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Recent advances in calculation algorithms have led to a new level of image processing for mineral
identification and mapping. Mineral outcrop mapping has a decade’s history of using conventional
methods like band combintion, band ratioing and relative absorption band depth (RBD) technique.
Modification of these algorithms enriches the capabilities...
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... blue patches in the north-western and south corner of the study area confirm the presence of hydrothermal alteration zones (RGB 5, 6, 7; Figure 3). The second RGB (7, 6, 4) shows dark brown colour in the same areas ( Figure 4). Sabins' ratio (4/2, 6/7 and 6/5 as RGB) helps to recognize the hydrothermally altered zones in violet colour which can be seen in the North, South and North Eastern portions (Figure 5 b). ...
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Multiplex immunoassays capture a comprehensive profile of the humoral response against SARS-CoV-2 and human endemic coronaviruses. We validated a multiplex panel (V-PLEX Panel 2) from Meso Scale Diagnostics targeting antibodies against nine coronavirus antigens. Performance was compared against alternative single- and multi-antigen immun...
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... Therefore, additional reference detectors collect the signal from the 20.7, 21.5, and 31.5 µm lines (483, 465, and 317 cm −1 ), where sulfides and ilmenite do not show spectral features. Such an approach will allow determining the influence of the Sun's geometry and topography on the obtained results -a similar approach is applied in the Landsat 8 (Safari et al., 2018;Banerjee et al., 2019;Sekandari et al., 2020), ASTER (Safari et al., 2018;Zoheir et al., 2019;Sekandari et al., 2020), Sentinel-2 (Zoheir et al., 2019;Sekandari et al., 2020;Soydan et al., 2021), or PRISMA (Loizzo et al., 2018;Bedini and Chen, 2022;Chirico et al., 2023) spectral bands on Earth. Apart from minor interferences with H 2 O and CO 2 molecules in the FIR band, which in any case is nearly irrelevant on the Moon, the main FIR advantage is the robust absorption features of oxides and sulfides ( Figure 6A) compared to rock-forming silicates ( Figure 6B) and other common minerals ( Figure 6C; Figure 7). ...
Lunar sulfides and oxides are a significant source of noble and base metals and will be vital for future human colonies’ self-sustainability. Sulfide detection (pyrite and troilite) applies to many technological fields and use cases, for example, as a raw material source (available in situ on the Lunar surface) for new solar panel production methods. Ilmenite is the primary iron and titanium ore on the Moon and can provide helium-3 for nuclear fusion and oxygen for rocket fuel. The most important ore minerals have prominent absorption peaks in a narrow far-infrared (FIR) wavelength range of 20–40 μm, much stronger than the spectral features of other common minerals, including significant silicates, sulfates, and carbonates. Our simulations based on the linear mixing of pyrite with the silicates mentioned above indicated that areas containing at least 10%–20% pyrite could be detected from the orbit in the FIR range. MIRORES, Multiplanetary far-IR ORE Spectrometer, proposed here, would operate with a resolution down to <5 m, enabling the detection of areas covered by 2–3 m² of pyrite (or ilmenite) on a surface of ∼17 m² from an altitude of 50 km, creating possibilities for detecting large and local smaller orebodies along with their stockworks. The use of the Cassegrain optical system achieves this capability. MIRORES will measure radiation in eight narrow bands (0.3 µm in width) that can include up to five bands centered on the ore mineral absorption bands, for example, 24.3, 24.9, 27.6, 34.2, and 38.8 µm for pyrite, marcasite, chalcopyrite, ilmenite, and troilite, respectively. The instrument size is 32 x 32 x 42 cm, and the mass is <10 kg, which fits the standard microsatellite requirements.
... Recently, remote sensing data has been the most beneficial information used globally in several studies pertaining to economic and natural resource exploitation by detecting and mapping the various alteration minerals (Abdelnasser, 2016;Abdelnasser et al., 2018;Banerjee et al., 2019;Khaleghi et al., 2020;Sekandari et al., 2020;AL-Shammari et al., 2021;Hagag and Abdelnasser, 2021;Azzazy et al., 2022). However, the diversity of remote sensing images and their integration with several other geological and geophysical data made it possible to provide valuable and more precise results in many applications, particularly in mineralisation mapping (Parsa and Pour, 2021;Bencharef et al., 2022;Yousefi et al., 2022). ...
Field and mineralogical studies are integrated with multispectral and radar satellite data to unravel the occurrence of sulfide dissemination in the Gabal Monqul area (Eastern Desert, Egypt). This study was motivated by the strong belief that the widespread hydrothermal alteration haloes and sulfide disseminations in this area were ambiguously deciphered as a porphyry-style mineralisation. NE-Elongate bodies of silicified and sulfidized rocks frequently occur at the contacts between andesite-dacite, granodiorite, and porphyritic biotite granite intrusions.
Hydrothermal alteration zones are best identified and outlined by employing band ratios (BR) and independent component analysis (ICA) techniques for the distinction between ferric and ferrous iron minerals. If fused with the clay and OH-bearing minerals maps, ferric iron oxides may characterise epithermal and porphyry mineralisation in which ore formation occurs under oxidising conditions. Iron-hydroxide, copper hydro-carbonate (malachite), and hydrous copper phosphate (pseudomalachite) are supergene mineral phases.
The resultant processed images show that alteration extends beyond unit boundaries and overlaps different crosscutting lithologies. This observation implies that hydrothermal alteration of the host rock represents a secondary overprint, yet gypsum (±anhydrite) and barite in association with iron oxides and pyrite disseminations pinpoint a porphyry-related alteration assemblage. The poor metal endowment in the potassic alteration zones goes against the supergene enrichment typical of the porphyry mineralisation system and is coupled with the lack of hydrothermal breccia bodies, implying a rather epithermal sulfidation genesis. However, a thorough assay program is required to outline the potential metal-rich lithological unit(s) using XRD and remote sensing investigations that point to zonal alteration anomalies.
... μm parallel band 6 (1.56-1.66 μm) of Landsat 8. Therefore, SWIR bands of Landsat 8, or BR 6/7, are the most suitable ratio to discriminate hydroxyl-bearing alterations and carbonate minerals (Gupta 2003(Gupta , 2018Pour and Hashim 2015;El Arafy 2016;Banerjee et al. 2019;Zoheir et al. 2019;Traore et al. 2020;Araffa et al. 2022;ElGalladi et al. 2022). ...
... μm). Thence, the OLI BR 6/5 is used for detecting the ferrous mafic rocks (El Arafy 2016; Banerjee et al. 2019;Zoheir et al. 2019;Traore et al. 2020;Araffa et al. 2022;ElGalladi et al. 2022). Moreover, BR 6/5 helps identify the weathered ferruginous rocks (gossans) produced by oxidation and leaching of sulphide mineralisation and represent a probably surface indicator of buried ore deposits (Sabins 1999;Haldar 2018) especially gold occurrences in the Arabian Nubian Shield, ANS (Ramadan and Sultan 2003;Zeinelabdein and El Nadi 2014;Gahlan and Ghrefat 2018;ElGalladi et al. 2022). ...
Reducing expenses is a critical aspect of natural resource explorations, especially in the reconnaissance stage. Accordingly, GIS algorithms using the free remote sensing data were used to rank the probable mineralised zones before any future implementations of the high-cost drilling and/or detailed geophysical programmes. Geological and tectonic settings, and being a historical mineral resource were motivations to choose the Allaqi-Heiani Suture (AHS), Upper Egypt, as a study area. Remote sensing data were processed for tracing the probably mineralised alteration zones, determining fractures and dominating structural systems, and mapping different geological units. Various alteration minerals including hydroxyls–carbonates, ferrous and ferric iron oxides were detected over different rock units using band ratio (BR) and Crosta techniques. Different geological units were distinguished using false colour composite (FCC) images. Moreover, an intense fractured system, demonstrating the area, was revealed by tracing lineaments using informative, spatially enhanced remote-sensed images. Fractures within the altered rocks represent 35% of the total fracturing system in the AHS to indicate a structural system controlling mineralisation occurrences. The processing of magnetic data suggested a deep/buried nature of these remotely detected lineaments/structures. Reduced to pole (RTP) and tilt derivative (TDR) maps detected the buried magnetic sources, whereas zero contours of TDR, Euler deconvolution, analytic signal and source parameter imaging (SPI) techniques traced buried contacts/structures and estimated their depths. A GIS strategy depending on the intensity of the fracturing system and the presence of more than one type of alteration was applied to potential-rank the prospective mineralised occurrences over AHS. The correlation between ranked zones with the old/known mines showed encouraging evaluation.
... Multispectral images are generated from monochromatic bands by the application of a layer-stacking process [38][39][40][41]. CC allows the production of color images using the spectral signature of the targets [42]. They are commonly deployed to highlight different surface types in multispectral images or to make evident some crucial environmental phenomena, such as sandstorms, forest fires, and sea ice The CC simplifies it to describe and understand a multiband image by using different colors as indicators of the values of single-channel [43]. ...
... ASTER); Table S1: Summary of selected satellite sensors; Table S2: Details of the most color composite used in geology; Table S3: Details band ratios usefulness in geological studies; Table S4: Accuracy assessment for SAM for SAM classification of ASTER image. Refs [23][24][25][26][39][40][41][42][43] are citied in supplementary materials. ...
Together with geological survey data, satellite imagery provides useful information for
geological mapping. In this context, the aim of this study is to map geological units of the Saka region,
situated in the northeast part of Morocco based on Landsat Oli-8 and ASTER images. Specifically,
this study aims to: (1) map the lithological facies of the Saka volcanic zone, (2) discriminate the
different minerals using Landsat Oli-8 and ASTER imagery, and (3) validate the results with field
observations and geological maps. To do so, in this study we used different techniques to achieve the
above objectives including color composition (CC), band ratio (BR), minimum noise fraction (MNF),
principal component analysis (PCA), and spectral angle mapper (SAM) classification. The results
obtained show good discrimination between the different lithological facies, which is confirmed
by the supervised classification of the images and validated by field missions and the geological
map with a scale of 1/500,000. The classification results show that the study area is dominated by
Basaltic rocks, followed by Trachy andesites then Hawaites. These rocks are encased by quaternary
sedimentary rocks and an abundance of Quartz, Feldspar, Pyroxene, and Amphibole minerals.
Keywords: remote sensing; mapping; volcanoes rocks; minerals index; Landsat Oli-8; ASTER;
Saka area
... The effectiveness of the combination of remote sensing data with diverse data such as geophysics and geochemistry has been proven in many studies and explorations (e.g.: Gemail et al., 2016;Attwa et al., 2020;Henaish et al., 2022). Multispectral remote sensing has been used in geological mapping and mineral exploration as identifying lithological units, hydrothermal alteration zones and other near-surface radioactive anomalies with visible, near infrared (VNIR) and shortwave infrared (SWIR) electromagnetic regions (e.g.: Nikolakopoulos et al., 2013;Panda et al., 2018;Banerjee et al., 2019). In addition, Geographic Information Systems (GIS)-based multi-criteria spatial analysis tools propose great prospective for exploring natural resources (e.g.: Lee et al., 2019;Aboud et al., 2021;AL-Shammari et al., 2021). ...
Considering the current economic growth that Egypt is going through, it is necessary to increase research about the exploration of mineral resources. The current study is one of those studies that aim to define highly radioactive zones at East Wadi Qena area (EWQ), Eastern Desert using airborne radiometric and remote sensing data. This area is characterized by a complex geological setting which encountered multi-phases of deformation and tectonic events. Airborne radiometric data are used for identifying the presence of uranium, thorium, and potassium in the present study. Ternary composite map is important in radioelement exploration, as they reveal the source of radioactivity. In addition, semi-quantitative statistical analysis is an effective way in calculating radiometric anomalies. Moreover, processing and classification of remote sensing data are applied for valuable mapping of alteration and mineralization zones in the granitic rocks in the considered area. In this regard, radioactive potential zones (RPZ) have been evaluated using the Analytical Hierarchy Process (AHP) through geospatial analysis tools in Geographic Information System (GIS). Five spatial maps are extracted from among the dominant and contributing factors to the concentration of radioactive elements for resolving a radioactive prediction model. The results show that EWQ area is promising for radioactive minerals exploration at diverse phases of granitic rocks, unexpectedly Dokhan volcanics and metavolcanic rocks. The integration between remote sensing and airborne radiometric data can effectively expect the radioactive favorable zones in the study site that can be help for future investigations in other difficult accessible areas.
... BSI can produce a detailed bare index over a large area on the earth's surface except for a detailed survey and it is used as a proxy of land use/land cover map. BSI has the capability to demarcate different types of vegetation cover such as thick vegetation, sparse vegetation, completely bare soil, and built-up area (Banerjee et al. 2019). BSI value increases with the increasing bareness of the soil (Jamal and Mandal 2016;Erener et al. 2016). ...
Landslides have become a common lithospheric hazard in the mountainous areas of Bangladesh, increasing rapidly in the last 20 years. This study aims to produce a landslide susceptibility map of Rangamati District using and comparing frequency ratio (FR), logistic regression (LR) models, and the combination of the two models. Among the 261 landslide locations, 75% were used as training data and 25% were used as testing data by random selection. Training data was used for landslide susceptibility mapping and the testing data was used for validating the map. Fourteen causative factors of elevation, aspect, geology, distance to road, distance to faults, distance to stream, stream density, plan curvature, profile curvature, normalized difference vegetation index, bare soil index, rainfall, and slope degree have been used to prepare the susceptibility map. The importance of the causative factors varies according to the model. ROC was used to validate the map. ROC values of 0.836, 0.816, and 0.842 were found for training data and 0.808, 0.758, and 0.826 were found for testing data for FR, LR, and FR integrated LR, respectively. Integration of the models slightly improved the accuracy. The outcome of the research will be helpful for landslide hazard assessment and policymaking. The study is indispensable to reveal the landslide-susceptible zone in the region and landslide can be mitigated by proper planning through this map.
... Presently, remote sensing is experiencing rapid and diverse ascents in terms of sensor types (passive and active; spatial and temporal resolution), recorded electromagnetic partitions, and a matching diversity of processing (e.g., band ratio, minimum noise fraction and principle component analysis), enhancement, and analysing methods to keep pace with these developments. Therefore, the use of remote sensing and aerial photographs has become more effective, favourable and one of the basic steps to be used in the exploration of minerals and geological mapping (e.g., Pour et al. 2016;Modabberi et al. 2017;Panda et al. 2018;Safari et al. 2018;Banerjee et al. 2019;Elsayed Zeinelabdein et al. 2020;Parsa 2021;Pour et al. 2020;Tende et al. 2021). Furthermore, their enhanced products that resulted from using different processing techniques such as band rationing and/or principal component analysis have proven their superiority and accuracy over the conventional field observations in mapping tectonically complex geological areas such as forested and mountainous (e.g., Kayadibi and Aydal 2019; Sekandari et al. 2022;Skakni et al. 2021;Ishagh et al. 2021;Khalifa et al. 2021). ...
Prospecting and exploring minerals present major challenges in tectonically complex regions for sustainable development as in Northeastern Algeria. This area is promising for its mineral potential, especially the metallogenic province "The Diapiric Zone". This study concerns mapping and predicting potential polymetallic mineralization locations by integration of remote sensing, gravity, and magnetic datasets. Several enhancement and processing methods have been applied on Landsat8_OLI and ASTER_1T remote sensed data to reduce uncertainty for achieving the best detection of hydrothermal alteration zones and lithological mapping. Furthermore, the Centre for Exploration Targeting grid analysis technique, the contact occurrence density and entropy orientation tools were employed on ground-gravity and aeromagnetic data to understand and visualize the pathways for hydrothermal fluids circulation of mineral deposits. The polymetallic mineralization prospective areas were produced using a logistic regression model on the resulting multifactor. High zones of lead-zinc cover most the area that has been confirmed by field investigation.
... The most commonly used data includes the Landsat 5 thematic mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM +), Landsat 8 operational land imager (OLI) and terra advanced spaceborne thermal emission and reflection radiometer (ASTER). The processing and application of these data through spectral transformation methods such as optimal index factor (OIF), band ratio (BR), spectral angle mapper (SAM) and principal component analysis (PCA), considers these data an important source of information to researchers for lithologic mapping and determination of hydrothermal alteration zones (Pournamdari et al. 2014;Jellouli et al. 2019;Banerjee et al. 2019;Ahmadi and Uygucgil 2021). ...
Satellite multispectral systems are fundamental and crucial data sources for the application of spatial classification methods , such as PCA. This statistical approach focuses first on the constitution of new bands that maximize the information in decreasing order. It also focuses on the assignment of the bands of high inertia to the main RGB color to generate a diversified color composite that can be capable of discriminating the lithology. The objective of this study is to extract information from noisy bands and more precisely from degraded bands with low inertia using the image denoising method by total variation regularization (TVR). The study is based on a comparative approach between the two algorithms: finite difference (with fixed-point iterations) and the Primal-Dual. The experimental results obtained with multispectral datasets confirm the validity of this TVR denoising technique and the superiority of the Primal-Dual algorithm. The remarkable obtained results show clear colored compounds and prove that the low inertia bands produced by PCA are capable of providing additional information.
... A similar study was carried out by (27) who used band combinations on Landsat 8 imagery to delineate rock outcrops from clouds, sea and snow in Antarctica. In (28) , band combinations were also used on Landsat 8 OLI data (the same band combinations as the ones used in this study) to successfully delineate hydrothermally altered rocks and rock outcrops at Singhbhum Shear Zone in East India. ...
Objective: To map areas of possible hydrothermal alteration using remote sensing technology; To map geological structures controlling mineralisation using remote sensing; To carryout field mapping to ground truth the features identified by remote sensed data. Methods: Landsat 8 Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) remote sensed images were downloaded from USGS website. Landsat images were processed using band ratios, band composites, principal component analysis techniques in ArcGIS to map areas of possible hydrothermal alteration. SRTM image was analysed using hillshade analysis technique in ArcGIS to map geological structural features controlling mineralisation. Findings: The study found that in several areas especially Southern, South Eastern, Central and North Western part of Lolgorien, there is a possibility of hydrothermal alteration as spectral signatures associated with iron oxide and clay minerals were identified. It was also found that areas with possibility of hydrothermal alteration are also associated with relatively large number of lineaments. It was also found that Southern and SouthEastern part of Lolgorien are also associated with numerous artisanal mines proving the fact that indeed gold mineralisation may be found in these places. However, due to thick vegetation cover, mapping of different types of lithological units found in Lolgorien was not possible. Novelty/Application: The application of remote sensed technology helped in identification of new areas of possible mineralisation such as Central and NorthWestern parts of Lolgorien which despite having similar geological properties (in terms of lineament density and hydrothermal alteration) have never been exploited for gold or other minerals.
... A similar study was carried out by (27) who used band combinations on Landsat 8 imagery to delineate rock outcrops from clouds, sea and snow in Antarctica. In (28) , band combinations were also used on Landsat 8 OLI data (the same band combinations as the ones used in this study) to successfully delineate hydrothermally altered rocks and rock outcrops at Singhbhum Shear Zone in East India. ...
