6.4 Pouru-au-Bois Formation - PAB (old: Rv5)

Author: after Beugnies, 1960.

Description: Subdivided into three members: the unnamed lower member (old: Rv5a): black slate, easily affected by microfolds (Beugnies, 1960); the unnamed middle member (old: Rv5b): some lenticular grey quartzite beds of 0,50 to 1 m thick, alternating with slate layers of the same thickness; the unnamed upper member (old: Rv5c): black slate and silty slate (called “quartzophyllade” in the older literature), sometimes laminated and often intensely deformed by microfolds.

Stratotype: Not yet defined; type area in the valley of the Pouru, in and north of the village of Pouru-au-Bois.

Area: Givonne Massif.

Thickness: 410 - 415 m with 100 m for the upper member, 10 to 15 m for the middle member and 300 m for the lower member (Beugnies, 1960).

Age: No fossils discovered yet; correlated by Beugnies (1960) on lithological grounds with the upper part of the Revin Group and the lower part of the Salm Group.

Remarks: Synonyms: originally described as the "Assise de Muno" (Beugnies, 1960); however, the locality name Muno was already in use for a Lockhovian unit by Maillieux & Demanet (1929); hence the name is here replaced by Pouru-au-Bois, the locality of the parastratotype section of the unit as mentioned by Beugnies (1960).

(M. VANGUESTAINE)