Mississippian coral assemblages from the Khenifra area, Central Morocco: Biostratigraphy, biofacies, palaeoecology and palaeobiogeography

Mississippian coral assemblages from the Khenifra area, Central Morocco: Biostratigraphy, biofacies, palaeoecology and palaeobiogeography

Gondwana Research 23 (2013) 367–379 Contents lists available at SciVerse ScienceDirect Gondwana Research journal homepage: www.elsevier.com/locate/g...

3MB Sizes 0 Downloads 29 Views

Gondwana Research 23 (2013) 367–379

Contents lists available at SciVerse ScienceDirect

Gondwana Research journal homepage: www.elsevier.com/locate/gr

Mississippian coral assemblages from the Khenifra area, Central Morocco: Biostratigraphy, biofacies, palaeoecology and palaeobiogeography Ismail Said a, Ian D. Somerville b, Sergio Rodríguez a,⁎, Pedro Cózar c a b c

Departamento y U.E.I. de Paleontología, Facultad de Ciencias Geológicas e Instituto de Geociencias, CSIC-UCM, José Antonio Novais 2, 28040 Madrid, Spain UCD School of Geological Sciences, University College Dublin, Belfield, Dublin 4, Ireland UK UEI de Paleontología, Instituto de Geociencias CSIC-UCM, José Antonio Novais 2, 28040 Madrid, Spain

a r t i c l e

i n f o

Article history: Received 7 July 2011 Received in revised form 10 April 2012 Accepted 17 April 2012 Available online 2 May 2012 Handling Editor: P.G. Eriksson Keywords: Morocco Khenifra Mississippian Mounds Reefs Corals

a b s t r a c t Analysis of Mississippian coral assemblages from the Khenifra region of Central Morocco together with data from foraminiferal/algal microfossils has established new age dating of 5 localities within the Azrou–Khenifra Basin: Souk El Had and Sidi Lamine, where corals occur mainly in biostromes protected by oolitic shoals, Tabainout, where corals have been recorded in different environments related to microbial mounds, Alhajra Almatkouba, where corals occur in biostromal reworked beds and Tiouinine, where corals occur in a well structured, fringing reef. This study demonstrates the presence of richer more diverse coral assemblages than previously recorded, in a variety of environmental settings. These coral assemblages strengthen correlations with the Adarouch area in the NE part of the Azrou–Khenifra Basin. It is emphasised that in the upper Viséan there are close similarities with rugose coral assemblages in other parts of the Western Palaeotethys including North Africa, SW Spain and NW Europe, and that all belong to the same biogeographic province. © 2012 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

1. Introduction In North Africa, especially Morocco and Algeria, coral-bearing mounds, bioherms and reefs are well-known from the Devonian (e.g., Wendt et al., 1997; Wendt and Kaufmann, 2006), but are less well documented from the Carboniferous. The exceptions are the late Viséan mounds of the Erfoud region, eastern Morocco (Wendt et al., 2001) and bioherms from the Béchar Basin, W. Algeria (Pareyn, 1959, 1961; Bourque et al., 1995). Recently, rugose corals have been described from platform limestones and microbial mounds from the Jerada Basin (NE Morocco) (Aretz and Herbig, 2008; Aretz, 2010a,b), as well as from the Adarouch area of north central Morocco (Said, 2005; Said et al., 2007; Cózar et al., 2008b; Said et al., 2010, 2011) (Fig. 1A). A brief summary of corals recorded from platform limestones and mounds from the Azrou-Khenifra Basin (north-central Morocco) has been recently noted (Aretz and Herbig, 2010). In recent global reconstructions of the Carboniferous (Scotese, 2002; Blakey, 2008) Morocco is situated south of the palaeoequator on the northern margin of Gondwana with Palaeotethys to the north. A comprehensive palaeobiogeographical analysis of Carboniferous faunas from North Africa was undertaken by Weyant et al. (1985) with a

⁎ Corresponding author. Tel.: + 34 913944854; fax: + 34 913944849. E-mail address: [email protected] (S. Rodríguez).

detailed synthesis of the rugose coral faunas by Semenoff-TianChansky (1985). This was updated in Legrand-Blain et al. (1989). Since then, little has been published on the palaeobiogeographic distribution of rugosan corals in this region except in eastern Morocco (Aretz, 2010a) and the Algerian Sahara (Aretz, 2011a). The earlier global syntheses (Fedorowski, 1981; Sando, 1990) of Lower Carboniferous coral faunas suggested that North African faunas had many rugose genera in common with those of other regions of the Western Palaeotethys, although recent work by Said and Rodríguez (2007) had recognised some genera endemic to Morocco. In this study, we present a detailed description of coral faunas obtained from Upper Viséan–Serpukhovian (Mississippian) limestones in the Khenifra area of north central Morocco (Fig. 1A). It lies 170 km ESE from Rabat and between 25 and 75 km SSE of the Adarouch area (Said, 2005). The aim of the paper is to compare the coral faunas from the Khenifra and Adarouch regions and to relate their differences to local changes in facies and palaeoecology. It is also hoped to demonstrate that the coral faunas from both areas belong to the same biogeographical province and have similar assemblages to other upper Viséan limestone sequences in the Western Palaeotethys. The studied area is important for the understanding of the palaeogeography of the Late Palaeozoic, because it represents an epicontinental sea, located in the northern border of Gondwana, with the Palaeotethys extending to the northeast, and the Rheic Ocean being closed to the northwest by the collision between

1342-937X/$ – see front matter © 2012 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.gr.2012.04.008

368

I. Said et al. / Gondwana Research 23 (2013) 367–379

Gondwana and Laurussia (Sacks and Secor, 1990; Vai, 2003; Braid et al., 2009; Nance et al., 2009). Consequently, it is a key area for the biogeographical relationships between North Africa and Europe during the Mississippian and may provide data for the way in which such a collision occurred (Murphy et al., 2009; Nance et al., 2009). 2. Previous coral studies in Morocco Previous coral collecting from Carboniferous rocks in Morocco has been very limited, with occasional samples collected as part of reconnaissance mapping by the Moroccan Geological Survey (Termier, 1936; Owodenko, 1946; Termier and Termier, 1950). The dating of the Mississippian limestone successions was subsequently established as Upper Viséan from microfaunal and microfloral studies (ChantonGüvenç et al., 1971; Chanton-Güvenç and Morin, 1973; Verset, 1988; Huvelin and Mamet, 1997). In 1995 a limited suite of coral samples was collected from the Khenifra–Azrou region (Aretz and Herbig, 2010), but these authors admitted that it only represented a fraction of the overall coral diversity present in the region. Some studies have been undertaken during the last decade on the coral assemblages from the Jerada Massif (Aretz and Herbig, 2008; Aretz, 2010a), from the Adarouch area (northern Khenifra–Azrou region) (Said, 2005; Said and Rodríguez, 2007; Said et al., 2007, 2010, 2011) and from the Khenifra area (Aretz and Herbig, 2010; Rodríguez et al., 2010a,b, 2011a,b; Somerville et al., 2011). 3. Geological setting and lithostratigraphy of coral-bearing sections The Palaeozoic Meseta of north central Morocco is divisible into three regions: in the west, near Rabat, the mostly Carboniferous siliciclastic rocks of the Sidi Bettache Basin, a central belt of mainly pre-Carboniferous rocks, and in the east, the Azrou–Khenifra Basin, extending from Azrou in the north to Jebel Hadid in the south. This latter basin comprises Carboniferous siliciclastic and carbonate rocks resting unconformably on, and in thrust contact with, Ordovician and Devonian rocks, all affected by the later Variscan Orogeny (Allary et al., 1976; Hollard, 1978; Piqué, 1983; Beauchamp and Izart, 1987; Hoepffner, 1987; Bouabdelli and Piqué, 1996; Hoepffner et al., 2005). Five sections were examined in the Khenifra region: Souk-El-Had, Sidi Lamine, Tabainout, Tiouinine and Alhajra Almatkouba (Fig. 1B). They represent isolated exposures of Mississippian limestones within predominantly Ordovician and Devonian siliciclastics. The Tournaisian and lower Viséan rocks are composed mainly of sandstones and conglomerates, with the oldest limestones dated as middle Viséan age (Berkhli et al., 2000). However, a widespread transgression

in the upper Viséan introduced limestones throughout the region (Chanton-Güvenç et al., 1971; Chanton-Güvenç and Morin, 1973; Verset, 1988; Huvelin and Mamet, 1997). Two main types of emplacements have been described in the Khenifra area: transgressive sequences on lower Palaeozoic rocks and olistoliths in flysch successions (Huvelin and Mamet, 1997). Most of the studied outcrops are typical transgressive sequences where the Mississippian sedimentation is developed on the lower Paleozoic rocks showing distinct palaeorelief. Only Alhajra Almatkouba could be regarded as being part of a large olistolith. The Khenifra area which is characterised by isolated outcrops of Mississippian limestones formed part of a larger basin, the Azrou– Khenifra Basin, which is elongated NE-SW for c. 100 km and is c. 40 km wide. This basin has been affected by Variscan tectonics, in particular thrusting, on the eastern side. The Adarouch area lies some 40 km NW of Azrou at the northern end of the basin, where it is surrounded by younger Mesozoic and Cenozoic rocks (Berkhli, 1999; Berkhli and Vachard, 2001; Berkhli et al., 2001; Berkhli and Vachard, 2002; Cózar et al., 2008b). 3.1. Souk-El-Had This represents a scarp section, 2 km south of the town of Souk-ElHad (UTM coordinates E 0266925, N 3685949), and 20 km SW of Azrou (Figs. 1B, 2A). The section exposed on the eastern limb of a NE–SW trending syncline is c. 50 m thick, with a repetition of the succession in rotated fault blocks. A basal polymict conglomerate (c. 1 m exposed), is followed by thinly bedded limestones with thin shale interbeds. This unit is 4 m thick but thickens to >20 m on the western limb of the syncline at Hajrat-sebaâ (UTM coordinates E 0264595, N 3682210, Fig. 2B) where it contains fasciculate coral colonies. The succeeding massive unit is composed of cross-bedded oolitic and crinoidal limestones (>30 m thick). It contains occasional bands of gigantoproductid brachiopods and, at the top, local concentrations of well-rounded sandstone pebbles up to 10 cm in diameter. Above the oolite and forming a recessive ledge is 3–4 m of nodular, finegrained limestones and shales with abundant colonial and solitary corals forming a biostrome (labelled B in Fig. 2A). Above this unit are c. 10 m of thick-bedded, laminated calcareous sandstones with sparse macrofauna, mainly gigantoproductids. The biostromal unit near the top of the section is mostly a finegrained wackestone with locally abundant algae, foraminifers and fenestellid bryozoans. Encrusting problematica are present including Claracrusta, Sparaphralysia and Fasciella. Foraminifers are relatively diverse with common Lasiodiscidae (Tetrataxis and Valvulinella), large archaediscids, palaeotextulariids (Cribrostomum lecomptei) and

Fig. 1. Sketch map with location of coral localities. A. Map of Northern and Central Morocco, with location of Khenifra area. B. Location of coral localities around Khenifra.

I. Said et al. / Gondwana Research 23 (2013) 367–379

Omphalotis. Green algae include Koninckopora, Windsoporella and Kamaenella, with the red alga Neoprincipia and problematical Algospongia (Kamaenella and Ungdarella). Draffania is also recorded. One horizon contains an exceptionally large number of specimens of Omphalotis omphalota. Most foraminifers and algae are typical of a late Asbian (Cf6γ Subzone) age. However, there are a few taxa which first appear in the Brigantian (Cf6δ Subzone) in the Tizra Formation at Adarouch (Cózar et al., 2008b), e.g. Claracrusta, Sparaphralysia and Neoprincipia. Moreover, the presence of Pseudocornuspira would suggest a later Brigantian age, as it is recorded close to the Viséan–Serpukhovian boundary in the Akerchi Formation at Adarouch (Cózar et al., 2008b, 2011). Coral assemblages also suggest a Brigantian rather than late Asbian age, because of the presence of several specimens of Dibunophyllum bipartitum and Arachnolasma sp., but typical western European markers, e.g., Actinocyathus, Lonsdaleia and Corwenia (Rodríguez and Somerville, 2007), have not been recorded.

369

pebbly limestones with occasional massive cross-bedded and laminated sandy limestones. Above is c. 40 m of medium- to coarsegrained bioclastic limestones and cross-bedded oolitic limestones with occasional gigantoproductid brachiopods and solitary corals. Near the top of the unit is a 2 m-thick interval rich in corals with abraded colonies and solitary corals. Above the coral limestone are >5 m of well-bedded laminated sandy oolitic limestones virtually without fauna. The total thickness of the section is c. 60 m. The succession has been assigned to the Bou-Rifi Formation (Verset, 1988; Aretz and Herbig, 2010). The bedded limestones are mostly coarse-grained oolitic and crinoidal grainstones with extensive recrystallisation. The limestones are locally replaced by silica and dolomite. Algae are generally sparse with Koninckopora (problematic green algae) and the problematicum Fasciella and Ungdarella and foraminifers are also rare. Most of the foraminifers and Ungdarella are typical of a late Asbian (Cf6γ Subzone) age. However, the presence of Archaediscus karreri grandis and Pseudocornuspira at the top of the section would suggest a later Brigantian (Cf6δ Subzone) age.

3.2. Sidi Lamine 3.3. Tabainout A prominent hill scarp section overlooks the town of Sidi-Lamine, 40 km west of Khenifra (Figs. 1B, 2C). It has a similar succession to that of Souk-El Had. A basal polymict conglomerate (c. 1 m exposed) rests on grey pebbly Ordovician shales. This is followed by 11 m of

The Tabainout outcrop (UTM coordinates E 0233902 and N 3648632; Fig. 1B) forms a prominent NE–SW trending ridge parallel to the Khenifra Sidi-Lamine road composed mainly of massive microbial-

Fig. 2. A. Limestone ridge at Souk-El-Had (view looking west); coral biostrome is marked with dotted line (B). B. Massive limestones (grainstones) in a quarry at Hajrat-sebaâ. C. Limestone ridge at Sidi-Lamine (view looking south). D. General view looking northeast towards the mounds at Tabainout. E. Detail of the bioclastic beds at the base of Tabainout mounds with fasciculate colony of Siphonodendron. F. Detail of the core of Tabainout mounds with cavities (dotted line) filled with ochrous mudstone.

370

I. Said et al. / Gondwana Research 23 (2013) 367–379

mound facies (Fig. 2D). North of a track cutting E–W through the mound at the base of the section are 2 m of well-bedded, nodular, fine-grained bioclastic wackestones and packstones with thin interbedded shales occurring below the mound facies. These beds rest unconformably on Ordovician shales and sandstones. The bedded limestones are relatively rich in corals, both solitary and colonial (Fig. 2E). At the SW end of the ridge, below the mound, are massive and brecciated micritic limestones with occasional solitary corals. The base of the succession here comprises 2 m of conglomerate, which thickens to >8 m southwestwards (Fig. 5A), and is overlain by 1 m of sandstone with calcareous cement and 2 m of thinly-bedded bioclastic limestones and shales. The basal limestone bed contains angular sandstone clasts. The basal beds of the mound are massive and bioclastic, with micritic facies containing stromatactoid cavities first appearing c. 8 m above the base (Fig. 2F). The measured thickness of the mound is c. 100 m. The upper 20–25 m of the mound shows interfingering of microbial mudstones containing stromatactoid cavities, with crinoidal limestones and bedded grainstones (coquinas) with rich horizons of brachiopods, bivalves, goniatites and locally, rich concentrations of mostly solitary corals on the flanks north of the track (see Somerville et al., 2011) (Fig. 5A). The bedded limestones at the base of the section are mostly medium-grained wackestones/packstones with extensive micritisation of bioclasts. Algae and Algospongia are locally very common with kamaenids, Koninckopora, Borladella, Praedonezella cespeformis, Fasciella, Ungdarella uralica, Sparaphralysia tacanica and Draffania. The foraminifers are relatively abundant with Tetrataxis, Endotaxis, Vissariotaxis, Howchinia and archaediscids. The heterocoral Hexaphyllia is also recorded. The bulk of the Tabainout section is composed of massive limestones which in thin section are predominantly mudstones and sparse wackestones with peloidal microbial fabrics and stromatactis cavity networks with geopetals. This microfacies has a sparse fauna with very rare foraminifers and is virtually devoid of algae. Fenestellid bryozoans and encrusting bryozoans can be conspicuous elements. The top of the mound is more crinoidal rich with intraclasts, but algae and foraminifers are generally very sparse, mainly Tetrataxis, Endotaxis and Neoarchaediscus. In a stream section south of the main mound yellow shales, marls and thin interbedded bioclastic limestone bands contain a rich assemblage of solitary corals (zaphrentids). This sequence is a deeper water basinal facies lying stratigraphically above the microbialmound. Most of the fauna at the base of the section from the bedded limestones below the microbial-mound are typically of a late Asbian age. However, in Adarouch, the presence of Howchinia has been recorded only at a slightly later Brigantian horizon (Cózar et al., 2008b). The top limestone beds expose a completely different suite of foraminifers, with Neoarchaediscus (relatively common), Asteroarchaediscus (rare), Euxinita efremovi, Pseudocornuspira, Archaediscus karreri, Globivalvulina parva and Planospirodiscus taimyricus. This assemblage can be assigned to the late Brigantian (Cózar et al., 2008a,b; Somerville et al., 2011).

3.4. Alhajra Almatkouba This is an abandoned quarry section beside the Khenifra SidiLamine road (UTM coordinates E 0245923, N 3649107; Fig. 1B), 12 km E of Tabainout (Fig. 3A). The main interval quarried comprises >25 m of massive coarse-grained bioclastic limestones with crinoids and brachiopods. Above this unit by the quarry entrance are c. 3 m of thinly bedded (20–30 cm thick) fine-grained bioclastic limestones interbedded with shales, within a predominantly shaly flysch interval. The limestones contain large solitary rugose corals and fasciculate colonies. The base of the massive limestone is intensively tectonized, indicating that the whole mass of limestones could represent an olistolith. However, the continuous and transitional sedimentation in

the upper part of the section (where the corals occur) seems to indicate a normal sedimentary sequence. The bedded limestones are bioclastic wackestones with extensive recrystallisation. The limestones are locally replaced by silica. Algae are generally very sparse with Palepimastoporella and the Algospongia Praedonezella cespeformis. Foraminifers are also rare with archaediscids at angulatus stage and Endothyranopsis crassa. E. crassa is a traditional marker of the late Asbian (Cf6γ Subzone) although also typically recorded in Brigantian rocks. A similar case is observed for Praedonezella cespeformis, for which its first appearance can be located in the latest Asbian, although it usually occurs in Brigantian or younger rocks (Conil et al., 1991; Cózar, 2004; Vachard and Cózar, 2006). Corals are not diagnostic enough to establish a precise age determination of the rocks. 3.5. Tiouinine A quarry close to the main road (Tiouinine 1; UTM coordinates E 0252860, N 3643003; Fig. 1B), 7 km SE of Khenifra, comprises about 15 m of massive coarse-grained bioclastic limestones with rare thin purple shale bands (Fig. 3B). Locally, areas of dolomite, ironstone and barite occur. Several facies occur, from sandy limestones to massive biohermal limestones containing solitary and colonial tabulate and rugose corals, both massive and fasciculate (Fig. 3C). Many colonies are upright and in growth position. Some are overturned. Large solitary corals are also relatively common. The base of the Mississippian section is exposed further up the hill to the west of the quarry where sandy, pebbly and bioclastic limestones rich in brachiopods rest unconformably on Ordovician sandstones (Figs. 3D, 6A). The sandy limestones pass laterally and upwards into well bedded biostromal limestones in a progressive way. The biostromal limestones show some colonies in growth position and high concentrations of skeletal debris. They gradually pass into massive boundstones composed mainly of coral colonies. The limestone succession continues above the quarry to the south in small scarps for at least 500 m and then massive and thinly bedded limestones showing erosive surfaces and mixed debris and growth position colonies are exposed in a large quarry (Tiouinine 3; UTM coordinates E0252980, N 3642697). Another section (Tiouinine 2) c. 1 km to the northwest of the quarry of Tiouinine 1 exposes a similar distribution, with much thicker development of the basal sandy and pebbly limestones, that are interbedded with sandstones and conglomerates. Massive boundstone limestones occur also in the southern border of this outcrop. The massive limestones are mostly medium-grained algal packstones, but with extensive peloidal-rich geopetal cavities and microbial fabrics in the matrix. Dasycladacean green algae (Borladella, Windsoporella, Coelosporella and Palepimastoporella), Koninckopora, together with Fasciella crustosa form large encrusting masses coating intraclasts. Foraminifers are relatively common with archaediscids, palaeotextulariids, Vissariotaxis compressa and Euxinita sp. The problematicum Saccamminopsis is also recorded. The microfacies is a boundstone where the corals are bounded by algae, micritic films and micropeloidal masses. Some cavities filled with skeletal grainstone are common in the structure of the rock. The bedded limestones at Tiouinine 2 also have peloidal-rich microbial fabrics but also comprise wackestones and packstones. The latter are rich in archaediscids, palaeotextulariids and have common Koninckopora, Fasciella and rare Forschia. The bedded limestones in the abandoned quarry at Tiouinine 3 have common Palepimastoporella, Claracrusta, Cribrostomum lecomptei and E. crassa. As documented previously at Alhajra Almatkouba E. crassa is a traditional marker of the late Asbian (Cf6γ Subzone) although also typically recorded in Brigantian rocks. A similar case is observed for Claracrusta and Fasciella crustosa, (Cózar, 2004; Cózar and Somerville, 2004, 2005; Cózar et al., 2008a; Vachard and Cózar, 2010).

I. Said et al. / Gondwana Research 23 (2013) 367–379

4. Description of coral faunas A total of over 450 coral specimens were collected from the Khenifra area and all the material is reposited in the Departamento de Paleontología, Facultad de Ciencias Geológicas, Universidad de Complutense. The abbreviations for the localities are: SEH—Souk-ElHad; SLA—Sidi-Lamine; TAB—Tabainout; ALH—Alhajara Almatkouba and TIO—Tiouinine. 4.1. Souk-El-Had In the thinly-bedded limestones below the oolite unit are occasional colonies of Siphonodendron martini (Milne-Edwards and Haime, 1848). In the middle of the oolite unit is a 2 m-thick interval of gigantoproductid brachiopod bands with the solitary coral Palaeosmilia murchisoni Milne-Edwards and Haime, 1851 and rare colonies of Diphyphyllum sp. and Syringopora sp. Above the oolite, in the nodular fine-grained limestone and shale, are common fasciculate colonies forming a biostromal unit. Taxa recorded include S. martini, Siphonodendron pauciradiale (M'Coy, 1844), Siphonodendron sociale (Phillips, 1836), Diphyphyllum furcatum (Hill, 1940), Lithostrotion araneum (M'Coy 1844) (rare), L. decipiens (M'Coy, 1849), Solenodendron furcatum (Smith, 1925) (very rare, Fig. 4A), Amplexus sp., Arachnolasma cylindricum Yu, 1934, Axophyllum aff. pseudokirsopianum Semenoff-Tian-Chansky, 1974, D. bipartitum (M'Coy, 1849), P. murchisoni, Pseudozaphrentoides sp. (Fig. 4B), Siphononophyllia samsonensis (Salée, 1913) and the tabulates Michelinia sp. and Syringopora sp. Corals are less abundant and diverse in the biostromal beds above the oolite at Hajrat-sebaâ, but bioclastic beds below the oolite contain abundant colonies of Siphonodendron and Diphyphyllum. 4.1.1. Discussion The biostrome contains 11 genera and 14 species of rugosans (Table 1), with moderately high diversity and abundance and

371

dominated by S. martini. The biostrome, directly succeeding the oolite unit, represents a shallow-water facies with many in situ colonies. The largest S. martini colony measured was 1.8 × 1.1 m and 40 cm high. It is typical of rugose coral association (RCA4A and 4B) of Somerville and Rodríguez (2007), characterised by an abundance of fasciculate colonies (particularly Siphonodendron) mostly in growth position, and in having a diverse assemblage of both colonial and solitary rugosans. It probably formed in a shallow-water environment typical of RCA4. It is comparable to the assemblage from the Akerchi biostrome (Adarouch area, Said et al., 2010). It also has affinities with the late Asbian Siphonodendron limestone biostrome of SW Spain (Rodríguez et al., 1994) and biostromes in Belgium (Aretz, 2001). It corresponds to the coral biostrome C3 (Aretz, 2010b). 4.1.2. Summary The Souk-El-Had biostrome is comparable both in facies, thickness and approximate stratigraphic position to the biostrome at Akerchi Hill 40 km to NW. The coral biostrome at Souk-El-Had has a similar abundance and diversity, but differs in the absence of Tizraia berkhlii Said and Rodríguez, 2007 and Siphonodendron junceum (Fleming, 1828). The coral faunas would suggest a late Asbian to early Brigantian age, but there are no diagnostic Brigantian species present. For this reason (without any foraminiferal/algal constraints) it is likely to be an older biostrome than that of Akerchi, which is late Brigantian in age (Cózar et al., 2008b). 4.2. Sidi Lamine The massive bioclastic limestones are generally poorly fossiliferous with fragments of Siphonodendron colonies and occasional solitary corals such as P. murchisoni. In the upper part of this unit is a 2 mthick interval rich in corals with fragmented colonies of Siphonodendron intermedium Poty, 1981, S. martini, Siphonodendron scaleberense Nudds and Somerville, 1988 (Fig. 4D), S. sociale, L. araneum, and abraded solitary corals A. cylindricum, Axophyllum aff. pseudokirsopianum,

Fig. 3. A. Massive limestones in the quarry of Alhajra Almatkouba (view looking west). B. Massive reefal limestones at Tiouinine (view looking north). C. Detail of fasciculate and massive corals in Tiouinine reef. D. Transition from well-bedded limestone (top right) to massive limestones (lower left) lying on red Ordovician sandstones (lower right) (view looking south).

372

I. Said et al. / Gondwana Research 23 (2013) 367–379

Koninckophyllum magnificum Thomson and Nicholson, 1876, and a colonial Koninckophyllum (Fig. 4C). 4.2.1. Discussion In this formation 6 genera and 9 species of rugose corals are recorded (Table 1) with moderate diversity and abundance. There are many small abraded and silicified fasciculate colonies of Siphonodendron. The assemblage is typical of rugose coral association RCA4 of Somerville and Rodríguez (2007), but is not as diverse or abundant as in Souk-El-Had, nor does it show typical autobiostromal development (Kershaw, 1994) In many aspects though, it also resembles RCA2, particularly in the abraded and fragmented nature of many corals associated with a shallow water turbulent setting with ooids, and showing slightly more abundant solitary corals. It resembles the ‘coral meadow’ habitat (B1) of Aretz (2010b). The age of the coral fauna is probably late Asbian, although the presence of K. magnificum would suggest a younger Brigantian age. 4.2.2. Summary This locally named Bou-Rifi Fm. is possibly the lateral equivalent of the Akerchi Fm. at Adarouch. The coral biostrome is not as well developed, but the local concentration of corals above the massive oolitic unit does appear to occur at a similar stratigraphic level and represents the same type of coral meadow protected by oolite shoals. It is, probably, also the equivalent horizon as the biostrome at Souk-El-Had. However, in the absence of diagnostic foraminiferal/algal data, it may be older. 4.3. Tabainout Corals are recorded at several distinct stratigraphic levels within the section (Fig. 5A). Below the mounds in thickly-bedded bioclastic limestones was recorded a relatively rich assemblage of solitary rugose corals and colonial taxa: Amplexizaphrentis sp., Amplexocarinia sp., A. cylindricum, Clisiophyllum keyserlingi M'Coy, 1849, D. bipartitum,

Lithostrotion vorticale (Parkinson, 1808), Michelinia sp., Palaeosmilia murchisoni, Pseudozaphrentoides sp., Rotiphyllum sp., Siphonodendron irregulare (Phillips, 1836), S. martini, S. intermedium, S. pauciradiale (Fig. 5H), S. sociale, and Siphonophyllia samsonensis (Somerville et al., 2011). There are 11 genera and 14 species of rugosans; 1 genus and 1 species of tabulates in total. In the lower part of the massive limestones, particularly in the brecciated micritic facies that is interbedded with thickly-bedded bioclastic limestones, occur solitary corals, notably Amplexus sp., Axophyllum sp., Rotiphyllum and Palaeosmilia, with Michelinia and rare fragments of colonies of L. vorticale (Fig. 5I), L. araneum, S. martini and S. sociale. In the main massive mound facies characterised by the presence of stromatactid cavities were recorded occasionally ‘Amplexus’ sp. (Fig. 5E), Axophyllum aff. pseudokirsopianum and Michelinia. In the upper part of the mound which shows interbedded layers of bivalve/ brachiopod coquinas and microbial limestones with stromatactoid cavities and contains numerous goniatites, are locally, rich pockets of rugose corals including D. furcatum (Fig. 5D), L. araneum, P. murchisoni, Siphonodendron irregulare, S. martini, S. pauciradiale, S. sociale, and rare colonial ‘Axophyllum’ (Fig. 5B). In the mound flank on the northeast side close to the E-W track, similar bedded facies are locally rich in large solitary corals, especially Pseudozaphrentoides juddi (Thomson, 1893) and P. murchisoni. In addition were recorded ‘Amplexocarinia’ sp. (a gregarious form) (Fig. 5C), A. cylindricum, Diphyphyllum lateseptatum (M'Coy, 1849), Kizilia sp., L. vorticale, Michelinia sp., Haplolasma sp., Rotiphyllum sp., S. martini, S. pauciradiale and Syringopora sp. The entire assemblage in the mound facies (including basal beds, core and flank beds) comprises 16 genera and 21 species of rugosans; 2 genera and 2 species of tabulates. In the stream section above the mound there are shales with interbedded marls where solitary corals are abundant including ‘Amplexus’, Bradyphyllum, Claviphyllum? sp., Cyathaxonia cornu and Rotiphyllum sp. (Fig. 5G). Occasional tabulate corals recorded are Michelinia sp. (Fig. 5F), and Syringopora sp.

Fig. 4. Corals from Souk-El-Had and Sidi-Lamine. A. Solenodendron furcatum SEH/1-10, B. Pseudozaphrentoides sp. SEH/1-18. C. Colonial Koninckophyllum SLA/1-17. D. Siphonodendron scaleberense (single corallite) SLA/1-5. Divisions in the rulers equal 0.5 mm.

I. Said et al. / Gondwana Research 23 (2013) 367–379

4.3.1. Discussion The bedded limestones below the mound which are dominated by solitary rugosans are typical of RCA5 of Somerville and Rodríguez (2007). The mound as a whole shows a very high diversity compared to other examples in Morocco (and Europe). The mound core facies (those that can be regarded as “microbial mound” or “mud mound” facies) are particularly poor in corals, with only the occasional amplexoid solitary rugosan. The remarkable features of this mound that are not present in other mounds (e.g.,Tizra, Jerada (eastern Morocco) and

373

Sierra Morena, (SW Spain)) are the capping and flank facies that contain a rich rugose coral assemblage. It is not comparable to the biostromes at the top of Tizra mounds, because they lie above the mound, whereas in Tabainout, the corals occur interbedded with horizons showing stromatactid cavities and can be regarded as part of the mound. At Tizra the mounds are surrounded by marly limestones containing solitary corals and abundant crinoids (similar to those in the stream section at Tabainout), but do not have the cemented coquinas alternating with beds having microbial textures that occur in Tabainout. The complete

Table 1 Comparison of coral taxa recorded in different outcrops from the Azrou–Khenifra Basin and Jerada (NE Morocco). The data from Jerada is from Aretz (2010a). Taxa Amplexizaphrentis sp. Amplexocarinia sp. Amplexus sp. Arachnolasma cylindrica Arachnolasma sinense Auloclisia sp. Aulokoninckophyllum carinatum Aulokoninckophyllum sp. Aulophyllum fungites Axoclisia sp. Axophyllum aff. pseudokirsopianum Axophyllum densum Axophyllum dibunoides Bradyphyllum sp. Claviphyllum? sp. Clisiophyllum crassiseptatum Clisiophyllum garwoodi Clisiophyllum keyserlingi Clisiophyllum macrocolumellatum Clisiophyllum sp. 1 Clisiophyllum sp. 2 Corwenia sp.1 Corwenia sp.2 Cyathaxonia cornu Dibunophyllum bipartitum Diphyphyllum fasciculatum Diphyphyllum furcatum Diphyphyllum lateseptatum Gangamophyllum sp. Haplolasma densum Haplolasma sp. Kizilia sp. Koninckophyllum magnificum Lithostrotion araneum Lithostrotion decipiens Lithostrotion maccoyanum Lithostrotion vorticale Michelinia spp. Palaeosmilia murchisoni Palastraea regia Pareynia splendens Pseudozaphrentoides juddi Pseudozaphrentoides sp. Rotiphyllum sp. Semenoffia sp. Siphonodendron intermedium Siphonodendron irregulare Siphonodendron junceum Siphonodendron martini Siphonodendron multiradiale Siphonodendron pauciradiale Siphonodendron scaleberense Siphonodendron sociale Siphonophyllia samsonensis Siphonophyllia siblyi Solenodendron furcatum Syringopora spp. Tizraia berkhlii Tizraia sp. Total taxa

Tizra X X X

Akerchi

X X

X

X X X

Idmarr.

X X X X X X X X X

S. Had

Alhajra

X X

Tiouine

Tabain.

Sidi L.

X X

X X X X

X

Jerada

X X

X

X

X

X

X

X X

X X X X

X X X X X

X X X

X

X

X

X X X X X X

X X X

X X

X X

X X

X

X X X

X X

X X

X X

X

X

X X X X X X

X X X

X X X X X X

X

X X

X X

X

X

X

X X X

X X X X X X X

X X X

X

X X X

X X

X X X

X X X X X

X

X

X

X

X

X

X X X X

5

X X X 28

X X X

X

X X

X

X X

X X

X

X X

20

28

X X X X X 30

X X X

16

X X

X

X X

X X X X

X X X

X X 28

9

13

374

I. Said et al. / Gondwana Research 23 (2013) 367–379

assemblages from Tabainout comprise 21 genera and 28 species (Table 1). It represents a high diversity, increased by the occurrence of diverse environments containing rugose and tabulate corals. The mounds probably grew in a relatively shallow-water environment, especially in the upper part. The mound facies itself is remarkable for the high diversity and abundance of rugose corals with 12 genera and 18 species recorded. This is similar to assemblage RCA6 of Somerville and Rodríguez (2007), particularly those large mounds (c. 100 m thick) which grew up into shallower water where the corals could flourish. The age of the mound complex is late Asbian in the lower part but in the upper part, is probably Brigantian, based on the presence of D. lateseptatum, Kizilia sp. and P. juddi. The corals of the basinal section above the mound are typical of the RCA8 of Somerville and Rodríguez (2007), characterised by undissepimented solitary taxa (the Cyathaxonia fauna). 4.3.2. Summary This mound facies at Tabainout is similar to the mounds at Adarouch, particularly Tizra 2 section (Tizra 3 member), where flank beds are recorded rich in shells and solitary corals (Table 1). This is, however, a rich coral assemblage for microbial-mounds. It

does have comparability to the Ardagh mound, Ireland, especially in the upper part of that mound (RCA6) where Brigantian colonial corals are abundant (Somerville et al., 1996; Somerville, 1997; Rodríguez and Somerville, 2007). 4.4. Tiouinine 1 Colonial corals recorded from the massive limestones include: D. furcatum, D. lateseptatum, Lithostrotion decipiens (Fig. 6C), L. maccoyanum Milne-Edwards and Haime, 1851, L. vorticale, Palastraea regia (Phillips, 1836), S. intermedium, S. martini (Fig. 6B), S. pauciradiale, S. sociale, S. scaleberense, T. berkhlii (Fig. 6D), Tizraia sp. and the tabulates Michelinia spp. and Syringopora sp. Solitary forms include ‘Amplexus’, A. cylindricum, Aulokoninckophyllum carinatum (Carruthers, 1909), Gangamophyllum sp., Axophyllum pseudokirsopianum, Kizilia sp. (Fig. 6E), C. keyserlingi, Haplolasma sp., P. murchisoni, Pareynia splendens Semenoff-Tian-Chansky, 1974, Semenoffia sp., S. samsonensis and Rotiphyllum sp. 4.4.1. Discussion At least 18 genera and 26 rugose species, together with 2 genera and 3 tabulate species have been recorded in Tiouinine 1 (Table 1).

Fig. 5. Corals from Tabainout. A. Model of the facies distribution in Tabainout (mounds not to scale). B. Gregarious Axophyllum TAB/1-27. C. ‘Amplexocarinia’ sp. TAB/1-42b. D. Diphyphyllum furcatum TAB/1-3. E. ‘Amplexus’ sp. TAB/2-31. F. Michelinia sp. TAB/1-109a. G. Rotiphyllum sp. TAB/2-73. H. Siphonodendron pauciradiale TAB/1-35. I. Lithostrotion vorticale TAB/1-42a. Divisions in the rulers equal 0.5 mm; scale bars equal 5 mm.

I. Said et al. / Gondwana Research 23 (2013) 367–379

This represents an exceptionally rich and diverse coral assemblage — probably the highest for any single Mississippian locality in Morocco. This is mainly because all the species have been recorded in a relatively small area of massive limestones, representing a single environment. However, it does show strong similarity with the Idmarrach section at Adarouch (Table 1), in terms of diversity and abundance of colonies, but the facies there is quite different. At Idmarrach the coral fauna occurs in well-bedded, dark grey, finegrained limestones interbedded with thin shales and it is distributed in several beds, containing different assemblages belonging to several environments (Said, 2005; Said et al., 2007). This facies was probably developed in a quiet water, deeper shelf environment. Tiouinine 1 section probably represents optimum growing conditions for numerous colonies and equally abundant solitary forms in a reef. The corals of the Tiouinine 1 section are typical of the RCA4B of Somerville and Rodríguez (2007), characterised by the abundance of fasciculate rugose colonies and solitary genera. The majority of the colonies are upright and in growth position and form a true reef. The fasciculate colonies of Siphonodendron, Diphyphyllum and Tizraia form the dominant framework elements assisted by massive colonies of Lithostrotion and Palastraea and locally, the tabulates Michelinia and Syringopora. The age of the assemblage is probably Brigantian to early Serpukhovian. A similar rich suite of Brigantian corals has been recorded from Brigantian biostromes in SE Ireland (Cózar and Somerville, 2005; Rodríguez and Somerville, 2007; Somerville et al.,

375

2007). It is comparable to the D4 bioherm of Aretz (2010b), except that the Tiouinine reef has a very much higher diversity. 4.4.2. Summary The Tiouinine 1 section has comparable taxa and diversity to the coral biostrome at Akerchi Hill, except without S. junceum. It also has many taxa in common with those of the Béchar Basin in Algeria (Semenoff-TianChansky, 1974) of late Viséan–Serpukhovian (Namurian) age (see below). 4.4.3. Tiouinine 2 This section has coral colonies dominated by S. pauciradiale, S. martini and S. sociale, with rarer S. intermedium, S. irregulare, S. pauciradiale, T. berkhlii, D. furcatum, very rare L. decipiens and Syringopora sp. (Fig. 6G). Solitary forms include ‘Amplexus’ sp. (Fig. 6F), Arachnolasma sp., Axophyllum aff. pseudokirsopianum, S. samsonensis, Clisiophyllum garwoodi, P. murchisoni and D. bipartitum. 4.5. Alhajra Almatkouba Corals collected from the thinly-bedded limestone unit comprises colonies of S. scaleberense, S. pauciradiale and many large dissepimented solitary corals including Axophyllum sp., S. samsonensis and P. murchisoni.

Fig. 6. Corals from Tiouinine. A. Model of the facies distribution in Tiouinine reef (not to scale). B. Siphonodendron martini TIO/1-21. C. Lithostrotion decipiens TIO/1-13. D. Tizraia berkhlii TIO/1-2. E. Kizilia sp. TIO/1-79. F. ‘Amplexus’ sp. TIO/2-38. G. Syringopora sp. TIO/2-4. Divisions in the rulers equal 0.5 mm; scale bars equal 5 mm.

376

I. Said et al. / Gondwana Research 23 (2013) 367–379

4.5.1. Summary This limited assemblage comprising 5 rugosan species is typically late Asbian in age. 5. Assessment of the new coral data 5.1. Comparison with previous coral studies in the region Previous studies on the coral assemblages from the middle and southern Azrou-Khenifra region are very scarce. Termier and Termier (1950) mentioned the presence of corals from the Djebel Ouarziz. Unfortunately, the geographic name is used for a broad zone of hills around Khenifra and cannot be precisely identified with any of the studied outcrops. It hampers a detailed comparison of the records. However, most of the taxa described by Termier and Termier (1950) are present in several outcrops. Aretz and Herbig (2010) provided preliminary data on the assemblages from Souk-ElHad, Sidi- Lamine and Tabainout, but as these authors indicated, their sampling was not comprehensive. In Souk-El-Had they only recorded one rugose taxon, P. murchisoni, whereas the biostrome contains at least 13 genera and 16 species (Table 1). At Sidi-Lamine, Aretz and Herbig (2010) listed 4 genera and 7 species from Unit 3, which is comparable to our record of 6 genera and 9 species. They only recorded S. scaleberense from this locality. In Tabainout there is a marked difference in coral records. Aretz and Herbig (2010) did not record any rugose corals from the mound core (‘reef’) and only three taxa below the ‘reef’ (L. vorticale, S. irregulare and P. murchisoni). They also recorded S. martini, S. pauciradiale, Axophyllum sp. and Amygdalophyllum sp. in the upper limestones (allegedly from above the mound, although in fact the bedded limestones represent the capping and flank beds ‘coquinas’ that are interbedded with peloidal mudstones, dipping 40 0 to SE towards the village of Sidi-Amar). Our recent sampling has recorded 11 genera and 14 species of rugose corals from beds below the mound and 12 genera and 17 species from the massive mound facies. When combined the mound section comprises 16 genera and 21 species of rugosans and 2 tabulate genera. In addition, the shales above the mound have yielded 5 genera and 5 species of solitary rugosans. Thus in total, 21 genera and 28 species have been collected from the Tabainout area (Table 1). The total number of coral taxa collected from the Khenifra area is 29 genera and 40 species (excluding heterocorals). This greatly exceeds the total of 11 genera and 15 species in Aretz and Herbig (2010), demonstrating the under-representation of the coral diversity in the basin in that study. 5.2. Comparisons of coral diversity in Khenifra sections and palaeoecological relationships The studied outcrops in the Khenifra region show a high coral diversity in the Mississippian because of two reasons. Firstly, all of the outcrops were formerly located in tropical palaeolatitudes favourable for coral development, despite the fact that most palaeogeographical reconstructions locate this area at a latitude higher than 30º south in northern Gondwana. Secondly, most sections show different environmental conditions providing different possibilities for adaptation of colonial and solitary corals in a variety of palaeoecological settings. The sedimentary features of Sidi-Lamine indicate a shallow-water platform related to oolite shoals, without extensive development of corals, although, uniquely here, is recorded K. magnificum (Table 1) and a colonial form of ‘Koninckophyllum’. Souk-El-Had (and nearby Hajrat-Sebaâ) shows a complex community of colonial and solitary corals within a biostrome developed in an area protected by large oolite shoals. Tabainout exhibits large microbial mounds with clear differentiation of basal beds, microbial mound core, capping and flank beds and surrounding deeper water shaly facies. It provides ecological

niches for very different suites of corals and assemblages that are quite diverse. Interestingly, a colonial form of ‘Axophyllum’ is recorded from the upper mound coquinas. Tiouinine shows a structured fringing reef where core reef, back reef and fore reef facies can be distinguished. Corals constitute the main building organisms in this reef and show the highest diversity in any known Carboniferous single outcrop in Morocco. Alhajra Almatkouba represents the distal facies of a platform, where bioclastic limestones contain an allochthonous assemblage which may have been derived from a shallower water platform setting such as Sidi-Lamine. The complete assemblages are listed in Table 1. 5.3. Comparison with other areas in North Africa Carboniferous rugose corals have been previously studied in detail only in two areas from Morocco: Adarouch region and Jerada Basin. The Adarouch area lies between 20 and 40 km north of the Khenifra outcrops and belongs to the same basin (Azrou–Khenifra Basin). Three formations with different coral assemblages and representing different environments have been studied in that area (Said, 2005; Said et al., 2007 2010, 2011): Tizra Formation, Akerchi Formation and Idmarrach Formation (see Table 1). The Tizra Formation was sedimented in an area with the development of microbial mounds, similar to those at Tabainout. The basal facies of mounds and mound core show similar features in both localities and, consequently, coral assemblages are very similar in those facies. The main differences are related with facies developed in the upper part of the mounds and above them. Spectacular coquinas containing large solitary and some colonial corals are developed as capping and flank beds in Tabainout. On the other hand, biostromal beds dominated by fasciculate corals occur some metres above the mounds in Tizra. The Akerchi Formation shows a closely comparable succession and sedimentary features to those of Souk-El-Had and, to a lesser degree, to Sidi-Lamine. The coral assemblages are dominated by fasciculate corals (similar generic assemblage) with abundant solitary corals in both cases. The main differences are (a) more diverse and richer assemblage of solitary corals in Akerchi, and (b) different dominant species; S. martini and S. pauciradiale in Souk-El-Had, but S. junceum in Akerchi. Those differences may be related with the age of the assemblages (Late Brigantian in Akerchi versus probable late Asbian to early Brigantian in Tabainout). The Tiouinine outcrops are not comparable to any outcrop in the northern region of the basin, because it represents a structured reef that shows a very high diversity. The Idmarrach Formation at Adarouch shows also a very high diversity, but it represents a different environment; a quiet, deeper water platform where corals flourished together with gigantoproductid brachiopods. The Alhajra Almatkouba assemblage occurs in some beds from a single locality and it is comparable to allochthonous assemblages at the base of the Tizra mounds (Said et al., 2011). The Jerada Basin is located in eastern Morocco, 375 km NE of Khenifra (Fig. 1A), and shows similar lithological features to the Tabainout outcrops. Consequently, the coral assemblages are comparable in general, but show many differences in detail (Aretz, 2010a). Fasciculate corals are dominant in Jerada, and the same genera as in Khenifra are recorded. However, S. junceum is present in Jerada (as well as in Adarouch), but not in Khenifra. On the other hand, larger species such as S. sociale and S. scaleberense are absent in Jerada. Aulophyllidae and axophyllidae are the most common solitary corals in Jerada (as well as in Khenifra), but only two species are common in those areas (D. bipartitum and Axophyllum aff. pseudokirsopianum). It demonstrates that although both areas belong to the same palaeogeographical province, either the distance between the 2 regions in Morocco was large, or that communication between the regions was difficult and restricted the extent of migrations. Corals collected from the Béchar Basin, 325 km SE of Khenifra (Fig. 1A), have been only partly described (Semenoff-Tian-Chansky,

I. Said et al. / Gondwana Research 23 (2013) 367–379

1974, 1985). Detailed lists of undissepimented corals are not known. However, solitary dissepimented corals e.g., A. cylindricum, A. carinatum, A. pseudokirsopianum, C. keyserlingi, D. bipartitum, Gangamophyllum, Haplolasma, K. magnificum, P. murchisoni, P. splendens, P. juddi and S. samsonensis, show many similarities with those from Khenifra and indicate significant connections, but a more detailed comparison cannot be achieved until the complete assemblages from Béchar are published. The Khenifra assemblages contain many rugose genera (Table 2) and species that are also common throughout Western Europe (SW Spain, Belgium, France, British Isles) e.g., Palastraea regia, S. pauciradiale, S. martini, S. sociale, L. vorticale, L. decipiens, D. lateseptatum, S. samsonensis, D. bipartitum, and K. magnificum, as well as those which are rare e.g., S. scaleberense, Solenodendron furcatum and Aulokoninckophyllum. Moreover, assemblages corresponding to similar environments in Europe are dominated by the same species (compare with the standard assemblages of Somerville and Rodríguez, 2007). Consequently, the Khenifra upper Viséan coral assemblages indicate that the Azrou-Khenifra region should be considered as part of the Western European Province (Fedorowski, 1981, Fig. 2; Hill, 1981) and constitute part of Global Coral Zone 4A of Sando (1990). Although these Moroccan faunas accumulated on the NW margin of Gondwana they formed part of a wider Western Palaeotethyan fauna which was linked to eastern Canada (Nova Scotia) and much of Western Europe, often incorporated within the wider

377

Eurasiatic region (Dubatolov and Vasilyuk, 1980; Hill, 1981). Aretz (2010a) alleged an absence in North Africa of some genera typical from Europe, such as Kizilia, to invoke an “important palaeobiogeographic barrier” between North Africa and Southern European basins. However, this suggestion is contested, with the discovery of Kizilia in both Tiouinine and Tabainout. Furthermore, the recent identification of Lonsdaleia and Actinocyathus from the northern Tindouf Basin in Saharan Morocco (Rodríguez et al., 2011a,b), genera that are common in Britain, Ireland, Belgium and France (Table 2), give more support to a wider palaeobiogeographic province (Aretz, 2011b). On the other hand, the Khenifra assemblages do contain rugose genera and species that are endemic to Morocco (e.g., T. berkhlii) and recorded at Adarouch (Said and Rodríguez, 2007; Said et al., 2007) and Jerada (Aretz, 2010a). This species is not only present, but abundant and dominant in shallow-water environments from the Tizra and Akerchi formations in Adarouch and from Tiouinine in Khenifra. In the latter locality Tizraia colonies are almost as abundant as Siphonodendron within the reef. Khenifra assemblages also contain rugose genera and species that are known in other North African basins such as Jerada and Béchar (Table 2), e.g., P. splendens (Semenoff-Tian-Chansky, 1974; Aretz, 2010a) but are very rare elsewhere in Europe (Poty, 1981). That species has been not recorded in Adarouch. An additional difference with

Table 2 Comparison of coral taxa recorded in the Azrou–Khenifra Basin (Adarouch and Khenifra areas) with those recorded in other Western Palaeotethys areas. (Data based mainly on Semenoff-Tian-Chansky, 1974; Poty, 1981; Semenoff-Tian-Chansky, 1985; Aretz, 2001, 2002; Aretz and Herbig, 2003; Said, 2005; Rodríguez and Somerville, 2007; Said and Rodríguez, 2007). Genera Actinocyathus Amplexizaphrentis ‘Amplexocarinia’ ‘Amplexus’ Amygdalophyllum Arachnolasma Aulina Auloclisia Aulokoninckophyllum Aulophyllum Axoclisia Axophyllum Bothrophyllum Bradyphyllum Caninia Caninophyllum Claviphyllum Clisiophyllum Corwenia Cyathaxonia Dibunophyllum Diphyphyllum Gangamophyllum Haplolasma Koninckophyllum Lithostrotion Lonsdaleia Kizilia Nemistium Orionastraea Palaeosmilia Palastraea Pareynia Pseudozaphrentoides Rotiphyllum Semenoffia Siphonodendron Siphonophyllia Slimoniphyllum Solenodendron Tizraia

Poland

British Islands

Belgium

X X X

X X X X

X X X X X

X X

X

Armorica

Montagne Noire

Sierra Morena

Adarouch–Khenifra

X X X X X

X X X

X X X X X

X X X X X X X X

X X

X

X

X

X

X X

X X X X

X X X X X

X X X X X

X

X

X X X

X

X X X X X X X X X X X

X X X X X

X

X

X

X X X X X X X X X X

X X X

X X X

X

X X

X X

X X

X X X

X

X X

X X

X X

X X

X X

X X

X

X

X X X X

X X X

X X X X

X

X X

X X X

X X X X

Sahara

X

X

X X X

X X X X X

X X X X X X X X X X X

X

X X X X X X X X X X

X X X X X X X X X X X X X X X X X X X X

X

X

X X X X X X X X

X X X X X

X X

X

X X

378

I. Said et al. / Gondwana Research 23 (2013) 367–379

the Adarouch area, is the total absence of S. junceum in the Khenifra localities, which is one of the most abundant species in that area and also very common in Eastern Europe. The Khenifra assemblages contain rugose genera (and species?) that are also known in southern Spain (Marbella Fm.), but absent in Adarouch e.g., P. juddi, Gangamophyllum boreale and Kizilia concavitabulata (Herbig and Mamet, 1985; Herbig, 1986). The latter two taxa, however, are more typical of the Eastern European Province (Fedorowski, 1981). All these comparisons provide an important advance in the knowledge of relationships between areas in the northern and southern part of the western Palaeotethys. However, it is necessary for the study of additional areas in the eastern Mediterranean region, such as Turkey (Denayer, 2011; Denayer and Aretz, 2011) or Libya, where the knowledge of Upper Devonian stratigraphy and palaeontology is quite good, but the Mississippian is still little known (Fröhlich et al., 2009; Wehrmann et al., 2009). 6. Results and conclusions Carboniferous (Mississippian) rocks containing rich coral assemblages in the Azrou–Khenifra region have been studied. Five localities have been dated by means of corals, algae and foraminifers: Souk-ElHad (including its southern prolongation at Hajrat-sebaâ), SidiLamine, Tabainout, Tiouinine and Alhajra Almatkouba. Two of the localities (Tiouinine and Alhajra Almatkouba) have been studied for the first time and provided additional valuable information on the total coral diversity in the area, Tiouinine showing the highest diversity in a single outcrop (and environment) in the Mississippian of Morocco. Detailed sampling and analysis of the coral assemblages have proved that they are richer and more diverse than previously recorded. The assemblages comprise a high variety of environments including reefs (Tiouinine), biostromes (basal layers in Tabainout and above the oolitic shoal in Souk-El-Had), microbial mounds (Tabainout), oolitic shoals (Souk-El-Had) and deep-water facies (shaly beds around the mounds in Tabainout). Comparison of the coral assemblages with those previously known at Adarouch, in the NE part of the Azrou–Khenifra Basin, has established many similarities between both areas. Further comparison with coral assemblages in other parts of western Palaeotethys shows recognition of close similarities with assemblages from the Jerada Basin (Eastern Morocco), Béchar Basin (western Algeria) and south-western Spain, confirming the location of all these areas within the same biogeographic province, on the NW margin of Gondwana during the Mississippian. Acknowledgements The authors would like to thank the collaboration of the Department of Mine Development of the Ministère de l'Energie et des Mines of Morocco, which kindly gave us permission to carry out field work. We would like to thank Markus Aretz and Robert Elias for constructive comments which have helped improve the paper. This research was supported by the projects CGL2006-03085 and CGL2009-10340 of the Spanish Ministry of Research and Innovation. This paper is a contribution to the IGCP 596. References Allary, A., Lavenu, A., Ribeyrolles, M., 1976. Etude tectonique et microtectonique d'un segment de chaîne hercynienne dans la partie sud-orientale du Maroc central. Notes et Mémoires du Service géologique, Maroc, 261, pp. 113–166. Aretz, M., 2001. The Upper Viséan coral horizons of Royseux. The development of an unusual facies in Belgian Early Carboniferous. Bulletin of the Tohoku University Museum 1, 86–95 Sendai.

Aretz, M., 2002. Rugose corals annd associated carbonate microfossils from the Brigantian (Mississippian) of Castelsec (Montagne Noire, southern France). Geobios 35, 187–200. Aretz, M., 2010a. Rugose corals from the upper Viséan (Carboniferous) of the Jerada Massif (NE Morocco): taxonomy, biostratigraphy, facies and palaeobiogeography. Palaeontologische Zeitschrift 84 (3), 323–344. Aretz, M., 2010b. Habitats of colonial rugose corals: the Mississippian of western Europe as example for a general classification. Lethaia, http://dx.doi.org/10.1111/ j.1502-3931,2010.00218.x. Aretz, M., 2011a. Corals from the Carboniferous of the central Sahara (Algeria): the collection of “Marie Legrand-Blain”. Geodiversitas 33 (4), 581–624. Aretz, M., 2011b. Palaeobiogeographical analysis for the late Viséan corals in the Variscan Realm of Western Europe and Northern Africa. Abstract X1 International Symposium on Fossil Cnidaria and Sponges, Liege. Kölner Forum für Geologie und Paleontologie 19, 12–13. Aretz, M., Herbig, H.-G., 2003. Contribution of rugose corals to Late Viséan and Serpukhovian bioreconstructions in the Montagne Noire (southern France). In: Ahr, W.M., Harris, P.M., Morgan, W.A., Somerville, I.D. (Eds.), Permo-Carboniferous Carbonate Platforms and Reefs: Society of Economic Paleontologists and Mineralogists, Special Publication 78 and American Association of Petroleum Geologists, Memoir, 83, pp. 119–132. Aretz, M., Herbig, H.-G., 2008. Microbial-sponge and microbial-metazoan buildups in the late Viséan basin-fill sequence of the Jerada Massif (Carboniferous, NE Morocco). Geological Journal 43 (2–3), 307–336. Aretz, M., Herbig, H.-G., 2010. Corals from the Viséan of the central and southern part of Azrou-Khénifra Basin (Carboniferous, Central Moroccan Meseta). X Coral Symposium St. Petersburg. Palaeoworld 19 (3–4), 295–304. Beauchamp, J., Izart, A., 1987. Early Carboniferous basins of the Atlas–Meseta domain (Morocco); sedimentary model and geodynamic evolution. Geology 15 (9), 797–800. Berkhli, M., 1999. Sédimentologie, biostratigraphie et stratigraphie séquentielle du NE de la Méséta occidentale marocaine pendant le Carbonifère inférieur (ViséenSerpoukhovien) (unpublished). Thèse État, Université Moulay Ismaïl de Meknès, Meknès, 290 pp. Berkhli, M., Vachard, D., 2001. New biostratigraphical data from the early Carboniferous sequences of the Adarouch area (NE Central Morocco). Newsletter on Stratigraphy 39, 33–54. Berkhli, M., Vachard, D., 2002. Le Carbonifère du Maroc central: les formations de Migoumess, de Tirhela et d'Idmarrach. Lithologie, biostratigraphie et conséquences géodynamiques. Comptes Rendus Geoscience 334, 67–72. Berkhli, M., Vachard, D., Paicheler, J.C., Tahiri, A., Saidi, M., 2000. Le Carbonifère inférieur de la région d'Agourai (Nord du Maroc central): facies, biostratigraphie et paléogéographie. Géologie Méditerranéenne 27 (1–2), 71–79. Berkhli, M., Vachard, D., Paicheler, J.C., 2001. Les séries du Carbonifère inférieur de la region d'Adarouch, NE du Maroc central: lithologie et biostratigraphie. Journal of African Earth Sciences 32, 557–571. Blakey, R.C., 2008. Gondwana paleogeography from assembly to breakup; a 500 m.y. odyssey. Special Paper — Geological Society of America 441, 1–28. Bouabdelli, M., Piqué, A., 1996. Du bassin sur décrochement au bassin d'avant-pays : dynamique du Basin d'Azrou-Khenifra (Maroc hercynien central). Journal of African Earth Sciences 22, 213–224. Bourque, P.-A., Madi, A., Mamet, B.L., 1995. Waulsortian-type bioherm development and response to sea-level fluctuations: Upper Viséan of Béchar basin, western Algeria. Journal of Sedimentary Research B65, 80–95. Braid, J.A., Murphy, J.B., Quesada, C., 2009. Structural analysis of an accretionary prism in a continental collisional setting, the Late Paleozoic Pulo do Lobo Zone, Southern Iberia. Gondwana Research 17 (2–3), 422–439. Chanton-Güvenç, N., Morin, P., 1973. Phénomènes récifaux dans le chaînon calcaire viséen du Tabainout (SE du Massif hercynien central du Maroc). Service Géologique du Maroc Notes 34, 87–91. Chanton-Güvenç, N., Huvelin, P., Semenoff-Tian-Chansky, P., 1971. Les deux series d'âge viséen supérieur du Jbel Hadid près de Khénifra (Maroc hercynien central). Service Géologique du Maroc Notes 31, 7–10. Conil, R., Groessens, E., Laloux, M., Poty, E., Tourneur, F., 1991. Carboniferous guide foraminifera, corals and conodonts in the Franco–Belgian and Campine basins. Their potential for widespread correlation. Courier Forschungsinstitut Senckenberg 130, 15–30. Cózar, P., 2004. Foraminiferal and algal evidence for the recognition of the Asbian/ Brigantian boundary in the Guadiato area (Mississippian, southwestern Spain). Revista Española de Micropaleontología 36, 367–388. Cózar, P., Somerville, I.D., 2004. New algal and foraminiferal assemblages and evidence for the recognition of the Asbian–Brigantian boundary in northern England. Proceedings of the Yorkshire Geological Society 55, 43–65. Cózar, P., Somerville, I.D., 2005. Stratigraphy of upper Viséan platform rocks in the Carlow area, southeast Ireland. Geological Journal 40, 43–65. Cózar, P., Somerville, I.D., Burgess, I., 2008a. New foraminifers in the Visean/ Serpukhovian boundary interval of the Lower Limestone Formation, Midland Valley, Scotland. Journal of Paleontology 82 (5), 906–923. Cózar, P., Vachard, D., Somerville, I.D., Berkhli, M., Medina-Varea, P., Rodríguez, S., Said, I., 2008b. Late Viséan–Serpukhovian foraminiferans and calcareous algae from the Adarouch region (central Morocco). Geological Journal 43 (4), 463–486. Cózar, P., Said, I., Somerville, I.D., Vachard, D., Medina-Varea, P., Rodríguez, S., Berkhli, M., 2011. Potential foraminiferal markers for the Viséan–Serpukhovian and Serpukhovian–Bashkirian boundaries — a case study from Central Morocco. Journal of Paleontology 85 (6), 1105–1127. Denayer, J., 2011. Mississippian Lithostrotionidae from Zonguldak and Bartim (NW Turkey). Abstract X1 International Symposium on Fossil Cnidaria and Sponges, Liege. Kölner Forum Geologie und Paleontologie 19, 34.

I. Said et al. / Gondwana Research 23 (2013) 367–379 Denayer, J., Aretz, M., 2011. Discovery of a Mississippian reef in Turkey: the Upper Viséan microbial‐sponge‐bryozoan-coral bioherm from Kongul Yayla (Taurides, S. Turkey). Turkish Journal of Earth Sciences 20, 1–15. Dubatolov, V.N., Vasilyuk, N.P., 1980. Coral paleozoogeography in the Devonian and Carboniferous of Eurasia. Acta Palaeontologica Polonica 25 (3–4), 519–529. Fedorowski, J., 1981. Carboniferous corals: distribution and sequence. Acta Palaeontologica Polonica 26 (2), 87–160. Frohlich, S., Petitpierre, L., Redfern, J., Grech, P., Bodin, S., Lang, S., 2009. Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: recording the sedimentary response of the northern Gondwana margin to climate and sea-level changes. Journal of African Earth Sciences 57 (4), 279–296. Herbig, H.-G., 1986. Rugosa und Heterocorallia aus Obervise´-Geröllen der MarbellaFormation (Betische Kordilliere, Südspanien). Palaeontologische Zeitschrift 60, 189–225. Herbig, H.-G., Mamet, B.L., 1985. Stratigraphy of the limestone boulders, Marbella Formation (Betic Cordillera, Southern Spain). Comptes Rendues du 10ème Congres International du Stratigraphie et Géologie du Carbonifère, Madrid 1983, vol. 1, pp. 199–212. Hill, D., 1981. Rugosa and Tabulata. In: Teichert, C. (Ed.), Treatise on Invertebrate Paleontology Part F (Supplement 1), 2 vols. Geological Society of America and University of Kansas Press, Boulder Colorado and Lawrence, Kansas, pp. 1–762. Hoepffner, C., 1987. La tectonique hercynienne dans l'Est du Maroc. Thèse d'état, Université Louis Pasteur, Strasbourg: 280 pp. Hoepffner, C., Soulaimani, A., Piqué, A., 2005. The Moroccan Hercynides. Journal of African Earth Sciences 43, 144–165. Hollard, H., 1978. L'evolution hercynienne au Maroc. Zeitschrift der Deutschen Geologischen Gesellschaft 129, 495–512. Huvelin, P., Mamet, B., 1997. Transgressions, faulting and redeposition phenomenon during the Visean in the Khénifra area, western Moroccan Meseta. Journal of African Earth Sciences 26, 383–389. Kershaw, S., 1994. Classification and geological significance of biostromes. Facies 31, 81–92. Legrand-Blain, M., Conrad, J., Coquel, R., Lejal-Nicol, A., Lys, M., Poncet, J., SemenoffTian-Chansky, P., 1989. Carboniferous palaeobiogeography of North Africa. Comptes Rendues du 11ème Congres International du Stratigraphie et Géologie du Carbonifère, Beijing 1987, 4, pp. 216–230. Murphy, J.B., Nance, R.D., Cawood, P.A., 2009. Contrasting modes of supercontinent formation and the conundrum of Pangea. Gondwana Research 15, 408–420. Nance, R.D., Gutiérrez-Alonso, G., Duncan-Keppie, J., Linnemann, U., Murphy, J.B., Quesada, C., Strachan, R.A., Woodcock, N.H., 2009. Evolution of the Rheic Ocean. Gondwana Research 17 (2–3), 194–222. Owodenko, B., 1946. Mémoire explicatif de la carte géologique du bassin houiller de Djerada et de la région au sud d'Oujda. Société Géologique de Belgique Mémoire 70, 1–168. Pareyn, C., 1959. Les récifs carbonifères du Grand Erg occidental. Bulletin de la Société géologique de France, Série 7 (1), 347–364. Pareyn, C., 1961. Les Massifs Carbonifères du Sahara Sud-Oranais. Publications du Centre de Recherches sahariennes, Série Géologie, CNRS Paris (Ed.) 1, 1–324. Piqué, A., 1983. Structural domains of the Hercynian Belt in Morocco. In: Schenk, P.E. (Ed.), Regional Trends in the Geology of the Appalachian–Caledonian–Hercynian– Mauritanide orogen. Reidel Publication Company, Dordrecht, Holland, pp. 339–345. Poty, E., 1981. Recherches sur les Tétracoralliaires et les Hétérocoralliaires du Viséen de la Belgique. Mededelingen Rijks Geologische Dienst 35, 1–161. Rodríguez, S., Somerville, I.D., 2007. Comparisons of rugose corals from the Upper Viséan of SW Spain and Ireland: implications for improved resolutions in late Mississippian coral biostratigraphy. In: Hubmann, B., Piller, W.E. (Eds.), Fossil Corals and Sponges. Proceedings of the 9th International Symposium on Fossil Cnidaria and Porifera, Graz, 2003: Austrian Academy of Sciences, Schriftenreihe der Erdwissenschaftlichen Kommissionen, 17, pp. 275–305. Rodríguez, S., Arribas, M.E., Falces, S., Moreno-Eiris, E., De la Peña, J.A., 1994. The Siphonodendron limestone of Los Santos de Maimona Basin: development of an extensive reef-flat during the Viséan in Ossa-Morena, SW Spain. Courier Forschungsinstitut Senckenberg 172, 203–214. Rodríguez, S., Somerville, I.D., Said, I., Cózár, P., 2010a. Los montículos microbianos del Misisípico de Tabainout (región de Azrou-Khenifra, Marruecos). III Congreso Ibérico de Paleontología, pp. 261–264. Rodríguez, S., Somerville, I.D., Said, I., Cózár, P., 2010b. Tiouinine: un arrecife franjeante con la estructura preservada en el Misisípico de Marruecos. III Congreso Ibérico de Paleontología, pp. 265–268. Rodríguez, S., Somerville, I., Said, I., Cózar, P., 2011a. An upper Viséan (Asbian-Brigantian) coral succession at Djebel Ouarkziz (northern Tindouf Basin, Morocco). In: Aretz, M., Deculée, S., Denayer, J., Poty, E. (Eds.), Abstracts, 11th Symposium on Fossil Cnidaria and Sponges: Kölner Forum für Geologie und Paläontologie, 19, pp. 144–146. Rodríguez, S., Somerville, I., Said, I., Cózar, P., 2011b. Late Viséan coral fringing reef at Tiouinine (Morocco): implications for the role of rugose as building organisms in the Mississppian. In: Aretz, M., Deculée, S., Denayer, J., Poty, E. (Eds.), Abstracts, 11th Symposium on Fossil Cnidaria and Sponges: Kölner Forum für Geologie und Paläontologie, 19, pp. 147–148. Sacks, P.E., Secor Jr., D.T., 1990. Kinematics of Late Paleozoic continental collision between Laurentia and Gondwana. Science 250, 1702–1705. Said, I., 2005. Estudio de los corales rugosos con disepimentos del Mississippiense del NE de la meseta marroquí (sectores de Adarouch y Agouaraï) (unpublished). Ph.D. Thesis, Universidad Complutense de Madrid, Madrid, 240 pp.

379

Said, I., Rodríguez, S., 2007. Description of Tizraia berkhlii gen. et sp. nov. (Rugosa) from Adarouch Area (Brigantian, NE Central Morocco). Coloquios de Paleontología 57, 23–35. Said, I., Rodríguez, S., Berkhli, M., 2007. Preliminary data on the coral distribution in the Upper Visean (Mississippian) succession from Adarouch area (NE Central Morocco). In: Hubmann, B., Piller, W. (Eds.), Fossil Corals and Sponges. Proceedings of the 9th International Symposium on Fossil Cnidaria and Porifera, Graz 2003: Schriftenreihe der Erdwissenschaftlichen Kommission, 17, pp. 353–364. Wien. Said, I., Rodríguez, S., Berkhli, M., Cózar, P., Gómez-Herguedas, A., 2010. Environmental parameters of a coral assemblage from the Akerchi Formation (Carboniferous), Adarouch Area, central Morocco. Journal of Iberian Geology 36 (1), 7–19. Said, I., Rodríguez, S., Somerville, I.D., Cózar, P., 2011. Environmental study of coral assemblages from the upper Viséan Tizra Formation (Adarouch area, Morocco): implications for Western Palaeotethys biogeography. Neues Jahrbuch für Geologie und Paläontologie 260 (1), 101–118. Sando, W.J., 1990. Global Mississippian coral zonation. Courier Forschungsinstitut Senckenberg 130, 173–187. Scotese, C.R., 2002. Paleomap project. , http://www.scotese.com/earth.htm2002. Semenoff-Tian-Chansky, P., 1974. Recherches sur les Tétracoralliaires du Carbonifére du sahara Occidental. Editions du Centre Nationale de la Recherche Scientifique. Ser. 6, Science de la Terre, 30, pp. 1–316. Paris. Semenoff-Tian-Chansky, P., 1985. Corals. In: Wagner, R.H., Winkler-Prins, C.F., Granados, L.F. (Eds.), The Carboniferous of the World, II, Australia, Indian subcontinent, South Africa, South America and North Africa, 20. IUGS Publication, pp. 374–381. Somerville, I.D., 1997. Rugosa coral faunas from Upper Viséan (Asbian-Brigantian) buildups and adjacent platform limestones, Kingscourt, Ireland. Boletin Real Sociedad Española de Historia Natural, (Seccion Geologie) 92 (1–4). Somerville, I.D., Rodríguez, S., 2007. Rugose coral associations from the Upper Viséan of Ireland., Britain and SW Spain. In: Hubmann, B., Piller, W.E. (Eds.), Fossil Corals and Sponges. Proceedings of the 9th International Symposium on Fossil Cnidaria and Porifera, Graz, 2003: Austrian Academy of Sciences, Schriftenreihe der Erdwissenschaftlichen Kommissionen, 17, pp. 329–351. Vienna. Somerville, I.D., Strogen, P., Jones, G.Ll., Somerville, H.E.A., 1996. Late Viséan buildups of the Kingscourt Outlier, Ireland: possible precursors for Upper Carboniferous bioherms. In: Strogen, P., Somerville, I.D., Jones, G.Ll. (Eds.), Recent Advances in Lower Carboniferous Geology: Geological Society, London, Special Publications, 107, pp. 127–144. Somerville, I.D., Cózar, P., Rodríguez, S., 2007. Late Viséan rugose coral faunas from south-eastern Ireland: composition, depositional setting and palaeoecology of Siphonodendron biostromes. In: Hubmann, B., Piller, W.E. (Eds.), Fossil Corals and Sponges. Proceedings of the 9th International Symposium on Fossil Cnidaria and Porifera, Graz, 2003: Austrian Academy of Sciences, Schriftenreihe der Erdwissenschaftlichen Kommissionen, 17, pp. 307–328. Vienna. Somerville, I.D., Rodríguez, S., Said, I., Cózar, P., 2011. Coral assemblages from a Mississippian mud-mound complex, Central Morocco. In: Aretz, M., Deculée, S., Denayer, J., Poty, E. (Eds.), Abstracts, 11th Symposium on Fossil Cnidaria and Sponges: Kölner Forum für Geologie und Paläontologie, 19, pp. 158–159. Termier, H., 1936. Etudes géologiques sur le Maroc Central et le Moyen-Atlas septentrional. Notes et Mémoires du Service de Mines et Cartes Géologiques du Maroc 33 (1–4), 1–1566. Termier, G., Termier, H., 1950. Paléontologie marocaine. Tome II: Invertébrés de l'ère primaire. Fasc. 1, foraminifères, spongiaires et coelentérés. Notes et Mémoires du Service Géologique, Maroc 73, 1–218. Vachard, D., Cózar, P., 2006. The Family Calcifoliacea emend., Mississippian–Early Pennsylvanian algae. Rivista Italiana di Paleontologia e Stratigrafia 112, 23–34. Vachard, D., Cózar, P., 2010. An attempt of classification of the Palaeozoic incertae sedis Algospongia. Revista Española de Micropaleontología 42 (2), 129–241. Vai, G.B., 2003. Development of the palaeogeography of Pangaea from Late Carboniferous to Early Permian. Palaeogeography, Palaeoclimatology, Palaeoecology 196, 125–155. Verset, Y., 1988. Carte géologique du Maroc au 1/100,000. Feuille Qasbat-Tadla. Mémoire Explicatif Notes et Mémoires du Service Géologique, Maroc 340, 1–133. Wehrmann, A., Yilmaz, I., Yalçin, M.N., Wilde, V., Schindler, E., Weddige, K., SaydamDermitas, G., Özkan, R., Nazik, A., Nalcioglu, G., Kozlu, H., Karslioglu, Ö., Jansen, U., Ertug, K., Brocke, R., Bozdogan, N., 2009. Devonian shallow-water sequences from the North Gondwana coastal margin (Central and Eastern Taurides, Turkey): sedimentology, facies and global events. Gondwana Research 17 (2–3), 546–560. Wendt, J., Kaufmann, B., 2006. Middle Devonian (Givetian) coral-stromatoporid reefs in West Sahara (Morocco). Journal of African Earth Sciences 44, 339–350. Wendt, J., Belka, Z., Kaufmann, B., Kostrewa, R., Hayer, J., 1997. The world's most spectacular carbonate mud mounds (Middle Devonian, Algerian Sahara). Journal of Sedimentary Research 67, 424–436. Wendt, J., Kaufmann, B., Belka, Z., 2001. An exhumed Palaeozoic underwater scenery: the Viséan mud mounds of the eastern Anti-Atlas (Morocco). Sedimentary Geology 145, 215–233. Weyant, M., Conrad, J., Lemosquet, Y., Pareyn, C., Legrand-Blain, M., Bensaid, M., Termier, H., Termier, G., Massa, D., Lys, M., Manger, W.L., Semenoff-Tian-Chansky, P., Coquel, R., Lejal-Nicol, A., 1985. North Africa. In: Martínez-Díaz, Carlos (Ed.), The Carboniferous of the World. Instituto Geológico y Minero de España, Madrid, pp. 299–447.