1.2.14. Marteau Formation - MAR

Author: Gosselet, 1888; Dejonghe, Hance & Steemans, 1994a.

 

Description: In the Marteau stratotype, the formation unconformably rests on the Caledonian (Salmian) basement and is overlaid by the sandstones and quartzites of the Bois d'Ausse Fm.  At the bottom, occur a conglomerate of 1.5 m thick at Eupen, increasing S of Eupen and in the Amblève valley (Quarreux Member, locally > 10 m thick).  These rocks are overlaid by maroon (red) and mottled siltstones and argillaceous fine-grained sandstones, alternating with green, olive or mottled argillaceous sandstones.  The maroon (red) colour is widely dominant.  Carbonate nodules are concentrated in some beds and responsible for a cellular structure if dissolved.  Light-coloured quartzite banks, sometimes gravely, occur in the lower part.  In the Gileppe valley, there are coarse-grained to conglomerate bearing kaolinitic sandstones.

 

Stratotype: Theux Window, Marteau locality, along the Spa-Pépinster railway.

 

Area: W and N flanks of the Stavelot Massif.

 

Thickness: 163 m at Eupen.

 

Age: Lochkovian (Ma-GSubzones of the MN Oppel Miospore Biozonation in the Vesdre Nappe; R subzone in the Theux Window pointing out to an older age to the S than to the N).