3.10 Aubange Formation - AUB

Authors: Dumont, 1842; Dewalque, 1854; Boulvain et al. (2001).

Description: Grey sandy marl with centimetric to pluri-decimetric lenses of limestone and argillaceous-sandy limestone. Locally, limonitic crusts or conglomerate. Fauna is relatively abundant and bioturbation generally high. A pluri-decimetric coquina bed is almost always present near the top of the formation, under the Ottemt Member. The extreme top of the formation is locally constituted by bluish marls with blue-grey limestone nodules (Ottemt Member, see Boulvain et al., 1995), or by blue-grey marly limestone beds (Saint-Mard), towards the west.

Stratotype: Latour borehole.

Area and thickness: In the western part of Belgian Lorraine, the thickness of Aubange and Messancy Formations varies between 35 and 40 m. It reaches approximately 45 m for Aubange Formation alone towards the east.

Age: Aubange Formation is dated from Upper Pliensbachian to Lower Toarcian Pleuroceras spinatum Zone to Dactylioceras tenuicostatum Zone (Maubeuge, 1954, 1971; Delsate, 1990).