Iron bacteria in Devonian carbonates (Tafilalt, Anti-Atlas, Morocco)

A condensed Mid-Upper Devonian succession of the Tafilalt (Anti-Atlas) contains numerous red carbonate intervals. Bioclastic tempestites form a transition between an outer shelf and a hemipelagic setting. The red pigmentation is not related to the abundance of detrital iron oxides, but to the presence of iron bacteria and fungi. They form bioconstructions remarkably similar to those previously described in the Jurassic Ammonitico Rosso from Italy and Spain. Thus, dysaerobic microenvironments are proposed and not oxic conditions for these Fe-poor sediments.