Northern Niger Research Articles

Thermodynamic, economical and environmental performance evaluation of a 330 MW solar-aided coal-fired power plant located in Niger

The integration of solar thermal energy into a coal-fired power plant is one of the best ways to reduce the environmental impact of the latter linked to the release of carbon dioxide (CO2) into the atmosphere. In this paper, solar energy is used before the boiler, just after the first high-pressure feed water heater via a solar preheater (Water/Heat Transfer Fluid exchanger). It should be noted that in this study, there is no feed water heater displacement, and so the plant will operate in pure fuel-saving mode. To carry out an analysis of the integration of solar thermal energy in a coal-fired power plant, a 330 MW Solar Aided Coal Power Plant (SACPP) in northern Niger was studied. The results bring out that the annual solar energy production is 208 GWh, and solar energy can contribute up to approximately 15 % in the production of electricity. The considered SACPP significantly reduces the environmental impact of coal-fired power plants, leading to a reduction in CO2 emissions of around 381358 tons/year. In addition, the annual energy production cost from solar energy in the hybrid system is obtained as 0.0357 $/kWh and the investment payback period is around 12 months.

Naturally fractured reservoir characterisation in heterogeneous sandstones: insight for uranium in situ recovery (Imouraren, Niger)

Abstract. This study delves into the characterisation of a heterogenous reservoir, the Tchirezrine II sandstone unit in northern Niger. The characterisation is crucial for potential uranium in situ recovery (ISR) in a naturally fractured and faulted context. Employing a multifaceted approach, including well log data, optical borehole imagery, and hydrogeological tests, alongside satellite-based lineament analysis, this study provides a comprehensive understanding of the structures and their impact on fluid flow. Lineament analysis reveals scale-dependent patterns, consistent with spatially homogeneous joint networks restricted to mechanical units, as well as nearly scale-invariant patterns, better corresponding to spatially heterogeneous fault networks. Various deformation structures are detected from borehole imagery, including extensional fractures, cataclastic deformation bands, and brecciated–cataclastic fault cores. Based on well log data, the Tchirezrine II reservoir displays heterogeneous porosity and permeability related to its fluvial context. These data differ from the traditional porosity–permeability relationship obtained in a sandstone reservoir matrix but are instead consistent with Nelson's classification, emphasising the impact of deformation structures on such petrophysical properties. Hydrological tests have been implemented into a zone of E–W-trending deformation structures, revealing a strong permeability anisotropy. This strong E–W anisotropy is consistent with the presence of the observed E–W structures, i.e. with a draining behaviour of extensional open fractures and a sealing behaviour of both cataclastic bands and fault rocks. Considering implications for ISR mining, this study allows the discussion of the interplay between fractures, faults, and fluid flow properties. It suggests that a well pattern perpendicular to the main permeability orientation can attenuate channelled flow, thus improving the contact of the leach solution with the mineralised matrix. These results provide an integrated approach and a multi-scale characterisation of naturally fractured reservoir (NFR) properties in sandstone, offering a basis for the optimisation of NFR production such as ISR development.

Informality and insecurity in the Sahel: unravelling the hybrid political orders of Northern Mali and Northern Niger

Since the Sahelian crisis broke out in 2012, Northern Mali and Northern Niger have been identified as the two potential epicentres of violence in the region. Nevertheless, while sharing very similar structural conditions and constraints, during the last decade these two subregions have scored very differently in terms of stability and armed conflict along the centre-periphery divide. Aiming to understand the divergent security patterns in Northern Mali and Northern Niger, this work highlights the importance of informal institutions as politically – and spatially contingent networks whose mechanisms for regulating authority and power are key for the appreciation of state capacity and political ordering, and essential for understanding statehood in the Sahel. We stress the importance of hybrid political orders and informality for the definition of political settlements which result in (a) the cooptation of political/economic competitors and the stabilisation of viable governance arrangements; or (b) an open contestation of authority and value-extraction that paves the way for destabilising dynamics. The diverging pattern exhibited by the two cases demonstrates that hybrid networks that straddle political and informal institutions are crucial in determining either the stabilisation or destabilisation of political settlements.

Detection of Ring Structures and Their Surrounding Tectonic Pattern in South-Algeria, North-Mali and North- Niger based on Satellite Data

This study is focused on the detection of circular features with different sizes, origins, and state of erosion as well as on their surrounding tectonic pattern based on different satellite images of Southern Algeria, Northern Mali and Northern Niger. Sentinel 2- and Landsat 8/9-images and Sentinel 1- and ALOS L-band Phased Array Synthetic Aperture Radar (PALSAR)-radar data help to identify larger ring structures and smaller circular features, most of them related to magmatic intrusions into the subsurface, but also to cosmic impacts, with varying ages and state of erosion. Some of them seem to be unknown so far as they are partly covered by aeolian sediments and become only visible on radar images. Digital Elevation Model (DEM) data and the DEM derived morphometric maps support these investigations in a GeoInformation System (GIS) embedded environment. Some of the ring structures are only visible on morphometric maps, traced by circular arrangements of slope gradients or concentric drainage patterns. The large, circular structures and the smaller circular features such as volcanic features (cinder cones, calderas, maars, impact craters) were digitized and merged in a GIS with available geologic information.

Descriptive systematics of Upper Palaeocene–Lower Eocene pollen and spores from the northern Niger Delta, south-eastern Nigeria

Fossil pollen and spores are a vital source of information on the geological history of tropical vegetation including reconstructions of vegetation diversity and composition. However, such work relies on a sound taxonomic framework, and this is challenging to achieve because of the large number of pollen and spore morphotypes that are encountered in palynological preparations from tropical sediments. In tropical West Africa, for example, extensive taxonomic work on Cretaceous–Paleogene pollen and spores was undertaken in the later part of the twentieth century, but more recent palynological work has focussed on stratigraphy and basin evolution, and there is a need for additional taxonomic work on the pollen and spores of this region. We have undertaken a descriptive systematic study of pollen and spores (sporomorphs) from 15 sediment samples spanning the Upper Palaeocene–Lower Eocene of south-eastern Nigeria. A palynoflora consisting of 29 spores, two gymnosperm pollen grains, and 138 angiosperm pollen grains is described. Two new spore species are proposed, and one new genus and 18 new species of angiosperm pollen are proposed. The general vegetation type represented by the palynoflora consists of palm-dominated swamps, perhaps with mangroves. The richness of each sample ranges from 29 to 76 sporomorph taxa, and rarefaction analysis suggests an increase in diversity from the Palaeocene to the Eocene in this region. Samples from the Palaeocene Upper Nsukka Formation are dominated by pollen with botanical affinities to the Arecaceae (palms) and Araceae (arums), and this assemblage is very similar to the Palaeocene in the Neotropics.

Quasilegality and migrant smuggling in Northern Niger

Quasilegality and migrant smuggling in Northern Niger

STRUCTURAL INTERPRETATION OF ASSA-FIELD RESERVOIR IN NORTHERN NIGER DELTA NIGERIA, USING WELL LOG

Structural interpretation and characterization of Assa-field in Northern Niger Delta was done to map the primary structures responsible for hydrocarbon entrapment and closures that are favorable for the accumulation of hydrocarbon as well as to indicate areas for hydrocarbon exploration in the field. The method used for this research involved delineation of lithology, identification of reservoir, interpretation of horizon and fault to generate structural maps of the subsurface. Depth and time structure maps were generated to show more detailed structure of the field. Three major horizons (sand 1, sand 2, and sand 3) were mapped based on uniqueness and clarity of their features. Major faults were delineated from the 3-D seismic section. The appearance of these faults in the field is a sign of possible hydrocarbon accumulation. The knowledge from the results of this study can be applied in exploration and production to identify hydrocarbon trapping potential of a field and volumetric evaluation of fluid in a field.

The Tim Mersoï Basin uranium deposits (Northern Niger): Geochronology and genetic model

The Tim Mersoï uranium province in northern Niger is one of the world’s largest uranium reserves and fourth-highest uranium producer. The main uranium deposits (Arlit, Akouta, and Imouraren) are located in continental siliciclastic formations. The regional north–south-trending fault (the Arlit Fault) strongly controls them, as well as secondary discontinuity networks oriented NNE-SSW, ENE-WSW, and WNW-ESE. The Arlit and Akouta uranium-ores are hosted in reduced Carboniferous formations and occur as reduced U4+ phase mineralizations. Besides, the Imouraren deposit is hosted by an oxidized Jurassic formation with a predominance of U6+ silicate and vanadate minerals and relics of reduced mineralization. New U-Pb SIMS data have been obtained on the three deposits, and the results reveal two main stages of uranium deposition and ore metallogenesis. (i) the 90–145 Ma Lower Cretaceous mineralization is related to a significant tectonothermal event, synchronous with the Atlantic rifting that induced the deformation and brine migration from Triassic formations. Primary uraninite and chalcocite are formed by fluid mixing in a reduced environment at that stage at a depth of 1 km at less at a temperature 115–150 °C, hotter than that of the reservoir. (ii) During later Cenozoic exhumation of the basin, a series of remobilizations of primary uranium stock resulted in the formation of much younger uraninites under reduced conditions at Arlit-Akouta around 50 Ma. At Imouraren, younger uraninites formed between 34 and 8 Ma under locally reduced conditions, and were followed by secondary U-minerals from 21 Ma up to 3–1.6 Ma during supergene events. These ages are close or superimposed with the main oxidation stages, affecting West Africa during the Cenozoic, and attest of water table oscillations.

Resolving the location of small intracontinental earthquakes using Open Access seismic and geodetic data: lessons from the 2017 January 18mb 4.3, Ténéré, Niger, earthquake

SUMMARYA low-magnitude earthquake was recorded on 2017 January 18, in the Ténéré desert in northern Niger. This intraplate region is exceptionally sparsely covered with seismic stations and the closest open seismic station, G.TAM in Algeria at a distance of approximately 600 km, was unusually and unfortunately not operational at the time of the event. Body-wave magnitude estimates range from mb 4.2 to mb 4.7 and both seismic location and magnitude constraints are dominated by stations at teleseismic distances. The seismic constraints are strengthened considerably by array stations of the International Monitoring System for verifying compliance with the Comprehensive Nuclear Test-Ban-Treaty. This event, with magnitude relevant to low-yield nuclear tests, provides a valuable validation of the detection and location procedure for small land-based seismic disturbances at significant distances. For seismologists not in the CTBT system, the event is problematic as data from many of the key stations are not openly available. We examine the uncertainty in published routinely determined epicentres by performing multiple Bayesloc location estimates with published arrival times considering both all published arrival times and those from open stations only. This location exercise confirms lateral uncertainties in seismologically derived location no smaller than 10 km. Coherence for interferometric synthetic aperture radar in this region is exceptionally high, and allows us to confidently detect a displacement of the order 6 mm in the time frame containing the earthquake, consistent with the seismic location estimates, and with a lateral length scale consistent with an earthquake of this size, allowing location constraint to within one rupture length (≤5 km)—significantly reducing the lateral uncertainty compared with relying on seismological data only. Combining Open Access-only seismological and geodetic data, we precisely constrain the source location, and conclude that this earthquake likely had a shallow source. We then discuss potential ways to continue the integration of geodetic data in the calibration of seismological earthquake location.

EU-Driven Border Control in Niger: From Migrants to Gold, Drugs, and Rare Animals

The Agadez province in northern Niger, a nucleus for trans-Saharan migration to Libya, has in recent years been at the forefront of Europe’s interventions to curb migration movements on the African continent. This essay discusses the transmutations of the cross-border economy in the wake of EU pressure and its implications for local lifeworlds. Trade and smuggling networks have shown resilience and adaptability in the face of the EU-driven crackdown on migration, but often at the cost of migrant safety. Border practices of the EU create situations where migrants are increasingly subject to predatory economic practices that consequently serve as necropolitical deterrence. At the same time, the cross-border economy is increasingly turning to other commodities to which Libya’s European partners are less sensitive, such as gold, synthetic opioids, and rare animals.

Enjeux territoriaux et éthiques de la régulation de la ruée vers l’or au nord du Niger

Fondé sur des enquêtes de terrain, cet article s’intéresse à la phase d’évolution actuelle de la ruée vers l’or au nord du Niger. Elle est marquée par la volonté de l’État de mieux encadrer juridiquement une activité jusque-là informelle dans ses régions périphériques. L’intervention de l’État engendre des recompositions territoriales, un rapprochement des intérêts politico-économiques entre les élites des périphéries aurifères et le pouvoir central, ainsi que des conflits d’ordre éthique quant à l’accès aux gisements et à la répartition des bénéfices. La redistribution des équilibres dans la gestion de l’informel fait basculer les orpailleurs vers la régularisation ou la précarisation, voire la criminalisation. Le maintien des illégalismes repose sur des enjeux d’appropriation foncière et de conditions de mobilité.

Re-Thinking a Matrilineal Myth of Healing: Tuareg Medicine Women, Islam, and the Market in Niger

Abstract This article explores the changing metaphoric logic and contextual uses of a mythical-historical popular religious account of matrilineal origins of herbal medicine women among Tuareg in northern Niger. Medicine women both reproduce and modify this origin myth’s motif in their Tamajaq-speaking, Muslim, traditionally ranked, and semi-nomadic communities, where many have faced religious, socioeconomic, and political upheavals challenging local women’s material wealth and symbolic/cultural capital of authoritative medico-ritual healing. How is medicine women’s healing legacy evoked and re-interpreted in encounters with Qur’anic healing and western biomedicine, as impacted by recent religious debates, neoliberal structural adjustments, droughts, sedentarization, and political violence? The Tuareg data offer fresh perspectives on how religion and economy co-produce each other in some contexts, but contradict each other in others. More broadly, this article critically disrupts categories of sacred and secular, tradition and modernity, and brings mythico-histories into discussions of intertwining religious and economic idioms, practices, and infrastructures.

The vertebrate fauna of the upper Permian of Niger—XI. Cranial material of a juvenile Moradisaurus grandis (Reptilia: Captorhinidae)

ABSTRACT We describe two partial skulls of juvenile individuals of Moradisaurus grandis, a moradisaurine captorhinid from the upper Permian Moradi Formation of northern Niger. The juvenile skulls are less than half the length of the largest known skull of M. grandis, and differ in featuring a transversely narrow mandible, only five rows of maxillary teeth, a relatively larger orbit, a relatively taller skull, a cultriform process of the parasphenoid angled upwards at 20–30° from the basal plate, and reduced ossification of the braincase. Most of these features have been considered characteristic of the less derived members of the family (e.g., Protocaptorhinus pricei, Captorhinus laticeps). Data from juvenile Moradisaurus allow us to amend a previous inference that the braincase of the holotype and largest known skull of the moradisaurine Labidosaurikos meachami is characterized by poor ossification: we infer instead that this skull is not skeletally mature and that the braincase would have fully ossified in larger, ontogenetically older individuals of this moradisaurine. An updated cladistic analysis of captorhinids yields Moradisaurus as the sister taxon to Gansurhinus + Rothianiscus, replicating the results of several previous analyses, but improving slightly the robustness of Moradisaurinae and the clade of Labidosaurus + Moradisaurinae with respect to previous work.

Tectono-Sedimentary Evolution of the Uranium Deposits of the DASA Graben, Northern Niger

This study presents the structural evolution of the N70° trending Paleozoic-Mesozoic DASA graben, which is considered a sub-basin of the Tim Mersoï basin, and is located in northern Niger. The DASA graben is a uranium-rich trough discovered in recent exploration surveys. A tectono-sedimentary analysis of the DASA graben was implemented with a combined use of satellite imagery, field observations, borehole data analysis and available literature. This graben was affected from the Carboniferous to the Early Cretaceous by two major tectonic periods. The first period was an uplifting stage, which prevailed during the Carboniferous-Permian times and the second, ranging from the Triassic to the Early Cretaceous, corresponds to a rifting episode. The particularity of the DASA graben is that the sediments contain very high uranium grades. Lithological and tectonic factors controlled the emplacement of the uranium mineralization in the graben. The successive fracturing phases that affected the DASA graben were associated with a greater circulation of hydrothermal fluids and would have favoured higher grades of uranium mineralization.

Increased and sex-selective avian predation of desert locusts Schistocerca gregaria treated with Metarhizium acridum.

The entomopathogenic fungus Metarhizium acridum in oil-based formulations (Green Muscle® (GM)) is a biopesticide for locust control lacking side-effects on biodiversity, unlike chemical insecticides. Under controlled conditions, GM-treated locusts and grasshoppers attract predators, a complementary advantage in locust control. We assessed avian predation on a population of desert locusts in northern Niger aerially sprayed operationally with GM with 107 g viable conidia ha-1. Populations of adult locusts and birds and vegetation greenness were assessed simultaneously along two transects from 12 days before until 23 days after treatment. Common kestrels Falco tinnunculus and lanners F. biarmicus were the predominant avian predators. Regurgitated pellets and prey remains were collected daily beneath "plucking posts" of kestrels. Locusts started dying five days post-spray and GM had its maximum effect one-two weeks after the spray, with 80% efficacy at day 21. After spraying, bird numbers increased significantly (P<0.05) concurrent with decreasing desert locust densities. Locust numbers decreased significantly (P<0.001) with both time since spraying and decreasing greenness. Before spraying, kestrel food remains under plucking posts accounted for 34.3 ±13.4 prey items day-1, of which 31.0 ±11.9 were adult desert locusts (90.3%), reducing post-spray to 21.1 ±7.3 prey items day-1, of which19.5 ±6.7 were adult desert locusts (92.5%), attributable to decreased use of the plucking-posts by the kestrels rather than an effect of the spray. After spraying, kestrels took significantly (P<0.05) more larger female (75-80%) than smaller male (20-25%) locusts. Avian predation probably enhanced the impact of the GM on the desert locust population, especially by removing large adult females. No direct or indirect adverse side-effects were observed on non-target organisms including locust predators such as ants and birds. These substantial ecological advantages should also be considered when choosing between conventional chemical and biopesticide-based locust control.

Prediction of properties of reservoir using Artificial Neural Network and Monte Carlo Simulation

Two methods for forecasting reservoir distribution are used: Monte Carlo Simulation and Artificial Neural Network. The data used in this research was obtained from the drilling sheet report of the Efe04 well located in the Northern Niger Delta Depobelt. The operator released the data set of the Efe field. Amukpe well data from the Amukpe field was also used as part of the test data to see how the model works on different fields. To minimize uncertainties, only the surface drilling parameters are used for the model. Mode of operation (rotation or sliding), Torque, Surface Revolution, Flow rate (gallons per minute), Stand Pipe Pressure, Revolutions per Minute, hole size. When reservoir distribution can be predicted, it is extremely beneficial since it increases exploration accuracy and lowers costs by delaying the next round of exploration. Geostatistics, on the other hand, is rarely used in areas with few wells drilled. A new technique called Geology Driven Integration Tool (GDI) has been developed to estimate reservoir parameters when just a few wells are available. Due to the lack of well data and regional geological constraints in the GDI model, several pseudo-wells are constructed by Monte Carlo Simulation to make up for the deficiency of a few real wells. They can also be used to create fake seismograms. To determine the weighting factors that link the selected seismic attributes to the given reservoir features, the appropriate seismic attributes and the given reservoir parameters are input to the Artificial Neural Network (ANN). In the end, the ANN is trained on all of the seismic data in the area and then used to estimate reservoir property distribution. In addition to the areas that have already been explored, the estimated results suggest exploring the southern portion of the Efe field and the northern portion of the Efe field as potential prospect locations. In the southern half of the Amukpe field, the gas zone's net thickness is expected to rise to 27 meters, thanks to increased porosity of 27%. North of the Efe field, a 15-25-meter-thick porosity-rich reservoir is predicted to be distributed.

European Union and Italian Migration Policy and the Probable Destabilization of Southern Libya and Northern Niger

ABSTRACT European Union and Italian policies, while achieving their objectives of suppressing migration across the Mediterranean Sea, have at the same time created social and economic dislocation in southern Libya and northern Niger that will further destabilize the region. Using field research involving interviews and surveys, the authors document these dislocations, predict instability, and suggest future research.

Polyphasic tectonic history of the N70° DASA Graben (northern, Niger)

Located in northern Niger, the N70° DASA graben is a trough discovered recently in the Tim Mersoï basin. In this study, a tectonic history of the DASA graben was presented based on the combined use of satellite imagery, field observations and measures, available literature and borehole data. These data were used to analyse the sedimentary facies and the tectonic deformations in the DASA graben, and derive their relative chronology. For this purpose, uplift and rift deformations and their interactions with sedimentation were characterized. Overall, the analyses suggest that the DASA graben was affected from the Carboniferous to the Cretaceous by three major tectonic phases: the first phase was an uplifting stage with extension during the Carboniferous to Permian; the second phase was a rifting stage. The mean extension was ~ N160° and dominantly produced ENE-WSW trending normal faults; and the third phase was a postrift stage. It was characterized by a ~ N130° compression. The structural and sedimentological features defined the DASA graben as a particular type of syn-sedimentary basin evolving from a transpressive tectonic regime during the period ranging from Carboniferous to Permian to an extensive tectonic regime during the period ranging from Triassic to Lower Cretaceous. Thus, the second period marked by an extensional regime would probably be related to the initial stage of the opening of the Atlantic Ocean. After this rifting period, the DASA graben was affected by a compressional phase related to the collision between Africa and Europe.

The DASA Graben in Northern Niger: A Case of a Paleo-Mesozoic Basin Evolving from Uplifting to Rifting

The DASA Graben in Northern Niger: A Case of a Paleo-Mesozoic Basin Evolving from Uplifting to Rifting

Images of loneliness in Tuareg narratives of travel, dispersion, and return.

This article examines how social, economic, and political upheavals in the Sahara have stimulated re-thinking about loneliness in relation to trauma from mobility, dispersion, and return home in communities of Tamajaq-speaking, Muslim, and semi-nomadic Tuareg in northern Niger and Mali. How do Tuareg, sometimes called Kel Tamajaq after their language, draw on and re-formulate longstanding and new ways of coping with loneliness in regional droughts and wars, which have driven many to alternately disperse from their communities and return to homes that are no longer the same? What is the connection between changing modes of travel, concepts of loneliness, and ways of coping with this experience? In these communities, loneliness is a recurrent theme in personal life histories-in particular, in narratives of both geographic travel and spiritual travel in medico-ritual healing-and is alluded to in poetry, song, and everyday conversation. This article explores the meanings of loneliness and ways of coping with it in this society through analysis of this emotion in symbol, subjective perception, and social experience. The focus is upon representations of loneliness in narratives by travelers who have confronted this emotion, and upon relevant Tamajaq terms often used to express loneliness: namely, essuf (the wild, solitude, and nostalgia); tamazai (approximately, a depression); and tarama (unrequited love), illustrating with cases and examples. More broadly, the article is guided by and builds on insights in psychological anthropology into emotion and affect as well as suffering and subjectivity.