References of "Fagel, Nathalie"
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See detailA 3400 year lacustrine paleoseismic record from the North Anatolian Fault, Turkey: Implications for bimodal recurrence behavior
Avsar, Ulas; Hubert, Aurelia ULg; De Batist, Marc et al

in Geophysical Research Letters (2014), 41(2), 377-384

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of ... [more ▼]

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of paleoearthquakes. A robust sediment chronology, spanning the last 3400 years, is constructed by radiocarbon dating and time-stratigraphical correlation with the precisely dated Sofular Cave speleothem record. Yeniçağa sedimentary sequence contains 11 seismically induced event deposits characterized by siliciclastic-enriched intervals. Some of the event deposits are also associated with implications of sudden lake deepening, which may be related to coseismic subsidence. The paleoearthquake series having an average recurrence interval of ca. 260 years are interrupted by two possible seismic gaps of ca. 420 and 540 years. [less ▲]

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See detailMineralogical, Physicochemical Properties of smectite clays from Bana (Western Cameroon) and Preliminary test as Potential oil bleaching earth
Mache, Jacques Richard; Signing, P.; Mbey, J.A. et al

in Applied Clay Science (2014)

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See detailPalaeogeographic controls on palygorskite occurrence in Maastrichtian-Palaeogene sediments of the Western High Atlas and Meseta basins (Morocco)
Knidiri, A.; Daoudi, Lachen; El Ouahabi, Meriam ULg et al

in Clay Minerals (2014), 49

The Maastrichtian-Palaeogene series of the Western High Atlas and Meseta Basins in Morocco are particularly rich in palygorskite. The present work is aimed at clarifying the genesis of palygorskite from ... [more ▼]

The Maastrichtian-Palaeogene series of the Western High Atlas and Meseta Basins in Morocco are particularly rich in palygorskite. The present work is aimed at clarifying the genesis of palygorskite from the interbedded facies and gaining an understanding of their relationships with the depositional environment. The mineralogical characteristics of palygorskite from these series were studied by X-ray diffraction (XRD) and electron microscopy (SEM/TEM). The palygorskite content and microstructure show large geographical and stratigraphical variations in the deposits studied. The palygorskite occurrence is directly related to palaeobathymetry, since it is the dominant clay mineral in shallow marine and restricted environments. According to the morphology of palygorskite crystallites, four types of textures were distinguished. These types of palygorskite are polygenetic, formed by chemical precipitation, by the recrystallization of smectite clays or reworked by wind or water from sub-aerial environments. The difference between the two studied sub-basins with respect to palygorskite occurrence is attributed to the palaeomorphology of the hinterlands, to the tectonic differentiation and to the physical-chemical conditions of sea water. [less ▲]

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See detailSeismically-triggered organic-rich layers in recent sediments from lake Gollukoy (North Anatolian Fault, Turkey
Avşar, Ulaş; Hubert, Aurelia ULg; De Batist, Marc et al

in Quaternary Science Reviews (2014), 103

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See detailMineralogical and Physical Changes during Sintering of Plastic Red Clays from Sanaga Swampy Valley, Cameroon.
Nzeukou, Aubin; Traina, K.; Mjedo, E.R. et al

in International ceramique review (2014), 63(4), 186-192

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See detailLate Quaternary evolution of sediment provenances in the Central
Fagel, Nathalie ULg; Not, Christelle; Gueibe, Jonathan et al

in Quaternary Science Reviews (2014), 92

Mineral assemblage, trace element content and Nd and Pb isotope signatures were analysed on the fine fraction (<20 mm) of sedimentary records from the Northern Mendeleev Ridge in the Central Arctic Ocean ... [more ▼]

Mineral assemblage, trace element content and Nd and Pb isotope signatures were analysed on the fine fraction (<20 mm) of sedimentary records from the Northern Mendeleev Ridge in the Central Arctic Ocean. Our aimwas to identify the detrital particle provenance and to interpret the changes over the past w250 ka in the relative contribution of the different source-areas in relation to paleoenvironmental conditions. The clay mineral assemblage and the Nd and Pb isotope signatures depict systematic changes over the Late Quaternary. The bulk mineralogy exhibits increases in the relative contribution of carbonate minerals vs. silicates in interglacial/deglacial intervals. In glacial intervals, the mineral assemblage of the <20 mm fraction is characterised by an enrichment in kaolinite, counterbalanced by a decrease in illite. The Nd and Pb isotope signatures of <20 mm fraction are interpreted using a three end-member mixing model, involving crustal supplies from North America and Canada, from the Siberian margin and some from volcanic material. A compilation of geochemical signatures of geological terraines surrounding the Arctic Ocean allowed each end-member to be assigned a representative signature, averaging the signal of the eroded terraines. The Suspended Particulate Matter (SPM) of the MacKenzie River represents an average signature of the sedimentary supplies delivered from the North American platform and Canadian margin. The SPM of the Lena River reflects the mean sedimentary signature of the Siberian platform. The Okhotsh-Chukotka province from the Eastern border of Siberia is identified as the most probable volcanic source. Late Quaternary evolution of the estimated relative contribution of the three end-members confirms that the sediment provenances in the Central Arctic Ocean remain close to the current conditions during past interglacials/deglacials MIS1e3, MIS5/TII and MIS7/TIII. In contrast, glacial conditions (MIS4 and MIS6) record minimum supplies from the American margin, associated with increased volcanic contribution, to the Mendeleev Ridge core location suggesting a different sea-ice circulation associated with a low sea-level and reduced shelf area. [less ▲]

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See detailPotentiality of clay raw materials from northern Morocco in ceramic industry: Tetouan and Meknes areas
El Ouahabi, Meriam ULg; Daoudi, Lahcen; De Vleeschouwer, François et al

in Journal of Minerals and Materials Characterization and Engineering (2014)

This study aims at evaluating the potential suitability of Tetouan and Meknes (central Morocco) clay material as raw materials in various ceramic applications by investigating their textural, chemical ... [more ▼]

This study aims at evaluating the potential suitability of Tetouan and Meknes (central Morocco) clay material as raw materials in various ceramic applications by investigating their textural, chemical, thermal and firing characteristics. Textural properties were identified by specific surface area, cation exchange capacity (CEC) and bulk density (ρs). Chemical and thermal properties were assessed using XRF and TG/DTA techniques, respectively. Firing characteristics at temperatures from 800°C to 1100°C were determined by linear firing shrinkage, loss on weight and water absorption capacity. The Meknes clays are characterised by medium cation exchange capacity (CEC) and specific surface area (SSA) values due to their moderate smectite content. The Tetouan clays have medium to low CEC and medium SSA values. The main oxides in the clayey samples are SiO2 (35 – 54.3 wt.%), Al2O3 (20.6 – 43.9 wt.%), and Fe2O3 (9.7 – 22.4 wt.%). The amount of CaO in Meknes clays ranges from 8 to 12 wt.%, whereas CaO is only present in some Tetouan clay (TE4, TE7, TN4 and TN5). A significant densification of ceramic behaviour could be noticed for most of Tetouan clays at firing temperatures above 1000°C. Meknes clays show earlier densification from 800 °C. The chemical, textural and ceramic properties of Tetouan and Meknes clays indicate their suitability as raw materials for the production of structural ceramics. The high amount of Fe2O3 in all clays makes them inappropriate in fine ceramics. [less ▲]

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See detailBiological nitrate utilization in south Siberian lakes (Baikal and Hovsgol) during the last glacial period: the influence of climate changes on primary productivity
Watanabe Nara, F.; Watanabe, T.; Kakegawa, T. et al

in Quaternary Science Reviews (2014), 90

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See detailCharacterization of clay deposits of Nanga-Eboko (Central Cameroon): Suitability in the production of building materials
Nzeukou Nzeugang, A.; Medjo Eko, R.; Fagel, Nathalie ULg et al

in Clay Minerals (2013), 48(4), 655-662

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See detailHolocene dust record in a NW European peat bog: A multiproxy approach
Allan, Mohammed ULg; LE ROUX, gael; VERHEYDEN, SOPHIE et al

Conference (2013, August 28)

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic bog. The analyses of Rare Earth Elements (REE) and lithogenic element concentrations as well as Nd ... [more ▼]

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic bog. The analyses of Rare Earth Elements (REE) and lithogenic element concentrations as well as Nd isotopes were performed by HR-ICP-MS and MC-ICP-MS respectively, in a  6 m peat section representing 5300 years, from 30 BC to 5300 BC dated by the 14C method. REE concentration variations in peat samples were used as a dust proxy and the Nd isotopes to trace the sources. Peat humification and testate amoebae were used to evaluate hydroclimatic conditions. The range of dust deposition varied from 0.03 to 4 g m-2 yr-1. The highest dust fluxes were observed from 800 to 600 BC, and from 3200 to 2800 BC and correspond to cold periods. The Nd values show large variability, between -5 and –13, identifying three major sources of dust: local soils, distal volcanic and desert particles. By comparing our results with the dust recorded in other peat bogs and ice cores from different latitudes, we evidence that the Misten peat is a valid archive for dust deposition. [less ▲]

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See detailSmectite clay from the Sabga deposit (Cameroon): mineralogical and physicochemical properties
Mache, Jacques Richard ULg; Nyoja, A.; Signing, P. et al

in Clay Minerals (2013), 48(48), 499-512

The physicochemical and mineralogical characterization of the < 250 µm particle-size fraction from six the clay-rich samples from the Sabga deposit (North-west, Cameroon) were carried out in order to ... [more ▼]

The physicochemical and mineralogical characterization of the < 250 µm particle-size fraction from six the clay-rich samples from the Sabga deposit (North-west, Cameroon) were carried out in order to evaluate their potential applications. Analyses revealed that the major clay mineral was dioctahedral smectite along with small amounts of kaolinite in three clay samples. Cristobalite, feldspars, ilmenite and heulandites were also found as accessory minerals. A Li-saturation test (Greene-Kelly test) revealed the montmorillonitic nature of the smectite component. The chemical composition of the bulk clays consists of (66-70%) SiO2, (13-16%) Al2O3 and (2-7%) Fe2O3. These clays present mineralogical (high montmorillonite content) and physico-chemical (cation exchange capacity (CEC): 38 to 46 meq/100g and specific surface areas ranging from 33 to 90 m2/g). These physical and chemical properties are fully compatible with potential uses in environmental applications. After some pretreatment (purification, chemical modification), these materials could also be used in refining edible oil as adsorbent, waste water treatment and wine technology. [less ▲]

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See detailDust historical record in ombrotrophic peat: The case study of a NW European bog
Allan, Mohammed ULg; Fagel, Nathalie ULg; Le Roux, Gael et al

Poster (2013, May 16)

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes ... [more ▼]

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes have been often used to evidence any anthropogenic influence in peat, but they only record trace metal pollution. Another radiogenic isotope, the Neodymium (Nd), could be also use to discriminate the sources of dust in peat bogs. Dust fluxes were investigated over the last 2500 years in the Misten peat bog in Eastern Belgium. Our aims were to use Nd isotope signature to decipher between local and distal dust supplies, the Pb isotopes to trace the antropogenic influences. To address these aims we analyzed REE and lithogenic element analyses, as well as the Nd and Pb isotopes, using HR-ICP-MS and MC-ICP-MS, respectively in peat layers dated by 210Pb and 14C. Changes in REE concentration variations in peat samples are correlated with Ti, Al, and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Dust fluxes show pronounced increase at BC300, AD600, 1000AD, 1200AD and from 1700AD, recording either influence of human activities (regional erosion due to forest clearing and soil cultivation activities) or local and regional climate changes. Lead enrichments reveal strong human impact over the last 300 years. Lead isotope signatures are consistent with local and regional contamination by coal combustion and smelting activities. Neodymium isotopes allow to identify three periods characterised by dominant-distal sources (at 320AD, 1000 AD and 1700AD). Those periods are consistent with local wetter intervals as indicated by lower humification degree. Local erosion prevails durier drier (higher humification) intervals (-100AD, 600AD). On a global scale more distal supplies are driven during colder periods, in particular Oort and Maunder minima, confirming the hypothesis that cold climate conditions favor distal supplies. Combining geochemical elementary content and isotope data in ombrotrophic peat allows to decipher between dust flux changes related to human and climate forcing. [less ▲]

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See detailLes gisements d'argiles de la région de Marrakech, Maroc
El Boudour El Idrissi, Hicham ULg; Daoudi, Lahcen; Fagel, Nathalie ULg

Poster (2013, May 08)

L'argile est une matière première abondante à la surface de la Terre. En raison de ces propriétés physico-chimiques, elle possède une grande variété d'utilisations. Le Maroc est l'un des plus grands ... [more ▼]

L'argile est une matière première abondante à la surface de la Terre. En raison de ces propriétés physico-chimiques, elle possède une grande variété d'utilisations. Le Maroc est l'un des plus grands consommateurs au monde d'argiles, cependant, le domaine majoritaire d’utilisation d’argiles est celui de la céramique. Dans la région de Marrakech, les argiles sont surtout utilisées dans les domaines de basse classe tels que la céramique traditionnelle et la poterie. Jusqu’à présent très peu d’études sont effectués pour valoriser ces argiles. C’est dans cet objectif que s’inscrit l’étude que nous menons sur les argiles du Haut Atlas de Marrakech ; le présent travail a pour objectif de dresser un inventaire des principaux gisements d’argiles de cette région. Les séries du Primaire (en particulier le Viséen) de la région de Marrakech ne sont pas assez altérées pour exploiter les argiles, tel est le cas de la région de Benhmed qui approvisionne les usines céramiques de la région de Settat. Dans les formations triasiques, malgré l'épaisseur et l'apparence argileuse des séries, seuls quelques gisements d'argiles y sont exploités pour la poterie. Les faciès triasiques, riches en illite, sont en effet silteux et assez pauvres en argiles à l'exception de quelques niveaux très minces. Ces argiles sont utilisées au niveau d’Ourika pour la fabrication d’ustensiles rustiques, pots de terre et objets ornementaux. Ces argiles peuvent également constituées des matières premières pour l’élaboration de briques et de substrats pour le revêtement des murs et des sols. Les argiles des formations jurassiques et crétacées sont assez riches en carbonates, ce qui ne convient pas à leur utilisation dans l’industrie céramique. Les séries du Paléocène et de l’Eocène de toute la région sont riches en argiles fibreuses non exploitées, surtout la palygorskite (argile avec de grandes propriétés physiques), ce qui donne des perspective d’utilisation dans des différents domaines industriels. Le Mioplicoène largement développé au pied du Haut Atlas est surtout connu par sa richesse en smectite, plus particulièrement dans la région de Tassaout. En ce qui concerne les séries quaternaires, certains niveaux d’alluvions sont exploités dans la région pour l’industrie céramique (site potier de Tamsloht, Briqueterie Menara,…). Dans la région de Bouchane, le sol quaternaire est considéré comme la seule source d’argiles et d’ustensiles dans cette zone. Enfin des dépôts actuels sont également exploités (limons des oueds Tensift et N’fis, canal la Rocade) pour la fabrication de briques de murailles ou additionnés à d’autres argiles pour augmenter la consistance des pâtes céramiques. [less ▲]

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See detailDeciphering human-climate interactions in ombrotrophic peat record : REE, Nd and Pb isotope signatures of dust supplies over the last 2500 years (Misten bog, Belgium)
Fagel, Nathalie ULg; Allan, Mohammed ULg; le roux, Gael et al

Poster (2013, April 08)

A core of 173 cm of ombrotrophic Misten peat bog from the Hautes-Fagnes Plateau in Eastern Belgium provides a record of Rare Earth Elements (REE) deposition allowing to trace dust fluxes in West Europe ... [more ▼]

A core of 173 cm of ombrotrophic Misten peat bog from the Hautes-Fagnes Plateau in Eastern Belgium provides a record of Rare Earth Elements (REE) deposition allowing to trace dust fluxes in West Europe during the historical record (last 2500 years). REE and lithogenic element analyses, as well as the Nd isotopes, were performed by HR-ICP-MS and MC-ICP-MS, respectively in peat layers dated by 210Pb and 14C. The parallel variations of REE concentration with lithogenic conservative elements confirms that REE are immobile in the studied peat bog and can be used as tracers of dust deposition. Dust fluxes show pronounced increase at BC300, AD600, 1000AD,1200AD and from 1700AD, recording either influence of human activities (regional erosion due to forest clearing and soil cultivation activities) or local and regional climate changes. Using Nd isotope allows to decipher between local and distal causes. The ENd variability (-13 to -9) is interpreted by a mixing between dust sources fromlocal soils and desert particles. Three periods characterised by dominant-distal sources (at 320AD, 1000 AD and 1700AD) are consistent with local wetter intervals as indicated by lower humi[U+FB01]cation degree. Local erosion prevails durier drier (higher humification) intervals (-100AD, 600AD). On a global scale more distal supplies are driven during colder periods, in particular Oort and Maunder minima. Combining geochemical elementary content and isotope data in ombrotrophic peat allows to decipher between dust flux changes related to human and climate forcing. [less ▲]

Detailed reference viewed: 43 (6 ULg)