Relationship between sedimentary features and permeability at different scales in the Brussels Sands

in Geologica Belgica (2012), 15(3), 156-164

The Brussels Sands display a complex three-dimensional subsurface architecture. This sedimentological heterogeneity induces a highly heterogeneous spatial distribution of hydrogeological parameters at ... [more ▼]

The Brussels Sands display a complex three-dimensional subsurface architecture. This sedimentological heterogeneity induces a highly heterogeneous spatial distribution of hydrogeological parameters at different scales and may consequently influence subsurface fluid flow and solute migration. This study aims at characterizing spatial variability of permeability at different scales in the Brussels Sands. Firstly, a literature review on the permeability distribution of the Brussels Sands was performed. Secondly, a field campaign was carried out consisting of field observations of the small-scale sedimentary structures and in situ measurements of air permeability. A total of 6550 cm-scale air permeability measurements were carried out in situ in three Brussels Sands quarries in the central part of Belgium: Bierbeek, Mont Saint Guibert and Chaumont Gistoux. On the large basin scale, substantial differences in permeability are observed. A literature data analysis shows that there is no clear correlation between hydraulic conductivity and sedimentary facies. At the small scale, results show that permeability heterogeneity and anisotropy are strongly influenced by sedimentary heterogeneity in all three quarries. Clay-rich sedimentary features such as bottomsets and distinct mud drapes exhibit a different statistical and geostatistical permeability distribution compared to the cross-bedded lithofacies, where the permeability anisotropy is dominated by the foreset lamination orientation. [less ▲]

Proceedings of the XIth International Symposium on Fossil Cnidaria and Porifera, Liège, Belgium, August 19-29, 2011: Preface

in Geologica Belgica (2012), 15(4), 200-203

A new representative of the lichid genus Ohleum (Trilobita) from the Eifelian (Middle Devonian) of southern Belgium

in Geologica Belgica (2012), 15(3), 120-125

Trilobites of the family Lichidae are relatively poorly diversified within the Eifelian mixed siliciclastic-carbonate succession of the southern margin of the Dinant Synclinorium (Belgium). Until now ... [more ▼]

Trilobites of the family Lichidae are relatively poorly diversified within the Eifelian mixed siliciclastic-carbonate succession of the southern margin of the Dinant Synclinorium (Belgium). Until now, they were only represented by species belonging to the genera Ceratarges and Eifliarges. The recent discovery of a well-preserved specimen within the Eifelian-aged Jemelle Formation in the Couvin area led us to propose the first detailed description of a representative of the genus Ohleum (Ohleum magreani sp. nov.) in the Ardennes. [less ▲]

Redéfinition des unités structurales du front varisque utilisées dans le cadre de la nouvelle Carte géologique de Wallonie (Belgique)

in Geologica Belgica (2012), 15(3), 169-175

The new geological map of Wallonia permits to obtain a more global view of the tectonic organization of the Palaeozoic terrains around the Variscan Front in southern Belgium. This zone oriented WSW-ENE ... [more ▼]

The new geological map of Wallonia permits to obtain a more global view of the tectonic organization of the Palaeozoic terrains around the Variscan Front in southern Belgium. This zone oriented WSW-ENE and passing south of an axis Charleroi-Namur, was firstly highlighted by the coal mining works, but has been significantly documented notably through deep boreholes and seismic profiles. A coherent structural sketch of the Variscan Front is proposed for its entire longitudinal course, where the following structural units are distinguished, from north to south: the Brabant Massif and the base of the cover unaffected by the Variscan orogeny, the Brabant Parautochthon, the Haine-Sambre-Meuse Overturned Thrust sheets (HSM-OTS) and the Ardenne Allochthon. Undeformed terrains during Variscan event constitute the northern border of the Variscan Front. The Brabant Parautochthon includes Devono-Carboniferous terrains, which are folded and faulted. The HSM-OTS are formed by the superposition of several sheets (e.g. La Tombe sheet), which are supported by various thrust faults (e.g. Masse fault). The Ardenne Allochthon, which has been displaced during the Variscan orogeny, rests on the Brabant Parautochthon and the HSM-OTS through a faulted zone, which is locally known as the Midi Fault. [less ▲]

Short note: Synthetic ilmenite as a blank to XRF trace element determination

in Geologica Belgica (2011), 14(1-2), 103-106

Early-Middle Frasnian (early Late Devonian) sedimentology and magnetic susceptibility of the Ardennes area (Belgium): identification of severe and rapid sea-level fluctuations

in Geologica Belgica (2010), 13(4), 319-332

Application of magnetic susceptibility to the Maastrichtian-Eocene phosphatic deposits of Séjla section in Gafsa-Métlaoui basin (Southern Tunisia)

in Geologica Belgica (2010, December), 13(4),

sequence-stratigraphic correlation and characterization of cyclic facies arrangements using magnetic susceptibility, Late Devonian (Frasnian) Hull platform, Canning Basin, Australia.

in Geologica Belgica (2010, December), 13(4),

Orbital forcing of the Devonian climate ? a search for Milankovich cycles in the magnetic susceptibility record of a km-thick Eifelian-Frasnian section (Belgium).

in Geologica Belgica (2010, December), 13(4),

Earthquake-induced hazards in mountain regions: a review of case histories from Central Asia – an inaugural lecture to the society.

in Geologica Belgica (2010), 13/3

This paper presents a summary of the main trigger factors of earthquake-induced landslides as well as a review of case histories of major landslide-triggering earthquake events in Central Asia. The goal ... [more ▼]

This paper presents a summary of the main trigger factors of earthquake-induced landslides as well as a review of case histories of major landslide-triggering earthquake events in Central Asia. The goal is to analyse the relationship between geological, tectonic and morphological conditions and the susceptibility to seismic slope failure and to show the potential long-term contribution of seismic ground motion dynamics, such as site effects and liquefaction, to slope failure. Case histories related to five M>7 earthquake events in the Tien Shan and Pamir Mountains are outlined: the earthquakes of Kemin in 1911, Sarez in 1911, Khait in 1949, Gissar in 1989 and Suusamyr in 1992. The Kainama earth-flow case history of 2005 is added to document possible mid-term effects of smaller earthquakes. These events show that in the Central Asian Mountains, two types of seismically triggered mass movements may have particularly disastrous effects: massive long rockslides and medium-sized earth flows made of loess – or a mixture of both. Actually, the most catastrophic mass movement of the last century in Central Asia triggered by the 1949 Khait earthquake was a massive long runout rock avalanche, which had gained a very high velocity due to the entrainment of loess sediments and related lubrification. [less ▲]