LE SONDAGE DE FOCANT ...
LE SONDAGE DE FOCANT: LITHOSTRATIGRAPHIE ET IMPLICATIONS STRUCTURALES
F. Boulvain & M. Coen-AubertMemoirs of the GSB n°43 - 1997
ABSTRACT.
The Focant borehole (185W 407) is located in the Famenne depression, at the southern border of the Dinant Synclinorium. With a depth of 3208 m, this borehole intersects the Famenne Formation (Famennian), the Matagne, Neuville, Grands Breux, Moulin Lienaux and Nismes Formations (Frasnian) and terminates in the Fromelennes Formation (Givetian). The present paper deals with the lithostratigraphy of these formations, their lateral variations and the tectonic structure of the section traversed by the borehole. Four tectonic units can be distinguished: an upper unit consisting of the inverted limb of a complex overturned north facing syncline, cut by numerous reverse south dipping faults; a second unit showing the superposition of tight overturned folds cut by south dipping faults; a third unit consisting of a succession of more gentle north facing anticlines and synclines and a fourth unit made up of a normal succession gently dipping to the south. These observations lead to a new interpretation of the Focant seismic section.
