Sophie Decrée

Sophie Decrée
Royal Belgian Institute of Natural Sciences · Geological Survey of Belgium

PhD

About

49
Publications
27,135
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928
Citations
Additional affiliations
November 2009 - December 2013
Royal Museum for Central Africa
Position
  • Researcher

Publications

Publications (49)
Article
Meteorites are prone to errestrial weathering not only after their fall on the Earth’s surface but also during storage in museum collections. To study the susceptibility of this material to weathering, weathering experiments were carried out on polished sections of the H5 chondrite Asuka 10177. The experiments consisted of four 100‐days cycles duri...
Article
Phosphate rocks and the Rare Earth Elements (REE) as potential by-products are listed as Critical Raw Materials (CRMs) by the European Commission. In Europe, igneous-related phosphate deposits are associated with carbonatites, alkaline complexes, (ultra)mafic intrusions, iron oxide apatite - iron oxide copper gold mineralisation, granites or formed...
Article
Full-text available
Laser-Induced Breakdown Spectroscopy (LIBS) is a fast in-situ analytical technique based on spectroscopic analysis of atomic emission in laser-induced plasmas. Geochemical mapping at macroscopic scale using LIBS was applied to a decimetric Zn-Pb ore sample from east Belgium, which consists of alternating sphalerite and galena bands. A range of elem...
Conference Paper
Full-text available
The rare earth element (REE) mineralization of Gakara (Burundi) was discovered in 1936 and has periodically been the subject of geological studies because of economic REE concentrations (Thoreau et al., 1958; Aderca & Van Tassel, 1971; Lehmann et al., 1994). The Neoproterozoic Gakara REE mineralization is situated in the Western Domain of the Mesop...
Article
The mining district of Nefza-Sejnane (Tunisia) encloses numerous ores and raw material deposits, all formed in relation with successive Fe-rich fluids of meteoric and/or hydrothermal origins. Here, for the first time in Tunisia, (U-Th)/He ages were obtained on supergene goethite from various localities/deposits of the district highlight direct dati...
Article
The Siilinjärvi phosphate deposit (Finland) is hosted by an Archean carbonatite complex. The main body is composed of glimmerite, carbonatite and combinations thereof. It is surrounded by a well-developed fenitization zone. Almost all the rocks pertaining to the glimmerite-carbonatite series are considered for exploitation of phosphate. New petrolo...
Article
The rare earth element (REE) mineralization of Gakara (Burundi) has first been discovered in 1936 and has periodically been the subject of geological studies, at times when the exploitation of bastnäsite-(Ce) and monazite-(Ce) was economically interesting. This study focuses on the establishment of a mineral paragenesis for Gakara, with special att...
Article
Full-text available
The Phalaborwa world-class phosphate deposit (South Africa) is hosted by a Paleoproterozoic alkaline complex mainly composed of phoscorite, carbonatite, pyroxenitic rocks, and subordinate fenite. In addition, syenite and trachyte occur in numerous satellite bodies. New petrological and in-situ geochemical data along with O and Sr isotope data obtai...
Article
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The Luiswishi Cu–Co ore deposit (Haut-Katanga, D.R. Congo) belongs to the Katanga Copperbelt (KCB), a worldclass Cu–Co district. The primary orebodies in the KCB consist of sulphide ore hosted in Neoproterozoic finegrained siliciclastic and carbonate sedimentary rocks. The secondary weathered ores are still poorly documented, though most of them ar...
Chapter
The cathodoluminescence (CL) of minerals reflects with great sensitivity the physiochemical conditions in mineralized systems and their evolution through time. CL textures, colors, and spectra provide Earth scientists with unique signatures that can decipher multistage mineralization, fingerprint ore deposit type, relate ore deposition to specific...
Conference Paper
Full-text available
The Nefza polymetallic mining district is located in the Tellian “Nappe Zone” of northern Tunisia. The Cenozoic deposits overlay a basement made up of Albian-late Priabonian folded marls and Chattian-Burdigalian sandstones. Late Miocene felsic subvolcanic rocks and basaltic flows are regionally observed. New samples were collected for (U-Th)/He dat...
Preprint
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. This mineralization results from i) synsedimentary weathering/pedogenesis, and ii) mixing surface water and regional hydrothermal fluids....
Presentation
Full-text available
Societies rely on a secure, responsible and affordable supply of resources to meet their basic needs, in order to live life in a safe and healthy environment. The natural resources from the subsurface, i.e. groundwater, geo-energy and raw materials, represent essential elements in this provision. Safety from catastrophic events, such as those linke...
Article
Full-text available
Magmatism in the Rocroi inlier (Ardenne Allochton, southeastern Avalonia during eo-Hercynian times) consists of a swarm of bimodal dykes (diabase and/or microgranite) emplaced in Middle to Upper Cambrian siliciclastics (Revin Group). Felsic volcanites interbedded within the Upper Silurian/Lower Devonian transgressive strata on the eastern edge of t...
Chapter
The Nefza region (Nappe Zone, northern Tunisia) is known both as a Late Miocene magmatic province and a base-metal district. In this region, small, post-nappe, continental extensional basins (Sidi Driss and 497 Douahria) host syndiagenetic Pb–Zn ore deposits that have been classified as Sediment-Hosted Massive Sulphide (SHMS)–Sedimentary-exhalative...
Article
Full-text available
The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic syst...
Article
Full-text available
Metal and metalloid (As, Cd, Co, Cu, Pb and Zn) distribution in soils from the Katanga Copperbelt (Democratic Republic of Congo) is investigated in order to characterize the environmental impacts of mining and smelting activities in that area. The concentrations of Cu, Co, As, Zn, Pb and Cd in soils from mining sites are higher than in non-metallif...
Article
The Neoproterozoic Upper Ruvubu Alkaline Plutonic Complex (URAPC), Burundi, is located along the western branch of the East African Rift. It comprises oversaturated and undersaturated syenites and a shallow-level carbonatite body (the Matongo carbonatite) that does not outcrop but has been sampled by drill-cores. The elliptic map contour of the URA...
Conference Paper
Alkaline massifs worldwide are generally atectonic. In Burundi, during the break-up of Rodinia, 700 Ma ago, the Upper Ruvubu Alkaline Plutonic Complex emplaced syntectonically. Large shear zones affecting the intrusion accommodated a regional NE-SW shortening in the regional extensional setting associated with Rodinia breakup. Magmatic dykes and ma...
Conference Paper
Full-text available
En Belgique, des phosphates de terres rares diagénétiques ont été décrits dans les terrains paléozoïques des massifs du Brabant et de l’Ardenne. Il s’agit classiquement des monazites « grises », d’abord identifiées dans les concentrés d’orpaillage, puis dans les pélites paléozoïques. L’utilisation de la cathodoluminescence permet de repérer rapidem...
Article
Full-text available
The Nefza mining district in Northern Tunisia comprises late Miocene (Serravallian to Messinian) magmatic rocks belonging to the post-collisional magmatism of the Mediterranean Maghreb margin. They are mainly made up of Serravallian granodiorite (Oued Belif massif), Tortonian rhyodacites (Oued Belif and Haddada massifs) and cordierite-bearing rhyod...
Data
The upper Miocene Oued Belif ring-shaped breccia is located in the Nefza mining district of northern Tuni-sia, within the internal zone of the collisional Alpine Maghrebide belt. It encloses chaotic Triassic material (evaporites, altered siltites, and pelites) within an extrusive diapiric structure reactivated in a late Miocene nappe emplacement ep...
Conference Paper
Full-text available
The Lufilian belt formed between the Congo and Kalahari cratons with the evolution of the Gondwana supercontinent during the Panafrican orogeny [1]. This orogenic belt hosts (i) world-class Cu-Co deposits and (ii) uranium occurrences within deformed Neoproterozoic Katanga metasedimentary rocks [2]. To decipher the geochemical (REE and Y) signatures...
Conference Paper
Full-text available
Impregnative malachite Possible replacive malachite Scattered crystals and aggregates, most likely impregnative rather than replacive (Etoile, frame width 650 µm). Largely displacive laminated intercalation, with associated coarse-grained pendant features (Kinsevere, frame width 1.3 mm). Circular features, suggesting an association with alteration...
Conference Paper
Full-text available
Impregnative malachite Possible replacive malachite Scattered crystals and aggregates, most likely impregnative rather than replacive (Etoile, frame width 650 µm). Largely displacive laminated intercalation, with associated coarse-grained pendant features (Kinsevere, frame width 1.3 mm). Circular features, suggesting an association with alteration...
Article
Full-text available
The Katanga Copperbelt, in the southeastern part of the Democratic Republic of the Congo (DRC), occurs within the Pan-African Lufilian fold-and-thrust belt and hosts numerous uraniferous mineral occurrences in addition to the world-class sediment-hosted copper and cobalt ore deposits. In the 1950s and 1960s, Cahen et al. gave a relatively wide rang...
Conference Paper
Full-text available
The Katanga Copperbelt (Democratic Republic of the Congo, DRC) is part of a world-class copper and cobalt deposit stretching over SE DRC and NE Zambia. The Copperbelt accounts for >5% of the world’s copper (Cu) reserves and ~55% of the cobalt (Co) reserves. Uranium and other trace elements are frequently associated to cobalt. Due to the “recent” (l...
Article
Full-text available
The Katanga province, Democratic Republic of Congo, hosts world-class cobalt deposits accounting for ~50% of the world reserves. They originated from sediment-hosted stratiform copper and cobalt sulfide deposits within Neoproterozoic metasedimentary rocks. Heterogenite, the main oxidized cobalt mineral, is concentrated as “cobalt caps” along the to...
Article
Full-text available
Malachite [Cu3(OH)2(CO3)] is a common mineral in the Central African Copperbelt, where it constitutes a high-grade (~57% Cu) copper ore and is exploited industrially and by artisanal miners. The genesis of this supergene ore in Katanga has yet received little attention. Here we focus on the genetic processes giving rise to this regionally important...
Article
Full-text available
The karstic system in Aïn Khamouda (Central Tunisia) has been briefly exploited for its Pb–Zn mineralization in the first 20 years of the 20th century. Since then, little work has been dedicated to this system, apart from some detailed mineralogical studies. Here we place the Aïn Khamouda karsts in their regional geological framework, which is mark...
Article
Full-text available
The human health impact of the historic and current mining and processing of non-ferrous metals in the African Copperbelt is not known. This study assessed the exposure to metals in the population of Katanga, in the south east of the Democratic Republic of Congo, using biomonitoring. Seventeen metals (including Cd, Co, Cu, Pb, U) and non-metals (in...
Article
Full-text available
The Tamra mine, located in the Nefza mining district (NW Tunisia), exploits a 50 m-thick layer of Mio-Pliocene sediments that are heavily mineralized with Fe and other metals (Mn, Pb, Zn), especially in its eastern part, which is highly mineralized in Mn and known as the “manganiferous zone”. The textural and geochemical studies of manganiferous mi...
Article
Full-text available
The Sidi Driss and Douahria sulfide ore deposits and showings are located in the Nefza mining district, northern Tunisia. The ores are hosted within Upper Miocene (Messinian) basins, within carbonate lenses composed of Fe–Mn-enriched dedolomite partially or totally replaced by early barite and celestite. The ore mainly consists of galena and spheru...
Article
Full-text available
The Tamra iron mine (Nefza mining district, N. Tunisia) has been exploited for about one century. There are, however, very few publications modelling the mineralisation within this 50 m-thick Messinian–Zanclean sedimentary series. We present the result of a detailed sedimentological, mineralogical and geochemical study on the siliciclastic sediment...
Article
Full-text available
A 65 m thick altered volcanic profile was studied in the Cava di Caolino (Lipari Island) in order to (1) identify the alteration event(s), (2) model these events, and (3) propose estimates of the degree of chemical alteration (CIA, chemical index of alteration). Two mineral parageneses were identified: one comprising silico-aluminous phases, with w...

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