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A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Deposits".

Deadline for manuscript submissions: closed (30 October 2022) | Viewed by 34099

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Special Issue Editors

Prof. Dr. Adalene Moreira Silva

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Guest Editor

Instituto de Geociências, Universidade de Brasília, Brasília 70910-900, Brazil
Interests: regional geophysics; geophysical responses of mineral systems; petrophysics; mineral mapping; geodynamic settings of mineral deposit systems; spatial data analysis

Prof. Dr. Catarina Labouré Bemfica Toledo

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Guest Editor

Instituto de Geociências, Universidade de Brasília, Brasília 70910-900, Brazil
Interests: regional geology; mineral mapping; geodynamic settings of mineral systems; lithogeochemistry

Prof. Dr. António Manuel Nunes Mateus

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Guest Editor

Department of Geology, University of Lisbon, 1749-016 Lisbon, Portugal
Interests: ore-forming processes and plate tectonics; geology of ore deposits; hydrothermal geochemistry; geochemical exploration; mineralogy; geochemistry and fluid/rock interaction

Special Issue Information

Dear Colleagues,

Mineral deposits are local expressions of a mineral system that involve multiscale mass and energy transfer processes. The footprint of a deposit can be defined from the integration of several methods and, when well characterized, indicates important exploration vectors for the identification of new targets in mineralized terrains. The big challenge is to understand how mineralizing fluids affect the physical and chemical properties of rocks, but also the magnitude of interaction between fluids and host and temperature gradients related to the distance of the main fluid conduits.

These questions have been addressed by different research groups in an attempt to improve the understanding of the petrophysical, geophysical, mineralogical, geochemical, and surface mapping responses of important geological processes for the formation of mineral deposits, especially hydrothermal fluid circulations in mineral systems.

This issue aims to highlight the latest advances in applied science to the understanding of the footprint of mineral systems, which highlights (1) geodynamics and mineral systems through integrated multidisciplinary approaches; (2) processes that form mineral deposits; (3) characterization of the footprint through geophysical, geochemical, petrophysical, and/or mineral mapping data; and (4) multisource data integration using expert systems, machine learning or artificial intelligence.

Prof. Dr. Adalene Moreira Silva
Prof. Dr. Catarina Labouré Bemfica Toledo
Prof. Dr. António Manuel Nunes Mateus
Guest Editors

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Keywords

geodynamic settings of mineral systems
ore footprint
petrophysical footprint
mineralogical footprint
geophysical footprint
geochemical footprint
hydrothermal alteration footprint
surficial footprint in regolith
integrated multiparameter exploration footprints

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Published Papers (11 papers)

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Research

26 pages, 41135 KiB

Open AccessArticle

Predictive Mapping of Prospectivity for Gold in the Central Portion of the Tapajós Mineral Province, Brazil

by Sulsiene Machado de Souza Gaia and Carlos Roberto de Souza Filho

Minerals 2023, 13(11), 1432; https://doi.org/10.3390/min13111432 - 12 Nov 2023

Viewed by 2155

Abstract

This work aims to model mineral prospectivity for intrusion–related gold deposits in the central portion of the Tapajós Mineral Province (TMP), southwestern Pará state. The scope includes experimentation and evaluation of knowledge and data-driven methods applied to multisource data to predict potential targets for gold mineralization. The radiometric data processing allowed to identify a hydrothermal alteration footprint of known gold deposits, providing information in regions with little or no field data available. The aeromagnetic data analysis prompted the identification of high magnetic zones, which are probably related to hydrothermal fluid transport. Linear features extracted from digital elevation data revealed an NNW–SSE general trend, which is consistent with the main structural control of deposits. The data were integrated through three modeling techniques—fuzzy logic (knowledge-driven), weights of evidence (WofE, data-driven), and a machine learning algorithm (SVM, data-driven)—resulting in three prospective models. In all models, the majority of indicated prospective regions coincide with the known deposits. The results obtained in the models were combined to generate an agreement map, which mapped the overlapping of their highest prospective scores, indicating new areas of prospective interest in the central portion of the TMP. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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31 pages, 15737 KiB

Open AccessArticle

Application of Satellite Remote Sensing, UAV-Geological Mapping, and Machine Learning Methods in the Exploration of Podiform Chromite Deposits

by Amir Eskandari, Mohsen Hosseini and Eugenio Nicotra

Minerals 2023, 13(2), 251; https://doi.org/10.3390/min13020251 - 10 Feb 2023

Cited by 10 | Viewed by 3549

Abstract

The irregular and sporadic occurrence of chromite pods in podiform chromite deposits (PCD), especially in mountainous terranes with rough topography, necessitates finding innovative methods for reconnaissance and prospecting. This research combines several remote sensing methods to discriminate the highly serpentinized peridotites hosting chromite pods from the other barren ultramafic and mafic cumulates. The case study is the area of the Sabzevar Ophiolite (NE Iran), which hosts several known chromite and other mineral deposits. The integration of satellite images [e.g., Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite sensor, Landsat series, and Sentinel-2] coupled with change detection, band rationing, and target detection algorithms [including the Spectral Angle Mapper (SAM)] were used to distinguish potential lithological units hosting chromites. Results have been verified by an initial on-field checking and compared with the high-resolution (GSD ~6 cm) orthomosaic images obtained by the processing of photographs taken from an Unmanned Aerial Vehicle (UAV) at a promising area of 35 km². The combination of visual interpretation and supervised classification by machine learning methods [Support Vector Machine (SVM)] yielded the production of a geological map, in which the lithological units and structures are outlined, including the crust-mantle transition zone units, mafic cumulates, crosscutting dykes, and mantle sequences. The validation of the results was performed through a second phase, made up of field mapping, sampling, chemical analysis, and microscopic studies, leading to the discovery of new chromite occurrences and mineralized zones. All ultramafic units were classified into four groups based on the degree of serpentinization, represented by the intensity of their average spectral reflectance. Based on their presumed protolith, the highly serpentinized ultramafics and serpentinites were classified into two main categories (dunite or harzburgite). The serpentinite with probable dunitic protolith, discriminated for a peculiar Fe-rich Ni-bearing lateritic crust, is more productive for chromite prospecting. This is particularly true at the contact with mafic dykes, akin to some worldwide chromite deposits. The results of our work highlight the potential of multi-scale satellite and UAV-based remote sensing to find footprints of some chromite mineral deposits. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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20 pages, 14689 KiB

Open AccessEditor’s ChoiceArticle

Geoelectric Signature of Gold Mineralization in the Alta Floresta Gold Province, Mato Grosso State, Brazil

by Eduardo Xavier Seimetz, Alexandre Santos Jeronimo da Costa, Welitom Rodrigues Borges, Marco Ianniruberto and Rafael Espindola Canata

Minerals 2023, 13(2), 203; https://doi.org/10.3390/min13020203 - 31 Jan 2023

Cited by 1 | Viewed by 2093 | Correction

Abstract

The Alta Floresta Gold Province (PAAF) is abundant in gold deposits and, located in the state of Mato Grosso, Brazil, is an ideal place to study the geoelectric signature of gold mineralization. Auriferous mineralization occurs along shear zones in quartz veins and disseminated granites in this region. Ores are associated with oxides and sulfides, mainly with pyrites. To identify primary gold or continuities of the mineralized zones, data were acquired using the geophysical methods of electrical resistivity and induced polarization in three gold mines: Raimunda, Truilio, and Porteira. Dipole–dipole arrays with electrode spacings of 20 and 25 m were used to investigate up to 100 m in depth. Resistivity and chargeability range scales were developed with statistical analyses of all the geophysical and geological data. The geophysical models of the Raimunda and Truilio gold mines showed coherence with the boreholes, but the geophysical models of the Porteira gold mine were not coherent with the boreholes. The resistivity and chargeability parameters indicated that the lithotypes (soils, saprolites, and monzogranites) could be characterized and identified as potential mineralized targets. The soils ranged from 1000 to 8000 ohm.m, the saprolites had values from 150 to 800 ohm.m, and the monzogranite values were from 1100 to 9000 ohm.m. The mineralized targets had values from 18 to 35 mV/V. The results confirm the efficiency of the resistivity and induced polarization methods to find sulfides in shear zones in the Alta Floresta Gold Province. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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23 pages, 23591 KiB

Open AccessFeature PaperArticle

Strategies for Targeting in Undercover Terrains: Modeling Multi-Source Data in Apuí Region, SW Amazon Craton, Brazil

by Lila Costa Queiroz, Adalene Moreira Silva, Frederico Ricardo Ferreira Rodrigues de Oliveira e Sousa, Michele Zorzetti Pitarello and Márcia Abrahão Moura

Minerals 2023, 13(1), 78; https://doi.org/10.3390/min13010078 - 4 Jan 2023

Cited by 1 | Viewed by 2485

Abstract

Exploring covered terrains is a challenge that requires the integration of multiple sources of knowledge, particularly in the initial stages of mineral exploration. The Apuí region, located in the Southwestern Amazon Craton, has a small and constant gold production, despite the deep cover and limited geological knowledge. The gold is mainly hosted in quartz veins and breccias that cut Paleoproterozoic volcano-sedimentary sequences. The occurrences have similar characteristics to magmatic–hydrothermal deposits, such as a lack of regional metamorphism and intense hydrothermalization. We undertook a multi-source prospective investigation on different scales using 2D and 3D techniques to translate the footprints of the mineral system into mappable criteria. Gold prospectivity maps for the Juma District and Guida Target were produced by integrating geological, geochemical, and geophysical datasets in knowledge-driven fuzzy systems. Regional airborne magnetization vector inversion (MVI) models were utilized. The correlation between the drill cores and the magnetic susceptibility models highlighted a potential surface for gold mineralization associated with the boundary between a granitic intrusion and volcano-sedimentary rocks. The prospectivity maps reduced the search area, and the regional susceptibility models allowed for the reconnaissance of structures and bodies that may be related to gold mineralization at depth. The results present new strategies for increasing discovery performance in the Southern Amazon Craton under cover. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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28 pages, 19834 KiB

Open AccessArticle

Hydrothermal Alteration Zones’ Magnetic Susceptibility Footprints and 3D Model of Iron Oxide-Copper-Gold (IOCG) Mineralization, Carajás Mineral Province, Brazil

by Marcelo Leão-Santos, Roberto Moraes, Yaoguo Li, Maria Irene Raposo and Boxin Zuo

Minerals 2022, 12(12), 1581; https://doi.org/10.3390/min12121581 - 9 Dec 2022

Cited by 2 | Viewed by 3343

Abstract

Brownfield areas are important targets of exploration; however, the extensive drilling present in these areas has not fully exploited their prospective potential. The appropriate use of drill hole cores in these areas can play an important role in deep exploration. We present a case study of iron oxide-copper-gold (IOCG) Furnas Southeast deposit, located in the Carajás Mineral Province, Brazil. This deposit has disseminated chalcopyrite, bornite and gold mineralization associated with a silicic (Si), potassic (K), calcic (Na), sodic-calcic (Na-Ca) hydrothermal alteration, and intense iron metasomatism with massive magnetite (Fe) alteration. Petrophysical hand-held equipment measurements were carried out on drill core samples with the purpose of studying the potential roles that magnetic susceptibility properties can play in high-grade mineralization. The results indicate that the geological complexity of the IOCG deposit is readily reflected in the extensive variation of the measurements. The statistical analysis shows how the detailed characterization of this physical property carried out for this mineral association could effectively define and describe ore, and the magnetic susceptibility footprints of hydrothermal alteration zones. Furthermore, we were able to perform a magnetic susceptibility 3D modeling of diamagnetic, paramagnetic, and ferrimagnetic responses strictly correlated with known orebody. Thus, petrophysical analyses can form a quantitative geological criterion for ore delineation. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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34 pages, 19066 KiB

Open AccessArticle

New Insights into the Evolution and Footprints of the Paraíba Au-Cu-Mo Deposit, Alta Floresta Mineral Province (Brazil), through Integration of Spectral and Conventional Methods

by Luciano Poggi, Diego Fernando Ducart, Maria José Mesquita, Igor Camargo Moreira, Márcia Elisa Boscato Gomes and Carlos Roberto de Souza Filho

Minerals 2022, 12(10), 1327; https://doi.org/10.3390/min12101327 - 20 Oct 2022

Cited by 2 | Viewed by 3252

Abstract

The Paraíba is an Au-Cu-Mo deposit located in the southern part of the Amazon Craton, in the Alta Floresta Mineral Province, Mato Grosso State, Brazil. It is composed of Au-Cu-bearing quartz veins and Cu-Mo-rich hydrothermal breccias and stockworks, both associated with several hydrothermal alteration zones. The integration of spectral (reflectance and imaging spectroscopy) and conventional techniques (core logging, petrography, mineral chemistry, and scanning electron microscopy) was applied to map alteration zones, identify mineral parageneses, and determine the evolution of the deposit to generate a solid proxy for mineralized zones. This study shows an overlapping of two different mineralization systems in the AFMP, referenced hereafter as alteration Groups 1 and 2. Group 1 is an Orogenic Gold system related to Au-Cu-rich quartz veins in phyllonites and mylonites. Group 2 is a Cu-Mo Porphyry system related to a syenogranite intrusion and the subsequent generation of several hydrothermal alteration zones, Cu and Mo hydrothermal breccias, and stockwork mineralization. This study reveals several alteration footprints, guides, and vectors for the mineral exploration of these deposits in the Alta Floresta Mineral Province. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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31 pages, 13109 KiB

Open AccessFeature PaperArticle

Chromite Oxidation Patterns Associated to Serpentinization: Case Studies from the Mid-Atlantic Ridge, the Alter do Chão Massif (NE Alentejo, Portugal) and the Ronda Massif (Spain)

by Isabel Ribeiro da Costa and Fernando J. A. S. Barriga

Minerals 2022, 12(10), 1300; https://doi.org/10.3390/min12101300 - 15 Oct 2022

Cited by 5 | Viewed by 2299

Abstract

Chromite oxidation during serpentinization of host peridotites is a well-documented process. Detailed compositional characterization of chromites and Cr-rich spinels from three geotectonic settings provided the basis for this study, focused on the comparison of their oxidation patterns as a means to evaluate the relative mobility of spinel components during serpentinization-related oxidation in those different contexts, namely: (i) tectonic exposures of serpentinized oceanic upper-mantle in the Azores sector of the Mid-Atlantic Ridge (MAR); (ii) serpentinized peridotites from Cabeço de Vide (CV, Alter do Chão Massif, Portugal); and (iii) serpentinized subcontinental mantle peridotites from the Ronda Massif (Spain). Electron microprobe data show that: (i) irrespective of geotectonic setting and original composition, Cr-spinels follow similar oxidation trends; (ii) early Cr-spinel oxidation, involving significant Mg- and Al-depletion leading to the formation of ferritchromit rims, has been more intense in the CV serpentinites than in the more recent MAR and Ronda serpentinites; (iii) with the possible exception of Zn, trace components (Mn, Ti, V, Ni and Co) seem to be relatively immobile during spinel oxidation, thus becoming slightly enriched in ferritchromit rims; (iv) extreme Cr-spinel oxidation is responsible for incomplete outer rims of magnetite on several grains. Time, fluid pH, and fluid/rock ratios seem to be the main factors controlling the intensity and extension of chromite oxidation. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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30 pages, 15950 KiB

Open AccessFeature PaperArticle

Trace Element Geochemistry of Alluvial TiO₂ Polymorphs as a Proxy for Sn and W Deposits

by Miguel Gaspar, Nuno Grácio, Rute Salgueiro and Mafalda Costa

Minerals 2022, 12(10), 1248; https://doi.org/10.3390/min12101248 - 30 Sep 2022

Cited by 2 | Viewed by 4094

Abstract

The Segura mining field, the easternmost segment of the Góis–Panasqueira–Segura tin–tungsten metallogenic belt (north–central Portugal), includes Sn-W quartz veins and Li-Sn aplite-pegmatites, which are believed to be genetically related to Variscan Granites. Sediment geochemistry indicates granite-related Ti-enrichments, locally disturbed by mineralization, suggesting magmatic and metamorphic/metasomatic titaniferous phases. Therefore, Segura alluvial samples and the geochemistry of their TiO₂ polymorphs (rutile, anatase, and brookite) were investigated, and their potential as exploration tools for Sn and W deposits was evaluated. The heavy-mineral assemblages proved to be good proxies for bedrock geology, and TiO₂ polymorph abundances were found to be suitable indicators of magmatic and/or metasomatic hydrothermal processes. The trace element geochemistry of Segura’s alluvial rutile, anatase, and brookite is highly variable, implying multiple sources and a diversity of mineral-forming processes. The main compositional differences between TiO₂ polymorphs are related to intrinsic (structural) factors, and to the P-T-X extrinsic parameters of their forming environments. Anomalous enrichments, up to 9% Nb, 6% Sn and W, 3% Fe, 2% Ta, and 1% V in rutile, and up to 1.8% Fe, 1.7% Ta, 1.2% Nb, 1.1% W 0.5% Sn and V in anatase, were registered. Brookite usually has low trace element content (<0.5%), except for Fe (~1%). HFSE-rich and granitophile-rich rutile is most likely magmatic, forming in extremely differentiated melts, with Sn and W contents enabling the discrimination between Sn-dominant and W-dominant systems. Trace element geochemical distribution maps show pronounced negative Sn (rutile+anatase) and W (rutile) anomalies linked to hydrothermal cassiterite precipitation, as opposed to their hydrothermal alteration halos and to W-dominant cassiterite-free mineralized areas, where primary hydrothermal rutile shows enrichments similar to magmatic rutile. This contribution recognizes that trace element geochemistry of alluvial TiO₂ polymorphs can be a robust, cost- and time-effective, exploration tool for Sn(W) and W(Sn) ore deposit systems. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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27 pages, 20733 KiB

Open AccessArticle

The Lanthanide “Tetrad Effect” as an Exploration Tool for Granite-Related Rare Metal Ore Systems: Examples from the Iberian Variscan Belt

by Ivo Martins, António Mateus, Michel Cathelineau, Marie Christine Boiron, Isabel Ribeiro da Costa, Ícaro Dias da Silva and Miguel Gaspar

Minerals 2022, 12(9), 1067; https://doi.org/10.3390/min12091067 - 24 Aug 2022

Cited by 3 | Viewed by 2912

Abstract

Highly fractionated granites and related magmatic-hydrothermal ore-forming processes can be traced by elemental ratios such as Nb/Ta, K/Rb, Y/Ho, Sr/Eu, Eu/Eu*, Zr/Hf, and Rb/Sr. The lanthanide “tetrad effect” parameter (TE_1,3) can also be a useful geochemical fingerprint of highly fractionated granites. This work assesses its application as an exploration vector for granite-related mineralization in the Central Iberian Zone by examining TE_1,3 variations with different elemental ratios and with the concentrations of rare metals and fluxing elements (such as F, P, and B). The multi-elemental whole-rock characterization of the main Cambrian–Ordovician and Carboniferous–Permian granite plutons and late aplite–pegmatite dykes exposed across the Segura–Panasqueira Sn-W-Li belt show that the increase in TE_1,3 values co-vary with magmatic differentiation and metal-enrichment, being the Carboniferous–Permian granite rocks the most differentiated, and metal specialized. The Argemela Li-Sn-bearing rare metal granite and the Segura Li-phosphate-bearing aplite–pegmatite dykes deviate from this geochemical trend, displaying TE_1,3 < 1.1, but high P₂O₅ contents. The results suggest that mineralized rocks related to peraluminous-high-phosphorus Li-Sn granite systems are typified by TE_1,3 < 1.1, whereas those associated with peraluminous-high-phosphorus Sn-W-Li (lepidolite) and peraluminous-low-phosphorus Sn-Ta-Nb granite systems display TE_1,3 > 1.1, reaching values as high as 1.4 and 2.1, respectively. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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27 pages, 8565 KiB

Open AccessArticle

LA-ICP-MS Trace Element Composition of Sphalerite and Galena of the Proterozoic Carbonate-Hosted Morro Agudo Zn-Pb Sulfide District, Brazil: Insights into Ore Genesis

by Colin Aldis, Gema R. Olivo and Samuel Morfin

Minerals 2022, 12(8), 1028; https://doi.org/10.3390/min12081028 - 16 Aug 2022

Cited by 4 | Viewed by 2360

Abstract

The metal-rich Vazante-Paracatu Mineral Belt, in central Brazil, hosts the Zn-Pb sulfide Morro Agudo District in the Mesoproterozoic (1.3–1.1 Ga) upper carbonate sequence of the Vazante Group. The Morro Agudo district is comprised of the Morro Agudo deposit and the Bento Carmelo, Sucuri, and Morro do Capão occurrences. This carbonate sequence also hosts the Fagundes, Ambrósia and Bonsucesso Zn-Pb sulfide deposits (northern part) and the zinc silicate Vazante and North Extension deposits (southern part). The structurally controlled, stratabound and stratiform styles of mineralization in the Morro Agudo orebodies have been variably classified as sedimentary exhalative, Irish-type and Mississippi Valley-type. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analyses of sphalerite and galena from the Morro Agudo district revealed that red sphalerite (interpreted as the last stage) has higher Fe and Mn and lower Bi, Co, Cu, Ge, Hg, Tl compared to the other types of sphalerite, whereas the first generation of galena (Gn-I) is enriched in Ag, Cd, and Se and depleted in Cu and Mn relative to later galena (Gn-II). Mineral paragenesis and principal component analysis (PCA) of ore mineral composition suggest that the Morro Agudo, Sucuri and Morro do Capão mineralized zones formed by similar processes involving Zn-Pb mineralizing fluids with various compositions, comprising two main elemental associations: (1) Fe, As, In, Mn, Sb, Ag; and (2) Cd, Bi, Co, Ga, and Se. Bento Carmelo is distinguished in PCA by its unique dolomite-hosted sphalerite composition with elevated concentrations of Cu, Ge, Hg and likely formed from distinct fluids or processes. Temperatures of the mineralizing fluids for the Morro Agudo district range from 82 to 320 °C, calculated based on the trace element composition of sphalerite. The styles of mineralization and ore compositions are consistent with MVT deposits; however, fluid temperatures are hotter than typical MVT mineralizing fluids and may reflect a higher geothermal gradient or active advective fluid flow during the Brasiliano orogeny. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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25 pages, 7164 KiB

Open AccessArticle

Energy Drive for the Kiruna Mining District Mineral System(s): Insights from U-Pb Zircon Geochronology

by Leslie Logan, Joel B. H. Andersson, Martin J. Whitehouse, Olof Martinsson and Tobias E. Bauer

Minerals 2022, 12(7), 875; https://doi.org/10.3390/min12070875 - 11 Jul 2022

Cited by 5 | Viewed by 3351

Abstract

The Kiruna mining district, Sweden, known for the type locality of Kiruna-type iron oxide–apatite (IOA) deposits, also hosts several Cu-mineralized deposits including iron oxide–copper–gold (IOCG), exhalative stratiform Cu-(Fe-Zn), and structurally controlled to stratabound Cu ± Au. However the relationship between the IOA and Cu-systems has not been contextualized within the regional tectonic evolution. A broader mineral systems approach is taken to assess the timing of energy drive(s) within a regional tectonic framework by conducting U-Pb zircon geochronology on intrusions from areas where Cu-mineralization is spatially proximal. Results unanimously yield U-Pb ages from the early Svecokarelian orogeny (ca. 1923–1867 Ma including age uncertainties), except one sample from the Archean basement (2698 ± 3 Ma), indicating that a distinct thermal drive from magmatic activity was prominent for the early orogenic phase. A weighted average ²⁰⁷Pb/²⁰⁶Pb age of 1877 ± 10 Ma of an iron-oxide-enriched gabbroic pluton overlaps in age with the Kiirunavaara IOA deposit and is suggested as a candidate for contributing mafic signatures to the IOA ore. The results leave the role of a late energy drive (and subsequent late Cu-mineralization and/or remobilization) ambiguous, despite evidence showing a late regional magmatic-style hydrothermal alteration is present in the district. Full article

(This article belongs to the Special Issue Footprints of Mineral Systems)

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