South Eastern Desert Research Articles

Geological, Geochemical and Spectrometric Studies on the Trachyte Dykes of Wadi El Hora area, South Eastern Desert, Egypt

Geological, Geochemical and Spectrometric Studies on the Trachyte Dykes of Wadi El Hora area, South Eastern Desert, Egypt

ِA new occurrence of rift-related damtjernite (ultramafic) lamprophyre, Gebel Anweiyib area, Arabian Nubian shield: Insights from bulk rock geochemistry and remote sensing data analysis

The occurrence of lamprophyre dikes is being reported first time in the Gebel Anweiyib area, south Eastern Desert, Egypt. The investigation of the ultramafic lamprophyre (damtjernite) dikes intruded into the crustal younger granites and metasediments based on their spectral characteristics, mineralogical and geochemical compositions. Three multispectral sensors of Landsat-8, ASTER and S2 have been used to detect and characterize the lithologic units and the lamprophyre dikes. The reflectance and absorption signatures of the granitic rocks and lamprophyre dikes were the basis for detecting them from the remotely sensed data using the application of advanced image processing algorithms including FCC, BR, PCA, MNF, and DS. Geochemical studies inferred that the damtjernite dikes are under-saturated with SiO2 (<38.89 wt%), alkaline with total alkalis (avg. 4 wt%), metaluminous with A/CNK (0.22–0.51), and ultramafic with MgO (13.88–19.23 wt%). They exhibit unique geochemical characteristics of mantle (with high MgO, Ni, Cr, and Mg#) coupled with crustal (high Sr, Ba, Zr, Ga and REEs) sources, similar to global ultramafic lamprophyres. High TiO2 and highly fractionated REEs with low HREEs (avg. 23 ppm) relative to LREEs (avg. 354 ppm) contents, yielding residual garnet in melts. Low partial melting of primitive garnet lherzolite can account the obtained REEs in the ultramafic lamprophyres. These features signify their derivation from a deeper enriched asthenospheric (plume-type) magma like OIB, which is attested by the high Nb/La (avg. 1.32), Nb/U (avg. 102), La/Yb (avg. 43), and low Y/Nb < 0.52, Rb/Sr < 1, Rb/Ba (<0.14), and Sr/Ba (<0.9), suggesting their derivation from a mantle-derived source rather than crustal rocks. High concentrations of TiO2 and Fe2O3 in the ultramafic lamprophyres, reflecting their formation from a fertile peridotite by mantle plume-derived melts with K-residual phlogopite rather than amphibole as obtained by low Ba/Rb and high Rb/Sr ratios. The Anweiyib lamprophyres are anorogenic and confined to being derived from rifting regions, and their magma is not contaminated with crustal sources during emplacement.

Mafic and felsic magmatism in the Wadi Kalalat area, South Eastern Desert, Egypt: mineralogy, geochemistry and geodynamic evolution during the Neoproterozoic in the Nubian Shield

Mafic and felsic magmatism in the Wadi Kalalat area, South Eastern Desert, Egypt: mineralogy, geochemistry and geodynamic evolution during the Neoproterozoic in the Nubian Shield

Insight on uranium recovery valorization from El Sela highly altered granitic rocks, South Eastern Desert, Egypt

Insight on uranium recovery valorization from El Sela highly altered granitic rocks, South Eastern Desert, Egypt

A promising modified polyvinyl chloride for adsorption of boron: Preparation, adsorption kinetics, isotherm, and thermodynamic studies

AbstractA new promising N‐methyl‐D‐glucamine modified polyvinyl chloride via methyl glycinate linker (PVC‐MG‐NMDG) was designed to extract boron from tourmaline ore from the Sikait area in the South Eastern Desert of Egypt, which assays 10.43% B2O3. Specifications for PVC‐MG‐NMDG composite were executed successfully utilizing sundry approaches, such as FT‐IR, XPS, GC–MS, TGA, BET, EDX, 13C‐NMR, 1H‐NMR, ICP‐OES, and XRD, which assure an acceptable synthesis of PVC‐MG‐NMDG. Optimized factors like pH, agitation time, primary boron concentration, composite dose, co‐ions, eluting agents, and temperature have been improved. At ambient temperature, pH 9, 10 min of agitation, and 0.0138 mol/L boron ions (150 ppm), the PVC‐MG‐NMDG composite has a 25 mg/g maximal uptake. The extraction‐distribution isotherm modeling suggests that the Langmuir model, with a theoretical value of 25.38 mg/g, more closely matches the practical value of 25 mg/g than the Freundlich model. The adsorption kinetics of boron ions by PVC‐MG‐NMDG were predicted with high accuracy using a pseudo‐second order kinetic model, yielding a theoretical retention capacity of 27.93 mg/g. The extraction process was predicted, as shown by thermodynamic calculations, exothermic, spontaneous, and optimal extraction at low temperature; the thermodynamic factors controlling ΔS (−0.04 kJ/mol), ΔH (−13.74 kJ/mol), and ∆G values rise from −1.82 kJ/mol at 298 K to −0.19 kJ/mol at 338 K. Boron ions can be eluted from the overloaded composite by 0.5 M H2SO4 with a 95% efficiency rate. It was established that PVC‐MG‐NMDG composite reveals a worthy separation factor to most co‐ions and gives a good separation power. Boric acid with a boron content of 17.23% and purity of 98.56% can be obtained through alkali fusion with NaOH flux and subsequent adsorption using a PVC‐MG‐NMDG composite.Highlights A New modified polyvinyl chloride (PVC‐MG‐NMDG) was successfully prepared. The characteristics of new composite were verified via different techniques. The new composite reached its maximum boron absorption of 25 mg/g at 25°C. The extraction as an exothermic, spontaneous process at low temperature. The new composite has been applied to a real sample of Sikait tourmaline ore.

The geochemistry, origin, and hydrothermal alteration mapping associated with the gold-bearing quartz veins at Hamash district, South Eastern Desert, Egypt

Integrating diverse techniques and datasets, significantly enhances the accurate identification of various mineral deposits. This work aims to determine different types of mineral deposits in the Hamash district (Southern Eastern Desert, Egypt) by combining structural features (derived from ALOS PALSAR DEM), alteration zones (detected using ASTER and Sentinel-2), and ore mineralogy. Multispectral imaging, such as ASTER and Sentinel-2 satellite data, provides a cost-effective and efficient tool for lithological and hydrothermal alteration mapping utilizing selective band ratios (SBR), directed principal component analysis (DPCA), feature-oriented false-color composites (FFCC), and constrained energy minimization (CEM). The deductions drawn from the analysis of ASTER and Sentinel 2 satellite data are solidly corroborated through meticulous investigations of pre-existing lithological maps in the study area, on-site validation via fieldwork, and robust laboratory analysis, attesting to reliable results. Validation of remote sensing results was performed through field observations, petrographic investigations, X-ray diffraction technique (XRD), and SEM–EDX analyses. Based on ore mineralogy derived from XRD and SEM results the quartz-vein-associated ore minerals in the Hamash district include chalcopyrite, pyrite, hematite, goethite, bornite, covellite, and gold. According to the present paragenesis, the mineralization in the study area is classified into three types: sulfide mineralized zone, transitional zone, and supergene zone. Using an ore microscope, our studies identified that the alteration zones include gold-bearing sulfide minerals as well as the minerals goethite and malachite. In gold-bearing quartz samples, the concentrations of Cu, As, Ag, and Sb are positively correlated with Au at the degree of shear deformation. According to data gathered from the fire assay results, Au content varied from 0.027 to 57.20 ppm, along with Cu (10–6484 ppm), Ag (0.5–20.5 ppm), As (5–2046 ppm), Zn (3–1095 ppm), Pb (2–1383 ppm), and Sb (5–23). Our results confirmed that the Hamash region is one of the most important gold-bearing sites, with gold concentrations ranging from 0.027 up to 57.20 ppm. Furthermore, the current contribution highlighted four stages in the paragenetic sequence of the recorded ores, including magmatic, metamorphic, hydrothermal, and supergene by origin, indicating a considered similarity with the known Egyptian gold sites regarding host rocks, mineralization style, alteration assemblage, and several ore mineral conditions.

Enhanced boron recovery by a new synthesized polyvinyl alcohol anchored gallic acid moiety via ethyl carbamate linker

ABSTRACT An innovative promising Gallic acid anchored poly vinyl alcohol via ethyl carbamate linker (PVA-EC-GA), was functionalized to extract boron from a tourmaline ore sample from Sikait area in South Eastern Desert of Egypt, which assaying 10.45% boron oxide. Specifications for PVA-EC-GA composite were accomplished by employing a variety of methods including XPS, FT-IR, EDX, BET, 1 H-NMR, TGA, 13C-NMR and GC-MS analyses, which assure an equitable prepare of PVA-EC-GA. Investigational measurements, namely: pH, agitation time, initial concentration of boron, composite dose, co-ions, temp. and agents of eluting, have been improved. At 25°C, pH 10, 20 min agitation and 0.0092 mol/L boron ions, PVA-EC-GA composite has an extreme uptake capacity of 43.75 mg per gram which is equivalent to 175 mg/L boron ions. From the isotherm modeling, Langmuir’s quite fitting the practical data. Conferring to kinetic modeling, pseudo-second order kinetic model well predicted the kinetics of boron ions adsorption by PVA-EC-GA giving a theoretical retention capacity of 43.86 mg/g. Thermodynamic prospects expose that the adsorption process was expected as an exothermic, spontaneous, and preferable adsorption at low temp. Boron ions can be eluted from the loaded composite, by 0.5 M H2SO4 with a 97% effectiveness

Petrogenesis and possible fingerprints of the Najd shear system on the evolution of deformed granitic rocks in the west Wadi Nugrus area, Egypt

In this paper, we present petrological constraints on the geodynamic evolution of deformed granitic rocks in the west Wadi Nugrus area, south Eastern Desert of Egypt. The deformation belt trends NW-SE forming the so-called “Nugrus Shear Zone (NSZ)” a major tectonic feature in the Arabian-Nubian Shield (ANS) at the junction between Wadi El Gemal and Wadi Hafafit areas, namely “Site I″ and “Site II”. The deformed granitic rocks comprise highly sheared arc granitoids and post-collisional to within-plate younger granites. Although the investigated granitic rocks are highly deformed, they show no signs of metamorphism and retain their primary igneous minerals. The melts from which the investigated granitic types originated experienced considerable degrees of partial melting in the transitional lower crust/upper lithospheric mantle as indicated by the contents of incompatible and rare-earth elements (REEs). Typical A-type granites developed before deformation and during emplacement in a continental environment. Zircon has ThO2/UO2 > 0.1, which is typical of igneous zircon, which sometimes experiences little recrystallization during the late magmatic deuteric stage, either pre-or syn-deformational due to circulation of fluids along the shear zone. It is believed that the deformation of all granitic rocks in the west Wadi Nugrus area is possibly synchronous and related to the Najd Fault System (NFS). The (NFS) extends from the western Arabian Peninsula to develop the NW-trending Nugrus Shear Zone (NSZ) in the south Eastern Desert. Sub-magmatic, solid-state, and sub-solidus deformational microstructures are evidence for the deformation related to the (NFS). Chessboard patterns in quartz and sub-magmatic fractures in plagioclase indicate deformation at high temperatures (T > 650 °C) in the presence of melt, which demonstrate the shearing during granitic cooling. On the other hand, quartz grain boundary migration and sub-grain recrystallization are two examples of solid state-related high-temperature deformation-related microstructures (T > 450 °C). Mica kinks along feldspar twinning and bending planes refer to low-temperature sub-solidus microstructures (T < 450 °C).

Petrogenesis of Late Cretaceous A1-type alkali monogenetic volcanoes, Wadi Natash, South Eastern Desert, Egypt, and their implications for Nb mineralization and tectonic evolution

Petrogenesis of Late Cretaceous A1-type alkali monogenetic volcanoes, Wadi Natash, South Eastern Desert, Egypt, and their implications for Nb mineralization and tectonic evolution

Regional overview potential zones for groundwater recharge in Wadi Hodein, south Eastern Desert of Egypt

ABSTRACT Wadi Hodein (WH) is one of the largest arid wadies in the eastern desert, where the groundwater (GW) is the main water resource, to meet the water demand of its residents. Therefore, GW recharge (GWR) potential zones map is to be constructed as an effective tool for GW management in WH. Analytical hierarchy process (AHP) with geospatial analysis using ArcMap was used to delineate the GWR. Six thematic layers (soil map, slope, geology, geomorphology, lineament density, and drainage density) were used to produce the recharge map. The results classified the potential of WH recharging into five categories very low, low, moderate, high, and very high with their corresponding percentage areas of 2.60%, 9.30%, 42.9%, 31.30%, and 14.00%, respectively. Verification analysis using water quality data of the drilled wells inside the study area was conducted to confirm the resulted GWR potential map.

Mineralogical, geochemical and radioactivity of Gabal Nasb Hebili, Arabian Nubian Shield, Egypt: Implication for rare metals mineralization

Field geology, geochemical studies and spectrometric prospecting were used to detect rare metals and uranium mineralization in Neoproterozoic garnetiferous muscovite granites from Gabal Nasb Hebili area in the South Eastern Desert of the Egypt from the Arabian-Nubian Shield (ANS). They intrude the surrounding metaultramafic rocks, metagabbros, mélange matrix, older granitoids, younger granitoids (garnetiferous muscovite granites) and post-granitic dykes. The present study will focus on the garnetiferous muscovite granites, which occur as stocks of domal shape and composed of quartz, plagioclase, potash feldspars, muscovite and garnet. These garnetiferous muscovite granites were affected by sericitization, silicification and fluoritization processes. These alteration products are associated with visible uranium mineralization. Mineralogical study of the mineralized zones in the garnetiferous muscovite granites reveals the uranium minerals (zippeite, uranophane, kasolite and autunite) and rare earth-bearing minerals (monazite, allanite, bastnäsite, coronadite and garnet). The presence of these different paragenetic minerals with the various alterations in the studied granites, indicate that these rocks were subjected to the effect of mineralizing acidic and alkaline solutions in post magmatic stage. Geochemically, the garnetiferous muscovite granites are peraluminous (A/CNK= > 1.1) and showing of S-type granites which formed in a syn-collision tectonic regime. The Gabal Nasb Hebili granites exhibit positive slopes of LREEs (Ce/Sm)n (3.2) with negative HREE slopes [(Gd/Lu)n from 4.6). The negative Eu anomaly in the granite is very strong, suggesting serious addition of Eu during the alteration. The increase in the LREE, and other light isovalents, can be supported by the petrographic observations where monazite and allanite appear to be important refractory minerals in the sheared granite. Gabal Nasb Hebili is markedly enriched in eU, where its content varies between 4.3 and 199.2 ppm (averaging 34.4 ppm) with eU/eTh ratio (0.9–7.1), while eTh content varies between 2.2 and 95.3 ppm (averaging 13.8 ppm).

Dolphin-shaped island: Exploring the natural resources and radiological hazards of Wadi El Gemal Island

The objective of this study is to assess the natural resources and radiological risks of Wadi El Gemal Island by examining its topography, mineralogy, geochemistry, and radioactive distributions. This island, which is situated at the outlet of Wadi El Gemal in Egypt's southeastern Desert, has a unique shape resembling a dolphin based on Landsat imagery. It's a part of the Wadi El Gemal-Hamata Protectorate and is notable for its diverse environmental, geological, economic, and archeological features, including recent reefs, sandy deposits, Quaternary carbonate sediments, and mangroves. The main natural resources on the island are fauna, mangrove forests, and flora. Samples collected from the island were analyzed using a NaI detector to measure the concentrations of radionuclides such as 238U, 232Th, 226Ra, and 40K, which were found to be within acceptable levels according to UNSCAR guidelines. The radionuclide 238U, 232Th, 226Ra, and 40K activity concentrations of the collected samples were 32.55 ± 9, 12.63 ± 4, 12.49 ± 4, and 325 ± 34 Bq/kg, respectively. Regarding radiological hazard indices, the values of absorbed gamma dose rate (36.06 ± 5.42 nGy/h), radium equivalent activity (73.88 ± 14.4 Bq/kg), annual effective dose indoor (0.18 ± 0.03 mSv/y) and outdoor (0.04 ± 0.01 mSv/y), internal (0.29 ± 0.05) and external (0.2 ± 0.03) indices, and excess lifetime cancer index (0.15 ± 0.05 × 10−3).This is suggest that there is no significant risk associated with these sediments.

Aquifer characterization and groundwater potentiality in southeastern Desert, Egypt using integrated remote sensing techniques.

Aquifer characterization and groundwater potentiality in southeastern Desert, Egypt using integrated remote sensing techniques.

Assessing environmental and radiological impacts and lithological mapping of beryl-bearing rocks in Egypt using high-resolution sentinel-2 remote sensing images

Emerald and other beryls represent a family of the most valuable gemstone around the world and particularly in Egypt. Beryllium (Be) contents in beryl-bearing bedrocks in south Sinai (Wadi Ghazala and Wadi Sedri), and in central and south Eastern Desert of Egypt (Igla area, Zabara-Um Addebaa belt, Homret Akarem, and Homret Mukpid) were investigated in this study. The environmental risk levels of Be, associated major ions, and heavy metals in groundwater nearby to beryl-bearing mineralization were also evaluated. Results showed that Be contents ranged from 1 to 374 ppm in beryl-bearing bedrocks, while in nearby groundwater, Be content has a range of 0.0001–0.00044 mg/L with an average of 0.00032 mg/L, which is within the permissible levels and below (0.004) the U.S. EPA maximum contaminant level (MCL). Most levels of heavy metals (e.g., Be, B, Ni, V, Fe, and Al) in the investigated groundwater of central and south Eastern Desert and south Sinai are within the permissible levels and below their corresponding U.S. EPA MCLs. This study also investigated the radiological risk of natural radionuclides distributed in beryl-bearing bedrocks in the study area using gamma spectrometry; Sodium Iodide [NaI(Tl)] scintillation detector. Among the estimated mean 238U, 232Th, and 226Ra activity concentrations of the studied beryl-bearing rocks, Homret Mukpid (79, 87.15, 60.26 Bq kg−1) and Homret Akarem (111.6, 51.17, 85.1 Bq kg−1) contain the highest values. This may be attributed to their highly fractionated granitic rocks that host uranium and thorium reservoir minerals such as zircon, allanite, and monazite. The estimated data of multi-radiological parameters such as absorbed gamma dose, outdoor and indoor annual effective dose, radium equivalent activity, internal and external indices, index of excess cancer, and effective dose to human organs reflecting no significant impacts from the emitted natural gamma radiation.

Petrochemistry, rare metals-bearing minerals and spectrometric exploration in Khour Abalea, Abu Rusheid area, Eastern Desert, Egypt

On the Red Sea coast, Abu Rusheid area is located south Marsa Alam City (90 km) in the south Eastern Desert. Khour Abalea as a part of the Abu Rusheid area extends for about 1.0 km in E-W direction. It is subdivided into two main branches; the first one (the longest) extends about 0.7 km in E-W direction with 10–30 m in passing through mylonites, whereas the second branch extends about 0.5 km in ENE-WSW with about 5–20 m in width and passing through mylonites and ultra-mylonites. Microscopically, this rock is composed mainly of k-feldspars, plagioclases, biotite, and quartz as the main minerals, while the accessories include fluorite, allanite, secondary uranium (kasolite), and zircon. The hydrothermal alteration that occurs during the interaction of hydrothermal fluid and rock results in an M-W type tetrad effect range of 1.72–3.66 in the normalized REE chondrite patterns of the Khour Abalea mylonite rocks. The identified heavy minerals associated with Khour Abalea mylonite rocks can be categorized as a) radioactive minerals (soddyite, kasolite, thorite and uranothorite), b) rare earth minerals (monazite, xenotime and rare earth silicate), c) Nb–Ta minerals (columbite, fergusonite, ishikawaite and aeschynite), d) precious metals (gold, silver minerals (argentite, arcubisite and matildit), e) base metals (cassiterite, wolframite, chalcocite, galena, sphalerite pyrite and Bi minerals (bismite, bismuthinite and perite) and f) accessory mineral (zircon). According to the uranium mobilization equations, there are uranium enrichment in Khour Abalea mylonite.

Effect of mineralogical variations on physico-mechanical and thermal properties of granitic rocks

The present study aims to explain the geochemical and mineralogical details of the granitic rock types in Gabal EL-Faliq area, South Eastern Desert of Egypt, in relation to geotechnical engineering and their suitability as dimension stones. The objective of the current research was achieved through two steps; the first step involved geological studies such as the petrographic, geochemical, and mineralogical investigations. The second and applicable step involved the geotechnical assessment of the studied rocks by measuring their engineering properties such as physical, mechanical, and thermal expansion properties. The petrographic investigation revealed that the studied granitic rocks are divided into two main classes: (1) gneissose granites (Biotite–Perthite) of medium to fine-grained size and (2) alkali-feldspar granites of coarse to medium-grained size. Mineralogically, the studied rocks are composed mainly of albite, orthoclase and quartz in varying proportions, along with some accessory minerals such as apatite and rutile in addition to some minor quantities of iron-group minerals such as hematite and ilmenite. The engineering properties showed that the maximum water absorption and apparent porosity values are 0.34% and 0.77%, respectively, while the minimum bulk density is 2604.03 kg/m3. The compressive strength ranges from 999.68 to 2469.10 kg/cm2, while the abrasion resistance varies from 29.67 to 54.64 Ha. The increase in albite content led to an increase in water absorption while a decrease in bulk density and compressive strength. The increase in the grain size led to an increase in apparent porosity and a decrease in mechanical properties. A Great variation in the expansion coefficient as well as the length change, occurs under changes in temperature, mineral composition, and physical properties. The increase in heating temperatures caused an insignificant increase in linear thermal expansion with a maximum value of 0.0385% at 100 °C. These results indicated the suitability of the studied granites as dimension stones for use in indoor and outdoor decorative purposes (cladding/paving) under variable temperature conditions.

Impact of DEMs for Improvement Sentinel 2 Lithological Mapping Utilizing Support Vector Machine: A Case Study of Mineralized Fe-Ti-Rich Gabbroic Rocks from the South Eastern Desert of Egypt

Fused remote sensing datasets have greatly contributed to enhancing lithological targets and providing significant information for mineral exploration. For instance, multispectral datasets can discriminate rock units through their unique spectral signatures. Digital Elevation Models (DEMs) could be an effective tool boosting lithological discrimination based mainly on their topographic variations. Consequently, the current study applied the power of the support vector machine (SVM) algorithm and the integrated Phased Array L-type band Synthetic Aperture Radar (PALSAR) DEM and multispectral Sentinel 2 data to: 1—Create an updated lithological map of a poorly mapped arid terrain (Khashir-Ras El-Kharit district, Eastern Desert of Egypt), and 2—Compare and assess the distribution of ferrogabbros with the aim of improving the localization of these rock bodies and investigating their mineral content. Our results enhanced the lithological mapping and revealed a better generalization of mineralized ferrogabbros when the input was a fused DEM with Sentinel 2 compared to the salt and pepper effect observed when adopting the Sentinel 2 solely as the input data. Additionally, the current research strongly recommends detailed exploration programs for Fe-Ti oxide ores within the gabbroic rocks delineated through the resultant thematic map. The ferrogabbros were subjected to a comprehensive analysis involving whole rock geochemistry, XRD, EDX, and light-reflecting investigations, which revealed the existence of magnetite, titanomagnetite, and hematite. The titanomagnetite crystals display subhedral morphology and exhibit fine- to medium-grained surfaces with irregular shapes. X-ray diffraction (XRD) analysis revealed the presence of magnetite and hematite in the concentrated Fe-Ti oxides. Additionally, the whole rock geochemistry highlighted the origin of the ferrogabbros and their proposed tectonic setting as an alkaline to calc-alkaline magma type that developed in a continental arc setting.

Geochemical and remote sensing integrated with satellite gravity data of Darhib and Atshan talc deposits, South Eastern Desert, Egypt

The current contribution conducted new geochemical, remote sensing integrated with gravity detailed studies of talc deposits to identify the talc protolith as well as its extension, depth, and structures. There are two examined areas, distributed from north to south, Atshan and Darhib and both belong to the southern sector of the Egyptian Eastern Desert. They occur as individual lenses or pocket bodies in ultramafic-metavolcanics following NNW-SSE and E-W shear zones. Geochemically, among the investigated talc, Atshan samples have high contents of SiO2 (av. 60.73 wt.%), and higher concentrations of transition elements such as Co (av. 53.92 ppm), Cr (781 ppm), Ni (av. 1303.6 ppm), V (av. 16.67 ppm), and Zn (av. 55.7 ppm). Notably, the examined talc deposits contain low contents of CaO (av. 0.32 wt.%), TiO2 (av. 0.04 wt.%), SiO2/MgO (av. 2.15), and Al2O3 (av. 0.72 wt.%), which is comparable with ophiolitic peridotite and forearc setting. False color composite (FCC), principal component analysis (PCA), minimum noise fraction (MNF), and band ratio (BR) have been used to distinguish talc deposits in the investigated areas. Two new proposed band ratios were created to separate talc deposits. FCC band ratios (2/4, 4/7, 6/5) and (4 + 3/5, 5/7, 2 + 1/3) have been derived to focus on talc deposits in two case studies, Atshan and Darhib areas. The application of regional, residual, horizontal gradient (HG), and analytical signal (AS) techniques to gravity data are used in interpreting the structural directions of the study area. The analysis of this technique displays several notable faults trending in NW–SE, NE–SW, NNW–SSE, and E–W directions. Two techniques of gravity depth calculation were applied in the study areas, namely source parameter image (SPI), and Euler deconvolution (EU). The analysis of these techniques reflects that the depth of subsurface sources ranges between 383 and 3560 m. Talc deposits may be attributed to greenschist facies metamorphism or to a magmatic solution that is (associated with granitic intrusions) interacted with the surrounding volcanic rocks forming metasomatic minerals.

Detecting Oxides Mineralization Utilizing Remote Sensing and Comprehensive Mineralogical Analysis: A Case Study Around Mikbi-Zayatit District, South Eastern Desert, Egypt

Undoubtedly, involving more tools, datasets, and techniques for detecting the mineralized areas sharply narrow the zones to be investigated and delivered, in most cases highly potential zones. Consequently, this study is an attempt to apply remote sensing data including Sentinel 2 and ASTER, field observations, petrography of the hydrothermal alteration processes, ore microscopic investigations, X-ray examinations, and EDX analysis to detect and emphasize mineralization types at Wadi Mikbi and Wadi Zayatit district, South Eastern Desert, Egypt. Towards accurate lithological mapping, remote sensing data, previous geological maps, and the field investigations recorded serpentinites, ophiolitic metagabbros, amphibolites, epidosite, arc-related metasediments (schists and quartzites), metagabbro-tonalite complex, dunite, olivine gabbros, and granitic rocks encountered in the study district. Additionally, various hydrothermal alteration zones have been primarily outlined using ASTER and Sentinel 2 data by implementing informative band ratios and constrained energy minimization techniques. The mineralogical studies have confirmed most of the remotely-detected hydrothermal alteration minerals. Ore microscopy, XRD technique, and EDX microchemical analysis of representative mineralized samples of the study district identified magnetite, ilmenite, titanomagnetite, chromite, magnesioferrite, quartz, apatite, clinochlore, plagioclase, pyroxene and epidote. Cross-linking remote sensing results, field observations and laboratory studies revealed that the dominant hydrothermal alteration processes include oxidization, serpentinization, carbonatization, epidotization, silicification, zoisitization, muscovitization, sericitization, and chloritization. Spatial overlay analysis of the resultant altered features, structural dissection, field observations, and analytical studies were integrated to build a mineral potentiality map of the study district.

Spatiotemporal Monitoring of Land Reclamation in the Southeastern Desert, Upper Egypt Using Satellite Data and GIS

The objective of this study was to monitor the reclamation development and assess the LULC changes in a reclaimed area in Upper Egypt. GIS and remote sensing-based multi-temporal Landsat imageries (i.e., Landsat-5 and Landsat-8; 30m) were utilized for mapping and analyzing the spatiotemporal dynamics between 2005 to 2020. Both supervised-based maximum likelihood classifier (MLC) and normalized difference vegetation index (NDVI)-based thresholds were implemented. The results of both methods were cross-compared and showed that the agriculture activities started in 2004 with small and sparse agriculture patches. The bare land occupied more than 65.1% of the total area between 2005-2008. Overall, using the MLC and NDVI-based classification, the authors observed an increase of approximately 455.6% (17,027.7 ha) and 477.2% (16,973.5 ha) over 15 years (2005-2020), respectively. The results could be very useful for assessing the success of the Egyptian strategies to sustain the agricultural land areas and food production through horizontal expansion and investment in the desert areas.