2.2.7. Hanonet Formation - HNT

Authors: Tsien, 1976; Preat & Tourneur, 1991a.

 

Description: The lower, most typical part of the Hanonet Fm consists of blackish, argillaceous, pyritic nodulalar thin limestone beds alternating with thin calcareous shale beds; in the lowest part the limestones are slightly silty and micaceous; the megafauna contains chiefly brachiopods and rugose corals. The middle part is composed of dark thin bluish limestone beds with thin laminar anastomosed and globular tabulates. The upper part is made up of two biostromal units with stromatoporoids, rugose and tabultate corals and separated by an interval with argillaceous limestones and shales.

 

Stratotype; Couvin, La Couvinoise Quarry about 400m north-east of the railway-station.

 

Area: Southern and south-eastern flank of the Dinant Synclinorium up to the Xhoris Fault.

 

Thickness: 50 to 70m between Couvin and Givet; about 30m at Pondrôme, 70m at Resteigne and 30 to 70m in the Wellin area where the formation passes laterally into the Formation X.

 

Age: Latest Eifelian-Early Givetian; in the stratotype section the hemiansatus conodont Zone defining the base of the Givetian has been recognized near the top of the lower part of the Hanonet Fm.