At the NE edge of the Saghro inlier, the Tassafte mining district represents a promising area to understand the AgHg-Cu mineralization history of the Anti-Atlas belt. The area is located at the Ediacaran-Cambrian transition, where the ore mineralized bodies are hosted within Ediacaran volcano-sedimentary succession of the Ouarzazate Group and also continue within the Cambrian sedimentary sequences. Ore bodies occur in E-W striking structures, ranging from N80 degrees to N120 degrees, which dip 50 degrees-80 degrees to the south and rarely to the north. Mineralization is controlled by two tectonic stages within the E-W trending structures: a) right lateral shearing, syn-kinematic with centimetric quartz veins (QzII); and b) left lateral movement syn-kinematic with barite and calcite veins. Ore microscopy investigation illustrates a multistage ore including; i) the first stage, represented by microcrystalline quartz (QzI) and euhedral pyrite crystals, arsenopyrite and rare cobaltite crystals are also recognized; ii) the second stage which represents the main ore stage in which the most important Ag and Cu were deposited. It is represented by coarse geodic quartz (QzII), associated with chalcopyrite that occurs in veinlets. In addition, rare galena and sphalerite are also observed. This is followed by chalcocite which exhibits tiny veins and also replacing the chalcopyrite. The silver mineralization occurs in minute veins and in the corrosion zone, replacing the preexisting sulfide minerals. Silver mineralization comprises Ag-sulfosalt, Ag-sulfide, Ag-Hg amalgam and rare native silver; iii) centimetric veins of barite and carbonate, followed by zonal quartz (QzIII) which is associated with second generation of chalcopyrite, galena and also rare sphalerite; and iv) supergene alteration stage. The Tassafte mining area shares several common points with other Ag-Hg ore deposits in the Anti-Atlas. These points comprise comparable Ediacaran volcanic host rocks with a young Cambrian host rocks in The Tassafte area, E-W trending ore veins, and also analogous ore mineralogy. The mineralization studied here are related to post Cambrian tectonism and assumed likely associated with Variscan and Mesozoic tectonic events.

Geochemical halos surrounding Li-rich pegmatites represent a potentially effective vectoring tool for the exploration of concealed deposits. To determine the petrochemical processes triggered by fluids derived from evolved pegmatitic melts in granitic host rocks, this work investigates the geochemical anomalies around a lepidolite-rich pegmatite at Gonçalo (Portugal). The study combines EMPA and LA-ICP-MS analyses of rock-forming minerals from the pegmatite and host monzogranite, along with whole-rock geochemistry. Results indicate that fluid exsolution and infiltration into the monzogranite occurred prior to, or coeval with, the onset of pegmatite crystallization. Boron, W, Mo, and As (± Cs, ± Sn) show preferential incorporation into the fluid phase over remaining in the pegmatitic melt, while F, Be, Li, Ta, Rb, Tl, and Ge likely incorporated into metasomatizing fluids due to their strong enrichment in the melt, rather than a preferential incorporation. Greisenization, zinnwalditization and tourmalinization reactions led to the formation of metasomatic Li-rich micas, quartz, apatite, fluorite, rutile, ilmenite, schorl, and sulfides in the variably metasomatized monzogranite. The Li halo in whole-rock extends 4–5 m from the contact and, together with F, B, As, and Cs enrichments, serves as a reliable pathfinder for buried Li-rich pegmatites, detectable up to twice the dyke thickness. Mica chemistry may offer a more sensitive alternative, with Li, Cs, Sn, and Be representing key components of the geochemical fingerprint associated with Li-rich pegmatites. These results may be applicable to the exploration of rare-element pegmatite deposits in granitic terranes, particularly within the Li-metallogenic province of the European Variscides.

Abandoned mines are among the main sources of long-term soil contamination, often leaving behind persistent concentrations of potentially toxic elements (PTE) that pose environmental and health risks. Ribeiro da Serra Sb–Au mine, in Portugal, active from 1858 to 1890, has left a significant environmental legacy. This study mapped the spatial distribution of mine processing residues, elemental characterisation distinguishing between anthropogenic and natural enrichment by determining soil sample concentrations of PTE, Hg mobility, and Total Organic Carbon (TOC) quantification. Multivariate analysis, spatial interpolation and comparison with Enrichment Factor were employed with the aim of understanding the distributions and sources of PTEs in the soils. Mercury is still present at the site, revealing high mobile (18.72 mg kg−1) and semi-mobile (3.58 mg kg−1) concentrations accumulated in waste piles, a remnant of Au amalgamation processes. High Hg concentrations (20.75 mg kg−1) pose significant environmental risks, even after more than a century, such as bioaccumulation potential and soil toxicity. Also, there are high concentrations of Pb (449.03 mg kg−1) in the waste piles from the Sb processing. This study highlights the critical importance of interpreting natural enrichment values of elements of Hg (EF = 267) and Pb (EF = 18) to discern pollution pathways resulting from mining and processing activities. Interpretation of natural enrichment values leads to a more accurate evaluation of environmental contamination and its sources. The Enrichment Factor shows that Sb (EF = 133) and Hg (EF = 267) are the elements that present extremely high enrichment (EF > 40).

Traditional views regarding the essential role of water in forming pegmatite have been debated in favor of less water-intensive models, although the total volume of water present in pegmatite-forming liquids after emplacement is poorly constrained by field evidence. Non-isochemical interactions between country rocks and metasomatizing pegmatite-related fluids may offer crucial insights into their origin and properties. In our study of the Li-rich Volta Grande pegmatite, we draw on comprehensive geochemical exploration databases and structural volumetric strain constraints to compute representative mass balance estimates. In the exomorphic halo of the main pegmatite, an initial stage of holmquistite-dominated metasomatism can be recognized, followed by biotitization which produces a metasomatic rock with c. 80% Li-Rb-Cs-biotite. Major and trace elements in biotitite indicate alteration characterized by a volume loss factor of c. 0.94. Volume loss is compatible with structural profiles of a contact parallel reverse shear zone that overprinted metasomatism, characterized by upper greenschist to lower amphibolite facies mylonitization microstructures. At these doubly constrained volume loss factors, estimates suggest that adding K and Li to the exomorphic halo accounts for approximately 3–5% and 2% by weight, respectively, of the original mass within the pegmatite. Conversely, about 10% of Ca in the pegmatite may have been drawn in from the country rocks during late-stage metasomatism. This finding is backed by textural evidence of Ca-rich phases in the pegmatite and supports growing consensus regarding open-system interactions between pegmatite-forming liquids and surrounding country rocks, which are particularly effective in causing calcium incursions into pegmatite.

The genetic origin of the antimony deposits in the D & uacute;rico-Beir & atilde;o mining district has been studied for a long time, and this study intends to bring more knowledge to this subject. Currently, two main hypotheses are proposed for this: (1) They are genetically connected to non-outcropping granites; (2) they are connected to mafic intrusions at depth. For this study, a gravimetric campaign was performed on the entire D & uacute;rico-Beir & atilde; area. The Bouguer residual anomaly (RA) map (obtained from the removal of a regional anomaly from the complete Bouguer anomaly [CBA]) shows positive anomalies that appear associated with the Palaeozoic metasediments of the Valongo Anticline flanks, as well as some positive anomalies to the west and in the centre of the anticline. The spatial statistical analyses performed with the gravimetry values and the location of the antimony deposits show that these mineralisations are mainly associated with the positive anomalies on the CBA and the Bouguer RA. The same thing happens for the dolerite veins that outcrop in the studied area, although with some of the veins appearing on the negative anomalies. The results from this study are not enough to prove one of these two hypotheses, although we believe they will be very useful in future studies on this matter.

This contribution is a new multimethod toolset to explore for buried, small-scale (0.01-5 million m3) rare metal and high-purity quartz pegmatites, which was developed as part of the four-and-a-half-year European Union H2020 GREENPEG project. It is underpinned by a complementary suite of existing, revised, and new methodologies, the use of three GREENPEG-developed geophysical exploration devices (EASA-certified, helicoptercompatible nose stinger magnetometer, piezoelectric seismograph, and drone-borne hyperspectral system), and two new databases (spectral library and petrophysical database for pegmatite ores). The toolset is based on the latest understanding of how pegmatites form and become enriched in ore minerals. In this regard, the theoretical component of the toolset resembles that of a comprehensive review article. The toolset has been tested in four active pegmatite exploration areas in a representative range of European surface environments-from coastal Arctic to temperate forest, alpine, and Mediterranean settings. Individual tools or tool combinations can be used to vector toward buried pegmatite-related mineralization, such as for Li, high-purity quartz for silica and metallic Si, ceramic feldspar, rare earth elements, Ta, Be, and Cs, to maximize the success of subsequent more costly exploration such as drilling in ways that optimize environmental, social, and governance outcomes. The tools are optimized for the small size, variable surface environment, depth, geologic setting, mineralogy, chemistry, and often highly variable physicochemical properties of pegmatite ore deposits. They can be used at province, district, and/or prospect scale. This guide is for those who have exploration knowledge and/or experience but who may be new or need updating in the state of the art of pegmatite exploration.

Spectral Imaging techniques such as Laser-induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy (RS) enable the localized acquisition of spectral data, providing insights into the presence, quantity, and spatial distribution of chemical elements or molecules within a sample. This significantly expands the accessible information compared to conventional imaging approaches such as machine vision. However, despite its potential, spectral imaging also faces specific challenges depending on the limitations of the spectroscopy technique used, such as signal saturation, matrix interferences, fluorescence, or background emission. To address these challenges, this work explores the potential of using techniques from conventional RGB imaging to enhance the dynamic range of spectral imaging. Drawing inspiration from multi-exposure fusion techniques, we propose an algorithm that calculates a global weight map using exposure and contrast metrics. This map is then used to merge datasets acquired with the same technique under distinct acquisition conditions. With case studies focused on LIBS and Raman Imaging, we demonstrate the potential of our approach to enhance the quality of spectral data, mitigating the impact of the aforementioned limitations. Results show a consistent improvement in overall contrast and peak signal-to-noise ratios of the merged images compared to single-condition images. Additionally, from the application perspective, we also discuss the impact of our approach on sample classification problems. The results indicate that LIBS-based classification of Li-bearing minerals (with Raman serving as the ground truth), is significantly improved when using merged images, reinforcing the advantages of the proposed solution for practical applications.

Combining data from different sensing modalities has been a promising research topic for building better and more reliable data-driven models. In particular, it is known that multimodal spectral imaging can improve the analytical capabilities of standalone spectroscopy techniques through fusion, hyphenation, or knowledge distillation techniques. In this manuscript, we focus on the latter, exploring how one can increase the performance of a Laser-induced Breakdown Spectroscopy system for mineral classification problems using additional spectral imaging techniques. Specifically, focusing on a scenario where Raman spectroscopy delivers accurate mineral classification performance, we show how to deploy a knowledge distillation pipeline where Raman spectroscopy may act as an autonomous supervisor for LIBS. For a case study concerning a challenging Li-bearing mineral identification of spodumene and petalite, our results demonstrate the advantages of this method in improving the performance of a single-technique system. LIBS trained with labels obtained by Raman presents an enhanced classification performance. Furthermore, leveraging the interpretability of the model deployed, the workflow opens opportunities for the deployment of assisted feature discovery pipelines, which may impact future academic and industrial applications.

The increasing demand for critical raw materials, such as antimony—a semimetal with strategic relevance in fire-retardant applications, electronic components, and national security—has made the identification of European sources essential for the European Union’s strategic autonomy. Remote sensing offers a valuable tool for detecting alteration minerals associated with subsurface gold and antimony deposits that reach the surface. However, the coarse spatial resolution of the most freely available satellite data remains a limiting factor. The PlanetScope satellite constellation presents a promising low-cost alternative for the academic community, providing 3 m spatial resolution and eight spectral bands. In this study, we evaluated PlanetScope’s capacity to detect Fe3+-bearing iron oxides—key indicators of hydrothermal alteration—by applying targeted band ratios (BRs) in northern Portugal. A comparative analysis was conducted to validate its performance using established BRs from Sentinel-2, ASTER, and Landsat 9. The results were assessed through relative comparison methods, enabling both quantitative and qualitative evaluation of the spectral similarity among sensors. Spatial patterns were analyzed, and points of interest were identified and subsequently validated through fieldwork. Our findings demonstrate that PlanetScope is a viable option for mineral exploration applications, capable of detecting iron oxide anomalies associated with alteration zones while offering finer spatial detail than most freely accessible satellites.

Some potassium-feldspar crystals from lithium-rich aplite-pegmatites from Northern Portugal have been analyzed with a handheld X-Ray-Fluorescence (XRF) equipment. This study compares the impact of analyzing the samples with an XRF film versus analyzing them without it. The film used was a Hitachi Poly-S High Performance XRF Sample Film of 3.5 μm, commonly used for analyzing samples in cups and powders. Although Hitachi alerts for the unsuitability of the film for analyzing light elements, this study helps understand the extent of error that this film can cause when analyzing this type of sample. 15 cleaned potassium feldspar crystals with a size between 1-3 cm have been analyzed with a Bruker S1 TITAN 600 containing an X-ray tube with a 2 W and 5-100 μA Rh anode. The Geomining factory calibration was used for the sample analysis.The results show that the potassium-feldspars analyzed with the film had their major elements drop by 20-40% for silica (SiO2), 30-50% for aluminum (Al2O3) and 10-20% for potassium (K2O). As for the trace elements, calcium (Ca) dropped by 20-30%, phosphorous (P) by 20-40% and rubidium (Rb) and iron (Fe) have small errors that can vary from plus 0-10% to minus 0-10%. Knowing the film impact will hopefully be of assistance for the correct interpretation of portable XRF results during field campaigns for mineral exploration.This study was financially supported by FCT, I.P., in the framework of the ICT (UIDB/04683/2020 and UIDP/04683/2020), by the PhD project (2020.05534.BD) and by national funds from MCTES, through FCT, co-financed by ESF through POCH and NORTE 2020. This work is also supported by the Greenpeg project, reference 869274, funded by the Horizon 2020 framework program of the European Union.

Active remote sensing technologies such as Light Detection and Ranging (LiDAR) and Synthetic Aperture Radar ( SAR) have been established as tools for geological investigations since the 1980s. These sensors, deployable on Unmanned Aerial Vehicles (UAVs), aircrafts and satellites, emit their own electromagnetic signals to map Earth's surface features. LiDAR provides high-resolution topographic data, enabling detailed analysis of geomorphology, tectonics, and landslide identification. However, its spatial resolution and application scope depend on the platform: UAV-mounted sensors yield denser point clouds (hundreds/thousands of points per m(2)) suited for local-scale studies, whereas airborne or satellite systems offer broader coverage at reduced point densities, limiting fine-scale geological interpretation. SAR sensors capture amplitude and phase data from the backscattered signal, enabling advanced geological and engineering applications such as interferometric deformation monitoring and subsurface imaging. The utility of SAR further depends on wavelength selection (e.g., X-, L-, or C-band), where longer wavelengths (e.g., L-band) exhibit greater penetration through vegetation and surface layers, enabling soil moisture mapping or sediment thickness estimation, while shorter wavelengths (e.g., X-band) enhance surface displacement measurements. This study synthesizes recent advancements in the application of SAR and LiDAR technologies for geological analyses, performing a systematic review of peer-reviewed literature indexed in the Scopus database, focusing on the latest publications from 2015 to 2025. The key terms used for the techniques employed were SAR and LiDAR, which were combined with geological domain terms - mineral, geology, tectonics, lithology, structural geology, and geological exploration. The bibliometric analysis was structured in three stages: search, refinement, and screening. The study relied solely on abstract analysis to prioritize scalability, with no full-text review performed. The results provide insights into the evolution of the application of active remote sensors in geological studies.

Inductively coupled plasma-mass spectrometry analysis was conducted to examine the geochemical composition of Kfeldspars from various aplite-pegmatites in the Barroso-Alv & atilde;o field, focusing on the differences between Li-rich and Li-barren aplite-pegmatites. The study revealed significant variations in the concentrations of minor and trace elements (Rb, Tl, Li, Ga, Pb, Cs, Ba, Be, Ta, and Sn) present in the K-feldspars of Li-barren, spodumene-rich, and petalite-rich aplite-pegmatites. The data also indicate a geographical trend in both mineralogy and geochemistry across the aplite-pegmatites of the Barroso-Alv & atilde;o field. Li-barren aplite-pegmatites are more concentrated in the southeast, spodumene-rich dominate the center, and petalite-rich varieties are more common in the northwest. Additionally, portable X-ray fluorescence analysis was performed on the crystals of the same samples to evaluate the feasibility of in situ geochemical analysis of K-feldspars, aiming to determine whether an aplite-pegmatite can be quickly identified as Li-rich. This approach seeks to provide a rapid field assessment of whether an aplite-pegmatite justifies further exploration for Li mining. Notably, the trace amounts of Li, Sn, P, and Ta found in K-feldspars are likely due to mineral inclusions of spodumene, cassiterite, apatite, and columbite-tantalite minerals, as observed petrographically in one of these Li-rich aplite-pegmatites.

Mineral identification is a challenging task in geological sciences, which often implies multiple analyses of the physical and chemical properties of the samples for an accurate result. This task is particularly critical for the mining industry, where proper and fast mineral identification may translate into major efficiency and performance gains, such as in the case of the lithium mining industry. In this study, a mineral identification algorithm optimized for analyzing lithium-bearing samples using Laser-induced breakdown spectroscopy (LIBS) imaging, is put to the test with a set of representative samples. The algorithm incorporates advanced spectral processing techniques—baseline removal, Gaussian filtering, and data normalization—alongside unsupervised clustering to generate interpretable classification maps and auxiliary charts. These enhancements facilitate rapid and precise labelling of mineral compositions, significantly improving the interpretability and interactivity of the user interface. Extensive testing on diverse mineral samples with varying complexities confirmed the algorithm's robustness and broad applicability. Challenges related to sample granulometry and LIBS resolution were identified, suggesting future directions for optimizing system resolution to enhance classification accuracy in complex mineral matrices. The integration of this advanced algorithm with LIBS technology holds the potential to accelerate the mineral evaluation, paving the way for more efficient and sustainable mineral exploration.

This study addresses the challenge of subpixel occurrence in identifying Lithium Cesium Tantalum (LCT) pegmatites, crucial sources of lithium for electric batteries. Previous spectral unmixing methods have been applied in brownfield sites with pre-existing large mines, facilitating pegmatite endmember acquisition. However, this work focuses on a method for greenfield exploration, presenting a knowledge transfer approach to transfer pre-extracted pegmatite endmembers to new areas using a spectral unmixing based method. Two study areas in Minas Gerais, Brazil, were chosen: Area 1 (A1) as a brownfield site for deriving a pegmatite endmember, and Area 2 (A2) simulates a greenfield area to test the efficacy of the pre-extracted endmember. The Mixture Tuned Matched Filtering (MTMF) classification method was employed, showcasing potential value in scenarios where no pegmatite occurrences are known.

The Barroso–Alvão region is an excellent setting for studying Li mineralization associated with granitic pegmatites and developing Li exploration techniques. Among the distinguished pegmatite types in this pegmatite field, the spodumene-bearing dyke from Alijó is a representative example of an Iberian Li–Cs–Ta (LCT) pegmatite currently under exploitation. In this work, we examine the internal evolution of the Alijó dyke and its external metasomatic effect on the surrounding metasediments, contributing to lithium exploration techniques. Electron microprobe analyses provided clues about the crystallization conditions and the degree of differentiation of the pegmatitic melt, whereas the external metasomatism induced by the spodumene-bearing pegmatite was studied through whole-rock geochemistry. The obtained results indicate that the primary crystallization of the studied dyke likely occurred at temperatures between 450–500 °C, with emplacement at shallow crustal levels of about 2–3 kbar. The high concentrations of trace elements such as Li, Cs, Rb, Be, Sn, Nb, Ta, Ge, U, and Tl in the pegmatitic melt suggests high availability of these elements, allowing their partitioning into an early exsolved fluid phase. The exsolution of this fluid phase, subtracting components such as F and B, from the pegmatitic melt would cause a significant undercooling of the melt. Moreover, the interaction of this expelled fluid with the country rock generated a metasomatic overprint in the surrounding metasedimentary host rocks. The metasomatic effect in Alijó is strongly influenced by the nature of the host metasediments, with a significantly higher grade of metasomatism observed in pelitic (mica-rich) samples compared to psammitic (mica-poor) samples collected at same distances from the dyke. The greisen developed close to the pegmatite contact reflects this metasomatic signature, characterized by the mobilization of at least B, F, Li, Rb, Cs, Sn, Be, Nb, Ta, and Tl. We cautiously suggest that whole rock Li concentrations greater than 300 ppm, combined with a minimum value of 1000 ppm for the sum of B, F, Li, Rb, Cs, and Sn in pelitic metasediments of Barroso–Alvão, may be indicative of a mineralized pegmatite in this region.