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Viséan and Early Namurian Ammonoids from the Tafilalt (Eastern Anti-Atlas, Morocco)
Abstract and Figures
Aus dem Tafilalt (östlicher Anti-Atlas, Marokko) werden Ammonoideen-Faunen aus dem Ober-Visé (Gattungen Prolecanites, Eoglyphioceras, Calygirtyoceras n. gen., Beyrichoceras, Maxigoniatites n. gen.) und von der Visé/Namur-Grenze (Prolecanites, Sudeticeras, Neogoniatites, Hypergo-niatites, Lusitanoceras, Dombarites) beschrieben. Die biogeographische Analyse zeitäquivalenter Faunen führt zu der Unterscheidung von vier Faunenprovinzen: Nord-Gondwana (Nordafrika, Kantabrisches Gebirge), Kazakhia (Südural, Zentralasien), Laurentia (Amerikanischer Mid-continent) und das Subvariszikum (Britische Inseln, Mitteleuropa). Abstract From the Tafilalt, eastern Anti-Atlas, Morocco, ammonoid faunas of Late Viséan (genera Prolecanites, Eoglyphioceras, Calygirtyoceras gen. nov., Beyrichoceras, Maxigoniatites gen. nov.), and the Viséan-Namurian Boundary (Prolecanites, Sudeticeras, Neogoniatites, Hypergoniatites, Lusi-tanoceras, Dombarites) are described. Biogeographical analyses of time-equivalent faunas lead to the separation of four faunal provinces: a North Gondwanan (North Africa, Cantabrian Mountains), a Kazakhian (South Urals, Central Asia), a Laurentian (American Midcontinent), and a Subvariscan (British Isles, Central Europe) Province.
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... In this paper, we want to explore these links using the well preserved Carboniferous materials from Morocco. After some quiescence following the pioneering works on Early Carboniferous (Mississippian) ammonoids from northern Africa (e.g.,Delépine 1941;Pareyn 1961;Hollard 1958), research on these fossils is currently experiencing a renaissance (Korn et al. 1999;2002, 2003a, b, 2005, 2010Ebbighausen et al. 2004Ebbighausen et al. , 2010Bockwinkel and Ebbighausen 2006;Klug et al. 2006;). Possibly due to the quality of the outcrop (large plains covered in loose gravel with fossils aligned according to their source rock), several Carboniferous ammonoid assemblages (including the Entogonites-bearing assemblage described byKorn et al. 2005; see map inFig. ...
... The recently collected, well preserved specimens were all found in the pebble-covered reg-like desert (reg: gravel-covered flat area) about 12 km south of the oasis of Dar Kaoua. This assemblage described herein was partially presented byKorn et al. (1999Korn et al. ( , 2005Korn et al. ( , 2007) including one of the stratigraphically oldest occurrences of a member of the genus Goniatites (G. lazarus) and a new species of Entogonites (E. ...
... the original species diagnosis byKorn et al. (1999), the ontogenetic changes were described in a somewhat misleading way: in the same article, we (Korn et al. 1999: p. 354) had stated that the " Umbilicus[is]very narrow in early growth stages (uw/dm = 0.08 at 20–30 mm dm) and slightly opening during ontogeny (stages (uw/dm = 0.10 to 0.12 at 40–60 mm dm). " When measuring the umbilical width throughout the entire post-hatching ontogeny, a rather constant reduction of the uw/dm ratio from 0.62 to 0.14 was measured. ...
Early late Viséan ammonoid assemblages of the Tafilalt (Morocco) are composed of diverse and well-preserved specimens. Here, we describe mass-occurrences of juvenile specimens. Some of the juveniles display a conch morphology that differs fundamentally from the adult stages. Accordingly, we emend the species diagnoses of Goniatites lazarus as well as Calygirtyoceras darkaouaense, introduce the species Entogonites bucheri sp. nov., and discuss possible ecological implications of the morphologic changes throughout ontogeny. In particular, we compare the changes in conch morphology
through ontogeny in the light of Pareto Optimisation. Although shape is not a proof of function, it appears plausible that juvenile conchs were selected rather for compactness while adult conchs were positively selected for conchs with improved hydrodynamic properties.
... The pioneer workers established faunal lists containing mainly ammonoids, brachiopods and corals. It is only in recent years that this fauna has regained some attention; today modern data are available for ammonoids ( KORN et al. 1999, KLUG et al. 2006) and gastropods ( HEIDELBERGER et al. 2009). WENDT et al. (2001 provided some determinations of corals (family and genus level) and brachiopods from outcrops around mud mounds. ...
... The new data only partly confirm the previous biostratigraphic work. The data for upper part of the studied transect are largely in agreement with the existing data on ammonoids ( KORN et al. 1999, KLUG et al. 2006). As already observed elsewhere in Morocco (ARETZ 2010), typical European coral markers for the Brigantian do not occur although ammonoids indicate this age in the upper part of the Zrigat Formation. ...
... The continuous succession of the Upper Visean and all the Serpukhovian ammonoid genozones allows the correlation the Verkhnyaya Kardailovka section with synchronous sections of the Urals, Tien Shan, Western Europe, Canada, the United States, and China, characterized by ammonoids. The taxonomic composition of the ammonoids from the Verkhnyaya Kardailovka section is typical for the South Urals region and substantially differs from faunas of Europe and North America, although their generic composi tion is similar (Ruzhencev and Bogoslovskaya, 1971;Korn et al., 1999). Therefore, the interregional corre lation of the Upper Visean and Serpukhovian beds is based on identical ammonoid genera and comparison between evolutionarily close species. ...
... The occurrence of the foraminiferal species Aster oarchaediscus parvus in this interval is consistent with such a correlation, since the latter appears in the upper part of the Mikhailovian Horizon in the Moscow Basin and is distributed through the entire Ser pukhovian Stage (Rauser Chernousova et al., 1948;Makhlina et al., 1993). The ammonoid assemblage with Prolecanites librovitchi and Neogoniatites milleri found in the middle part of the Venevian Horizon likely corresponds to the upper half of the Brigantian Substage of Western Europe and North America (Korn, 1999;Korn and Feist, 2007) and the S. ornatissimus Zone of Texas, which is con firmed by the occurrence of the closely related Neogo niatites species (Titus, 1999). ...
The paper describes a Serpukhovian Stage section, exposed along the Ural River near the village of Verkhnyaya Kardailovka
(Bashkortostan). The section is uniquely complete and is proposed as a GSSP candidate for the base of the Serpukhovian. The
Upper Visean and Serpukhovian beds are represented by relatively deep facies, which contain ammonoids, conodonts, ostracods,
foraminifers, and other fossils. The section is described bed-by-bed and subdivided into zones based on four faunal groups.
The lower boundary of the Serpukhovian is placed at the base of the Lochriea ziegleri conodont zone. The stratigraphic units are correlated with synchronous beds of the East European Platform, the Donets Basin,
Western Europe, Central Asia, and North America.
KeywordsSerpukhovian Stage-Visean Stage-GSSP-Verkhnyaya Kardailovka-foraminifers-ostracods-conodonts-ammonoids
... Since the late 1990s, we studied a number of newly collected ammonoid faunas from Morocco and Algeria. These investigations were published in a series of articles (KORN et al. 1999KORN et al. , 2003KORN et al. , 2005 EBBIGHAUSEN et al. 2004; BOCKWINKEL & EBBIGHAUSEN 2006; KORN & EBBIGHAUSEN in KLUG et al. 2006), which focused on documenting of the North African ammonoid diversity. In this report, we present the overall stratigraphic synthesis based on these previous studies. ...
... This assemblage, which differs markedly in its generic composition from the preceding assemblage, occurs at the top of the Zrigat Formation of the Gara el Itima. Goniatites is no longer present and is replaced by the more advanced Dombarites and Neogoniatites; these are accompanied by new components such as Sudeticeras (KORN et al. 1999; KLUG et al. 2006). A possibly equivalent horizon was described by PAREYN (1961a) from Hadjer el Beïda in the Bechar region of northwestern Algeria. ...
Fifteen ammonoid assemblages can be distinguished in the Tournaisian and Viséan succession of Morocco and Algeria; these are (in ascending order): Gattendorfia-Eocanites Assemblage, Gattendorfia-Kahlacanites Ass., Goniocyclus-Protocanites Ass., Acrocanites-Kazakhstania Ass., Pericyclus-Progoniatites Ass., Ammonellipsites-Merocanites Ass., lower Bollandites-Bollandoceras Ass., upper Bollandites-Bollandoceras Ass., Entogonites-Maxigoniatites Ass., Goniatites tympanus Ass., Goniatites rodioni Ass., Goniatites gerberi Ass., Dombarites granofalcatus Ass., Platygoniatites rhanemensis Ass., and Ferganoceras torridum Ass. Several of these faunal complexes can be subdivided into species zones, which can be correlated with ammonoid successions in other regions such as Central Europe. The new family Acrocanitidae is erected and placed in the Prionoceratoidea. Additional new taxa are Acrocanites smidensis n. sp., Jdaidites serpentinus n. gen. n. sp., Beyrichoceras merzougense n. sp., and Goniatites tympanus n. sp.
... Since the late 1990s, we studied a number of newly collected ammonoid faunas from Morocco and Algeria. These investigations were published in a series of articles ( KORN et al. 1999KORN et al. , 2003KORN et al. , 2005EBBIGHAUSEN et al. 2004;BOCKWINKEL & EBBIGHAUSEN 2006;KORN & EBBIGHAUSEN in KLUG et al. 2006), which focused on documenting of the North African ammonoid diversity. In this report, we present the overall stratigraphic synthesis based on these previous studies. ...
... This assemblage, which differs markedly in its generic composition from the preceding assemblage, occurs at the top of the Zrigat Formation of the Gara el Itima. Goniatites is no longer present and is replaced by the more advanced Dombarites and Neogoniatites; these are accompanied by new components such as Sudeticeras ( KORN et al. 1999;KLUG et al. 2006). A possibly equivalent horizon was described by PAREYN (1961a) from Hadjer el Beïda in the Bechar region of northwestern Algeria. ...
... The extensive studies of the Palaeozoic rocks of the Anti-Atlas by Wendt et al. (1984) and Wendt (1985Wendt ( , 1988 have motivated special focus on the biostratigraphic subdivision of the Late Devonian and Carboniferous sequences (Fig. 1). The re-discovery, in the mid-1990's, of the ammonoid-bearing localities described by Delpine (1941) resulted in a first monograph on the Late Visan ammonoid faunas from the area of Taouz (Korn et al. 1999), followed by a number of studies (Korn et al. 2002(Korn et al. , 2003(Korn et al. , 2005(Korn et al. , 2007Klug et al. 2006), during which the gastropod material described here was assembled. Therefore, all the material can precisely be assigned to distinct horizons in terms of ammonoid biostratigraphy (Fig. 2). ...
Diverse and well-preserved Late Viséan (Early Carboniferous) gastropod faunas from the eastern Anti-Atlas of Morocco are described herein. The new genus Itimaspira n. gen. is described as well as the six new species Ananias weyeri n. sp., Itimaspira klugi n. sp., Nodospira krawczynskii n. sp., Baylea cordulae n. sp., Cinclidonema marocensis n. sp., and Schizostoma africanum n. sp., together with specimens of the genera Baylea, Orthonema, ?Knightella sp. and Macrochilina in open nomenclature.
doi:10.1002/mmng.200900006
... Data on macrofaunas from the Mississippian succession of eastern Tafilalt (Anti-Atlas, south-eastern Morocco) ( Fig. 1) were long-time restricted to the faunal lists and brief descriptions in the pioneer studies of the regional geology of Clariond (1932Clariond ( , 1934 and Delépine (1939Delépine ( , 1941. Quite recently, this area has regained some attention, especially for its rich cephalopod and gastropod faunas (Korn et al., 1999;Klug et al., 2006;Heidelberger et al., 2009;Korn et al., 2013). Aretz et al. (2013) provided some preliminary data related to rugose corals and brachiopods from the strata located between the Jebel Begaa to the SW and the Gara El Itima to the NE (Fig. 2). ...
Late Viséan brachiopods from the eastern Tafilalt (Morocco), and more precisely from the area comprised between the Jebel Begaa to the southwest, and Gara El Itima to the northeast (close to the Algerian border), are described systematically for the first time. Despite the limited material available, 18 species belonging to 17 genera have been recognized within the limestone beds of the Merdani and Zrigat formations, in which the productides (Productidina) and spiriferides are the most diverse. Representatives of the subfamily Gigantoproductidinae, which are close, if not conspecific, to those present in contemporaneous rocks of the nearby Béchar Basin (Algeria), occur in the late Viséan Zrigat Formation. Additional research based on more abundant material is necessary to investigate thoroughly the relationships existing between the Béchar Basin and the Tafilalt, which may have been part of the former during the Carboniferous.
Considerable progress has been made by international teams in refining the traditional ammonoid zonation that remains the backbone of Carboniferous stratigraphy. The Carboniferous ammonoid genozones, with a few gaps, are now recognized throughout the entire system in most successions worldwide. Refined collecting and documentation of occurrences in Western Europe, North Africa, the Urals, China, and North America, aimed to establish the first evolutionary occurrences, and facilitated correlation with foraminiferal and conodont scales for most of the Carboniferous. From ten to eleven ammonoid genozones are now recognized in the Mississippian, and eight to nine genozones in the Pennsylvanian. Of these, the established lower boundaries of the subsystems are reasonably well correlated with the ammonoid zonation, whereas correlations with the ratified foraminiferal-based lower boundary of the Viséan and other stage boundaries, currently under discussion, need further research. Future success in the ammonoid geochronology will also depend on accurate identification and re-illustration of the type material, including material described by pioneers of ammonoid biostratigraphy.
The Bashkirian (Late Carboniferous) ammonoid genus Bilinguites has a nearly global distribution in the tropical and subtropical zones and 25 species have been described up till now. Most of them are considered endemic, but some may have a wide geographic distribution. Our study on new and previously collected materials from North China (Gansu and Ningxia) shows that the stratigraphically youngest species of Bilinguites in North China and Western Europe are morphologically very similar, possibly indicating correspondence of the ammonoid faunas. Bilinguites scalpratus is revised and established as a stratigraphically important species of the genus in North China; it co-occurs with the first gastrioceratid species Cancelloceras pachygyrum. This occurrence can be correlated with the Western European co-occurrence of Cancelloceras cancellatum and Bilinguites superbilinguis at the base of the G1 Zone.
In some Devonian strata in the eastern Anti‐Atlas, fossil invertebrates are abundant, display a high taxonomic diversity and indicate many shifts in palaeoecology. This is reflected in changes in faunal composition of invertebrates and vertebrates. Fossils of jawed vertebrates of late Lochkovian and younger age have been recorded and are relatively common with their abundance and diversity increasing towards the Late Devonian. Environmental changes in the Devonian also left their mark in the preservation of vertebrates and invertebrates from the Anti‐Atlas, which varies strongly through time and regionally. This variation partially reflects environmental changes linked with the evolution of small marine basins during the disintegration of the continental shelf of Gondwana in this region, fluctuations of the regional sea level and other environmental changes. To improve our understanding of these ecological changes, of shifts in preservation through the succession and of the formation of Fossil‐Lagerstätten, we analysed the mineral composition of some invertebrate and vertebrate samples of Devonian and Early Carboniferous age by Raman spectroscopy and X‐ray diffraction. Additionally, we characterized some of these Fossil‐Lagerstätten using palaeontological and sedimentological parameters. We examined eight Devonian Konzentrat‐Lagerstätten and two Konservat‐Lagerstätten with soft‐tissue preservation (the Famennian Thylacocephalan Layer and the Hangenberg Black Shale of the southern Maïder). The last two are the first Konservat‐Lagerstätten described from the Devonian of North Africa. The taphonomic and oceanic settings suggest that these Konservat‐Lagerstätten are formed because of stagnation (related to vertical restriction of water exchange and water depth rather than limited spatial water exchange and a lateral restriction) in the relatively small Maïder Basin with limited water exchange with the neighbouring Tafilalt Basin. The temporally low oxygen levels in the Maïder Basin are a possible reason for the reduced chondrichthyan diversity (missing demersal and shallow water species) compared to the Tafilalt Platform.
In the South Portuguese Zone, sections located in the Bordeira Antiform (localities Praia de Murracao, Praia das Quebradas, and Rocha da Lagoa) show a Late Visean faunal succession of goniatites, which principally resembles that of Northwestern and Central Europe (e. g. the Rhenish Massif). The following goniatite zones were identified in Southwest Portugal: Goniatites budsoni Zone, Goniatites spirifer Zone, and the zones between the Arnsbergites gracilis Zone and the Lyrogoniatites liethensis Zone. On the basis of goniatites, a proposal for a subdivision of the Late Visean into the three substages Late Visean A, B and C is given.
Extract
INTRODUCTION
Intensive collecting during the past fifteen years from the marine bands in the Millstone Grit of the Pennines has shown the possibility of further faunal division of the lower part of that formation, especially in that great thickness of shales, the Sabden Shales, which occurs between the Kinderscout and Pendle Grit Groups. The need for that further subdivision is emphasized when correlation of the succession in various parts of the Pennines is attempted, especially when the successions are those obtained from borings and the fossils are few and far between. The authors, therefore, in this paper describe the various goniatite faunas that have been collected from the shales of the Kinderscout Grit Group and the Upper Sabden Shales, and put forward a more detailed faunal subdivision of the Lower Reticuloceras (R1) Stage. It was originally intended to collect from and describe the faunas from all available exposures of the Lower Reticuloceras Stage in the Pennines and describe not only the faunal succession but its variation from area to area. Circumstances have prevented this and the zonal succession put forward in this paper must therefore be regarded as a provisional one. The authors record their thanks to all those who have helped in the collecting of fossils or who have placed at the disposal of the authors their own collections or specimens from collections in their charge. In particular thanks are given to the officers of the Yorkshire Unit of the Geological Survey, to G. Cotton and Messrs. Steel Brothers ...
Extract
I. Introduction.
This zone, approximately of Middle Viséan age, was, together with the succeeding P zone, the period of greatest evolutionary activity in the goniatite fauna of the Carboniferous era.
For the first time we meet with practically the whole of those stocks, which either unchanged or in their derivative genera, were to play such an important and at times dominant part in the fauna of the Middle and Upper Carboniferous. Indeed the fresh evolutionary outburst in the Permian period of other areas concerned just those stocks which we see first in zone B.
For the first time we make the acquaintance of the genus Goniatites, s.s. The genus Dimorphoceras appears and introduces secondary saddles in the main lobes. The newly arrived genus Beyrichoceras and the allied genera Beyrichoceratoides and Sagittoceras appear to be the ancestral genera of all our dominant Middle and Upper Carboniferous goniatites. The Prolecanitids shew a sudden burst of evolutionary activity, and new genera such as Pronorites and Daraelites⁴ are seen for the first time, curiously enough to disappear again, except in Minorca⁷, until the close of the Carboniferous period. Zone B marks also the last appearance of the Devonian genus Aganides².
The material on which this paper has been based, in addition to specimens in my own collection, has been loaned by various collectors and officials of museums. I am especially indebted to Dr. R. G. S. Hudson, Mr. F. W. Anderson, Dr. D. Parkinson, Dr. J. W. Jackson, Mr. E. W. J. Moore, Mr.
Extract
Stratigraphy.
The Carboniferous strata consist, except near the shore lines of that age, of two clearly marked divisions: a lower division, consisting mainly of clear water deposits (Mountain Limestone) and an upper division (Millstone Grit and Coal Measures), almost entirely composed of beds of detrital origin. When, however, the sequence is examined more closely it is seen that the details of the lithological succession vary greatly in different areas, and hence arises doubt and hesitation in correlating widely separated areas.
The work of zoning the lower (Mountain Limestone) division by means of its contained fossils made great strides in Britain in the opening decade of the century, mainly through the researches of the late Dr. A. Vaughan. The main zonal divisions of the Lower Carboniferous propounded by him and based on the coral sequence, are now generally accepted as a basis for the correlation of widely separated deposits in North West Europe. His views on the succession exposed in the North of England formed Dr. Vaughan’s last paper, published in the Proceedings of this Society for 1916 (Vol. XIX, Part II, p. 41 et seq.).
In Britain and Western Europe generally, the oncoming of the coarse detrital deposits of Upper Carboniferous time drove out the coral fauna, and this group is, therefore, not available as a time-index for the Upper Carboniferous rocks. We are, therefore, compelled to turn to other groups more or less abundantly preserved in these beds, namely the lamellibranchs and goniatites. The researches of the late Dr. …
Thèse--Université de Montpellier. Each plate accompanied by leaf with descriptive letterpress not included in the paging. "Listes bibliographiques": p. [19]-29.
Über ein neues Vorkommen unterkarbonischer Pericyclus-Schichten im Oberharz. – Neues Jahrbuch für Geologie und Paläontologie
SCHINDEWOLF, O.H. (1951) Über ein neues Vorkommen unterkarbonischer Pericyclus-Schichten im Oberharz. – Neues Jahrbuch
für Geologie und Paläontologie, Abhandlungen, 93 (1), 23–116,
Fig. 1–36, Pl. 3–7, Stuttgart.