This study presents an integrated petrographic and whole-rock geochemical investigation of sandstones from the lower Cenomanian Bahariya and Oligocene Radwan Formations in the Bahariya Depression, Western Desert, Egypt. The aim of this study is to constrain their provenance, evaluate weathering intensity, and to reconstruct the tectonic and palaeogeographic evolution of the Bahariya Depression during the early Cenomanian and Oligocene periods. Petrography data revealed that the Bahariya sandstones are composed of quartz arenite and sub-arkose, whereas the Radwan sandstones consist of quartz arenite and sub-litharenite. Modal component analysis of the Bahariya sandstones (Q87.6F8L2.5) indicated a relatively distal cratonic-interior provenance, with moderate to intense chemical weathering under sub-humid to humid climatic conditions. The Radwan sandstones reveal a quartz-rich composition, with an average ratio of Q91.7F0.87L6.53, suggesting a more proximal, orogenic source and weak to moderate weathering intensity, under subtropical to tropical climate. Geochemical data are consistent with the petrographic findings as the Bahariya sandstones show high SiO2 (average = 92.2 wt
Deltas are dynamic transitional environments where complex morphology and hydrodynamics have a great influence on benthic communities. This study investigates the distribution of foraminifera and thecamoebians in the Paraíba do Sul River Delta (Brazil), with emphasis on distinguishing living assemblages (biocenosis) from dead assemblages (thanatocoenosis). A total of 24 sediment samples were analysed for faunal composition, water parameters, and sedimentological characteristics. Results reveal significant discrepancies between living and dead assemblages, reflecting both ecological preferences and taphonomic processes such as dissolution, transport, and differential preservation. Ammonia tepida, Criboelphidium excavatum, Haplophragmoides wilberti and Trochamminita salsa dominated living assemblages. A higher diversity of calcareous species from the inner shelf characterized the dead assemblages, evidencing post-mortem transport from adjacent marine settings. The statistical analysis demonstrates clear sectorization of the delta: the northern sector is dominated by a marine influence zone and another with lagoon characteristics and overwash deposits; the southern sector is characterised by confinement conditions with mangrove fauna and a zone with a strong freshwater influence marked by thecamoebian species particularly Difflugia spp. and Centropyxis spp. These results underline the utility of combined foraminiferal and thecamoebian assemblages as sensitive indicators of hydrodynamic and environmental gradients in tropical deltas. By integrating biological, physical, and geochemical datasets, this study provides new insights into the functioning of a major South American deltaic system and supports the use of these protists as bioindicators in coastal monitoring and management strategies.
Hazardous metal pollution remains a major concern in developing nations. The abundance of potentially hazardous metals in thirty stream sediment samples from the Bidou I area (Cameroon) were analyzed using inductively coupled plasma mass spectrometry (ICP‒MS) to provide insights into the pollution status, ecotoxicological and human health risks. The average concentration (in mg/kg) of As, Pb, Th, Zn and La in the sediments were above background material values, suggesting potential contamination. The average As, Cr, Cu, Pb, Th and Zn concentrations in the sediments were also higher than sediment quality guideline standards, further indicating probable contamination. Pollution index proxies (average contamination factor: 1.35 ‒ 271.41, contamination degree: 17.36 ‒ 750.90, modified contamination degree: 1.93 ‒ 83.43, pollution load index: 0.52 ‒ 2.11, average enrichment factor: 1.37 ‒ 2857.58 and average geo‒accumulation index: ‒ 1.10 ‒ 2.09) indicated low to very high enrichments and contamination. Additionally, average ecological risk factor (0.69 ‒ 2714.08), potential ecological risk index (148.16 ‒ 7202.98), toxic risk index (3.43 ‒ 34.05) and toxic units (1.87 ‒ 16.89) indicated low to very high ecotoxicity risk. Human health risk assessment demonstrated acceptable to no potential carcinogenic and non‒carcinogenic health risks for both children and adults. However, ingestion is the primary intake pathway of the potentially hazardous metals in the Bidou I area sediments, with children being highly vulnerable. This requires steady monitoring and mitigation strategies including in‒situ and biological remediations. Integrated pollution index, ecotoxicological and human health risk assessments, multivariate analyses, and source discrimination cross‒plots suggest both lithologic and anthropogenic sources for the potentially hazardous metals in stream sediments of the Bidou I area, Cameroon.
A recent study on nickel laterite in Vietnam was conducted in the ultramafic Nui Nua intrusion, Thanh Hoa Province, providing an important basis for future exploration. Tropical weathering of apoharzburgite and apodunite has produced a typical lateritic profile with two main horizons: an upper limonite zone and a lower saprolite zone, each characterized by distinct mineralogical and geochemical features. Using X-ray diffraction (XRD), X-ray fluorescence (XRF), and mass balance calculations, the study identified strong depletion of Si, Mg, Ca, Na, and K in the limonite zone, alongside enrichment of Al, Ni, Co, Mn, and especially Fe (up to 451.39
Beachrock is often treated as a homogeneous body, while facies variability within beachrock receives comparatively less attention, limiting our understanding of depositional environments and beachrock formation mechanisms. The authors are developing artificial beachrock as a sustainable alternative measure for coastal erosion control. Understanding natural beachrock formation provides a useful basis for developing artificial beachrock. This study presents detailed morphological, sedimentological, and cementation descriptions and interpretations of beachrock facies from two contrasting climatic zones, a tropical coast in Sri Lanka and a subtropical coast in Okinawa (Japan), that exhibit major facies variability. Our analysis indicates the following: facies variability reflects spatial and temporal changes in coastal hydrodynamic conditions rather than a single depositional process. Sediment texture and pore-space characteristics strongly influence carbonate cementation and the degree of lithification. Mixed terrigenous and biogenic sediment inputs demonstrate that local sediment supply plays a major role in beachrock formation. Despite the variety of carbonate cement fabrics and textures rich in aragonite and calcite, the majority of the studied beachrock facies suggest precipitation under marine to mixed marine-meteoric conditions. The presence of traces of fungal filaments and organic matter further suggests a possible contribution of microbial activity to the cementation process. Comparative analysis of regional facies variability further indicates that there is no clear relationship between geographic region and cement mineralogy or cementation mechanisms. The findings of this study provide a basis for developing artificial beachrocks for tropical and subtropical coasts.
This research investigated the mechanisms governing land subsidence on the Yazd-Ardakan Plain, in Iran. The experiment was conducted in the laboratory using a leakage-tank model to simulate groundwater extraction and soil response. Measurements of soil properties were made in the laboratory and included; hydraulic conductivity (k = 2 × 10− 3 m/s); moisture content (3.3
Sedimentological and mineralogical investigations of sediments from Limbe beach, Southwest Cameroon, were conducted to examine sediment transport and depositional processes. The adopted methods include grain-size analysis, EPMA microanalyses, and chemical characterization of heavy minerals in the coastal sediments. The results show that the analyzed beach sediments are predominantly fine-grained sands (54.34–81.21
The eastern Great Rann of Kachchh (GRK) Basin represents a geomorphologically vast and complex terrain that has undergone several phases of depositional change driven by the interplay of climate variability, tectonic activity and Holocene sea-level fluctuations. Bordered by the Thar Desert and the Aravalli ranges to the north, the eastern GRK experiences an annual inundation and drying cycle by episodic monsoonal flooding primarily through the Luni River. During dry phases, aeolian reworking along the margins becomes active owing to semi-arid climatic conditions. The late Holocene marine withdrawal transformed this vast region into a monotonous, flat, desertic landscape devoid of exposed sections; however, this palaeogeographic change is not understood till date. Despite being referred to as featureless terrain, the eastern GRK exhibits subtle geomorphic variations and interacts with complex fluvio-aeolian processes that strongly influence sediment dispersal pattern across various depositional gradients in the eastern GRK Basin. The present work is based on studying modern surface morphology and four basin-wide transects across the major depositional gradients that include (1) the Luni River transect (LU), (2) Nada Bet (NB), (3) Chappariya-Kuda (CK) and (4) Bela-Chorar Island (BC) transect. The results show a strong micro-geomorphic control on sediment dispersal pattern across various depositional gradients in the eastern GRK Basin. The fluvially influenced Luni transect retains coarser sediments with better sorting near the basin entrance, whereas the NB, CK and BC in the basin interior is dominated by muddy, silt rich sediments (silt > 80
Landslides in the Eastern Ghats Mobile Belt pose an escalating threat to both human infrastructure and fragile ecosystems, yet integrated assessments that link geophysical instability with ecological vulnerability remain rare. This study advances landslide susceptibility and ecological risk assessment in the Koraput District (8,807 km2), Odisha, through an integrated multivariate framework combining Remote Sensing (RS), Geographic Information Systems (GIS), the Analytical Hierarchy Process (AHP), DAN3D debris-flow modeling, and key biophysical indicators including Normal Difference Vegetation Index (NDVI), Land Surface Temperature (LST), RUSLE-derived soil erosion, and biodiversity indices. In contrast to conventional studies that evaluate landslide hazards and ecological degradation independently, the present approach systematically examines their spatial interactions and associated environmental feedback to provide a comprehensive understanding of landscape vulnerability in the Eastern Ghats region. Key findings reveal that 86
In the present study mineralogy and modal analysis of the Miocene Surma sandstones of the Inner Fold Belt has been analysed to understand their source rock, the tectonic settings and the palaeoclimate. Surma sandstones are angular to subangular in shape, moderately to moderately well-sorted in nature and fine to medium grained in size. In the studied sediments the dominant framework constituent is quartz (avg. 51.67
Reservoir sedimentation in arid, high-sediment basins reflects coupled fluvial transport and shoreline aeolian reworking, yet the relative contributions of upstream versus shoreline sources remain poorly constrained. Using Danghe Reservoir in the Hexi Corridor, northwestern China, we developed a dual-pathway, dual-fingerprint, three-endmember framework to apportion inlet deposits among upstream bed load, upstream suspended load, and reservoir-bank aeolian sand. We sampled 16 along-channel and 6 shoreline sites and combined grain-size distributions with nine-element EDXRF fingerprints. Grain-size mixing was solved by NNLS fitting within a shared size window, and geochemical mixing was performed using CLR-transformed, covariance-weighted NNLS. Bed sediment D50 ranged from 37 to 364 μm, with a median of 147 μm, whereas suspended sediment D50 ranged from 7.07 to 81.63 μm, with a median of 10.02 μm. Shoreline aeolian sand showed D50 values of approximately 86–217 μm across banks. The deterministic NNLS solution gave central estimates of 26
This study investigates the vertical distribution and geochemical fractions of phosphorus (P), sediment texture, and total organic carbon (TOC) in sediment cores collected from two contrasting backwaters (Sadras - SA and Edaiyur - ED) adjacent to the Kalpakkam coast, Tamil Nadu, southeast India. P was partitioned into its operationally defined forms: loosely bound P (LP), aluminium-bound P (AlP), iron-bound P (FeP), calcium-bound P (CaP), organic P (OP), and bioavailable P (BP) to evaluate sedimentary P dynamics and their ecological significance. The total P (TP) content varied from 537 to 2,384 mg kg⁻¹ across depths (5–50 cm), with depth-averaged values of 922 mg kg⁻¹ in SA and 1,213 mg kg⁻¹ in ED. The calculated Phosphorus Pollution Index (PPI) values exceeded 1.0 in both regions (SA = 1.5; ED = 2.0), indicating that the sediments are P-enriched and ecologically stressed. Sediment texture and P speciation diverged between the backwaters. SA sediments were sand-dominated with CaP contributing 45
This study presents an integrated reservoir performance analysis of the C−14 reservoir in the Niger Delta, aimed at optimizing production sustainability in a structurally complex, compartmentalized setting. Utilizing a data-conditioned workflow, the study integrates 3D seismic variance (coherence) attributes, well log interpretation, PVT modeling, and production history matching to construct an applicable geological framework. The reservoir is characterized by a growth-fault architecture, where consistent pressure offsets across fault blocks confirm a highly compartmentalized system. PVT analysis reveals a bubble point pressure of approximately 3,300 psia. Pressure decline below this threshold triggered two-phase flow, evidenced by rapid Gas-Oil Ratio (GOR) increases and elevated oil viscosity, which serve as proxies for depletion in data-sparse zones. A hierarchical weighting strategy was employed to manage variable data quality. High-confidence wells, specifically OEM−1 and OEM−3D, constrained depletion trends, while more volatile wells (e.g., OEM−8D, OEM−6D) served as secondary control points for testing spatial continuity. Over a 37-year production span (1979–2016), the field recovered 20.5 MMSTB. OEM−1 emerged as the primary contributor due to sustained pressure support, whereas wells like OEM−8D and OEM−4 suffered from early gas and water influx. Increasing water cuts post−1986 indicate progressive aquifer encroachment. This integrated approach provides a transferable framework for diagnosing fault-controlled dynamics and identifying redevelopment opportunities in mature deltaic reservoirs.
The Indian monsoon system, a component of the Asian monsoon, was established and evolved during the Cenozoic because of the Himalayan orogeny. Numerous studies have found that its inception is commonly associated with a Late Miocene tectonic event. This is possibly due to voluminous studies conducted on the Neogene Himalayan Foreland Basin (HFB) deposits. However, it is equally essential to explore Palaeogene HFB deposits to improve understanding of the origin of the Indian monsoon and its temporal and spatial evolution during episodes of Himalayan orogeny. Thus, this study focused on identifying seasonal/monsoon climate signatures from the underexplored Palaeogene HFB palaeosols in the Kangra sub-basin using systematic morphological, micromorphological, and representative stable C O isotope analyses. The studied Palaeogene and Early Miocene-age HFB palaeosols reveal abundant matrix and intrusive pedofeatures indicative of seasonal conditions during their formation, similar to those characteristic of Indo-Gangetic soils formed under the present-day monsoon climate. Most conspicuous evidence includes intermixing and the occurrence of Fe–Mn oxide/sesquioxide pedofeatures and carbonate pedofeatures together. Also, the thick carbonate horizon consists of widely dispersed Fe–Mn oxide nodules/concretions along-with calcareous nodules/concretions. The study is the first of its kind from this part of the HFB deposits and provides additional data documenting seasonal-to-monsoon-like conditions during the Palaeogene, i.e., well before the Late Miocene tectonic episode of the Himalayan orogeny. Further, it paves the way for more such studies on the abundant and well-preserved yet overlooked Palaeogene-dated HFB palaeosols in the NW Himalaya (India).
This study represents the first integrated sedimentological, petrofacies, and diagenetic investigation of the Early Cretaceous El Abd Sandstone Member in the eastern Sirte Basin, Libya. By linking depositional processes with diagenetic overprinting, it provides a new and fundamental understanding of reservoir evolution and quality in this key hydrocarbon-bearing unit. Accordingly, this research is based on core data and incorporates petrographic as well as diagenetic analyses to investigate the sedimentological characteristics of the El Abd sandstones within the Early Cretaceous Sarir Formation, aiming to identify the factors influencing reservoir evolution. The sedimentological assessment reveals eight distinct petrofacies in the El Abd sandstones: quartz arenite, lithic arenite, sublithic arenite, quartz wacke, and lithic wacke sandstones, in addition silty claystones, conglomerates, and breccias. Core samples from various wells illustrate diverse sedimentary structures, including high- and low-angle cross-beddings, even and inclined laminations, current ripples, rubbles, and reactivation surfaces. On the basis of these petrofacies and sedimentary features, three facies associations are interpreted: braided fluvial, meandering fluvial, and estuarine environments. The braided facies association consists of braided bar and braided channel facies, whereas the meandering facies association contains point bar, crevasse splay, abandoned channel, and floodplain deposits. The estuarine facies association contains estuarine bay, as well as channel and bar facies. Diagenesis within the El Abd sandstones is characterized by significant quartz overgrowths, primarily in quartz arenite and sublithic arenite sandstones, leading to occluded intergranular pores. Kaolinite appears in multiple forms, with subordinate infiltrated clay, hematite, pyrite, and other diagenetic features. In fine-grained petrofacies, such as wacke sandstones and silty claystone, diagenetic characteristics involve pyrite replacement and hematite along with mixed clays. The quality of the El Abd reservoir is largely determined by the nature of sedimentation, with the meandering point bar and estuarine channel and bar recognized as prime for excellent reservoir quality. The present work proposes a conceptual model to guide the exploration and exploitation of the El Abd sandstones, a key reservoir in the eastern Sirte Basin, while offering a basis for addressing uncertainties in analogous hydrocarbon settings.
Vegetation cover, low-relief topography, and sparse bedrock exposure in western Kentucky hinder accurate delineation of stratigraphic boundaries within mixed siliciclastic–carbonate successions, limiting conventional field-based geologic mapping. To address this challenge, we present a new 1:10,000-scale geologic map of the McDaniels Quadrangle that integrates 1.5 m LiDAR-derived topography, Sentinel-2 multispectral imagery, river-profile analysis (χ and ksn), targeted field validation, thin-section petrography, and scanning electron microscopy (SEM). This integrated workflow is innovative in linking remote sensing, geomorphic metrics, and petrographic ground-truthing to refine the mapping of Upper Paleozoic sedimentary units along the structurally complex margin of the Rough Creek Graben. LiDAR-derived multi-azimuth hillshades and river-profile metrics delineate benches, knickpoints, and lineaments that correspond to lithologic boundaries and facies transitions, whereas Sentinel-2 band ratios and principal component analysis enhance discrimination between carbonate-rich and siliciclastic units. Mapped lineaments are predominantly < 1 km long and trend NE–SW, consistent with regional structures and supported by joint measurements. River-profile analysis reveals concave longitudinal profiles, abundant knickpoints, and elevated ksn corridors in the central–northeastern area. Many knickpoints coincide, within mapping tolerance, with mapped lineaments, indicating localized structural modulation of bedrock incision. Basin-scale χ values (< 50) show weak spatial coherence with mapped faults, suggesting that lithology exerts first-order control on regional relief while structure acts locally. Petrographic and SEM analysis further document carbonate-rich matrices in Reelsville and Haney Limestones and ferruginous, quartz-rich textures in the Big Clifty Sandstone. The resulting map refines stratigraphic boundaries and clarifies the interactions among depositional facies, diagenesis, and surface processes in a vegetated, low-exposure setting. More broadly, this study provides a transferable, high-resolution workflow for geologic mapping and hazard-relevant terrain assessment in covered sedimentary landscapes.
The Early Cretaceous drift deposits of the Douala Basin (Mungo River Formation) were investigated in order to determine the paleoclimatic conditions, compositional maturity, paleoweathering, and depositional environment, based on field geologic mapping and geochemical analyses. This study aims to evaluate weathering intensity, paleoclimatic conditions, and paleo-redox conditions using geochemical data and their various approaches for black shale samples of the Ediki River, Mungo River Formation, Cameroon. The black shale samples from Ediki River were collected and analyzed geochemically using inductively coupled plasma-mass spectrometry (ICP-MS) to reveal their major, trace, and rare earth element composition. The black shales show variable colors ranging from grey to dark, are fine-grained and highly fossiliferous, and have laminations, bedding, cast, and mold structures. The calculated Plagioclase Index of Alteration (PIA 66.36 to 88.21
The Late Cretaceous–Paleocene Gurpi Formation in the Izeh Zone of the Zagros Fold–Thrust Belt (SW Iran) was studied through palynology and Rock–Eval pyrolysis, revealing a proximal basin setting and providing data on organic matter quantity, type, and maturity. Total organic carbon (TOC) (0.06–0.60 wt.
Reservoir characterization and analysis are crucial for enhancing optimal production and hydrocarbon recovery in petroliferous basins. To describe the depositional history and determine the hydrocarbon potential, this study employed a suite of well logs to delineate electrofacies and depositional sequences in selected wells within the AVA Field, offshore Niger Delta, Nigeria. Lithofacies and depositional environments were interpreted from gamma ray log signatures, whereas hydrocarbon-bearing reservoirs were correlated across the wells via gamma ray and resistivity logs. Systems tracts were delineated on the basis of characteristic log motifs indicative of transgressive, highstand, and lowstand conditions, leading to the identification of two major depositional sequences within the study area. Reservoir units were identified and evaluated, and key petrophysical parameters, including porosity, permeability, net-to-gross ratio, water saturation, and volume of shale, were computed. Deterministic estimates indicate favourable reservoir quality with significant net thickness, moderate to high porosity and permeability, and relatively low water saturation values. The net-to-gross and volume of shale range from 44 ft–327 ft, 19
Despite growing evidence of climate- and human-mediated disruptions to sediment regimes in peninsular Indian river systems, integrated, process-based frameworks linking erosion, export, connectivity, and retention for reservoir management remain limited, particularly for aging infrastructures such as Hirakud Dam, which has lost 27
