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See detailDetailed characterization of the Late Pleistocene loess sequence stratigraphy of Remicourt (Hesbaye region, Belgium) with cone penetration tests
Delvoie, Simon ULg; Boulvain, Frédéric ULg; Charlier, Robert ULg et al

in Geologica Belgica (2016), 19(3-4), 281-289

Cone penetration tests (CPT) and drilling results are used to characterize the Middle Belgium loess sequence. A two scale study has been realized in the Hesbaye region (Belgium). The study on a regional ... [more ▼]

Cone penetration tests (CPT) and drilling results are used to characterize the Middle Belgium loess sequence. A two scale study has been realized in the Hesbaye region (Belgium). The study on a regional scale was performed along a 18 km long section of the high-speed railway Liège-Brussels. About 230 tests were compiled. Results show the loess thickness is very variable and can locally reach 20 m. Tertiary deposits become continuous and they rapidly thicken from Waremme to the West. The lower surface of the Tertiary deposits is characterized by a 0.3% apparent dipping to the NW. The dipping likely results from the Ardenne Massif uplift. The local scale study focuses on the site of Remicourt located along the high-speed railway. 24 CPT tests have been carried out very close to a series of archaeological trenches. The analysis shows penetrometers are able to define some stratigraphic markers within the loess layer. The most identifiable marker is stratigraphically located around the transition between the Humiferous Complex of Remicourt and the Rocourt Pedocomplex. The lens-shape of the loess ridge is also confirmed by the penetrometers’ interpretation. Furthermore, the 3D morphology of each stratigraphic marker can be estimated. These results offer interesting perspectives for the investigation of the loess sequence related to archaeological applications. [less ▲]

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See detailInsights into a million-year-scale Rhenohercynian carbonate platform evolution through a multi-disciplinary approach: example of a GIvetian carbonate record from Belgium
Pas, Damien ULg; Da Silva, Anne-Christine ULg; Devleeschouwer, Xavier et al

in Geological Magazine (2016)

In this paper we formulate answers to three important questions related to Givetian carbonate records and their use for reconstructing million-year past palaeoenvironmental changes. First, we provide ... [more ▼]

In this paper we formulate answers to three important questions related to Givetian carbonate records and their use for reconstructing million-year past palaeoenvironmental changes. First, we provide detailed illustrations of the fascinating diversity that shaped a significant shallow reefal platform during the early- to late-Givetian in the Rhenohercynian Ocean; secondly we improve the sedimentological model of the extensive Givetian carbonate platform in the Dinant Basin and thirdly we evaluate the application of magnetic susceptibility (MS) as a tool for long-term trend correlations and palaeoenvironmental reconstructions. These goals are reached by making sedimentological, geophysical and geochemical study of the La Thure section. Through the early-late Givetian interval we discerned eighteen microfacies ranging from a homoclinal ramp to a discontinuously rimmed shelf and then a drowning shelf. The comparison of these sedimentological results with those published in the south of the Dinant Syncline allowed us to provide an up to date model of the vertical and lateral environmental development for one of the largest Givetian carbonate platforms in Europe. This comparison also increased the knowledge on the facies belts distribution into the Dinant Basin and allowed us to highlight the Taghanic Event. Palaeo-redox proxies reveal a substantial change in the oxygenation level, from oxygen-depleted to more oxic condition, between middle and late Givetian. We demonstrated the relationship between variation in MS values and proxies for siliciclastic input (such as Si, Al). The La Thure is considered as a key section for the understanding of internal shelf settings bordering Laurussia’s south-eastern margin. [less ▲]

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See detailReappraisal of the deep Devonian strata under the Mons Basin
Licour, L.; Dupont, N.; Swennen, R. et al

Conference (2016, January)

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See detailInsights into a million-year-scale Rhenohercynian carbonate platform evolution through a multi-disciplinary approach: example of a GIvetian carbonate record from Belgium
Pas, Damien ULg; Da Silva, Anne-Christine ULg; Devleeschouwer, Xavier et al

Poster (2016)

In this study we formulate answers to three important questions related to Givetian carbonate records and their use for reconstructing million-year past palaeoenvironmental changes. First, we provide ... [more ▼]

In this study we formulate answers to three important questions related to Givetian carbonate records and their use for reconstructing million-year past palaeoenvironmental changes. First, we provide detailed illustrations of the fascinating depositional diversity that shaped a shallow reefal platform during the early- to late-Givetian in the Rhenohercynian Ocean; secondly we improve the sedimentological model of the Givetian carbonate platform in the Dinant Basin (Belgium) and thirdly we evaluate the application of magnetic susceptibility (MS) as a tool for long-term trends, correlation, and palaeoenvironmental reconstruction. These three goals are reached by making a detailed sedimentological, geophysical and geochemical study of the La Thure quarry. Petrographic analyses revealed eighteen microfacies which represent a carbonate platform evolution through early-late Givetian time, ranging from a homoclinal ramp to a discontinuously rimmed shelf and then a drowning shelf. These results allowed us to illustrate the fascinating environmental diversity that shaped one the largest carbonate platforms of Europe and provide an up to date model of the vertical and lateral development of the Belgian Givetian platform. Early-late Givetian La Thure sequence reveals five main depositional intervals, which could be correlated with the southern margin of the platform. These correlations allowed us to define the facies belts distribution, the major depositional changes that affected this platform and to highlight the Taghanic Event. Palaeo-redox proxies reveal a significant change in the oxygenation level, from oxygen-depleted to more oxic condition, between middle and late Givetian. This change is well-correlated with an increase in global temperature in the late Mid Devonian. Combination of MS and geochemistry demonstrates the inherent-parallel link existing between variation in MS values and proxies for siliciclastic input (such as Si, Al). Collected geochemical and MS data confirm that the La Thure can be considered as a key section for the internal shelf setting in the Rhenohercynian Ocean bordering Laurussia’s south-eastern margin. [less ▲]

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See detailPierres et marbres en Wallonie: reconnaissance et genèse
Boulvain, Frédéric ULg; Tourneur, Francis ULg

Book published by Académie royale de Belgique (2015)

Chacun a eu dans sa maison, sous forme de dalles, cheminées, bibelots, des pierres et marbres. Ces matériaux se sont formés dans des milieux variés, souvent des mers peu profondes et sont les témoins de ... [more ▼]

Chacun a eu dans sa maison, sous forme de dalles, cheminées, bibelots, des pierres et marbres. Ces matériaux se sont formés dans des milieux variés, souvent des mers peu profondes et sont les témoins de près d’un demi-milliard d’années d’histoire de notre région! Cette richesse géologique représente aussi une fabuleuse richesse archéologique et patrimoniale dans l’utilisation exceptionnellement variée qui en a été faite, depuis l’époque romaine jusqu’à nos jours. Donner à chacun l’occasion d’identifier et de comprendre ces pierres et marbres est le but de ce livre. [less ▲]

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See detailSILURIAN – DEVONIAN BLACK SHALES IN THE ORIENTAL ALGERIAN SAHARA: implication of new field data from Tassili n'Ajjer outcrops and Berkine Basin (SE, Algeria).
Djouder, Hocine ULg; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

Scientific conference (2015, November)

The Silurian (Llandovery) and the Devonian (Frasnian) are a periods of interest because sediments and organic-rich shales were deposited in many places that form important hydrocarbon reservoirs and ... [more ▼]

The Silurian (Llandovery) and the Devonian (Frasnian) are a periods of interest because sediments and organic-rich shales were deposited in many places that form important hydrocarbon reservoirs and source rocks throughout North Africa basins and Middle East (Boot et al., 1998 ; Lüning et al., 2000). These organic-rich shales lead Algeria to hold the fourth position in terms of the estimates of technically recoverable shale oil and shale gas resources, based on major basin assessment in the world (EIA, 2013). In the prolific Illizi and Berkine basins (western Ghadames, Algeria) a basin-wide approach is needed, especially with the new “shale gas and shale oil” frontier in the upcoming years, in order to capture regional trends and re-assessment the Siluro-Devonian successions. Wireline-logs from more than 146 (Berkine – Illizi Basin) Algerian petroleum exploration wells have been studied (Djouder et al., 2012; Djouder et al., 2014). In addition, a complete logging of spectacular large-scale and well exposed outcrops of the Siluro-Devonian sediments was carried out at the south margin (SE, Tassili n’Ajjer) of the Illizi-Berkine basins. The following analysis incorporates biostratigraphic, ichnological, sedimentological, magnetic susceptibility and high resolution stratigraphic data. It would allow providing a framework of deposits, ranging from offshore to deltaic deposits for the Silurian and from fluvial to normal-marine depositional conditions for the Devonian. References cited: Boote, D.R.D., Clark-Lowes, D.D., Traut, M.W., 1998. Palaeozoic petroleum systems of North Africa. In: Macgregor, D.S., Moo- dy, R.T.J., Clark-Lowes, D.D. (Eds.), Petroleum Geology of North Africa. Geol. Soc. London Sp. Publ., vol. 132, pp. 7–68. Lüning, S., Craig, J., Loydell, D.K., Štorch, P., Fitches, B., 2000. Lower Silurian ‘hot shales’ in North Africa and Arabia: regional distribution and depositional model. Earth-Science Reviews, 121-200. EIA – U.S. Energy Information Administration, 2013. Technically Recoverable Shale Oil and Shale Gas Resources: An Assessment of 137 Shale Formations in 41 Countries Outside the United States. Rapport de 730 p. Djouder, H., Pagel, M., Murat, B., Orsingher, M., 2012. Le Silurien du Bassin de Berkine. Projet « Shale Gas » Profond. 10éme Colloque du Groupe Français des Argiles, Présentation Orale, Limoge, France 14-18 Mai 2012. http://hdl.handle.net/2268/171556 Djouder, H., Boulvain, F., Da Silva, A-C., Cornet, P., Lüning, S., 2014. Tassili n’Ajjer (Sahara Oriental Algérien) – Résultats préliminaires sur le Silurien – Dévonien : Journée Thématique de l’Association des Sédimentologistes Français (ASF) – Diagenèse : avancées récentes et perspectives, Présentation Poster, Orsay-Paris, France 04 Juillet 2014. http://hdl.handle.net/2268/171557 [less ▲]

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See detailSILURIAN – DEVONIAN OF THE ORIENTAL ALGERIAN SAHARA: implication of new field data from Tassili n'Ajjer outcrops and Berkine Basin (SE, Algeria) for shale gas exploration.
Djouder, Hocine ULg; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in EPC'2015 THE THIRTEENTH TUNISIAN PETROLEUM EXPLORATION & PRODUCTION CONFERENCE (2015, October)

The Silurian – Devonian succession have been deposited in wide sags and sub-basins in a cratonic setting, along the northwestern passive margin of the Gondwana during the opening of the proto-Tethyan ... [more ▼]

The Silurian – Devonian succession have been deposited in wide sags and sub-basins in a cratonic setting, along the northwestern passive margin of the Gondwana during the opening of the proto-Tethyan ocean. During this Siluro-Devonian Period, a high subsidence occurs stacked sediment bodies and organic-rich shales were deposited in many places that respectively form important hydrocarbon reservoirs and source rocks throughout North Africa basins and Arabia (Boot et al., 1998 ; Lüning et al., 2000), which lead Algeria to hold the fourth position in terms of the estimates of technically recoverable shale oil and shale gas resources, based on major basin assessment in the world (EIA, 2013). In the prolific Illizi and Berkine basins (western Ghadames, Algeria) a basin-wide approach is needed, especially with the new “shale gas and shale oil” frontier in the upcoming years, in order to capture regional trends and re-assessment on organic-rich (‘hot’) shale unites which in smaller-scale industrial studies are overlooked. Berkine Basin covers nearly 102.000 km2. This basin has been a thick sedimentary series of 7000 m corresponding to complex reservoirs but also black shales of the basal Silurian and Frasnian respectively major and secondary source rock systems. Wireline-logs from more than 146 (Berkine – Illizi Basins) Algerian petroleum exploration wells have been studies (Djouder et al., 2012; Djouder et al., 2014), and recently 03 months extensive field study of outcrops of the Siluro-Devonian sediments was carried out at the south margin (SE, Tassili n’Ajjer) of the basin. The following analysis incorporates biostratigraphic, ichnological, sedimentological and high resolution stratigraphic data, which provides a framework evolution from offshore to deltaic deposition for the Silurian then fluvial to normal-marine depositional conditions for the Devonian. A total of 06 short-term, third-order sequences can be identified for the Silurian deposits: (i) 'Hot Shale' Oued Imihrou Formation, organic-rich shales with carbonates nodules (Si-1); (ii) above is the Atafaïtafa Formation 500 to 650 m thick with HCS, gutter casts and Cruziana Ichnofacies (Si-2, Si-3); (iii) then overlaid by coarsening-shallowing-upward units. These sequences (Si-4, Si-5 & Si-6) with Storm-wave dominated and Skolithos Ichnofacies are interpreted to reflect deltaic origin. This delta is the result of a significant sea-level drop during the Upper Silurian (Beuf et al, 1971) but also from the high sedimentation rates prograding northwards (Eschard et al., 2005). Devonian deposit also can be divided into fourth third-order sequences (Dev-1 to 4), by the same previous analysis. The base of the cycle is the Caledonian unconformity linked to a tectonic event which affected most of the Gondwanan margin at the Silurian – Devonian boundary and a major relative sea-level fall (Eschard et al., 2005). Previous sequences defined from Tassili n’Ajjer outcrops are well recognized at the basin-scale (Berkine Basin) and can be correlated in the subsurface of the Illizi – Berkine basins (Djouder et al., 2012). Finally, the full depositional cycle for the Silurian – Devonian is reached and capped by the Frasnian maximum flooding surface, with black shales across North Africa (Algeria, western Libya and southern Tunisia) and which are also developed in many parts of the world (Lüning et al., 2003). [less ▲]

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See detailTHE SILURO – DEVONIAN SUCCESSIONS IN THE TASSILI N'AJJER OUTCROPS (SE, ALGERIA): SEDIMENTOLOGY AND STRATIGRAPHY
Djouder, Hocine ULg; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in IGCP 596 - SDS SYMPOSIUM : Climate change and Biodiversity patterns in the Mid-Palaeozoic (2015, September)

The sedimentary basins of North Africa have been accumulated a thick sedimentary succession of Palaeozoic, especially Siluro – Devonian sediments. These successions have been deposited in wide sags and ... [more ▼]

The sedimentary basins of North Africa have been accumulated a thick sedimentary succession of Palaeozoic, especially Siluro – Devonian sediments. These successions have been deposited in wide sags and sub-basins in a cratonic setting, along the northwestern passive margin of the Gondwana. This sedimentation is mainly controlled by rapid eustatic sea-level variations and by the opening of the proto-Tethyan Ocean during the Early Palaeozoic (Beuf et al., 1971; Boot et al., 1998). During this Siluro-Devonian Period, a high subsidence occurred, allowing a high pile of sediments and organic-rich shales were deposited in many places that form important hydrocarbon reservoirs and source rocks throughout North Africa basins and Middle East (Lüning et al., 2000). In the prolific Illizi and Berkine basins (Western Ghadames, Algeria) a basin-wide approach is needed, especially with the new “shale gas and shale oil” frontier in the upcoming years, in order to capture regional trends and re-assessment the Siluro-Devonian successions. Our project focuses on the Berkine Basin and its margin, which covers nearly 102.000 km2. This basin includes a thick sedimentary series of 7000 m corresponding to complex reservoirs but also black shales of the basal Silurian and Frasnian, which are respectively major and secondary source rock systems. Complete logging of spectacular large-scale and well exposed outcrops of the Siluro-Devonian sediments was carried out at the south margin (SE, Tassili n’Ajjer) of the Illizi-Berkine basins (Djouder et al., 2012; Djouder et al., 2014). The following analysis incorporates biostratigraphic, ichnological, sedimentological, Magnetic susceptibility (MS) and high resolution stratigraphic data. It would allow providing a framework of deposits, ranging from offshore to deltaic deposits for the Silurian and from fluvial to normal-marine depositional conditions for the Devonian. References Cited: Beuf, S., Biju-Duval, B., De Charpal, O., Rognon, P., Gariel, O., Bennacef, A., 1971. Les Grès du Paléozoïque inférieur au Sahara : Sédimentation et Discontinuité, Évolution Structurale d’un Craton. Publication de l‘Institut Français du Pétrole. N° 18, Edition Technip, Paris. p. 464. Boote, D.R.D., Clark-Lowes, D.D., Traut, M.W., 1998. Palaeozoic petroleum systems of North Africa. In: Macgregor, D.S., Moo- dy, R.T.J., Clark-Lowes, D.D. (Eds.), Petroleum Geology of North Africa. Geol. Soc. London Sp. Publ., vol. 132, pp. 7–68. Lüning, S., Craig, J., Loydell, D.K., Štorch, P., Fitches, B., 2000. Lower Silurian ‘hot shales’ in North Africa and Arabia: regional distribution and depositional model. Earth-Science Reviews, vol. 49, pp. 121-200. Djouder, H., Pagel, M., Murat, B., Orsingher, M., 2012. Le Silurien du Bassin de Berkine. Projet « Shale Gas » Profond. 10éme Colloque du Groupe Français des Argiles, Présentation Orale, Limoge, France 14-18 Mai 2012. http://hdl.handle.net/2268/171556 Djouder, H., Boulvain, F., Da Silva, A-C., Cornet, P., Lüning, S., 2014. Tassili n’Ajjer (Sahara Oriental Algérien) – Résultats préliminaires sur le Silurien – Dévonien : Journée Thématique de l’Association des Sédimentologistes Français (ASF) – Diagenèse : avancées récentes et perspectives, Présentation Poster, Orsay-Paris, France 04 Juillet 2014. http://hdl.handle.net/2268/171557 [less ▲]

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See detailEarly Carboniferous events along the north-eastern Gondwanan margin: an example from the Mobarak Formation of the Central Alborz Mountains, Northern Iran.
Sardar Abadi, Mehrdad ULg; Da Silva, Anne-Christine ULg; Poty, Edouard ULg et al

Poster (2015, July 14)

The transition from the Late Devonian to the Early Carboniferous was marked by tectonic events, environmental change and global oceanic biological turnover that influenced sedimentary regimes. The end ... [more ▼]

The transition from the Late Devonian to the Early Carboniferous was marked by tectonic events, environmental change and global oceanic biological turnover that influenced sedimentary regimes. The end-Devonian faunal extinction event, for example, eliminated most of the reef building taxa, which, coupled with an increasing rate of subsidence in response to the opening of the Paleo–Tethys and a sea-ward shift of carbonate factories during the Lower Carboniferous, led to the formation of extensive carbonate ramp platforms along the Laurasian and Gondwanan margins. This development has already been reported from the western Gondwanan and southern Laurasian margins but not from northern to north-eastern Gondwanan margin yet. We aim to improve the knowledge on the main factors controlling the development and growth of carbonate ramps during the Lower Carboniferous by examining the Alborz basin along the northern margin of Gondwana. The Lower Carboniferous Mobarak Formation records the development of a storm-sensitive pervasive carbonate factory on the southern Paleo-Tethys passive margin following the opening of the Paleo-Tethys Ocean into the Alborz basin along the northern margin of Gondwana. Four outcrops in the central Alborz Mountains were studied: the Jaban, Aroo, Shahmirzad and Labnesar sections. Four events have been described as the principal factors controlling carbonate platform evolution in the Lower Carboniferous: (1) A transgression linked to global temperature rise in the Early Tournaisian (Middle Hastarain) resulted in the formation of thick-bedded argillaceous limestones. This interval is represented by massive beds of dark mudstones–wackestones to packstones that laterally interfinger with finely laminated limestones, and with bed thickness ranging on the centimeter to meter scale. This interval correlates with Lower Tournaisian nodular to argillaceous limestones of the Moravia Basin (Czech Republic), the Rhenish Slate Mountains (Poland) and the Dinant Basin (Belgium). (2) Late Hastarian–Early Ivorian glaciations were identified in Southern Gondwana but had not been evidenced in Northern Gondwana yet. This glaciation regime is recorded through the appearance of inner-ramp channel-form facies in mid– and outer-ramp settings. (3) During Late Ivorian–Early Visean?, a differentiation block faulting regime along the basin’s margin caused uplift of the westernmost parts of the Alborz basin and resulted in a sub-marine collapse in the eastern part of the central basin. This caused vast sub-aerial exposure and brecciation the top of the Mobarak Formation at the Jaban and Aroo sections. The sub-marine collapse was recorded through the occurrence of Zoophycos bearing fine-grained limestones in the top of the Labnesar and Shahmirzad sections. (4) Tectonic activity that coincided with considerable and abrupt sea level falls as an indirect consequence of the Viséan and Serpukhovian glaciations phases. This progressive sea level drop led to the stagnation of the carbonate factory, which is expressed as an erosional surface at the top of the Mobarak Formation. [less ▲]

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See detailMechanical approach for the characterization of loess deposits from the CBR’s Romont quarry (Eben-Emael, Belgium) and correlations with loess stratigraphy
Delvoie, Simon ULg; Boulvain, Frédéric ULg; Cerfontaine, Benjamin ULg et al

Conference (2015, June 01)

Aeolian silts (loess) are near surface deposits covering about 10% of the continent surfaces . Therefore a good knowledge of their mechanical behavior is an issue for designing subsurface engineering ... [more ▼]

Aeolian silts (loess) are near surface deposits covering about 10% of the continent surfaces . Therefore a good knowledge of their mechanical behavior is an issue for designing subsurface engineering structures. Usually this material is considered as homogeneous for an engineering point of view. Aeolian silt deposits are continuously well developed in Hesbaye Region (Belgium) reaching locally 20m thick (see document in attachment). They are mainly related to the last interglacial (Eemian) and glacial (Weichselian) periods . Nevertheless the pedostratigraphical, chronostratigraphical and paleoclimatic approaches have shown these silt deposits are usually composed of a series of paleosoils (i.e. Rocourt soil, Humiferous Complex of Remicourt, Harmignies Soil, Nagelbeek Tongued Horizon) interbedded with stratified or homogeneous aeolian silt layers. This study aims to characterize the variability of the in situ mechanical characteristics of the loess deposits from Hesbaye Region at the site scale and at the laboratory scale. Cone penetration tests (CPT), electrical resistivity tomographies (ERT) and drillings have been performed through a 10m thick loess layer in an investigation site located close to the CBR’s Romont quarry (Eben-Emael, Belgium) . Continuous undisturbed silt samples from drillings have been physically (granulometry, Atterberg limits, water content, organic matter content, carbonate content) and mechanically (oedometer test, triaxial test) characterized at the laboratory. Mechanical behavior and physical characteristics have underlined a series of layers with variable mechanical properties through depth. Some of these layers correlated with a detailed stratigraphy cross-section close to the investigation site could correspond to well-known paleosoils. [less ▲]

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See detailGenèse du sous-sol de la Wallonie
Boulvain, Frédéric ULg; Pingot, Jean-Louis

Book published by Académie royale de Belgique - 2e édition revue et augmentée (2015)

Cet ouvrage passe en revue les différentes formations géologiques de la Wallonie depuis un demi-milliard d’années. Elles sont décrites et interprétées en termes de paléoenvironnements et leur utilisation ... [more ▼]

Cet ouvrage passe en revue les différentes formations géologiques de la Wallonie depuis un demi-milliard d’années. Elles sont décrites et interprétées en termes de paléoenvironnements et leur utilisation ancienne et actuelle est précisée. Les deux orogenèses qui ont façonné nos paysages sont également abordées. La Wallonie est en effet un pays de pierres. Son histoire est tissée des nombreuses relations entre son sous-sol et ses habitants. L’exploitation immémoriale de ses ressources souterraines, depuis le silex jusqu’au calcaire, en passant évidemment par le charbon et le minerai de fer a façonné ses gens, ses paysages, ses monuments et son économie. Chaque terroir a ses racines plongées dans son sous-sol. Cette étonnante richesse géologique est aussi un atout qui doit continuer à être valorisé et protégé. Notre sous-sol est notre mémoire et ses roches doivent encore et toujours servir à embellir notre environnement. Un marbre rouge ou un grès du Condroz sont la signature d’une région, d’un village, d’une histoire. C’est une des raisons de ce livre : permettre à chacun de prendre conscience de cette richesse. [less ▲]

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See detailBelgium (Ardennes)
Da Silva, Anne-Christine ULg; Boulvain, Frédéric ULg

in Suttner, T.J.; Kido, E.; Königshof, P. (Eds.) et al Planet Earth in Deep Time. Palaeozoic Series. Devonian & Carboniferous (2015)

Devonian and Carboniferous deposits are found in many places around the world. The record of climate change preserved in them is the best (and only) resource of information on the Earth`s climate system ... [more ▼]

Devonian and Carboniferous deposits are found in many places around the world. The record of climate change preserved in them is the best (and only) resource of information on the Earth`s climate system then, at a time, when current and future climatic change is one of society`s greatest challenges. This book introduces some of the key areas of Mid-Palaeozoic sediment occurrence worldwide, authored by 114 specialists from more than 30 countries. The areas were studied as part of the UNESCO/IUGS project on climate change and biodiversity patterns in the mid-Palaeozoic (Devonian and Carboniferous). This large-scale taxonomic, stratigraphic and palaeoecological study of mid-Paleozoic floras and faunas has resulted in 86 contributions and more than 25 artistic reconstructions characterizing the biosphere of the Devonian and Carboniferous. Each contribution describes (in English and the respective national language) the scope of the IGCP project in the respective country, exemplified by representative Devonian/Carboniferous age geological sections and/or regions there. The authors intend to enhance the visibility and the perception of relevance of research on mid-Palaeozoic deposits beyond the Earth Science community. [less ▲]

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See detailSedimentary development and magnetic susceptibility evolution of the Frasnian in Western Belgium (Dinant Synclinorium, La Thure section)
Pas, Damien ULg; Da Silva, Anne-Christine ULg; Develeeschouwer, Xavier et al

in Geological Society Special Publication (2015), 414

Recent opening of the La Thure quarry in Western Belgium allowed the collection of new data from a poorly outcropping area of the Belgian Frasnian platform. The studied section covers an interval ... [more ▼]

Recent opening of the La Thure quarry in Western Belgium allowed the collection of new data from a poorly outcropping area of the Belgian Frasnian platform. The studied section covers an interval extending from thefalsiovalis to hassi s.l. Zones. Sedimentological analyses allowed the reconstruction of depositional settings in the northwestern part of the Dinant Synclinorium after the demise of the extended Givetian carbonate platform. Two depositional models are distinguished: (a) siliciclastic drowned platform during the Early Frasnian; and (b) a forereef depositional setting belonging to a rimmed shelf during the Middle Frasnian. Moreover, interpreted depositional settings in the northwestern part of the Dinant Synclinorium allowed to constraint the direction of the main facies belts for the Belgian Frasnian platform. Combination of MS and geochemistry demonstrates the inherent-parallel link existing between variation in MS values and proxy for terrestrial input (such as Si and Al). This observation means that, despite the remagnetization occurring within the Belgian Frasnian lithologies, the main trends in the MS signal from the La Thure section still reflect some syn-sedimentary conditions. The increase in MS and clastic input proxies recorded in distal fore-reef deposit within the punctata Zone are likely to be considered as enhanced by rapid and strong shallowing events recognized in the ‘puncataEvent’ interval. [less ▲]

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See detailMagnetic susceptibility application: A window onto ancient environments and climatic variations: Foreword
Da Silva, Anne-Christine ULg; Whalen; Hladil et al

in Geological Society Special Publication (2015), 414

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See detailThe astronomical calibration of the Givetian (Middle Devonian) timescale (Dinant Synclinorium, Belgium)
De Vleeschouwer, David; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in Geological Society Special Publication (2015), 414

Recent advances in radiometric dating result in significant improvements in the geological timescale and provide better insight into the timing of various processes and evolutions within the Earth’s ... [more ▼]

Recent advances in radiometric dating result in significant improvements in the geological timescale and provide better insight into the timing of various processes and evolutions within the Earth’s system. However, no radiometric ages are contained within the Givetian. Consequently, the absolute ages of the Givetian Stage boundaries, as well as the stage’s duration, remain poorly constrained. As an alternative, the analysis of sedimentary cycles allows for the estimation of the duration of this stage. We examined the high-resolution magnetic susceptibility signals of four Givetian outcrops in the Givet area for a possible astronomical imprint, to fully understand the rates of evolutionary and environmental change. All four sections are firmly correlated and wavelet analyses of the magnetic susceptibility signals reveal the imprint of astronomical eccentricity forcing. The highly stable 405 kyr cycles constrain the duration of the Givetian Stage at 4.35+0.45 Myr, which is in good agreement with the International Chronostratigraphic Chart (5.0 Myr). The studied sections also exhibit an imprint of obliquity, suggesting a climatic teleconnection between low and high latitudes. The corresponding microfacies curves demonstrate similar astronomical imprint, and thereby indicate that the observed 10 5year-scale cyclicity is the result of climatic and environmental change [less ▲]

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See detailMagnetic susceptibility application – a window onto ancient environments and climatic variations
Da Silva, Anne-Christine ULg; Whalen; Hladil et al

Book published by geological Society of London (2015)

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See detailLower Carboniferous ramp sedimentation of the Central Alborz Basin, northern Iran: Integrated sedimentological and rock-magnetic studies
Sardar Abadi, Mehrdad ULg; Da Silva, Anne-Christine ULg; Mosaddegh, hossein et al

in Geological Society Special Publication (2015), 414

The Lower Carboniferous Mobarak Formation in the Alborz Basin (northern Iran) was deposited along the northeastern margin of Gondwana in a carbonate ramp setting. This paper focuses on the Tournaisian ... [more ▼]

The Lower Carboniferous Mobarak Formation in the Alborz Basin (northern Iran) was deposited along the northeastern margin of Gondwana in a carbonate ramp setting. This paper focuses on the Tournaisian stratigraphic interval of this formation that crops out at the Jaban section in the southwestern Central Alborz Basin. The following facies associations, representing different ramp palaeoenvironments, have been identified: (1) mudstone–wackestone outer-ramp facies; (2) crinoidal to skeletal grainstone–packstone mid-ramp facies; (3) peloidal to crinoidal grainstone–packstone inner-ramp facies; and (4) coastal facies, which include a variety of microbial laminated to oncoidal grainstones and mudstones with evaporitic pseudomorphs. This ramp profile was affected by frequent storms that were responsible for the formation of several skeletal to non-skeletal shoals in the distal mid-ramp to the most proximal inner-ramp areas. The development of the skeletal to non-skeletal shoals along the sea side of the ramp formed a semi-enclosed lagoon sensitive to the influence of both high tides and storm surges.The magnetic susceptibility (xin) of all the samples was measured and compared with that of the facies from which the sample was taken. There is a clear link between xin and the facies; the average xin values were higher for the distal facies than for the proximal facies. The xin profile of this Lower Carboniferous carbonate sequence reflects stratigraphic variations in response to relative changes in sea level and the input of detrital materials. In the context of the sequence stratigraphic framework, the average xin values for lowstand and transgressive systems tract deposits are higher than for the highstand systems tract deposits. The clear link between xin and facies indicates at least a partly preserved primary xin signal related to the detrital inputs. However, to obtain a better understanding of the nature and origin of the minerals carrying the xin, we performed hysteresis measurements on selected samples. It appears that the xin signal is mainly carried by lowcoercivity ferromagnetic minerals such as magnetite, with a mixture of relatively coarse grains (detrital fraction) and ultra-fine grains (probably formed during diagenesis). [less ▲]

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