Limestones can preserve mineralogical and geochemical signatures of depositional environments and post-depositional processes, and hence provide valuable archives for paleoenvironmental reconstruction. This research investigates the mineralogical composition and major, trace, and rare earth element (REE) geochemistry of the limestones of the Triassic Elika Formation in the Shahindezh district, NW Iran, to constrain their paleoenvironment and sources and behavior of REE. Eleven limestone samples from a 240-m-thick interval were analyzed using XRD, SEM–EDS, ICP‒AES, and ICP‒MS. The limestones are dominated by calcite accompanied by subordinate quartz and trace amounts of kaolinite, illite, chlorite, apatite, and ilmenite. CaO contents range from 48.33–53.11 wt%, whereas low proportions of Al2O3 (0.25–0.81 wt%) and Fe2O3 (0.16–0.65 wt%) indicate limited terrigenous input. Total REE concentrations range from 4.42 to 25.67 ppm, and the LREE depict relatively depletion. High Y/Ho ratios (45.71–72.22) support preservation of a predominantly marine REE signature. Negative Ce anomalies (Ce/Ce* = 0.46–0.56) indicate primarily oxic conditions, whereas positive Eu anomalies (Eu/Eu* = 1.11–1.25) are mainly related to diagenetic modification. Significant correlations of REE with CaO, Sr, and P2O5 denote that the REE concentrations were controlled chiefly by carbonate and phosphatic phases, and the detrital materials had minor influence. Overall, the integrated mineralogical and geochemical evidence suggests that deposition of the limestones took place in a shallow-marine carbonate setting under predominantly oxidizing conditions. The depositional environment had normal to slightly higher salinity and limited siliciclastic input, followed by minor diagenetic modification of the primary marine geochemical signatures.
In the junction zone between the High Atlas and the Saharan margin (Bouanane region), we investigated the continental series and lagoonal-marine succession associated with the widespread Late Cenomanian-Turonian transgression.Integrating lithostratigraphic, biostratigraphic, and sequence stratigraphic data refines the stratigraphic framework, depositional architecture, and paleogeographic evolution during the Bathonian, Early and early Late Cretaceous.A major unconformity (D1) separates the Middle Jurassic regressive deposits (Anoual Formation) from the earliest Cretaceous deposits (Ifezouane Formation). The base of this formation (Mbr 1) is dominated by coarse conglomerates. This D1 unconformity records the exhumation and erosion of the Precambrian-Paleozoic basement, as well as its Triassic-Jurassic cover. Mbr 1 grades into cross-bedded sandstones deposited in braided fluvial channels. Following a second unconformity (D2), Mbr 2 indicates a precursor Cretaceous transgression characterized by lagoonal facies and a restricted euryhaline fauna, within which a site yielding ichthyofaunal remains was discovered.The Albian?-Cenomanian age can be assigned to Mbr 2 based on the occurrence of elasmobranch taxa. After a third unconformity (D3), Mbr 3 marks a transition from delta plain to sabkha and finally fully marine environments during the Late Cenomanian-Turonian.The transgressive systems tract that begins with a precursor lagoonal environment, extends E-W for at least 250 km. This Albian?–Cenomanian event marks the second transgressive episode, following initial Barremian–Aptian episodes recorded along the northern borders of the High Atlas. This Albian?-Cenomanian event was driven by the advance of a new Tethyan embayment into the suture zone between the southern Atlasic domain and the Saharan craton.
The Triassic basaltic rocks of Djebel Debadib (northwestern Tunisia) record the interaction between mafic intrusions emplaced within evaporitic sequences, hydrothermal circulation, and subsequent tectono-metamorphic evolution of the Tunisian Tell-Atlas fold and thrust belt. This study integrates petrography, bulk-rock X-ray diffraction (XRD), whole-rock geochemistry, and chemical alteration indices to investigate mineralogical transformations and the processes controlling basalt alteration. The intensity and style of alteration vary spatially according to fluid pathways, structural permeability, and proximity to the basalt–evaporite contact. Whole-rock geochemistry reveals MgO and K2O enrichment, depletion of mobile elements related to plagioclase alteration, elevated loss-on-ignition values, and coherent immobile-element trends, indicating that post-magmatic processes strongly modified the original basalt composition. Four alteration facies are recognized, characterized by variable proportions of chlorite, K-feldspar, epidote, amphibole, talc, mica, carbonates, and clay minerals. Early fluid circulation generated chlorite–epidote–amphibole assemblages under greenschist-facies conditions, whereas interaction with Mg-rich evaporite-derived brines promoted localized talc formation at the basalt–evaporite interface. Progressive fluid evolution resulted in K-metasomatism, with replacement of plagioclase by K-feldspar and mica. The observed mineral assemblages record a polyphase evolution involving (i) Triassic hydrothermal alteration related to basalt emplacement and evaporite interaction, (ii) a probable Late Cretaceous–Eocene low-grade metamorphic overprint associated with burial and convergence along the North Maghrebian margin, and (iii) Cenozoic hydrothermal reactivation and supergene weathering. These results emphasize the importance of recognizing superimposed hydrothermal, metamorphic, and weathering processes in altered basaltic successions and provide insights into basalt–evaporite systems within the western Tethyan domain.
The Kaiama–Shirigberia area of the Nigerian Basement Complex hosts cassiterite-bearing pegmatites and quartz veins associated with wolframite, tantalite, and minor copper mineralization. However, the complex structural and alteration controls on this tin-dominant polymetallic system and the limited integration of surface and subsurface datasets have constrained systematic assessment of its mineral potential. This study develops a multi-scale, process-based framework integrating field geological observations, structural analysis, Sentinel-2 multispectral imagery, digital elevation model (DEM)-based lineament analysis, and high-resolution aeromagnetic and radiometric datasets. Structural features were characterized using field measurements and DEM-based lineament analysis, while aeromagnetic data were processed using reduction-to-the-pole and first vertical derivative techniques to enhance lithological and structural contrasts. Radiometric potassium (K), thorium (Th), and uranium data were used to derive the K/Th ratio as an indicator of hydrothermal alteration and potassic enrichment. These datasets were integrated to develop a Tin Favorability Index (TFI), which was subsequently combined with Sentinel-2-derived spectral alteration indicators to generate an Integrated Mineral Potential Index (IMPI). Validation against 30 known tin occurrences shows that 86.66% fall within moderate to very high IMPI potential classes, including 33.33% within the very high class. The results indicate that mineralization is associated with NE–SW, N–S, and NW–SE structural corridors, elevated K/Th ratios, subdued magnetic responses, and surface alteration signatures, reflecting the combined influence of structural permeability and hydrothermal processes. The study provides a transparent, multi-scale framework linking field-scale geological evidence with regional geophysical and satellite-derived indicators for tin-dominant polymetallic prospectivity assessment and exploration targeting.
The Senjele Hill Carbonatite (SHC) is situated within the northwest-trending Tanganyika-Rukwa-Malawi Rift of the western branch of the East African Rift System, southwestern Tanzania. It intruded the Paleoproterozoic Ubendian Belt with a localized potassic fenite aureole. Despite its identification, detailed petrographic, mineralogical, and geochemical constraints on REE mineralization remain lacking. To address the gap, the study integrated field mapping, optical microscopy, XRD, XRF, SEM-EDS, and LA-ICP-MS. The results indicate that the SHC is exclusively dolomitic carbonatite, largely brecciated and transected by a steeply dipping, north-northwest–trending discrete late-stage calcite vein. Based on distinct mineral assemblages, Apatite-dolomite carbonatite (Ap-Dol-Cb), Monazite-dolomite carbonatite (Mnz-Dol-Cb), Bastnäsite-dolomite carbonatite (Bsn-Dol-Cb), and Calcite vein (Cal-vein) are identified. These lithologies exhibit idiomorphic to allotriomorphic textures with extensive mineral replacement, indicating progressive differentiation from magmatic (Ap-Dol-Cb) to carbothermal (Mnz-Dol-Cb and Bsn-Dol-Cb), and lastly, Cal-vein is coarse-grained, homogeneous, and monomineralic, typically calcite. REE minerals are dominated by monazite in Mnz-Dol-Cb and bastnäsite in Bsn-Dol-Cb, with minor synchysite and parisite, commonly associated with apatite and hematite. Whole-rock geochemistry reveals a coherent CaO-MgO differentiation trend, consistent with CaO depletion from Ap-Dol-Cb (30.8-35.1 wt.%), toward Mnz-Dol-Cb (28.0-30.8 wt.%) and Bsn-Dol-Cb (24.7-28.8 wt.%) and increasing REE2O3 from Ap-Dol-Cb (0.5 wt.%), Mnz-Dol-Cb (0.9 wt.%), and Bsn-Dol-Cb (2.7 wt.%), with high LREE/HREE, whereas Cal-vein exhibits high CaO content with negligible REE2O3. Significantly, textural evidence and the (La/Y)CN ratio highlight the genetic relationship between differentiation and REE enrichment in Ap-Dol-Cb, Mnz-Dol-Cb, and Bsn-Dol-Cb. These results establish SHC as a highly prospective REE-bearing carbonatite, warranting further exploration work.
This study presents an integrated analysis of planktonic foraminiferal biostratigraphy, paleoecology, and sequence stratigraphy from the offshore Nile Delta (Eastern Mediterranean). Based on 54 species identified in the PFDM-2R (BIS) well, eight biozones (O5–O7, M1–M5a) are established, providing a detailed chronostratigraphic framework. For the Miocene interval, biozones are correlated with both the global low-latitude zonation and the Mediterranean Neogene planktonic foraminiferal zonation, providing a regionally calibrated chronostratigraphic anchor for the eastern Mediterranean sub-basin. The Oligocene–Miocene (Chattian–Aquitanian) boundary is defined by the lowest occurrence (LO) of Paragloborotalia kugleri, which approximates the global Mi1 glaciation, anchoring this local stratigraphic transition within a broader narrative of Cenozoic climatic change. Paleoecological analysis indicates profound changes in upper water-column stratification and bioproductivity, likely linked to fluctuations in oceanic currents or Nile River input. Paleobathymetric reconstruction reveals three main transgressive-regressive cycles that show high synchronicity (∼85%) with global eustatic sea-level curves. Sequence stratigraphic interpretation delineates three third-order depositional sequences (DS1–DS3), each comprising transgressive and highstand systems tracts. These results demonstrate eustatic control on regional sedimentation and provide a robust analog for understanding past and future oceanographic changes in the Eastern Mediterranean. The refined sequence stratigraphic model also offers a predictive framework for identifying potential reservoir and seal units in this prolific hydrocarbon province.
The north-eastern part of the Tichoukt Ridge (folded Middle Atlas, Morocco) is a critical area for understanding the structural evolution of major faults crossing the Middle Atlas belt, their role in the structuring of Jurassic basins, and their influence on the Miocene deposits delimitation. However, this sector still lacks a detailed and updated geological map, which limits the understanding of its structural framework and lithological distribution. To address this gap, this work integrates remote sensing data from Landsat 9 OLI, ASTER and Sentinel-2 images, enhanced to high spatial resolution (5 m) by a panchromatic band from SPOT 5 HRS-2 sensor, with field investigations to produce detailed geological map at 1/50 000 scale. The use of color compositions optimized by OIF and PCA appears to have enabled the accurate discrimination and delineation of the geological formations present in the study area. Structural lineaments were manually extracted from the directionally filtered multispectral images. The structural lineaments identified have been grouped into two main systems. Faults inherited from the Paleozoic basement, responsible for the Atlas rifting, are included in the NE-SW to ENE-WSW system. The NW-SE transverse system corresponds to faults newly developed during the Jurassic (Middle Liassic). Paleostress analysis of fault-kinematic data revealed an NE–SW extensional to transtensional regime during the Bathonian, responsible for the subsidence and structural compartmentalization of the Jurassic basins through synsedimentary normal faulting. This tectonic phase was followed by NW–SE to NNW–SSE compressional-transpressional episodes, expressed by reverse and thrust faulting associated with dextral strike-slip reactivation of the major Middle Atlas fault systems during the Late Miocene–Pliocene. Furthermore, ASTER spectral band-ratio analysis identified two hydrothermal alteration anomalies, whose field validation confirmed the presence of polymetallic mineralization enriched in Pb, Cu, Mn, and Fe. The scientific and economic potential of the studied area is highlighted by these results, enhancing its relevance for geological research and mineral resource exploration.
The selection of environmentally secure landfill sites in geologically complex crystalline basement terrains remains a critical challenge in developing nations, where inadequate siting leads to pervasive groundwater contamination. This study presents a rigorous hydrogeophysical assessment framework to evaluate landfill suitability in Ede, Southwestern Nigeria, an area underlain by Precambrian Basement Complex rocks. Sixty-two (62) Vertical Electrical Sounding (VES) stations were deployed to characterize the subsurface, deriving key parameters including overburden thickness, weathered layer resistivity, longitudinal conductance, transmissivity and hydraulic conductivity. These parameters were spatially interpolated using GIS to generate thematic maps and a composite suitability model. Results from the study delineated a multi-layered subsurface architecture, identifying zones where a combination of thick overburden (>20 m), low weathered layer resistivity (<150 Ωm, indicating clay-rich content), high longitudinal conductance (>0.7 mhos), low transmissivity (< 0.3 m2/day) and low hydraulic conductivity (<0.02 m/day) provides optimal natural containment against leachate migration. The integrative analysis reveals that only 9.5% of the study area is classified as 'Most Suitable,' while 36.5% and 54% are deemed 'Moderately Suitable' and 'Least Suitable,' respectively. This finding highlights the significant hydrogeological constraints within the basement complex and the risk of relying solely on surface observations. This research demonstrates the critical efficacy of integrating geophysical methods with spatial analysis for sustainable environmental planning. It provides a framework that may be adapted for landfill siting in similar crystalline basement terrains, offering a basis for safeguarding groundwater resources. The approach contributes to environmental science, urban development, and aligns with multiple Sustainable Development Goals (SDGs), particularly SDGs 6, 11, 14 and 15.
This study investigates the vertical and lateral variability in geochemical, petrophysical, and mechanical properties of immature, organic-rich carbonate source rocks within the Upper Cretaceous Muwaqqar Chalk Marl Formation (MCM) in the Al-Lajjun Graben, central Jordan, using an inter-well transect approach. The study aims to evaluate the heterogeneity of geochemical, petrophysical, and mechanical parameters along the inter-well transect; identify the key controls governing this variability and reservoir quality; and assess the potential of mineralogical and petrophysical data for predicting rock mechanical properties. An integrated workflow was applied to 67 core plug samples extracted from two cored wells, including lithofacies analysis, bulk geochemical characterization, spectral gamma-ray logging (SGR), ultrasonic velocity measurements, micro-rebound hardness testing (MRT), and scratch testing. Multivariate linear and nonlinear regression models were developed to predict mechanical properties from geochemical and petrophysical data. Six lithofacies and three chemostratigraphic zones were identified, exhibiting systematic variations in mineral composition, porosity, total organic carbon (TOC), and diagenetic overprint. TOC values range from 1.9% to 34.7%, and HI values, spanning 662- 1001 mg HC/gTOC, indicate the presence of highly organic-rich, thermally immature Type I and IIS source rocks. Average estimated porosity is ∼30%, while unconfined compressive strength (UCS) varies from 38 to 165 MPa and hardness from 352 to 710 HLD, reflecting pronounced mechanical heterogeneity across the inter-well transect. Nonlinear regression models consistently outperform linear models in predicting mechanical behavior, yielding higher R2 values. The results demonstrate that mineralogy, porosity, TOC, depositional architecture, inter-well spatial variability, and diagenetic processes collectively control reservoir quality and mechanical behavior. This integrated framework improves the prediction of mechanical properties from log-derived and geochemical data and helps identify sweet spots for unconventional resource evaluation. These immature carbonate systems also provide valuable analogs for assessing similar unconventional reservoirs prior to thermal maturation.
This study investigated structurally controlled gold and associated mineralization in the Egambo area of the western Ethiopian Shield by integrating ground magnetic, radiometric, trench geochemical, and borehole datasets. The main objectives were to delineate litho-structural controls on mineralization, characterize hydrothermal alteration, and constrain the geometry of ore-related structures in Precambrian greenstone terrains. The trench geochemical data revealed that gold concentrations ranged from 0.0026 to 5.03 ppm (mean = 0.96 ppm), indicating pronounced variability from background to high-grade mineralization. The borehole data confirmed more continuous mineralization between 1.48 and 2.28 ppm Au within the interval of approximately 19.7–142.2 m, supporting the presence of subsurface ore continuity. These intervals were associated with elevated concentrations of As, Sb, Fe, and Se, which defined a sulfide-rich hydrothermal system. The magnetic data showed residual anomalies between −63 and 48 nT, delineating four litho-structural domains controlled by dominant NNE–SSW shear zones and subsidiary fault systems. The radiometric results suggested potassium enrichment (>0.49%), moderate equivalent uranium (8.7–13.4 ppm), and low equivalent thorium (1.3–4.7 ppm), reflecting intense potassic alteration. The high K/eTh ratios spatially coincided with magnetic lows and structural corridors, indicating zones of hydrothermal fluid flow and alteration. The Euler deconvolution results indicated source depths between 0 and 200 m, with strong clustering at 150–200 m corresponding to borehole mineralized zones. The 3D magnetic inversion delineated vertically continuous susceptibility bodies extending to ∼200 m depth with a normalized RMS misfit of 0.30, while forward modelling constrained shallow source tops at 30–39 m (RMS = 0.57). The integrated interpretation confirmed that gold mineralization was concentrated within potassic-altered NNE–SSW shear zones characterized by silicification, carbonatization, and sulfide enrichment. Overall, the study demonstrated that integrated geophysical and geochemical investigations provided a reliable predictive framework for targeting structurally controlled gold mineralization in Precambrian terrains.
Quantitative interpretation of 85 Schlumberger Vertical Electrical Sounding (VES) data and the evaluation of Dar Zarrouk parameters are used to characterize the hydrogeological parameters of Hawassa basin, Central Main Ethiopian Rift. From the interpretation of the VES, the geoelectrical sections reveal that the major aquifer systems comprise of volcanic and sedimentary formations. As a further analysis of the VES data, Dar Zarrouk parameters, including longitudinal conductance, transverse resistance, coefficient of anisotropy, and transmissivity were computed to evaluate groundwater potential zones. These were validated with borehole lithology logs and Global Gravity Model (GGM) satellite data. The results indicate that high longitudinal conductance (>10.1 Ω-1) correspond to the thick, clay-rich aquifers in the northwestern, central and southwestern parts of the basin suggesting good protective capacity. Conversely, high transverse resistance (>11,394.1 Ω m2) and aquifer transmissivity (>1243.4 m2/day) delineate fractured volcanic aquifers in the same region, indicating significant groundwater potential. The integration of Dar Zarrouk parameters with hydrogeological, borehole, and GGM data has enhanced the precision of groundwater exploration in this rift setting. Finally future studies are recommended to incorporate additional geophysical and hydrogeological data, particularly in those under-sampled zones, to improve the accuracy of groundwater potential and structural mapping.
