Géologie générale. Du minéral aux géosphères

Book published by Ellipses Edition Marketing SA (2013)

Ce livre introductif de géologie a pour but de mettre à la disposition du lecteur les bases essentielles à l’étude des Sciences de la Terre. Il part des minéraux pour aboutir à la Terre, en faisant ... [more ▼]

Ce livre introductif de géologie a pour but de mettre à la disposition du lecteur les bases essentielles à l’étude des Sciences de la Terre. Il part des minéraux pour aboutir à la Terre, en faisant intervenir une notion d’échelle et de complexité croissantes. Après une introduction et un bref historique, il explicite les propriétés des cristaux et des minéraux ainsi que leur répartition en familles. Les mécanismes aboutissant à la genèse des grands types de roches sont discutés, ce qui permet d’amorcer une réflexion sur les classifications et le cycle géologique. Les chapitres suivants sont consacrés successivement aux processus et aux roches magmatiques, à leur classification, occurrence et genèse en relation avec la tectonique des plaques ; aux principaux processus sédimentaires et aux familles de roches qui leur sont associées et enfin, aux roches et aux différents facteurs du métamorphisme. L’ouvrage se poursuit par un chapitre de synthèse mettant en perspective la formation des bassins sédimentaires et leur évolution au cours du temps, pour aboutir au développement des chaînes de montagnes. La Terre dans son ensemble fait l’objet du chapitre suivant: son anatomie est déduite des mesures géophysiques et des analogies avec les météorites. Cette approche globale se termine par une introduction aux cycles géochimiques. Après avoir évoqué le problème de la mesure du temps en géologie, un bref tableau de l’histoire de notre planète et de la vie qu’elle abrite est esquissé. Enfin, le dernier chapitre est consacré aux relations entre la Terre et l’humanité, dans l’optique des géoressources mais aussi des géorisques. Ce livre s’adresse aux étudiants en Sciences de la Terre ainsi qu’aux étudiants d’autres disciplines abordant ce type de matière dans leur cursus. Il intéressera également le curieux disposant d’un bagage scientifique général, désirant comprendre ce que nous enseignent les roches sur le passé et le présent de notre planète. [less ▲]

Sedimentary development and correlation of Mid-Late Devonian fore-reef deposits from Central Europe

Conference (2012, September 12)

INTRODUCTION: Despite the interest for the reconstruction of environmental changes over a long period of time, long-term successions have been relatively poorly investigated using a mutli-disciplinary ... [more ▼]

INTRODUCTION: Despite the interest for the reconstruction of environmental changes over a long period of time, long-term successions have been relatively poorly investigated using a mutli-disciplinary approach compared to short-term intervals such as Kačák, Taghanic, punctata, Kellwasser and Hangenberg events. Recently, BOULVAIN et al. (2010) compared two km-thick Eifelian-Frasnian sections from Belgium and Czeck Republic using magnetic susceptibility (SM) technique. Regardless the very different background of palaeogeography, sedimentary rate, facies and local sea-level changes history, a remarkable similarity in the MS trends can be observed between these two sections. These similarities brought questions on the nature of the long-term forcing parameters that were active at the inter-regional scale. In order to get a better understanding of the factors responsible of the inter-regional forcing, a detailed records of microfacies observations, MS measurements, selected trace and major elemental concentrations and conodonts biostratigraphy have been performed on two Middle to Upper Devonian successions from Germany (Sauerland, Burgberg) and Austria (Carnics Alps, Freikofel). CONODONT BIOSTRATIGRAPHY: In the Burgberg section, conodont biostratigraphy allowed us to confirm that the studied section extend from the Middle Givetian to the Lower Carboniferous. In the Freikofel section, it allowed to precisely identify the Eifelian-Givetian and the Frasnian-Famennian boundaries. SEDIMENTOLOGY: The field and microfacies observations allowed us to reconstruct the sedimentary environment and to highlight several major variations of this environment. In the Middle Devonian, both sections are mainly characterized by fore-reef sediments. In the Burgberg section, those fore-reef sediments, mainly correspond to bioclastic grainstone and rudstone related to gravity flow deposits derived from the shallow-water area. In the Freikofel section, the fore-reef area is dominated by breccia sediments suggesting a strong debris flow influence. Through the Upper Devonian the sedimentary setting evolves to an off-reef pelagic environment in both sections and even a basinal setting in the Burgberg section. Sediments are then dominated by thin-bedded and nodular limestone. In this Upper Devonian part, locally both sections, debris coming from the shallow-water area are still observed (suggestion: Even in the Upper Devonian, occasionally debris deriving from shallow water areas has been observed in both sections. MAGNETIC SUSCEPTIBILITY AND GEOCHEMISTRY: The mean MS values for the Burgberg and Freikofel sections are respectively 1,88x10-8m³/kg and 7,72x10-9m³/kg. Compared to the MSmarine standard of 5.5x10-8m³/kg defined by ELLWOOD et al. (2011) on the basis of ~11,000 marine rocks samples, our values are low, mostly in the Freikofel section, which could indicate a low terrestrial influx seaward during the Middle and Upper Devonian. Regarding the magnetic susceptibility curves from these two sections, several large-scaled trends can be highlighted. The evolution curves of some selected clastic input proxies such as Zr, Si, Al, Ti, Sr display similar large-scaled trends. This indicates that clastic input proxies and MS are inherently linked and MS techniques can thus be used here as a proxi for changes in source or amount or type of weathering (RIQUIER et al. 2010). Most of the long-term MS variations occurring in both sections are interpreted as being related to second order eustatic variations (T-R Cycles). Through this multi-disciplinary investigation, we would like to get a better idea on the causes of long-term trends in MS variations and to document the sedimentary changes in response to these long-term variations. Further aim is to develop the application of MS techniques as a correlation tools. BOULVAIN, F., DA SILVA, A-C., MABILLE, C., HLADIL, J., GERSL, M., KOPTIKOVA, L., SCHONABL P., 2010. Magnetic susceptibility correlation of km-thick Eifelian-Frasnian sections (Ardennes and Moravia). Geologica Belgica, 13/4, 309-318. ELLWOOD, B.B., ALGEO, T.J., EL HASSANI, A., TOMKIN, J.H., ROWE, H.D., 2011. Defining the timing and duration of Kačák Interval within the Eifelian/Givetian boundary GSSP, Mech Irdane, Morocco, using geochemical and magnetic susceptibility patterns. Palaeogeography, Palaeoclimatology, Palaeoecology, 304, 74-84. RIQUIER, L., AVERBUCH, O., DEVLEESCHOUWER, X., TRIBOVILLARD, N., 2010. Diagenetic versus detrital origin of the magnetic susceptibility variations in some carbonate Frasnian-Famennian boundary sections from Northern Africa and Western Europe: implications for palaeoenvironmental reconstructions. International Journal of Earth Sciences, 99, 57-73. [less ▲]

Sedimentary development of a continuous Middle Givetian to Lower Carboniferous section from the fore-reef fringe of the Brilon reef-complex (Rheinisches Schiefergebirge, Germany)

Poster (2012, June 25)

Depositional facies and magnetic susceptibility of Mobarak formation (Lower Carboniferous in central and eastern Alborz Mountains, North of Iran).

in Geologica Belgica Meeting 2012; Moving plates and melting icecaps. Processes and forcing factors; Abstract book (2012)

Scaphandre La science rencontre l'art: L'alimentation

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre La science rencontre l'art (2012)

Stable isotopes (d13C, d18O, 87Sr/86Sr) versus magnetic susceptibility at the Mid-Devonian La Couvinoise section: Does the astronomical interpretation stand?

in Geologica Belgica Meeting 2012; Moving plates and melting icecaps. Processes and forcing factors; Abstract book (2012)

Geochemistry, Magnetic Susceptibility and Gamma Ray spectrometry records Across the Frasnian-Famennian boundary at Fuhe, China.

in Geologica Belgica Meeting 2012; Moving plates and melting icecaps. Processes and forcing factors; Abstract book (2012)

The Devonian carbonate platform from Belgium: a multi-faceted approach for basin evolution reconstruction.

in 34th International Geological Congress. Unearthing our Past and Future — Resourcing Tomorrow; Brisbane; Abstract (2012)

A multi-faceted approach for basin evolution reconstruction: analysis of the Frasnian (Upper Devonian) platform from Belgium

in Basin Research (2012), 24

Genèse du sous-sol de la Wallonie

Book published by Académie royale de Belgique (2012)