The Viséan sedimentary succession at the Gara el Itima (Anti-Atlas, Morocco) and its ammonoid faunas

Abstract

A late Visé an section of clastic and carbonatic rocks is described from the eastern part of the Anti-Atlas (Morocco). The sedimentary succession is a mixed carbonate-siliciclastic system influenced by sea-level fluctuations. The sedimentology of the section is interpreted with respect to transgressive-regressive cycles and systems tracts. Highstand sediments yielded ammonoid assemblages from six horizons; a total of 1,040 specimens separated into 20 species are described in the palaeontological section. The genus Itimaites is new, together with the 16 new species Itimaites parabolicus n. sp

Goniatites Zone (middle Mississippian) ammonoids of the Antler Foreland Basin (Nevada, Utah)

“…-Reports of late Viséan ammonoids from Algeria and Morocco have been made for many years (Delépine 1941), however, only recently has the succession been documented in enough detail that relatively detailed comparisons can be made with Europe and North America (Korn et al 1999(Korn et al , 2005(Korn et al , 2007Klug et al 2006 and references within). The Tafilalt, particularly the area around the Gara el Itima, has produced a succession of which four assemblages correlate closely with those observed in North America.…”

“…Goniatites tympanus Korn, Bockwinkel & Ebbighausen, 2007 compares very closely to the European taxon G. moorei, leaving Korn et al (2007) to conclude that the Moroccan ammonoid assemblage correlates with the upper Asbian (B 2 ) of the British Isles, making it the equivalent of the Calygirtyoceras arcticum interval of Utah. Overlying the Goniatites tympanus assemblage is a more diverse assemblage containing G. rodioni Korn & Ebbighausen, 2006, advanced Calygirtyoceras (C. zrigatense Korn & Ebbighausen, 2006), Itimaites, and Prolecanites. The phylogenetic stage of the Calygirtyoceras in this assemblage suggest it is equivalent our G. primum or G. gordoni intervals, most likely the former.…”

“…The highest Goniatites interval in Morocco is characterized by a low diversity assemblage consisting of three species of the genus (G. stenumbilicatus Kullmann, 1961, G. gerberi Korn & Ebbighausen, 2006, and G. evelinae Korn & Ebbighausen, 2006). The lack of accessory taxa in the Moroccan assemblage make precise correlations difficult, but the species appear to be close phylogenetic equivalents of G. multiliratus Gordon (Korn & Ebbighausen in Klug et al 2006), G. deceptus sp.…”

“…The lack of accessory taxa in the Moroccan assemblage make precise correlations difficult, but the species appear to be close phylogenetic equivalents of G. multiliratus Gordon (Korn & Ebbighausen in Klug et al 2006), G. deceptus sp. nov., and G. eganensis sp.…”

“…Brüning 1923;Schmidt 1925;Nicolaus 1963;Korn 1988Korn , 1990Korn , 1997a, the Ardennes (e.g. de Koninck 1880, Delépine 1940, the South Portuguese Zone (Korn 1997b, Korn & Horn 1997, the Moroccan Meseta (Delé-pine 1941, Korn & Ebbighausen 2008), South Variscan basins such as the Cantabrian Mountains (Kullmann 1961), the Anti-Atlas of Morocco (Korn et al 2005(Korn et al , 2007Klug et al 2006), the South Urals (Bogoslovskaya 1966, Ruzhencev 1966, Novaya Zemlya (Kusina 1987, Kusina & Yatskov 1999, Xinjiang (Liang & Wang 1991), Alaska , and the United States Midcontinent (e.g. Girty 1909Girty , 1911Gordon 1962Gordon , 1965Drahovzal 1972;Drahovzal & Quinn 1972;Saunders et al 1977).…”