Article révisé par les pairs
Résumé : The Middle and Upper Devonian red 'griottes' limestones of the Montagne Noire (South of France) are deposited on a distal hemipelgic outer ramp, well below the storm wave base and the photic zone, by more than about a hundred meters of water, in poorly oxygenated environments. The red coloration of the micritic matrix is probably related to bacterial activity, and more specifically to iron-bacteria linked to the Siderocapsaceae. These bacterial communities formed benthic microtufts and mats which trapped the ferrous iron. The destruction of these mineralogical-microbial communities allowed dispersion of the submicronic hematite in the micritic matrices. In other European Paleozoic red carbonate matrices ('griottes'), the red pigmentation is also related to iron-bacteria similar to the Recent Beggiatoales and Siderocapsaceae