Zanhuang in the northeast part of craton, 2552 ± 24 Ma for trondhjemitic gneiss and 2554 ± 29 Ma for metadiorite at Dengfeng in the eastern and central part of, and 2820 ± 6 and 2821 ± 32 Ma for tonalite at Lushan in the southeast part of the craton. Lu-Hf isotopic data collected from granitic rocks for this study yield εHf(t) values and Hf crustal model ages (TDMc) of 3–5.8 and 2580–2600 Ma for the syenogranite at Zanhuang, 1.9–7.4 and 2550–2580 Ma for trondhjemitic gneiss and metadiorite at Dengfeng, and 0.5–5.2 and 3120–2840 Ma for tonalite at Lushan. Six major magmatic events have been recognised throughout the region. The crustal growth and reworking of the craton includes Eo- to Mesoarchean, early Neoarchean, and Paleoproterozoic events. The consistency in the evolution of Neoarchean magmatism coupled with zircon Hf isotope systematics indicate that similar crustal growth and reworking were in action in the Eastern, Trans-North China, and Western blocks. The crust architecture indicated by Hf isotopic mapping of the North China Craton constrains the distribution of mineral deposits. The BIF-hosted Fe deposits are spatially related to juvenile or reworked crustal domains, with groups of deposits located internal to and at the margins of Archean terranes, and orogenic Au deposits are spatially associated with juvenile crustal domains.