Geologica Belgica

1374-8505

 

Impact factor: 1.041 (2012)

since 05 February 2011 :
View(s): 201 (5 ULg)
Download(s): 183 (12 ULg)
print
Cédric MABILLE & Frédéric BOULVAIN

SEDIMENTOLOGY AND MAGNETIC SUSCEPTIBILITY OF THE COUVIN FORMATION (EIFELIAN, SOUTH WESTERN BELGIUM): CARBONATE PLATFORM INITIATION IN A HOSTILE WORLD

Article Open Access

Attached document(s)

Abstract

ABSTRACT. The Eifelian of Belgium is mainly characterised by a mixed siliciclastic-carbonate sedimentation on a ramp profile. In this context, the Couvin Formation is the more important and remarkable exception. It represents a carbonate platform initiation in a hostile environment. This work is mainly based on the stratotype, corresponding to two stratigraphic sections located in Couvin, along the southern border of the Dinant Synclinorium. These sections are the Eau Noire and Falaise de l'Abîme sections. Unfortunately, they are discontinuous. To allow a better understanding of the sedimentary dynamics, the data are complemented by a shorter but continuous section located in Villers-la-Tour (3.5 km West of Chimay).

Petrographic study leads to the definition of 14 microfacies which are integrated in a palaeogeographical model. It corresponds to a platform setting where the reef complex is mainly constituted by an accumulation of crinoids, stromatoporoids and tabulate corals. The microfacies evolution is interpreted in terms of bathymetrical variations. It shows a general shallowing-upward trend encompassing the vertical succession of fore-reef settings, reef development, back-reef and then lagoon environment. This interpretation is supported by trends in mean magnetic susceptibility data, providing a better understanding of the sedimentary dynamics. Moreover, these data show positive correlation with concentrations of detritic minerals, but an inverse relationship with well washed skeletal limestones.

The comparison of the three studied sections leads to considerations concerning the lateral variability in the Couvin Formation indicating more agitated conditions in the Abîme Member in Villers-le-Tour section.

KEYWORDS: Eifelian, Couvin Formation, type area, carbonate platform initiation.

To cite this article

Cédric MABILLE & Frédéric BOULVAIN, «SEDIMENTOLOGY AND MAGNETIC SUSCEPTIBILITY OF THE COUVIN FORMATION (EIFELIAN, SOUTH WESTERN BELGIUM): CARBONATE PLATFORM INITIATION IN A HOSTILE WORLD», Geologica Belgica [En ligne], number 1-2, volume 10 (2007), 47-69 URL : http://popups.ulg.ac.be/1374-8505/index.php?id=1377.

About: Cédric MABILLE

Pétrologie sédimentaire, Département de Géologie, Bat. B20, Université de Liège, Sart-Tilman, B-4000 Liège, E-mail : cmabille@ulg.ac.be

About: Frédéric BOULVAIN

Pétrologie sédimentaire, Département de Géologie, Bat. B20, Université de Liège, Sart-Tilman, B-4000 Liège, E-mail : fboulvain@ulg.ac.be