Research Articles (Earth Sciences)

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The potential for urban agriculture (UA) in Cape Town, South Africa: a suitability analysis
(Taylor and Francis Ltd, 2025) Kanosvamhira, Tinashe Paul; Musasa, Tatenda; Mupepi, Oshneck
Urban agriculture plays a pivotal role in enhancing human well-being by contributing to food security, economic prosperity, and environmental sustainability. Despite its significance, many cities lack accurate inventories to identify suitable sites for such initiatives. This study examines the potential for urban agriculture in Cape Town using Multi-Criteria Decision Making techniques. Factors such as temperature, soil fertility, road accessibility, and precipitation were analysed using weighted overlay to determine the agricultural potential in Cape Town. Utilizing methodologies like the Analytic Hierarchy Process and Weighted Linear Combination, the agricultural potential was established. Findings indicate that there are highly suitable areas for agriculture whose potential has not yet been fully exploited. Currently, agricultural activities like vineyards, crop production, and cattle farming, though situated on good agricultural land, are not as prominent despite the availability of vast tracts of highly suitable land. Therefore, there is a need to raise awareness and promote urban agriculture to alleviate poverty-related food insecurities. The implementation of urban agriculture is anticipated to significantly improve food security, create economic opportunities, and enhance environmental sustainability within urban areas. The study recommends the need for longitudinal studies to gather essential information for informed decision-making, ensuring the sustainability of urban agriculture initiatives.
Evaluation of carbon dioxide storage potential in wells of the Bredasdorp Basin offshore South Africa
(Taylor and Francis Ltd, 2025) Ngcobo, Luyanda; Afolayan, Blessing Ayotomiwa; Opuwari, Mimonitu
This study focuses on determining how carbon dioxide (CO2) storage can be stored in the central Bredasdorp basin offshore South Africa. Logs, seismic lines, and reports of three exploration wells were used to build a 3D static model, and the compressibility method was used to estimate the CO2 static storage capacity of the reservoir. The wells displayed fair to good porosity and moderate permeability. The zone of interest had little to no faulting, and there is evidence of differential deposition of marine sandstones that overlie fluvial shales. The sandstones have good reservoir characteristics and are overlain by thick shales that serve as seals. The reservoir displayed thinning in the eastern direction and over structural highs. A static storage assessment of the reservoir showed 0.64 Mt of CO2, and the effect of changing pore volume and water saturation on overall CO2 storage volume was observed. The results revealed that an increase in pore volume would also increase the amount of CO2 stored in the reservoir. Conversely, increased water saturation leads to decreased CO2 that can be stored in the reservoir. This study has shown that the pre-existing reservoir fluid has an impact on CO2 storage volume; the greater the volume of water in the reservoir, the less the volume of CO2 that can be stored in the reservoir; this is because water is less compressible than rock, oil or gas
Application of change detection techniques driven by expert opinions for small-area studies in developing countries
(Elsevier B.V., 2025) Kapangaziwiri, Evison; Mbendana, Tanaka A; Gumbo, Anesu D.
Rapid urbanisation in developing countries, fuelled by population growth and rural-to-urban migration, poses significant challenges for service delivery in under-resourced municipalities. Dangamvura Township in Mutare, Zimbabwe, exemplifies this issue, potentially overwhelming the City of Mutare services. Resource limitations have hindered the quantification of these changes. This study assesses changes in land use and land cover (LULC) in Dangamvura Township, Mutare, Zimbabwe, between 2010 and 2022, using stakeholder-driven methods, Google Earth Pro (GEP) and machine learning in R. A four-tier methodology was applied integrating R and expert validation through GEP to classify and quantify changes in LULC. The analysis identified built-up areas, cropland, and bare land as the main LULC classes. The results from R showed that built-up areas expanded from 3.74 km² in 2010 to 8.64 km² in 2022, the bare land decreased from 3.10 km² to 1.42 km², and the cropland declined from 6.06 km² to 2.84 km². GEP assessments indicated an increase in built-up areas from 5.08 km² to 8.91 km², a reduction in bare land from 3.57 km² to 1.97 km², and a decrease in cropland from 4.25 km² to 2.02 km² over the same period. These findings highlight significant urban expansion and declining agricultural and undeveloped land. The disparities between the R statistical software and the GEP results underscore the importance of integrating expert opinions to validate classifications, particularly in small-area studies with spatial heterogeneity. The results provide valuable insights for urban planning and decision-making, highlighting the need for adaptive strategies to manage urban growth and infrastructure development. The tiered methodology demonstrates the potential of combining advanced remote sensing tools with local knowledge to achieve robust LULC assessments in resource-limited settings, guiding sustainable urban planning and informing policy interventions to address challenges associated with rapid urbanisation in resource-limited countries.
Cloud-based big data analytics for monitoring invasive plants in groundwater-dependent ecosystems of Nuwejaars catchment, South Africa
(Elsevier B.V., 2026) Moropane, Mmasechaba L; Dube, Timothy; Mazvimavi, Dominic
Groundwater-dependent ecosystems (GDEs) provide crucial ecological and hydrological stability but are increasingly threatened by groundwater-dependent invasive plants (GDIPs), particularly in regions with limited water resources. Although GDEs have been widely studied, long-term quantitative assessments of how invasive plants alter these ecosystems remain limited. Hence, this study evaluated the impacts of invasive plants within the GDEs of the Nuwejaars Catchment, South Africa, by monitoring their spatial and temporal dynamics and quantifying the extent to which they displace native plants. Landsat-8 imagery, a Random Forest classifier, and Explainable Artificial Intelligence (XAI) techniques were integrated to map and quantify the annual distribution of GDIPs over a 12-year period. XAI interpretability techniques including SHapley Additive exPlanations (SHAP), partial dependence plots (PDPs), and recursive feature elimination (RFECV) were applied to identify key environmental conditions influencing GDIP occurrence. Spatial-temporal analysis revealed that GDIPs expanded from 40.9 % (1060 ha) in 2013 to 63.9 % (1660 ha) in 2024, displacing large areas of native fynbos vegetation. Inter-annual change analysis showed accelerated GDIP growth following the extreme 2015–2018 drought, which reduced groundwater availability for native species with shallow roots. Elevation, slope, and moisture vegetation indices emerged as the most influential predictors for classification, with PDPs revealing that GDIPs favoured lower elevations and steep slopes. Classification accuracy improved over time, with F1-Scores and overall accuracies ranging between 68.4 % to 82.5 % from 2013 to 2024. Overall, these findings highlight the persistent spread of GDIPs and their potential to transform GDEs in semi-arid areas. This study demonstrates the value of integrating remote sensing and interpretable machine learning to support ecological monitoring and targeted invasive species management.
Optical dating of Holocene extreme flood events in eastern South Africa and their connection to ENSO variability
(Elsevier Ltd, 2026) Grenfell, Michael C; Wood, Jamie C; Toms, Phillip S
Existing research examining tributary blocked-valley lake and wetland development upon the Mfolozi River floodplain (South African east coast) has highlighted the potential for blocked-valley lakes to act as mainstem palaeoflood archives. Sand and silt units preserved within the organic deposits of these floodplain-impounded features represent relatively large flood events and provide an opportunity to establish the frequency of extreme flooding in the region beyond the timespan of instrumental and historical records, thereby helping to reduce uncertainty around future tropical cyclone activity in a warming world. However, absolute age estimates for these sequences have been limited to radiocarbon dating of organic units, restricting flood history reconstruction. This study had two inter-related aims. Firstly, to evaluate the use of optically stimulated luminescence (OSL) dating for chronicling clastic sediments associated with the floodplain's blocked-valley lakes. Secondly, in combination with radiocarbon dating and Bayesian age-depth modelling, to reconstruct flood history across three sites on the Mfolozi floodplain and investigate the climatic factors that drove past extreme flooding in the region. The Finite Mixture Model (FMM) applied to single grain OSL data was identified as the most suitable equivalent dose (De) model, producing age estimates that either aligned with historical records and/or accounted for the largest population of grains with a common dose. The deposition models developed provide evidence for the occurrence of multiple extreme floods since the first event identified at 7.2 ka, providing the first long-term flood record for the region. Comparison of the Mfolozi palaeoflood record with independent sedimentary hydroclimatic evidence from the region indicates a historical tendency for more frequent extreme floods during weakened El Niño conditions (i.e., La Niña or neutral ENSO phases). This suggests that variations in ENSO conditions through the mid-to-late Holocene likely played a fundamental role in triggering extreme flooding along South Africa's east coast.
Macroinvertebrate diversity within pan wetlands in relation to geological type and hydroperiod in a protected subtropical Austral national park
(Taylor & Francis Ltd., 2025) Dube, Timothy; Leshaba, Elsie N; Dondofema, Farai
Despite their small size, wetland pan systems play a crucial role as habitats for diverse aquatic biota. Macroinvertebrate diversity across 12 pan wetlands in relation to geological type (i.e. sandstone, granite, basalt and rhyolite) and hydroperiod (i.e. high, low) in a protected subtropical national park in South Africa was studied. Water temperature, pH, TDS, conductivity, phosphates and salinity showed significant differences among hydroperiods, with significant differences among geological types being observed for water temperature and ammonium. Most of the sediment variables were found to be significant across hydroperiods and geological types. 5145 macroinvertebrate individuals belonging to 41 genera and 9 orders were identified. Macroinvertebrates were diverse during the high hydroperiod and abundant during the low hydroperiod. The canonical correspondence analysis explained 35.8% of the fitted cumulative variation in the macroinvertebrate community structure and environmental variables across different hydroperiods and geological types. This study aimed to provide a better understanding of how they are influenced by a pan geological type and hydroperiod, and this information is crucial as it aids in providing management options for refuge aquatic taxa in a protected area and for the protection of these wetlands
The potential for urban agriculture (UA) in Cape Town, South Africa: a suitability analysis
(Taylor and Francis Ltd., 2025) Musasa, Tatenda; Kanosvamhira, Tinashe P; Mupepi, Oshneck
Urban agriculture plays a pivotal role in enhancing human well-being by contributing to food security, economic prosperity, and environmental sustainability. Despite its significance, many cities lack accurate inventories to identify suitable sites for such initiatives. This study examines the potential for urban agriculture in Cape Town using Multi-Criteria Decision Making techniques. Factors such as temperature, soil fertility, road accessibility, and precipitation were analysed using weighted overlay to determine the agricultural potential in Cape Town. Utilizing methodologies like the Analytic Hierarchy Process and Weighted Linear Combination, the agricultural potential was established. Findings indicate that there are highly suitable areas for agriculture whose potential has not yet been fully exploited. Currently, agricultural activities like vineyards, crop production, and cattle farming, though situated on good agricultural land, are not as prominent despite the availability of vast tracts of highly suitable land. Therefore, there is a need to raise awareness and promote urban agriculture to alleviate poverty-related food insecurities. The implementation of urban agriculture is anticipated to significantly improve food security, create economic opportunities, and enhance environmental sustainability within urban areas. The study recommends the need for longitudinal studies to gather essential information for informed decision-making, ensuring the sustainability of urban agriculture initiatives.
Personal factors influencing emergency evacuation decisions under different flash flood characteristics
(Springer Science and Business Media B.V., 2025) Liu, Dedi; Xu, Yongxin; Zhang, Ruikang
Emergency evacuation has received more attention as an effective tool of flash flood disaster prevention that calls for systematic thinking rooted in natural and social sciences. Although personal factors influencing emergency evacuation decisions (EED) after receiving a flood warning have been widely discussed, few studies have referred this issue to the flash flood characteristics. This study explored the personal factors influencing EED under different flash flood characteristics (i.e., the frequency, occurrence time, and severity of flash floods) through field survey data. Three typical flash flood characteristics in three towns were selected as case studies. An ordinary logistical model and path analysis were used to analyze the independent influence and influence process of the personal factors on evacuation intention under the three flash flood characteristics. The results showed that personalized risk perception and warning type consistently influenced evacuation intention regardless of the flash flood characteristics, while the independent influence of flood experience and reliance on hazard information on evacuation intention was varied with the flash flood characteristics. Perceived exposure influenced evacuation intention through the mediations of flood experience when there were high-frequency, recent, and loss-causing flash floods, and of risk perception when there were low-frequency, distant, and few-loss-causing flash floods. The effect of warning type on evacuation intention was varied with the flash flood characteristics if the warning type changed from the suggestive rainstorm red warning to mandatory ready-to-evacuate warning. However, if the warning type changed from the ready-to-evacuate to immediate-evacuation warning, there was no significant difference in this effect regardless of the flash flood characteristics. Therefore, it is necessary to implement distinctive emergency management according to specific flash flood characteristics.
Wetland inundation and moisture dynamics in Tugwi-Zibagwe and Shashe sub-catchments, Zimbabwe: insights from 2017 to 2023
(Taylor and Francis Ltd., 2025) Dube, Timothy; Mupepi, Oshneck; Marambanyika, Thomas
We analysed the Modified Normalized Difference Water Index (MNDWI) from Sentinel-2 Level 1 C and the Topographic Wetness Index (TWI) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model (DEM). Total inundated wetland area dropped by 0.1% in the Tugwi-Zibagwe and by 0.2% in the Shashe between 2017 and 2023. Significant correlations between temperature and rainfall impacts were observed in the Shashe sub-catchment (r = −0.84; p = .02 and r = 0.77; p = .04), whereas in Tugwi-Zibagwe, these correlations were less pronounced (r = −0.60; p = .15 and r = 0.39; p = .39). Between 2017 and 2023, large and small seasonal wetlands fluctuated between 60.2% and 35.9% of the total wetland area in Shashe whilst in Tugwi-Zibagwe it varied from 17.4% to 14.9%. The findings underscore the critical importance of conserving and restoring small (<1 ha) unprotected wetlands in rural semi-arid regions.
Appropriate spatiotemporal scale selection for water use simulation in China
(Elsevier B.V., 2025) Xu, Yongxin; Liu, Dedi; Zhang, Jiayu
Water use simulation plays a pivotal role in water resource management globally. Simulating water use at regional raster scale enables better alignment with available water resources, facilitating efficient allocation. However, there remains a deficiency in methods of spatiotemporal scale selection for ensuring the simulation accuracy while also guaranteeing the information density at each raster scale. A novel framework has been proposed to select the appropriate spatiotemporal scales for water use simulation. The framework utilizes an iterative input variables selection (IIS) algorithm to identify optimal input variables for water use simulation and an end-to-end deep learning-based spatiotemporal scale adaptive selection (SSAS) model to determine the appropriate spatiotemporal scales. Due to China's substantial population, water demand, and the growing challenges of global warming, the country is particularly susceptible to water scarcity. The proposed framework was applied to select the appropriate spatiotemporal scales for simulating irrigation, domestic, and industrial water use across 341 prefectures in China. The results indicate that the appropriate spatial scales for irrigation water use simulation range from 1 km to 5 km in most places, while they vary from 1 km to 4 km for domestic and industrial water use simulation. Furthermore, the appropriate temporal scale generally spans from 10 days to 45 days for all three types of water use simulation. It is interesting to find that the simulation accuracy is significantly impacted by the selection of appropriate temporal scales through the parameter sensitivity analysis. Our proposed framework supports water resource management and facilitates efficient water resource allocation to mitigate water scarcity.
African humanitas: ubuntu and the global response to climate change
(Springer Science+Business Media, 2025) Chitando, Ezra; Mlambo, Kudzanai Melody; Mlambo, Obert Bernard
The human dimension within the climate change debate, involving the African ideals of Ubuntu, is persuasive and motivational in the fight against climate change. The chapter discusses the impact of Ubuntu praxis on the environment. It reflects on different forms of inequality that Ubuntu is strategically placed to addressed in the wake of climate change. Climate change has been linked to the loss of biodiversity, flooding, tsunamis and extreme heat waves, among other challenges. Our inclusion of an Ubuntu ethos in the climate change debate is an effort to relate African humane virtues to growing concerns about deteriorating environmental and climatic conditions worldwide. We explore how African humanitas (Ubuntu) promotes and establishes an important environmental ethos. We posit that Ubuntu can serve as a valuable resource in the global response to climate change.
Assessing spatially-compounding drought probabilities in inter-basin water diversion: insights from the Tao River water diversion project in China
(Elsevier B.V., 2025) Liu, Dedi; Zhou, Wan; Cheng, Yufei
Study regions The water-donating (Tao River Basin, TRB) and water-receiving (Zuli River Basin, ZRB, and Wei River Basin, WRB) regions of the Tao River Water Diversion Project (TRWDP) in Gansu Province, China. Study focus Inter-basin water diversion projects are critical for mitigating water shortages in arid and semi-arid regions. By addressing misestimations arising from solely precipitation-based analyses, this study integrates meteorological and hydrological perspectives to explore spatially-compounding drought probabilities between the water-donating and water-receiving regions. Moreover, the meteorological-hydrological propagation is explored using correlation analysis, runs theory and copula functions, while variance decomposition is applied to identify the dominant climatic drivers. New hydrological insights for the region Results show that: 1) Spatially-compounding hydrological droughts occur less frequently than meteorological droughts due to varying geomorphologies and human activities. From 1970–2020, meteorological droughts occurred in five years, while only one hydrological drought event (2016) was identified across the three sub-basins, which was not detected by meteorological indices. The probability of severe spatially-compounding droughts varies regionally, with a higher joint probability in TRB–WRB than in TRB–ZRB, highlighting regional differences in drought propagation. 2) Meteorological and hydrological droughts exhibit distinct seasonal propagation characteristics, with short PTs in summer and autumn due to rapid hydrological responses and longer PTs in winter and spring due to delayed runoff generation. Basins with short PTs require real-time monitoring and rapid response strategies, while those with prolonged PTs need adaptive measures. 3) Precipitation and temperature are the primary climatic drivers of drought, with extreme climatic indices—monthly maximum of daily minimum (TNx) and maximum (TXx) temperatures—contributing the most. The decline in Rx5day (maximum five-day precipitation) suggests a decreasing frequency of extreme rainfall events, further intensifying drought propagation. These findings improve understanding of concurrent droughts and provide practical insights for drought mitigation and sustainable operation of inter-basin water diversion project.
Statistical modelling of spatio-temporal rainfall trends, dependence, and extremes in Zimbabwe (1984–2024)
(Springer, 2025) Dube, Timothy; Hove, Kudakwashe; Nyamugure, Philimon
Understanding the spatio-temporal variability of extreme rainfall is critical for climate adaptation and for informed water-resource planning in Zimbabwe. This study develops a unified statistical framework to: (1) characterize annual rainfall variability and detect monotonic trends; (2) model extreme rainfall events via block maxima and peaks-over-threshold methods and quantify their long-range dependence; (3) assess the spatial autocorrelation patterns of rainfall across provinces; and (4) explore inter-provincial rainfall dynamics using a Vector Autoregressive (VAR) model. Monthly rainfall totals for ten provinces (1984–2024) were retrieved from NASA POWER at provincial centroids. Descriptive statistics reveal a pronounced east–west gradient in mean annual rainfall (390.1 mm in Manicaland; 190.8 mm in Matabeleland South) and variability (Standard deviation up to 147 mm in Manicaland). The Mann–Kendall and block-bootstrap tests indicate no significant monotonic trends (all 0.16), suggesting stationary annual totals over the study period. Extreme-value analysis shows uniformly positive Generalized Extreme Value (GEV) shape parameters (for example) with anomalously large estimates in Harare and the Midlands; Generalized Pareto Distribution (GPD) fits yield moderate heavy-tails () and scale parameters of 5.6–9.9 mm. Detrended fluctuation analysis produces Hurst exponents (0.25–0.35), indicating anti-persistence and mean-reversion in extreme-rainfall maxima. Spatial autocorrelation metrics (Global Moran’s I = 0.266; Geary’s) confirm significant clustering. Local Moran’s I identifies northeastern hot-spots and southwestern cold-spots. A VAR(2) model—selected via minimum Akaike Information Criterion/Bayesian Information Criterion (also known as the Schwarz Criterion)(AIC/BIC)—highlights significant two-month persistence in Manicaland (,) and one-month memory in Matabeleland North (,). These findings reveal heterogeneous heavy-tailed behaviour, mean-reversion, and spatial clustering in Zimbabwe’s rainfall extremes, underscoring the need for region-specific risk assessments and infrastructure design tailored to local hydro-climatic regimes.
Enhancing target crop discrimination: a novel shadow detection technique for RGB datasets in mixed agricultural environments
(Mapping Sciences Institute Australia, 2025) Dube, Timothy I.; Sibanda, Mbulisi; Mafuratidze, Pride
Shadows pose significant challenges in smallholder farming systems, where mixed cropping is common. This study introduces two novel techniques: the Hue-Intensity-Green-Blue (HIGB) difference method for shadow detection and the Light Intensity Ratio-Based (LIRB) method for shadow compensation. Their performance was tested against the C3 and NSVDI models using five accuracy metrics on RGB imagery. HIGB consistently achieved superior accuracies (77–95%) compared to NSVDI (63–84%) and C3 (69–81%) in five different crop mixtures. Both the models, HIGB and LIRB, provide an integrated, robust solution for shadow detection and compensation in heterogeneous agricultural environments.
Variability in the carbon management index and enzymatic activity under distinct altitudes in the alpine wetlands of Lesotho
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Mazvimavi, Dominic; Nthebere, Knight; Marake, Makoala Vitalis
Alpine wetlands, key carbon sinks and biodiversity hubs, remain understudied, especially under climate change pressures. Hence, the present study was conducted to assess the variability in soil enzyme activity (SEA) and the carbon management index (CMI) and to utilize principal component analysis (PCA) to explore the variation and correlation between SEA and CMI as influenced by altitudinal gradients in alpine wetlands. This information is essential for exploring the impacts of soil degradation and guiding restoration efforts. The study was designed in blocks (catchments) with six altitudinal variations (from 2500 to 3155 m a.s.l), equivalent to alpine wetlands from three catchments (Senqunyane, Khubelu and Sani) as follows: Khorong and Tenesolo in Senqunyane; Khamoqana and Khalong-la-Lichelete in Sani; and Lets’eng-la-Likhama and Koting-Sa-ha Ramosetsana in Khubelu. The soil samples were collected in February 2025 (autumn season, i.e., wet season) at depths of 0–15 and 15–30 cm and analyzed for bulk density, texture, pH, electrical conductivity (EC), soil organic carbon (SOC), SEA, and carbon pools, and the CMI was computed following standard procedures. The results demonstrated that the soil was loam to sandy loam and was slightly acidic and non-saline in nature in the 0–15 cm layer across the wetlands. The significant decreases in SEA were 45.33%, 32.20% and 15.11% (p < 0.05) for dehydrogenase, fluorescein di-acetate and β-Galactosidase activities, respectively, in KSHM compared with those in Khorong (lower elevated site). The passive carbon pool (CPSV) was dominant over the active carbon pool (CACT) and contributed 76–79% of the SOC to the total organic carbon, with a higher CPSV (79%) observed at KSHM. The CMI was also greater (91.05 and 75.88) under KSHM at the 0–15 cm and 15–30 cm soil depths, respectively, than in all the other alpine wetlands, suggesting better carbon management at higher altitudinal gradients and less enzymatic activity. These trends shape climate change outcomes by affecting soil carbon storage, with high-altitude regions serving as significant, though relatively less active, carbon reservoirs. The PCA-Biplot graph revealed a negative correlation between the CMI and SEA, and these variables drove more variation across sites, highlighting a complex interaction influenced by higher altitude with its multiple ecological drivers, such as temperature variation, nutrient dynamics, and shifts in microbial communities. Further studies on metagenomics in alpine soils are needed to uncover altitude-driven microbial adaptations and their role in carbon dynamics.
Impacts of diagenetic alterations on siliciclastic sediments of the pletmos basin: implications for reservoir quality
(Springer Science and Business Media Deutschland GmbH, 2025) Oghenekome, Monica Enifome; Chatterjee, Tapas Kumar; Van Bever Donker, Jan M.
The Pletmos sub-basin of Outeniqua Basin, South Africa hosts heterogeneous siliciclastic reservoirs sediments deposited under a complex tectonic setting and its diagenetic processes remain largely undefined. This study focuses on Cretaceous reservoir sediments, aiming to evaluates the impact of diagenetic alterations on the reservoir quality. Despite the basin’s recognition as a prolific hydrocarbon prospect, no detailed investigation into the diagenetic evolution of its reservoir rocks is available. This is the first integrated Petro-sedimentological characteristics in the basin, combining petrographic and petrophysical data derived from conventional core samples of 100% recovery and well logs data from three exploratory wells. The siliciclastic reservoirs are primarily composed of moderately to poorly sorted feldspathic litharenites and lithic arkoses sandstones deposited in fluvial environment. Two major porosity–permeability trends are identified; due to primary intergranular pore networks and secondary porosity generated by mineral dissolution. High effective porosity is attributed to the coexistence of preserved primary pores and timely development of secondary porosity, supporting enhanced fluid migration and reservoir quality. Diagenetic processes include early mechanical compaction, quartz and clay cementation, calcite and iron oxide precipitation, and extensive feldspar dissolution into kaolinite. Authigenic chlorite coatings, variations in quartz and calcite cementation are especially influential in porosity distribution. These changes reflect eogenetic and mesogenetic phases, which significantly modify petrophysical properties. The reservoir porosity ranges between 13.5 and 16.3%, primarily controlled by grain compaction, quartz, calcite cementation, and mineral dissolution. Diagenesis directly influences reservoir quality, making this study a valuable reference for reservoir assessment, exploration, and regional diagenetic comparison.
A general chopping peak function for a reservoirs group flood control regulating
(Elsevier B.V., 2025) Liu, Dedi; Mu, Zhenyu; Wang, Zhenyu
Flood event is one of the natural hazards and has affected the most people in the world. As the peak of the flood event is the most striking feature to its hazard, chopping flood peak is often the main goal of preventing flood hazard. To integrate the regulation of the flood storages in a reservoirs group for chopping flood peak, a general relationship among the flood events, the flood storages and the chopping peak has been quantified through Chopping Peak Function (CPF). And we have derived the analytical solutions for a single, a parallel or a cascade reservoirs group while numerical solution for a mixed reservoirs group to their corresponding CPF. Based on the solutions to their CPF, the mechanism is clarified for the integrated reservoirs flood storages regulation. The derived analytical solutions have also been proven to be more efficient for integrating the reservoirs regulation than for only every single reservoir regulation. The numerical solutions for the mixed reservoirs groups are found to be better than that of optimal reservoirs regulation model through NSGA-II in terms of the number and the distribution range of the Pareto frontier. Therefore, our study will not only help understand the regulation of the f lood storages in reservoirs groups for chopping flood peak, but also find an efficient way to prevent flood hazard.
The southwesternmost piece of the Grenville Orogen in Laurentia – New U-Pb and Sm-Nd ages, and P-T estimates from the Sierra del Cuervo, Chihuahua, Mexico.
(Elsevier B.V, 2025) Frei, Dirk; Weber, Bodo; Nayeli Chacón-Olivas C.
This paper elucidates the origin and tectonic setting of Mesoproterozoic metaigneous rocks of the Sierra de Cuervo, Chihuahua, Mexico, providing new evidence for the southwestern extension of the Grenville Orogeny in North America. Several geochronological approaches were used, including U-Pb zircon dating by LA-ICP-MS and the Sm-Nd isochron technique, using ID-TIMS. Igneous zircon domains reveal crystallization ages for felsic igneous protoliths ranging from ~ 1.38 Ga to ~ 1.33 Ga, with ~ 1.42 b.yr. old inherited zircon. Whole-rock SmNd isotopic data define an isochron at 1.52 ± 0.03 Ga, suggesting crustal growth during the early Mesoproterozoic. The timing of metamorphism is constrained by Sm-Nd leached garnet-whole-rock isochrons and by U-Pb zircon dates between ~ 1.06 and ~ 1.05 Ga. Metamorphic pressure and temperature conditions were estimated from a metamafic rock sample at 6.4 ± 1 kbar and 520 ± 20 ◦C using conventional geothermobarometry and pseudosection modeling. The results contextualize the Precambrian rocks of the Sierra del Cuervo with metamorphic rocks of the West Texas Uplift thrust over the Laurentian margin. We propose that this thrust represents a remnant of the unexposed Grenville Front and that the Chihuahua and West Texas metamorphic basement is characterized by contemporaneous magmatism and reworked from the Granite-Rhyolite Province of the North American midcontinent during the Grenville Orogeny, comparable to the low-medium pressure allochthonous Ottawan metamorphic belt of the Grenville Province in Canada
Short-term effects of cover crop species and termination methods on soil ph and key enzymatic activities (β-glucosidase, phosphatase and urease activities) in a citrus orchard (eureka lemons)
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Jovanovic, Nebo; Silwana, Sibongiseni; Mulidzi, Azwimbavhi Reckson
The best management practices for cover cropping in citrus orchards, particularly in terms of species selection and termination methods, remain unclear. This study assessed the short-term effects of different cover crop species (vetch, medics and oats) and termination methods (slashed vs. non-slashed) on soil pH and enzyme activities (β-glucosidase, acid phosphatase, and urease) in a citrus orchard with sandy soil. A randomized complete block design with a factorial treatment structure and six replications was used. Soil samples were collected before and one year after cover crop establishment. The results showed that cover cropping increased soil pH from 5.42 to 6.00 after one year. However, no statistically significant differences were observed in soil pH or enzyme activities among cover crop species or termination methods. Marginal increases in enzyme activities were observed under leguminous cover crops, and these changes were insufficient to indicate strong treatment effects. Correlation and principal component analyses revealed that soil enzyme activities were more strongly influenced by soil properties (depth, carbon content and moisture) than by cover crop species or termination methods. These findings suggest that, under sandy soil conditions and within a one-year period, cover cropping has limited immediate effects on soil biological indicators in citrus orchards. Longer-term studies are recommended to assess cumulative impacts
Impacts of inter-basin water diversion projects on the feedback loops of water supply–hydropower generation–environment conservation nexus
(Copernicus Publications, 2025) Liu, Dedi; Wang, Jiaoyang; Guo, Shenglian
To balance water resource distribution in different areas, inter-basin water diversion projects (IWDPs) have been constructed around the world. Unclear feedback loops of water supply-hydropower generation-environment conservation (SHE) nexus in IWDPs increase the uncertainty in rational scheduling of water resources for water receiving and water donation areas. To address the different impacts of IWDPs on a dynamic SHE nexus and explore synergies, a framework is proposed to identify these impacts across multiple temporal and spatial scales in a reservoir group. The proposed approach was applied to the Hanjiang River Basin (HRB) in China as a case study. Runoff series from the HRB at multiple temporal and spatial scales were provided through the Variable Infiltration Capacity hydrological model. Multi-level ecological flows were determined by the modified Tennant method based on a multi-level habitat condition method. 30 scenarios were set and modeled in a multisource input-output reservoir generalization model. Differences between scenarios were quantified with a response ratio indicator. The results indicate that without IWDPs there is negative feedback between water supply (S) and hydropower generation (H) and between S and environment conservation (E), while there is positive feedback between H and E. The negative feedback of S on H and the positive feedback of E on H are weakened or even broken in abundant-water periods. With IWDPs, water donation basins experience strengthened feedback loops, while water receiving basins experience weakened feedback loops. Feedback loops exhibit intrinsic similarity and stability across different time scales. Feedback loops in reservoirs with a regulation function remain stable under varying inflow conditions and feedback loops for downstream reservoirs are influenced by their upstream reservoirs, especially in low-flow periods. Simply increasing water receiving flow cannot resolve inherent SHE conflicts because of the persistent feedback polarity with IWDPs, and adaptive allocation rules are needed that account for these stable feedback patterns. The proposed approach can help quantify the impacts of IWDPs on SHE nexus and contribute to the sustainable development of SHE nexus.

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