Devonian carbonate facies patterns in the Dinant synclinorium, Belgium

Abstract

The Middle-Upper Devonian carbonate facies of the Dinant Synclinorium, Belgium are discussed. During the Middle Devonian the influence of the Old Red Continent is still appreciable and coarse to fine siliciclastics fringe the continent and the positive elements on the shelf. From Couvinian times onwards the shelfs of the Cornwall-Rhenish basin are partially covered by carbonate masses. During the Givetian and the Frasnian the influence of siliciclastic sediments on. Carbonate production is only noticeable in the northern lagoonal settings. In the Frasnian a distinct separation into a northerly carbonate platform and a southerly basin is apparent. Carbonate bodies within the basin are 'stacked' in the south, whereas they 'float' in the north. The 'stacked' bioherms are perhaps related to rejuvenation of block faults, whereas the 'floating' mud mounds are characterised by their red colour, their age and the fact that they overstep the middle Frasnian carbonate platform from a southerly direction. Textural and structural differences are discussed, illustrated and interpreted. The carbonate platform is characterised by a porous dolomitised edge and a lagoonal interior with cyclic carbonate deposition.