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Five types of reefs are described from the northern and southern parts of the Azrou-Khenifra Basin generated by the interactions of microbes and coral communities. The type 1 microbial reefs grew in both shallow- and deep-water settings, with a strong control by glacioeustasy. Type 2 microbial reefs developed in more tranquil periods, associated with common intermounds, and where only a single major regressive-transgressive sequence is recognised. Type 3 microbial reefs developed in constant deeper water conditions, generated by higher rates of subsidence in the basin, and creating an overall deepening-upward sequence. Type 4 microbial reefs recognised in the northern part of the basin have no clear counterparts in southern outcrops, but they are likely the capping strata observed in the latter area. Rugose corals allow to define a Type 5 reef, unrelated to microbial facies, and are recorded in oolitic-bioclastic backshoals or quiet inner platform settings. The presence of similar reefs in both the northern and southern parts of the basin demonstrates that conditions were not as different as previously proposed, and a lithostratigraphical, environmental uniformity occurs, which permits the analysis of different subsidence rates and glacioeustastic influence. In the Azrou-Khenifra Basin, the reefs, as well as other regional features, suggest that the basin, overall, evolved from an extensional tectonic regime during the early Brigantian into a complex extensional or compressional regime during the early Serpukhovian, passing into a predominantly compressional phase during the late Serpukhovian in a polyphase tectonic inversion during the onset of the Variscan Orogeny in the region.

Late Mississippian carbonates in southern Montagne Noire are dominantly domical to laterally-accreted microbial mounds in some formations, as well as stratiform microbial limestones occurring in hundreds of olistoliths within a flysch basin, constituting pieces of a giant puzzle that are used to help reconstruct a platform in a region that is no longer preserved. Petrographic data of limestone samples from 14 continuous long sections of olistoliths have been analyzed statistically, using multivariate clustering (Q-mode) of the components/matrix/cement and canonical correspondence analysis that allow the reconstruction of the environmental parameters of carbonate microbial communities in space and time. Clustering analysis separated microbial and non-microbial facies. The calculation of indices along the various axes from canonical correspondence analysis allows recognition of the controlling factors of the mounds and microbial growth as being turbidity, light penetration, bathymetry and storms. Turbidity and light penetration are the primary factors controlling the morphology of the microbial limestones. Representation of the light penetration and bathymetry indices on the stratigraphical sections defines two vertical environmental gradients. Light penetration can be subdivided into euphotic, euphotic–dysphotic and dysphotic-aphotic conditions. The representation of the bathymetry allows the subdivision of samples into a deeper outer ramp, external mid-ramp and internal mid-ramp. The curve distance from the section base = f (index) suggests a cyclicity for the platform that cannot be compared with the onlap curve defined from other cratonic areas (Moscow Basin), and thus the cyclic succession of the Montagne Noire is interpreted to have been mostly tectonically-controlled. Integration of the data allowed the reconstruction of the original Mississippian carbonate platform, where, up to the Mikhailovian, it appears to correspond to a platform morphology, with narrow s

In southern France, including the southern Montagne Noire and Mouthoumet Massif, foraminifers allow describing a biostratigraphical zonation for different formations included in those areas. Carbonate platforms are developed from the latest Tournaisian to the lower part of the late Viséan. In between, up to six additional zones have been recognized. The foraminiferal study also includes the first formal description of early Viséan foraminifers from the Vieussan area, a metamorphic area north of the main Mississippian stratigraphic sections of the Mont Peyroux nappe and écailles de Cabrières, as well as the dating of some preserved carbonates of the Mouthoumet Massif. Global foraminiferal guides are used for the definition of the zones, as well as other taxa considered as regional markers, but their detailed study might also be used for more continental to global level correlations. Lapparentidiscus irregularis nov. sp. and Ugurus intermedius nov. sp. are described.

The mainly calcareous succession from the mid Tournaisian to the lower part of the upper Viséan in the Southern Montagne Noire Mont Peyroux nappes and Cabrières slices is sedimentologically revised. From the late Viséan, the Variscan orogeny affected the area, and the studied Mississippian part of the succession was considered as part (together with the Devonian) of a period of tectonic quiescence, later included as nappes and olistolites in a wildflysch. This study presents the facies from pelagic limestones, calciturbidites, bioclastic limestones and microbial limestones, and the relationship between platform and calciturbidites in the pre-orogenic context of the Montagne Noire basin during the Mississippian. The differences in the lithostratigraphy is analyzed by means of four tectonostratigraphical units (Mont Peyroux nappe, Roquessels band, Cabrières area and La Serre band) previously defined by other authors, that together with the deep-water Vieussan-Caragnas unit (not studied here due to the poverty in chronostratigraphical data) allow reconstructing the original carbonate platform. The latter seems to correspond to a ramp for the latest Tournaisian to early Viséan, and a distally-steppened ramp from the middle Viséan to the early late Viséan, including basin plain to slope as the deepest water environments, and middle ramp as the shallowest, except for the uppermost part of the succession, where the inner ramp is recognized. During this period, the shallowing tendency in the tectonostratigraphic units is well marked: Mont Peyroux nappe – Roquessels band – Cabrières area – La Serre band (from deeper to shallower), which differs from the shallowing trend defined by previous authors during the Devonian. Strong similarities are observed with the preserved Mississippian carbonates in the Mouthoumet Massif to the south, which might represent the shallowest water deposits of the ramp, not preversed in the Cabrières-La Serre areas.

The tectonosedimentary and lithostratigraphic units of the Mont Peyroux nappe and Cabrières klippes, in the southeastern Montagne Noire, are revised. The Mont Peyroux nappe displays two Mississippian groups: SaintNazaire-de-Ladarez and Barrac. The Saint-Nazaire-deLadarez Group includes the traditional formations of Lydiennes, Faugères and Colonnes. The Barrac Group (new group) encompasses the Puech Capel Fm (with two new members: Puech Capel Mb and Landeyran Barn Mb), and the new Barrac and Fabrègues formations. The Puech Capel Mb corresponds to a period of erosion, reworking, and debris flow deposition in the basin, linked to a major tectonic event; hence, the distinction between two groups is made here. The Barrac Fm, overturned and normal, with classical Bouma turbidites, and without carbonate olistoliths, ends west of the Fabrègues Formation, bearing a few latest Viséan to Serpukhovian olistoliths. The Cabrières klippes contain numerous Ordovician, Silurian, Devonian and Mississippian klippes and olistoliths included in a detrital unit (formerly Flysch-units III-IV or Laurens Flysch Group); they are re-named here as the Laurens-Cabrières Group, and subdivided into three new complexes: the Laurens Complex, Roquessels Complex and Vailhan-Cabrières Complex. The Laurens Complex is not yet subdivided into formations. The Roquessels Complex shows characteristically the new Coteau de Bergue Fm and the Lentilles de la route D13 informal unit (including the former grauwacke de Roquessels). The Vailhan-Cabrières Complex is composed of three klippes: Vissou, La Serre and Tourière-Escandolgue -Mougno (TEM), and various disseminated smaller olistoliths, which are Early Ordovician to late Serpukhovian (Protvian) in age. The Vissou klippe probably corresponds to a fragment of the overturned limb of the Mont Peyroux nappe, because it exposes the traditional inverse succession of the Saint-Nazaire-de-Ladarez Group, followed by the equivalent of the Puech Capel Mb, with carbonate

The “calcaires à Productus” of the Montagne Noire (Aude-Hérault, southern France) are carbonate lenses embedded within a thick Carboniferous siliciclastic complex. Foraminiferal assemblages in some of the larger carbonate lenses are typically representative of the late Viséan and Serpukhovian. Eleven new species of foraminifers are described: Hemidiscopsis variabilis, H. pilleae, Planohowchinia rara, P. redondensis, Spireitlina minima, Rectoendothyra japhetensis, Mikhailovella enormis, Cribrospira? perretae, Pojarkovella occidentalis, Parabiseriella vailhanensis, and Biseriella delicata. Eight foraminiferal biozones are defined; they are based on the first occurrence of some taxa, and could be used for other regions of southern France (e.g., Mouthoumet and the Pyrenees). These biozones are informally named as A to H. Due to the problems with classical biozonations and substages in northern England as well as Belgium and northern France, the biozones established herein are mostly compared with the Russian standard substages. Thus, biozones A and B are correlated with the Mikhailovian, corresponding to the latest Asbian and earliest Brigantian in western Europe; biozones C, D and E are correlated with the Venevian, equivalent to the upper part of the early Brigantian in western Europe. Therefore, biozones A–E form part of the late and latest Viséan. The stratigraphically younger biozones F, G and H contain foraminiferal assemblages correlated with the Tarusian, Steshevian and Protvian, respectively.

A revision of the late Mississippian (late Viséan-early Serpukhovian) cyanobacterial and algal assemblages of Montagne Noire (Aude-Hérault, France) is undertaken, mainly based on new data recently obtained with the foraminiferal assemblages of this area. In this taxonomic contribution, one tribe Borlatellae trib. nov. is translated, and three new genera Ortonellopsis gen. nov., Anchisolenopora gen. nov. and Neoradiosphaeroporella gen. nov., and four new species of algae are described: Ortonellopsis laxa gen. et sp. nov., Anatolipora macroporelloidea sp. nov., Paraepimastopora somervillei sp. nov., and Neoradiosphaeroporella aprica gen. et sp. nov. In the Algospongia (incertae sedis algae), the genera Zidella, Valuzieria emend. herein and Asteroaoujgalia are revised. Most of the species appear to be restricted to the latest Viséan-early Serpukhovian interval in the Montagne Noire, and thus, they have to be investigated in coeval Tethyan and Uralian areas for their possible biostratigraphic importance.