Characterization and Management of Natural Resources

published in: 2021 - 2020 - 2019 - 2018 - 2017 - 2016


Antiskarn-hosted strategic metal mineralizationin Morocco

Bouabdellah M, Boukirou W, Jébrak M, Bigot F, Yans J, Mouttaqi A, El Gadarri M, Errami A, Levresse G. 2022. Discovery of antiskarn-hosted strategic metal mineralization in the Upper Cretaceous Twihinate carbonatite intrusion (West African Craton Margin, Moroccan Sahara). Ore Geology Reviews 149:105105. DOI: 10.1016/j.oregeorev.2022.105105.

Although volumetrically insignificant among igneous rocks, carbonatites and their metasomatized and weathered derivatives stand out as the ones most targeted rock types as they provide most of the world’s strategic metals production such as niobium, rare earth elements (REE), tantalum, phosphorous, copper, iron and fluorine. The Twihinate prospect is currently considered as one of the most promising carbonatite-hosted strategic metals discoveries that have been made in the Moroccan Sahara over the last two decades. The Nb-P-Fe ± LREE ± U-Th-rich mineralization and associated base metal sulfides, fluorite and baryte are hosted by an Upper Cretaceous calcite carbonatite and its overlying weathered derivates. Our petrographic, mineralogical and geochemical data indicate that part of the newly discovered mineralization is related to a widespread metasomatic event which resulted in development of the Twihinate antiskarn lithotypes. The ore mineralogy consists predominantly of oxides (vanadiferous titanomagnetite), pyrochlore group minerals, phosphates (apatite, monazite), and REE-fluorcarbonates (bastnäsite-(Ce)) with subordinate amounts of sulfides (chalcopyrite, sphalerite, and galena), fluorite and baryte. In addition to the above-referenced strategic metals, the Twihinate ore is characterized by widespread occurrence of vanadiferous titanomagnetite. This V enrichment could constitute a per value for the explored occurrences through the development of mining of magnetite-bearing carbonatitic rocks and related antiskarn rocks targeting V as a by-product. Petrogenetically, we propose that the calc-silicate antiskarn rocks and related Nb-P-Fe ± LREE ± U-Th-rich mineralization were formed as a result of silica contamination of the residual carbonatite-derived melts by the surrounding Silurian-Devonian granitic rocks.

Goethite record in the High Atlas Foreland (Morocco)

Verhaert M, Gautheron C, Dekoninck A, Vennemann T, Pinna-Jamme R, Mouttaqi A, Yans J. 2022. Unravelling the Temporal and Chemical Evolution of a Mineralizing Fluid in Karst-Hosted Deposits: A Record from Goethite in the High Atlas Foreland (Morocco). Minerals 12:1151. DOI: 10.3390/min12091151.

Timing and duration of ore deposit formation are crucial to understanding the mineralization process. To address this, the geochronological (U-Th)/He method, geochemical and H- and O-isotope compositions of pure goethite formed in the Imini karst-hosted Mn district (High Atlas, Morocco) were examined in detail. Two main generations of cavity-filling and fracture-filling goethite are identified, and both precipitated prior to the massive Mn oxide ore. The δD and δ18O values reveal that the mineralizing fluid of cavity and fracture-filling goethite is meteoric-derived but enriched in 18O due to fluid–rock interactions with the host rock dolostone or mixing with O2-rich surface water resident in an open karst system. The cavity-filling goethite precipitated between 95 to 80 Ma, whereas fracture-filling goethite formed between 80 to 50 Ma. Ore deposition occurred discontinuously during the early Atlas doming associated with one or more early compressional events in the Atlas tectonism. The increase in δD values and depletion in U content result from a change in the mineralizing fluid within the karst system. At about 50 Ma, the fluid is notably enriched in U, Cu and trace metals.

The Meuse River basin - book chapter

Tockner K, Zarfl C, Robinson CT (eds.). 2022. Chapter 5.1 - Continental Atlantic Rivers: The Meuse, Loire and Adour-Garonne Basins. In: Rivers of Europe (Second Edition). Elsevier, 225–289. DOI: 10.1016/B978-0-08-102612-0.00020-1. P. Kestemont co-author of subChapter 5.1.1. The Meuse River basin

The Meuse is an international river that has been used by man for centuries and it is still the main source of drinking water for large cities in Belgium and the Netherlands. In fact, water quantity and quality have been a major issue between the various riparian countries and political regions. Many kinds of data have been generated in the past decades on various aspects of the river: (a) hydrology for the need of predicting and controlling floods; (b) water chemistry in the context of water pollution assessment and control; and (c) biology and ecology for water quality assessment and studies on aquatic biodiversity community dynamics and ecosystem function.

Petrogenesis of dolomite carbonatite in Morocco

Boukirou W, Bouabdellah M, Chakhmouradian AR, Mouttaqi A, Reguir EP, Hauff F, Cuney M, Jébrak M, Yans J, Hoernle K. 2022. Petrogenesis of the late Paleoproterozoic Gleibat Lafhouda dolomite carbonatite (West African Craton Margin, Moroccan Sahara) and its relevance to the onset of fragmentation of the Columbia supercontinent. Chemical Geology 594:120764. DOI: 10.1016/j.chemgeo.2022.120764.

Carbonatites are considered among the deepest direct probes into the Earth's upper mantle and an important terrestrial carbon reservoir. Additionally, carbonatites are of economic interest because of their mineral endowment, which includes such low-abundance metals as rare earth elements (REE) and Nb. These metals are critically important for a wide array of advanced green energy, transportation, communication and digital technologies and are difficult to substitute or recycle. Dolomite carbonatites and calcite carbonatites represent, respectively, the Mg-rich and Ca-rich compositional end-members of the petrologically intriguing rock clan. The other, less common end-members are ankerite and siderite carbonatites (Fe-rich), silicocarbonatites sensu lato (Si-rich), and natrocarbonatites (Na- and K-rich). This study provides updated information on the regional and local geological setting of the GL carbonatites and describe in detail their petrography, mineralogy, whole-rock major- and trace-element geochemistry, and report new stable (C and O) and radiogenic (Sr, Nd, Pb) isotopic data for these rocks. This new information is interpreted in a petrogenetic and geodynamic context using published experimental work and data on similar carbonatites elsewhere in the world.


Mining for silver in Morocco

Diallo M, Bouabdellah M, Levresse G, Yans J, Castorina F, Klügel A, Mouhagir M, El Mouden S, Maacha L. 2021. Mineralogy, Fluid Inclusion, and C-O-Sr Isotope Geochemistry to Unravel the Evolution of the Magmatic-Hydrothermal System at the Igoudrane Silver-Rich Deposit (Imiter District, Eastern Anti-Atlas, Morocco). Minerals 11:997. DOI: 10.3390/min11090997.

The Igoudrane mine with a total production of 700,000 t of ore grading 485 g/t Ag is currently one of the most productive mines in the Imiter district of the eastern Anti-Atlas in Morocco. The silver-rich ± base metal deposit occurs dominantly as vein- and hydrothermal breccia-hosted orebodies at the interface between the lower Ediacaran turbidites of the Saghro Group and the unconformably overlying, dominantly felsic volcanic, and volcaniclastic rocks of the late Ediacaran Ouarzazate Group. This study reports the first attempt that combines underground mapping of the Igoudrane silver-rich deposit, drill core examination, petrographic, electron microprobe, and LA-ICP-MS analyses in conjunction with fluid inclusion microthermometry and stable (C, O) and radiogenic (Sr) isotopic data to constrain the origin and evolution of the mineralizing fluids and depositional processes that led to the precipitation of silver mineralization in this deposit.

Supergene Non-Sulfide Biomineralization

Bouabdellah M, Boukirou W, Potra A, Melchiorre E, Bouzahzah H, Yans J, Zaid K, Idbaroud M, Poot J, Dekoninck A, Levresse G. 2021. Origin of the Moroccan Touissit-Bou Beker and Jbel Bou Dahar Supergene Non-Sulfide Biomineralization and Its Relevance to Microbiological Activity, Late Miocene Uplift and Climate Changes. Minerals 11:401. DOI: 10.3390/min11040401.

Supergene non-sulfide Zn-Pb ± Cu deposits have long been ignored by the mining industry but become more and more attractive due to new developments in hydrometallurgy and higher Zn-Pb ± Cu grades than conventional deposits. Their economic value depends on the geologic setting and initial mineralogy. This study filled a gap of knowledge by assessing the role of microbial processes on the formation of such non-sulfide Zn-Pb ± Cu deposits in the Moroccan Atlasic system. Field observations have been combined with thorough mineralogical and geochemical investigations to constrain the origin(s) and evolution of the supergene fluid(s) and depositional processes that led to the precipitation of the non-sulfide mineralization. Macrotextural and carbon and sulfur isotope evidence support the hypothesis that microorganisms played a major role in the formation of the major Moroccan non-sulfide Pb-Zn ± Cu deposits in the Atlasic system.

Mineralization & mammalian biostratigraphy

Yans J, Verhaert M, Gautheron C, Antoine P-O, Moussi B, Dekoninck A, Decrée S, Chaftar H-R, Hatira N, Dupuis C, Pinna-Jamme R, Jamoussi F. 2021. (U-Th)/He Dating of Supergene Iron (Oxyhydr-)Oxides of the Nefza-Sejnane District (Tunisia): New Insights into Mineralization and Mammalian Biostratigraphy. Minerals 11:260. DOI: 10.3390/min11030260.

For nearly 15 years, the Geologist (team around Johan Yans) have been interested in the mineralization (Pb-Zn, Fe-Mn, U-REE-Au, clays) of the Nefza district in Tunisia. This article is a synthesis of their research, which highlights the iron oxide (goethite) dating of meteoric alteration events ~9 and ~1 million years ago. The originality of the article is that – for the very first time! - these dates make it possible to date certain Rhinoceroidae in the region with greater precision. The study was carried out in partnership with various Belgian, French and Tunisian research institutes.

Manganese formation in the Eastern High Atlas, Morocco

Lafforgue L, Dekoninck A, Barbarand J, Brigaud B, Bouabdellah M, Verhaert M, Mouttaqi A, Yans J. 2021. Geological and geochemical constrains on the genesis of the sedimentary-hosted Bou Arfa Mn(-Fe) deposit (Eastern High Atlas, Morocco). Ore Geology Reviews 133:104094. DOI: 10.1016/j.oregeorev.2021.104094.

Carbonate-hosted Mn deposits are widespread in North Africa with most of the Mn ores being hosted by Mesozoic dolomitic formations of the Moroccan Atlasic system. Previous studies suggested that the Bou Arfa Mn(-Fe) deposit has a strictly synsedimentary origin. New petrographical, mineralogical and geochemical data presented here show that three dolomitization phases accompanied the ore formation. The Bou Arfa Mn(-Fe) mineralization (High Atlas, Morocco) is thus formed by post-sedimentary processes and dolomitization is considered as the main driver for Mn and Fe concentration. These results  arise from a multi-year study in collaboration with the University of Paris-Saclay, Mohammed I of Oujda and the Office National des Mines et des Hydrocarbures.

Eels & hydropower plants

Ben Ammar I, Cornet V, Houndji A, Baekelandt S, Antipine S, Sonny D, Mandiki SNM, Kestemont P. 2021. Impact of downstream passage through hydropower plants on the physiological and health status of a critically endangered species: The European eel Anguilla anguilla. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 254:110876. DOI: 10.1016/j.cbpa.2020.110876.

Hydropower plants (HPPs) are a source of “green” energy but also a threat to migrating fish such as the European eel (Anguilla anguilla). They impede the free movement of eels and access to suitable habitats during their growth phase and prevent or delay downstream migration. Though fish survival and damages are well-documented, the condition of surviving and unharmed fish remains unknown. This study assesses the impact of the passage through HPPs on the survival, the physiological and health status of adult eels. After a deliberate passage through turbines, direct mortality, external and internal damages, stress and immune biomarkers such as plasma cortisol and glucose levels, alternative complement (ACH50), lysozyme and peroxidase activities, and total immunoglobulin (Ig) content were measured. Results show that the passage affected energy expenditure and innate immunity. Thus, HPPs can not only have an impact in terms of direct mortality and injuries but also affect the physiological and health condition of the surviving eels. This may explain the delayed mortality observed in telemetric studies and cumulative impact of the passage through several HPPs may compromise the ability of adult eels to successfully migrate to the ocean.

Boni M, Yans J. 2021. Editorial for Special Issue “Supergene Evolution of Polymetallic Deposits, Including Non-Laterite Fe and Mn Ores.” Minerals 11:946. DOI: 10.3390/min11090946.

Yans J. 2021. Maintien et développement de l’exploitation des ressources minérales en Europe : le cas de la Wallonie. In: L’économie des ressources minérales et le défi de la soutenabilité 2. ISTE Editions, 111–127.

Yans J, Boulvain F, Tourneur F, Poot J, Rochez G. 2021. D’où proviennent les pierres noires de l’église Saint-Loup? La science s’en mêle…. Société Archéologique de Namur.


Genesis of As-Pb-Rich Supergene Mineralization in Morocco

Verhaert M, Madi A, Basbas AE, Elharkaty M, Oummouch A, Oumohou L, Malfliet A, Maacha L, Yans J. 2020. Genesis of As-Pb-Rich Supergene Mineralization: The Tazalaght and Agoujgal Cu Deposits (Moroccan Anti-Atlas Copperbelt). Economic Geology 115:1725–1748. DOI: 10.5382/econgeo.4779.

In the Moroccan Anti-Atlas, sulfide deposits hosted by Neoproterozoic to Cambrian formations underwent significant weathering, leading to the formation of supergene profiles. Supergene deposits are of high interest for mining industries due to the near-surface situation and softened host rocks allowing easy and fast accessibility. An additional benefit of secondary ores is their common higher metal contents, compared to primary sulfides. Of special scientific interest is the formation of supergene ores at the interface between tectonic and climate processes, and their mineralogical diversity. The investigated Tazalaght and Agoujgal deposits are characterized by diversified copper secondary ores, including Cu-Pb arsenates. Even if some differences exist in terms of mineralogical and chemical contents between the two ore deposits, the processes responsible for the formation of these supergene ores are very similar. At both sites, the oxidation of base metal sulfides and tennantite resulted in an acidic environment and in the mobilization of several ions.

Multistage genesis of a Cretaceous manganese deposit in Morocco

Dekoninck A, Ruffet G, Missenard Y, Parizot O, Magoua M, Mouttaqi A, Rochez G, Yans J. 2020. Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco). Mineralium Deposita. DOI: 10.1007/s00126-020-01017-0.

In 2016, the Geology Department was prospecting for ancient manganese deposits in the Tasdremt region near the Aoulouz dam, 100 km east of Taroudant (Morocco), in collaboration with the University of Paris-Sud, the University of Rennes and the Moroccan National Office of Hydrocarbons and Mines. These karstic deposits are a crucial witness to the periods of meteoric alteration during the Upper Cretaceous, thanks to the Ar-Ar dating of Mn oxides (cryptomelane).

Environmental changes in the early Eocene

Garel S, Dupuis C, Quesnel F, Jacob J, Yans J, Magioncalda R, Fléhoc C, Schnyder J. 2020. Multiple early Eocene carbon isotope excursions associated with environmental changes in the Dieppe-Hampshire Basin (NW Europe)Multiples excursions isotopiques du carbone de l’Eocène inférieur associées à des changements environnementaux dans le Bassin de Dieppe-Hampshire (Europe du NO). Bulletin de la Société Géologique de France 191. DOI: 10.1051/bsgf/2020030.

The early Eocene experienced a series of short-lived global warming events, known as hyperthermals, associated with negative carbon isotope excursions (CIE). The Paleocene-Eocene Thermal Maximum (PETM or ETM-1) and Eocene Thermal Maximum 2 (ETM-2) are the two main events of this Epoch, both marked by massive sea-floor carbonate dissolution. Their timing, amplitude and impacts are rather well documented, but CIEs with lower amplitudes also associated with carbonate dissolution are still poorly studied (e.g. events E1 to H1), especially in the terrestrial realm where hiatus/disconformities and various sedimentary rates in a single succession may complicate the assignation to global isotopic events. This article presents a new high-resolution multi-proxy study on the terrestrial, lagoonal and shallow marine late Paleocene-early Eocene succession from two sites of the Cap d’Ailly area in the Dieppe-Hampshire Basin (Normandy, France).

The Giant Copper Deposit of Tizert (Morocco)

Poot J, Verhaert M, Dekoninck A, Oummouch A, El Basbas A, Maacha L, Yans J. 2020. Characterization of Weathering Processes of the Giant Copper Deposit of Tizert (Igherm Inlier, Anti-Atlas, Morocco). Minerals 10:620. DOI: 10.3390/min10070620.

The Tizert copper deposit in Morocco is considered to be the largest Copper deposit in the Western Anti-Atlas today. Its resources are estimated at almost 57 million tons with a Cu content of 1.03%. The site is characterized by Cu mineralization carried by malachite, chalcocite, covellite, bornite and chalcopyrite. The host rocks are mainly limestones and sandstones/siltstones. The supergene enrichment is most likely related to episodes of uplift/doming (last event since 30 Ma), which triggered the exhumation of primary/hypogene mineralization. Copper is highly demanded in renewable energies and high technology applications, due to its good electrical and thermal conductivity (up to 15% Cu in smartphones!).

Salmons & hydropower plants

Ben Ammar I, Baeklandt S, Cornet V, Antipine S, Sonny D, Mandiki SNM, Kestemont P. 2020. Passage through a hydropower plant affects the physiological and health status of Atlanstic salmon smolts. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 247:110745. DOI: 10.1016/j.cbpa.2020.110745.

Atlantic salmon migrate from nursery areas in rivers to the oceanic feeding areas at smolt stage and back again at adult stage. Dams associated with hydroelectric power plants (HPP) disrupt their migration routes and affect fish movement and survival. This study evaluates the short and mid-term physiological and immune response of salmon smolts after passing through Andenne HPP (Meuse River, Belgium). Direct mortality and external damages, stress and immune biomarkers such as plasma cortisol and glucose levels, complement and peroxidase activities were measured directly. Further, immune and oxidative stress parameters related to gene expression up to 120 h after passage. Results show that not only mortality and visible damages were higher after passage through the HPP compared to a control group, but also energy and immunity parameters were affected. This partially explains the delayed mortality observed in many studies leading to a poor success of restocking programs.

Underground Flash Flood Events

Watlet A, Camp MV, Francis O, Poulain A, Rochez G, Hallet V, Quinif Y, Kaufmann O. 2020. Gravity Monitoring of Underground Flash Flood Events to Study Their Impact on Groundwater Recharge and the Distribution of Karst Voids. Water Resources Research 56:e2019WR026673. DOI: 10.1029/2019WR026673.

Flash flood events are expected to become increasingly common with the global increases in weather extremes. They are a significant natural hazard that affects karst landscapes, which host large resources of drinking water worldwide. This study analyses 20 incave flash flood events affecting the Rochefort karst system (Belgium). Continuous gravity measurements at one single station were used and water level sensors installed in caves. Underground flood events typically produce a peak in the gravity signal, due to an increase in the associated mass change. After the flood, the gravity values drop but remain slightly increased compared to before the flood event. Via forward gravity modeling, the authors demonstrate that this remaining anomaly can be reasonably explained by the infiltration of local rainfall within the karst system rather than by allogenic recharge of the aquifer.

Hormonal stimulation in pikeperch

Żarski D, Ben Ammar I, Bernáth G, Baekelandt S, Bokor Z, Palińska-Żarska K, Fontaine P, Horváth Á, Kestemont P, Mandiki SNM. 2020. Repeated hormonal induction of spermiation affects the stress but not the immune response in pikeperch (Sander lucioperca). Fish & Shellfish Immunology 101:143–151. DOI: 10.1016/j.fsi.2020.03.057.

Controlled reproduction remains a challenge in aquaculture, especially for newly domesticated fish species, such as pikeperch (Sander lucioperca). Sperm quality and quantity is crucial for the success of a selective-breeding program. It is common practice to stimulate fish with hormones, either with human chorionic gonadotropin (hCG) or salmon gonadoliberine analogue (sGnRHa). This study shows that hormonal stimulation increased quality and quantity of sperm. No effects on immune response were detected, but HCG affected stress response in pikeperch males. Sperm quality was further negatively correlated with immune markers, pronouncing the need to carefully revise broodstock management and selection practices in aquaculture.

Biotic resource use by fisheries

Luong AD, Dewulf J, De Laender F. 2020. Quantifying the primary biotic resource use by fisheries: A global assessment. Science of The Total Environment 719:137352. DOI: 10.1016/j.scitotenv.2020.137352.

Capture fisheries contribute to fish production via fishmeal and fish oil which are important for livestock production as well as aquaculture systems. Estimates of primary production required (PPR) are used to assess the ecological impacts of fishing. Currently, the calculation of Specific PPR (SPPR) relies on simplified and invalid assumptions. In this study, SPPRs of more than 1700 species were directly calculated based on food web flow matrices using an advanced SPPR calculation framework for five countries. The trophic level of a species was the most important ecological factor determining its SPPR. The results indicate that the conventional approach underestimates PPRs by up to a factor of 5. This new approach gives a more conservative assessment of marine biotic resource use.

Fe-rich bentonites from Westerwald

Fontaine F, Christidis GE, Yans J, Hollanders S, Hoffman A, Fagel N. 2020. Characterization and origin of two Fe-rich bentonites from Westerwald (Germany). Applied Clay Science 187:105444. DOI: 10.1016/j.clay.2020.105444.

The Westerwald region is one of the major ceramic clay mining areas of Germany. The mined clays were deposited on the weathered Rhenish massif during Eocene and Oligocene and were protected from erosion by a large alkaline basalt cover. Two Fe-rich bentonite layers exposed in quarries of the Eastern part of the Westerwald were investigated with X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, optical microscopy, scanning electron microscopy, chemical analyses and cation exchange capacity (CEC). In both bentonite layers, the main mineral is a high-charge Fe-rich beidellite containing exchangeable Ca and Mg. Even if they both derive from mafic volcanic rocks, the difference in accessory minerals and trace element content leads to the conclusion that they have a different precursor.

Supergene ore of Cu–Co in the Kongo

Fontaine L, De Putter T, Bernard A, Decrée S, Cailteux J, Wouters J, Yans J. 2020. Complex mineralogical-geochemical sequences and weathering events in the supergene ore of the Cu–Co Luiswishi deposit (Katanga, D.R. Congo). Journal of African Earth Sciences 161:103674. DOI: 10.1016/j.jafrearsci.2019.103674.

The Luiswishi copper and cobalt (Cu–Co) ore deposit (Haut-Katanga, D.R. Congo) belongs to the Katanga Copperbelt (KCB), a world-class Cu–Co district. The primary orebodies in the KCB consist of sulphide ore hosted in Neoproterozoic fine-grained siliciclastic and carbonate sedimentary rocks. The secondary weathered ores are still poorly documented, though most of them are strongly enriched in both copper and cobalt with regard to the primary sulphide ores. Combined mineralogical and geochemical investigations on both host rocks and ore minerals allow identifying and characterizing three distinct zones in the studied profile, from base to top: the protore, which contains sulphides and massive dolomite; the cementation zone where oxides and sulphides coexist, and the saprolite, comprised of oxidized ores only.
The demand for these geological resources (such as copper and cobalt, but also manganese, see above) will be growing in the coming years / decades, in particular to supply high-tech products and renewable energies.


Belgian Black Marbles

Boulvain F, Poulain G, Tourneur F, Yans J. 2019. Potential Discrimination of Belgian Black Marbles Using Petrography, Magnetic Susceptibility and Geochemistry. Archaeometry. DOI: 10.1111/arcm.12530.

The world famous black marbles of Belgium are used since the Roman Antiquity. These rocks are not marbles in a petrographic meaning; instead they correspond to several varieties of fine‐grained, well‐cemented Paleozoic limestones, without dots, veins or fossils. But these marbles are difficult to distinguish from each other. This paper synthesizes the geological data already bibliographically available and provides new accurate geological data to compare and discriminate them. Five marbles were investigated in this study. The results confirm that discrimination is not straightforward and needs a combination of very different techniques, ranging from petrography to geochemical analysis. However, all these techniques are destructive.

Solé F, Noiret C, Desmares D, Adnet S, Taverne L, De Putter T, Mees F, Yans J, Steeman T, Louwye S, Folie A, Stevens NJ, Gunnell GF, Baudet D, Yaya NK, Smith T. 2019. Reassessment of historical sections from the Paleogene marine margin of the Congo Basin reveals an almost complete absence of Danian deposits. Geoscience Frontiers 10:1039–1063. DOI: 10.1016/j.gsf.2018.06.002.

Elementary analyses of willemite mineralisation

Choulet F, Richard J, Boiron M-C, Dekoninck A, Yans J. 2019. Distribution of trace elements in willemite from the Belgium non-sulphide deposits. European Journal of Mineralogy 31:983–997. DOI: 10.1127/ejm/2019/0031-2871.

Samples of willemite (Zn2SiO4) mineralisation from the historical non-sulphide Zn–Pb deposits of La Calamine (eastern Belgium) have been recovered from collections of the Geological Survey of Belgium. Textural and chemical analyses were used to evaluate the critical element distribution (Ge, In, Ga) and deportment. Willemite is a mineral of secondary origin and occurs as a variety of types that are continuously formed between the protore stage (sulphides) and the late supergene stage (carbonates and hydrated phases). Different types of willemite may be distinguished on the basis of their shape and zoning characteristics, also marked by a significant change of major-element compositions in the late generation of willemite. Among the trace elements, anomalous high contents of P, Cd, As, Pb, Ag and Sb were noted. While Ga and In contents are very low (less than 4 ppm) or even below detection limits, significant Ge contents up to 250 ppm were measured. Such contents are consistent with values reported from willemite mineralization throughout the world.

Dating of Manganese oxides

Dekoninck A, Monié P, Blockmans S, Hatert F, Rochez G, Yans J. 2019. Genesis and 40Ar/39Ar dating of K-Mn oxides from the Stavelot Massif (Ardenne, Belgium): Insights into Oligocene to Pliocene weathering periods in Western Europe. Ore Geology Reviews 115:103191. DOI: 10.1016/j.oregeorev.2019.103191.

The occurrence of Ordovician Fe-Mn-rich sediments in the Stavelot inlier (NE Ardennes, Rhenish Massif, Belgium) has drawn the attention of geoscientists for more than one century, as they contain natural “coticule” whetstones and numerous weathered Manganese (Mn) deposits. The Mn-bearing sediments have undergone greenschist facies metamorphism in relation to the Caledonian and Variscan orogenesis. More recent weathering processes transformed the early mineral assemblages into secondary Mn oxides. This study investigates the weathering processes of these Mn-rich rocks by new mineralogical, petrographical and geochemical data and a new 40Ar/39Ar geochronology of K-Mn oxides.

Climate change in the Palaeocene

Wouters S, Spassov S, Martinez M, Steurbaut E, Storme J-Y, Yans J, Devleeschouwer X. 2019. Depositional changes during the Danian–Selandian transition in Loubieng (France), Zumaia (Spain) and Sidi Nasseur (Tunisia): insights from and limits of rock magnetism. Geological Magazine:1–19. DOI: 10.1017/S0016756819000281.

Depositional changes that occurred during the Danian–Selandian transition are studied in France, Spain and Tunisia. These changes are linked to climatic events such as hyperthermals, i.e. short-term warming events. Here, rock-magnetic techniques are used that are very sensitive and allow the identification, characterization and quantification of magnetic minerals in rocks by measuring magnetic parameters. These help to understand a wide range of geological processes involving these minerals. For example, humidity levels or detrital or biogenic origin of minerals can be determined.

OM-MADE - an open-source program

Tinet A-J, Collon P, Philippe C, Dewaide L, Hallet V. 2019. OM-MADE: An open-source program to simulate one-dimensional solute transport in multiple exchanging conduits and storage zones. Computers & Geosciences 127:23–35. DOI: 10.1016/j.cageo.2019.03.001.

OM-MADE (One-dimensional Model for Multiple Advection, Dispersion, and storage in Exchanging zones) is an open-source python code to simulate one-dimensional solute transport in conduits. It enables the simulation of multiple exchanging flow and storage zones in steady-state flow conditions. It further helps with the interpretation of multi-peaked breakthrough curves that can be observed in karstic system tracer tests.

Geological analysis of fossil-bearing Dakhla

Benammi M, Adnet S, Marivaux L, Yans J, Noiret C, Tabuce R, Surault J, Kati IE, Enault S, Baidder L, Saddiqi O, Benammi M. 2019. Geology, biostratigraphy and carbon isotope chemostratigraphy of the Palaeogene fossil-bearing Dakhla sections, southwestern Moroccan Sahara. Geological Magazine 156:117–132. DOI: 10.1017/S0016756817000851.

Nature and age of the sedimentological deposits exposed in the Dakhla region (Sahara, Morocco) were described and refined based on lithological, palaeomagnetic, carbon isotope chemostratigraphy and biochronological data to date its Palaeogene faunas. Analyses show that the rodent assemblage (a high diversity of micromammals) found in the region represents the first Oligocene record of rodents from north-western Saharan Africa.

River channelization increases competition among young fish

Latli A, Michel LN, Lepoint G, Kestemont P. 2019. River habitat homogenisation enhances trophic competition and promotes individual specialisation among young of the year fish. Freshwater Biology 64:520–531. DOI: 10.1111/fwb.13239.

Large rivers are heavily modified for navigation, which may reduce food availability for young fish and their chance to reach the adult age. In the Meuse River, decrease of fish abundance is thought to be linked to a drastic reduction of phytoplankton biomass. The trophic niches of four fish species at various stages of development were studied to compare intra‐ and interspecific competition between reaches that differ in their degree of channelization. In the heavily channelized reach, resource diversity was lower. Trophic competition between larval stages was thus increased, leading also to the consumption of vegetation, which is a suboptimal energy source.


Underground galleries

Quinif Y, Hallet V. 2018. The Karstic System of Han-sur-Lesse. In: Demoulin A ed. Landscapes and Landforms of Belgium and Luxembourg. World Geomorphological Landscapes. Cham: Springer International Publishing, 139–158. DOI: 10.1007/978-3-319-58239-9_9.

The karstic system of Han-sur-Lesse is the archetype of underground meander cutoff. Located in the “Calestienne”, a narrow bench extending along the northern margin of the Lower Devonian Ardenne, it comprises all caves and underground flow paths related to the epigenetic Lesse River across the Givetian limestone anticline of Boine.

Post-Paleozoic evolution of the northern Ardenne Massif

Barbarand J, Bour I, Pagel M, Quesnel F, Delcambre B, Dupuis C, Yans J. 2018. Post-Paleozoic evolution of the northern Ardenne Massif constrained by apatite fission-track thermochronology and geological data. BSGF - Earth Sciences Bulletin 189:16. DOI: 10.1051/bsgf/2018015.

This work characterizes the vertical evolution of the northern Ardenne and the Brabant massifs considering new fission-track data, using robust geological constraints. Fission track dating is a radiometric dating technique based on analyses of the damage trails, or tracks, left by fission fragments in certain uranium-bearing minerals and glasses. The damage appears as linear features referred to as fission tracks. This technique is useful at unravelling the thermal evolution of rocks and minerals.

Unusual H- and O-isotope compositions in the Tamra deposit, Tunisia

Dekoninck, A, Moussi, B, Vennemann, T, Jamoussi, F, Mattielli, N, Decrée, S, Chaftar, H-R, Hatira, N, & Yans, J 2018, ‘Mixed hydrothermal and meteoric fluids evidenced by unusual H- and O-isotope compositions of kaolinite-halloysite in the Fe(-Mn) Tamra deposit (Nefza district, NW Tunisia)’, Applied Clay Science, vol. 163, pp. 33–45,

The iron mine of Tamra (Nefza District, NW Tunisia) is a 50 m thick Upper Mio-Pliocene sedimentary series impregnated by Fe-Mn oxides associated with white clay lenses with high halloysite and kaolinite content. The unusually high δ18O values of the kaolinite-halloysite and goethite-hematite deposit show that these latter minerals did not originate solely from an equilibrium state with pure meteoric waters. The most appropriate explanation for their relatively heavy isotopic values is a hydrothermal fluid-rock interaction of the meteoric fluid with the underlying carbonate rocks (marls and skarns).

Groundwater recharge processes

Poulain, A, Watlet, A, Kaufmann, O, Camp, MV, Jourde, H, Mazzilli, N, Rochez, G, Deleu, R, Quinif, Y, & Hallet, V 2018, ‘Assessment of groundwater recharge processes through karst vadose zone by cave percolation monitoring’, Hydrological Processes, vol. 32, no. 13, pp. 2069–2083, doi: 10.1002/hyp.13138

Recharge processes of karst aquifers are difficult to assess given their strong heterogeneity and the poorly known effect of vadose zone on infiltration. However, recharge assessment is crucial for the evaluation of groundwater resources. This experimental study identifies and quantifies recharge modes in the Rochefort Cave (Belgium). The quantification allowed investigating the question of recharge efficiency and aquifer vulnerability. Both methods used, i.e. discharge monitoring and artificial dye tracing highlighted a two‐flow component behaviour with a continuous diffuse recharge and an ephemeral quickflow recharge.

Where do the “Lorraine limestones” from the Saint-Paul Cathedral of Liège come from?

Lecuit, MX, Fronteau, G, Boulvain, F, Boulvain, F, Dechamps, F, Eyssautier-Chuine, S, Piavaux, M, Yans, J (2018) Geochemical characterization of “Lorraine limestones” from the Saint-Paul Cathedral of Liège (Belgium): assumptions for the true provenance of the building stones, Environmental Earth Sciences 77: 361.

Some architectural specific elements of the Saint-Paul Cathedral in Liège (Belgium) are made from ochre building stones, so-called “Lorraine limestones” (13th-15th century). However, within a radius of 200km, no such rocks can be found. This multi-analytical approach applied petrography, Rare Earth Elements geochemistry and studied archives and archeological material to characterize the stones used in the church and to compare them with ochre limestones outcropping in the north-east of the Paris Basin. The results make it highly probable that a very restricted geographical area near the ancient port of Donchery (Ardennes, France) including Dom-le-Mesnil and Hannogne ancient quarries of Bajocian limestones (Middle Jurassic) are the potential origin location for the stones used in the Saint-Paul Cathedral.

Underground lakes traced

Dewaide, L, Collon, P, Poulain, A, Rochez, G, & Hallet, V 2018, ‘Double-peaked breakthrough curves as a consequence of solute transport through underground lakes: a case study of the Furfooz karst system, Belgium’, Hydrogeology Journal, vol. 26, no.2, pp. 641–650, doi: 10.1007/s10040-017-1671-4

To study underground lakes, dye tracers are injected into the cave system and their transport measured. In karst systems, such measurements can result in double-peaked breakthrough curves (BTCs) – often reported but poorly understood. From physical laboratory experiments only, it has been proposed that these result from solute transport through underground lakes or pools. This report first describes field data (tracer tests in various hydrologic conditions) which point towards the double peak being linked to a nonlinear process that originates within the lakes. Observations took place on the Furfooz karst system in southern Belgium, where the River Lesse sinks partially into a swallow hole. The water follows a solitary conduit leading to an underground lake that is directly connected to a second underground lake.

Groundwater infiltration dynamics revealed with long-term ERT monitoring

Watlet, A, Kaufmann, O, Triantafyllou, A, Poulain, A, Chambers, JE, Meldrum, PI, Wilkinson, PB, Hallet, V, Quinif, Y, Van Ruymbeke, M, & Van Camp, M 2018, ‘Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring’, Hydrology and Earth System Sciences, vol. 22, no.2, pp. 1563–1592, doi: 10.5194/hess-22-1563-2018

Karst regions are important sources of drinking water and their improved management is essential. This necessitates a better understanding of superficial water movements (Water infiltration and recharge processes), which are strongly heterogeneous in karst areas and measure with conventional hydrological methods. This study is the first long-term (3 y) and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape (Rochefort Cave Laboratory, Belgium). Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified.

Mineralogy and Genesis of an Ore in the Eastern High Atlas, Morocco

Verhaert, M, Bernard, A, Saddiqi, O, Dekoninck, A, Essalhi, M & Yans, J 2018, ‘Mineralogy and Genesis of the Polymetallic and Polyphased Low Grade Fe-Mn-Cu Ore of Jbel Rhals Deposit (Eastern High Atlas, Morocco)’, Minerals, vol. 8, no. 2, p. 39. DOI: 10.3390/min8020039

The Jbel Rhals deposit, also known as “Guelb en Nahas” (“Copper Hill”) is located in the Oriental High Atlas of Morocco and hosts a polymetallic Fe-Mn-Cu ore. It has been shortly exploited during the 19th–20th centuries but receives again attention. This work presents a petrological, mineralogical, and geochemical synthesis of the deposit with a focus on the supergene processes responsible for the current ore mineralogy. A metallogenic model explains the genesis of the ores. Special attention is given to “strategic” or “critical” raw materials in supergene mineral phases.

Sourabié A, Mandiki SNM, Geay F, Sene T, Toguyeni A, Kestemont P. 2018. Fish proteins not lipids are the major nutrients limiting the use of vegetable ingredients in catfish nutrition. Aquaculture Nutrition 24:1393–1405. DOI: 10.1111/anu.12676.

Demoulin, A, Barbier, F, Dekoninck, A, Verhaert, M, Ruffet, G, Dupuis, C & Yans, J 2018, Erosion Surfaces in the Ardenne–Oesling and Their Associated Kaolinic Weathering Mantle. in A Demoulin (ed.), Landscapes and Landforms of Belgium and Luxembourg. World Geomorphological Landscapes, Springer Verlag, Cham, pp. 63-84. DOI: 10.1007/978-3-319-58239-9_5


Barral, A, Gomez, B, Zorrilla, JM, Serrano, JM, Yans, J, Daviero-Gomez, V, Ewin, TAM & Lécuyer, C 2017, 'Analysing the representativeness of local-scale palaeodiversity measurements: a case from the Lower Cretaceous plant assemblage of Hautrage (Mons Basin, Belgium)' Lethaia, vol 50, no. 2, pp. 244-257. DOI: 10.1111/let.12194

Capette, L & Hallet, V 2017, Captage SWDE de Blaton (Bernissart) - Aperçu hydrogéologique. Cellule de diagnostic "pesticide - captage" CRAW - SPGE. UNamur Département de géologie. Commissioned Report.

Capette, L & Hallet, V 2017, Site Lhoist de Marche-les-Dames - Estimation par modélisation des débits d'exhaure pour une cote altimétrique de +3 m du fond de fosse : situation actuelle et extension projetée. Commissioned Report.

Capette, L & Hallet, V 2017, SWDE - Prises d'eau de Gesves (Hoûte E1 et Houyoux G1) - Aperçu hydrogéologique. Cellule de diagnostic "pesticide - captage" CRAW - SPGE. UNamur Département de géologie. Commissioned Report.

Latli, A, Sturaro, N, Desjardin, N, Michel, LN, Otjacques, W, Lepoint, G & Kestemont, P 2017, 'Isotopic half-life and enrichment factor in two species of European freshwater fish larvae: an experimental approach' Rapid Communications in Mass Spectrometry, vol 31, no. 8, pp. 685-692. DOI: 10.1002/rcm.7838

Latli, A, Descy, J-P, Mondy, CP, Floury, M, Viroux, L, Otjacques, W, Marescaux, J, Depiereux, E, Ovidio, M, Usseglio-Polatera, P & Kestemont, P 2017, 'Long-term trends in trait structure of riverine communities facing predation risk increase and trophic resource decline' Ecological Applications, vol 27, no. 8, pp. 2458-2474.  DOI: 10.1002/eap.1621

Marivaux L, Adnet S, Benammi M, Tabuce R, Yans J, Benammi M. 2017. Earliest Oligocene hystricognathous rodents from the Atlantic margin of northwestern Saharan Africa (Dakhla, Morocco): systematic, paleobiogeographical, and paleoenvironmental implications. Journal of Vertebrate Paleontology 37:dem. DOI: 10.1080/02724634.2017.1357567.

Mellery J, Brel J, Dort J, Geay F, Kestemont P, Francis DS, Larondelle Y, Rollin X. 2017. A n-3 PUFA depletion applied to rainbow trout fry (Oncorhynchus mykiss) does not modulate its subsequent lipid bioconversion capacity. British Journal of Nutrition 117:187–199. DOI: 10.1017/S0007114516004487.

Poulain, A, Rochez, G, Van Roy, J-P, Dewaide, L, Hallet, V & De Sadelaer, G 2017, 'A compact field fluorometer and its application to dye tracing in karst environments' Hydrogeology Journal, vol 25, no. 5, pp. 1517–1524. DOI: 10.1007/s10040-017-1577-1

Schnyder J, Pons D, Yans J, Tramoy R, Abdulanova S. 2017. Integrated stratigraphy of a continental Pliensbachian–Toarcian Boundary (Lower Jurassic) section at Taskomirsay, Leontiev Graben, southwest Kazakhstan. Geological Society, London, Special Publications 427:337–356. DOI: 10.1144/SP427.15.

Verhaert, M, Bernard, A, Dekoninck, A, Lafforgue, L, Saddiqi, O & Yans, J 2017, 'Mineralogical and geochemical characterization of supergene Cu–Pb–Zn–V ores in the Oriental High Atlas, Morocco' Mineralium Deposita, vol 52, no. 7, pp. 1049-1064. DOI: 10.1007/s00126-017-0753-5, 10.1007/s00126-017-0753-5

Yans J, 2017. Gestion durable des ressources minérales en Wallonie (Belgique) : singularités et pistes de réflexion. In: L’industrie minière et le développement durable : une perspective internationale francophone. ed. Rouleau A, Gasquet D, CERM, Université du Québec à Chicoutimi et Institut de la Francophonie pour le développement durable, Collection Points de repère, 26, 99-114. link


Barthélemy, J, Carletti, T, Collier, L, Hallet, V, Moriamé, M & Sartenaer, A 2016, 'Interaction prediction between groundwater and quarry extension using discrete choice models and artificial neural networks' Environmental Earth Sciences, vol 75, no. 23, 1467. DOI: 10.1007/s12665-016-6268-z

Dekoninck, A, Bernard, A, Barbarand, J, Saint-Bezar, B, Missenard, Y, Lepretre, R, Saddiqi, O & Yans, J 2016, 'Detailed mineralogy and petrology of manganese oxyhydroxide deposits of the Imini district (Morocco)' Mineralium Deposita, vol 51, no. 1, pp. 13-23. DOI: 10.1007/s00126-015-0590-3

Dekoninck, A, Leprêtre, R, Saddiqi, O, Barbarand, J & Yans, J 2016, The high-grade Imini manganese district-karst-hosted deposits of Mn oxides and oxyhydroxides. In: Bouabdellah M., Slack J. (eds) Mineral Deposits of North Africa. Mineral Resource Reviews. Springer, Cham, pp. 575-594. DOI: 10.1007/978-3-319-31733-5_22

Dewaide, L, Bonniver, I, Rochez, G & Hallet, V 2016, 'Solute transport in heterogeneous karst systems: Dimensioning and estimation of the transport parameters via multi-sampling tracer-tests modelling using the OTIS (One-dimensional Transport with Inflow and Storage) program' Journal of Hydrology, vol 534, pp. 567-578. DOI: 10.1016/j.jhydrol.2016.01.049

Geay F, Mellery J, Tinti E, Douxfils J, Larondelle Y, Mandiki SNM, Kestemont P. 2016. Innate immune system modulation and disease resistance in Eurasian perch fed contrasted LC-PUFA dietary contents. Fish & Shellfish Immunology 53:70. DOI: 10.1016/j.fsi.2016.03.078.

Geay F, Tinti E, Mellery J, Michaux C, Larondelle Y, Perpète E, Kestemont P. 2016. Cloning and functional characterization of Δ6 fatty acid desaturase (FADS2) in Eurasian perch (Perca fluviatilis). Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 191:112–125. DOI: 10.1016/j.cbpb.2015.10.004.

Noiret, C, Steurbaut, E, Tabuce, R, Marandat, B, Schnyder, J, Storme, JY & Yans, J 2016, 'New bio-chemostratigraphic dating of a unique early eocene sequence from southern europe results in precise mammalian biochronological tie-points' Newsletters on Stratigraphy, vol 49, no. 3, pp. 469-480. DOI: 10.1127/nos/2016/0336

Otjacques, W, De Laender, F & Kestemont, P 2016, 'Discerning the causes of a decline in a common European fish, the roach (Rutilus rutilus L.): A modelling approach' Ecological Modelling , vol 322, pp. 92-100. DOI: 10.1016/j.ecolmodel.2015.12.002

Radinger, J, Hölker, F, Horký, P, Slavík, O, Dendoncker, N & Wolter, C 2016, 'Synergistic and antagonistic interactions of future land use and climate change on river fish assemblages' Global Change Biology, vol 22, no. 4, pp. 1505-1522. DOI: 10.1111/gcb.13183

Roland, S, Rorive, A, Capette, L & Hallet, V Carte hydrogéologique de Wallonie, Planchettes Rebecq - Ittre n° 39/1-2. link

Ruthy, I, Dassargues , A, Capette, L & Hallet, V Carte hydrogéologique de Wallonie, Planchettes Natoye – Ciney n° 54/1-2. link

Tramoy, R, Schnyder, J, Nguyen Tu, TT, Yans, J, Jacob, J, Sebilo, M, Derenne, S, Philippe, M, Huguet, A, Pons, D & Baudin, F 2016, 'The Pliensbachian-Toarcian paleoclimate transition: New insights from organic geochemistry and C, H, N isotopes in a continental section from Central Asia' Palaeogeography, Palaeoclimatology, Palaeoecology, vol 461, pp. 310-327. DOI: 10.1016/j.palaeo.2016.08.020

Verhaert, M-A, Bernard, A, Dekoninck, A & Yans, J 2016, 'Characterization and genesis of Cu-Pb-Zn-V-Fe-Mn supergene ore deposits in the area of Bou Arfa (Oriental High Atlas, Morocco)' Geologica Belgica, vol 19, no. 3/4, pp. 302-304.

Yans, J & Dekoninck, A 2016, Ressources du sous-sol wallon : historique, état des lieux et perspectives. in Mines et Carrières. vol. Hors Série 18, 236, Revue de la Société de l'Industrie Minérale, Paris, pp. 5-12. pdf


Fossil Feathers

Lindgren J, Sjövall P, Carney RM, Cincotta A, Uvdal P, Hutcheson SW, Gustafsson O, Lefèvre U, Escuillié F, Heimdal J, Engdahl A, Gren JA, Kear BP, Wakamatsu K, Yans J, Godefroit P. 2015. Molecular composition and ultrastructure of Jurassic paravian feathers. Scientific Reports 5:13520. DOI: 10.1038/srep13520.

Feathers are extremely complex epidermal structures. Their evolutionary trajectory across dinosaurs and basal birds is well documented. Melanosome-like microbodies preserved in association with fossil plumage have been used to reconstruct original colour, behaviour and physiology. However, these putative ancient melanosomes might alternatively represent microorganismal residues, a conflicting interpretation compounded by a lack of unambiguous chemical data. The authors used sensitive molecular imaging to provide novel insights into the early evolution of feathers at the sub-cellular level, and unequivocally determine that melanosomes can be preserved in fossil feathers.