Dieter Weyer

Numerical calibration of the Devonian-Carboniferous boundary: Two new U-Pb isotope dilution–thermal ionization mass spectrometry single-zircon ages from Hasselbachtal (Sauerland, Germany)

The Hasselbachtal section (Sauerland, Germany) is an auxiliary global stratotype of the Devonian-Carboniferous boundary and one of the most important reference sections for the evolution of the latest Famennian to earliest Tournaisian pelagic fauna. Biostratigraphically well controlled altered volcanic ash layers (metabentonites) intercalated in the section afford a perfect opportunity for a numerical fixing of this important Paleozoic period boundary. We have performed U-Pb isotope dilution-thermal ionization mass spectrometry (ID-TIMS) analyses on (sub)microgram-sized single zircons and zircon fragments extracted from two metabentonites (beds 79 and 70) in the lowermost Tournaisian part of the section. Bed 79 metabentonite is positioned directly above the Devonian-Carboniferous boundary within the Siphonodella sulcata conodont zone. Five concordant analyses form a cluster with a 2 0 6 Pb/ 3 3 8 U concordia age of 360.5 ′ 0.8 Ma. Zircons of the next younger metabentonite (bed 70), in the lower Siphonodella duplicata conodont zone, yielded a tightly grouped cluster of 10 concordant analyses with a 2 0 6 Pb/ 2 3 8 U concordia age of 360.2 ′ 0.7 Ma. On the basis of these two new single-zircon ages and previously published late Famennian U-Pb ID-TIMS ages, the Devonian-Carboniferous boundary is reinterpolated herein to 360.7 ′ 0.7 Ma.

Larval morphology and ontogeny of a Late Devonian phacopid with reduced sight from Thuringia, Germany

Exceptionally rich and well-preserved silicified exuviae comprising numerous immature growth stages allow the tracing of detailed morphological and morphogenetical features of the reduced-eyed phacopid species Cryphops ? ensae (Richter and Richter, 1926) from the latest Famennian of Thuringia (Central Germany). Ontogenetic features of this species are more similar to those of Phacops than to Trimerocephalus.

Discussion on high-precision 40Ar/39Ar spectrum dating on sanidine from the Donets Basin, Ukraine: evidence for correlation problems in the Upper Carboniferous Journal, Vol. 156, 1999, 527–533

Scientific editing by Ray Burgess. Manfred Menning, Dieter Weyer, Immo Wendt, Nicholas J. Riley & Vladimir I. Davydov write: ⇓Hess et al. (1999, p. 528) investigated ‘about one dozen rock samples from coal tonsteins’ from the Donets Basin for Ar/Ar sanidine dating. ‘Unfortunately, only one proved could be dated isotopically. All other samples contain no chronometer minerals that which were (1) of primary volcanic origin and (2) unaffected by secondary alterations’. The datable sample has an age of 305.5±1.5 Ma (±1σ without the age errors of the monitors) using sanidines for high-precision Ar/Ar spectrum dating. However, the expected age is about 6 Ma older according to sanidine tuff ages from Central Europe (⇓Lippolt et al. 1984). Hess et al. (p. 532) concluded that ‘the most plausible explanation [for this deviation] is an inaccurate or even erroneous [biostratigraphic] correlation of the Donets Basin Carboniferous with the Western European and non-European Carboniferous occurrences’. They ‘suggest a reconsideration of the validity of the current biostratigraphic correlation between the Carboniferous of western and East Europe’ (p. 527). We reconsider the biostratigraphic correlation because an age difference of about 6 Ma corresponds to the duration of about two substages (stages) of the Upper Carboniferous e.g., Westphalian B+C (Duckmantian+Bolsovian). Such fundamental biostratigraphic miscorrelation between best known mining areas is extremly improbable. We explain the presumed age difference by a significant correction of the erroneous biostratigraphic correlation used by Hess et al. (fig. 2), which reduces the discussed about 6 Ma to a markedly smaller difference of about 4 Ma. These 4 Ma are not significant if (necessarilly) 2σ analytical age uncertainties are taken into account. ### Biostratigraphy According to the lithostratigraphic standard scheme of the Donets Basin the tonstein in coal seam l31 studied by Hess et al. occurs in the middle part of the C26 suite …

Late Devonian stromatoporoid from the Sudetes Mountains (Poland), and endemicity of the Upper Famennian to Uppermost Famennian (=“Strunian”) stromatoporoid fauna in western Europe

A single large stromatoporoid specimen collected by one of us (D. W.) from the so called “Main Limestone” at Dzikowiec (= Ebersdorf) in the Sudetes Mountains of Lower Silesia, Poland, is here assigned toTrupetostromaParks 1936. It is typical of the Upper Famennian to Uppermost Famennian (= “Strunian”) stromatoporoid Assemblage no. 3 defined byStearn (1987) andStearn, Halim-Dihardja & Nishida (1987). This assemblage, confined to western Europe and Kazakhstan, is dominated by clathrodictyids but without labechiids. Other genera present together withTrupetostroma in this assemblage includeAmphipora, Anostylostroma, Atelodictyon, Clathrocoilona, Clathrodictyon, Clathrostroma, Gerronostroma, Petridiostroma andStromatopora. All those genera were widespread globally through the Middle and Upper Devonian (Givetian-Frasnian), but in the the Upper Famennian to Uppermost Famennian (= “Strunian”) deposits of western Europe they appear as typical “Lazarus taxa” — a consequence of the Frasnian/Famennian boundary Kellwasser Event which terminated reefal environments worldwide. Viewed at the generic level, the western European the Upper Famennian to Uppermost Famennian (= “Strunian”) stromatoporoid fauna is essentially ubiquitous, but at the species level endemism is pronounced. This may have resulted from reactivation of disjunct biotopes when conditions became conducive, locally, to renewed reefal development. This endemicity is analysed using the Jaccard Coefficient.RésuméUn unique spécimen de stromatopore de grande taille a été récolté par un de nous (D. W.) dans la localité polonaise de Dzikowiec (= Ebersdorf), en Basse Silésie, Monts Sudètes, dans le niveau qualifié «calcaire principal» d’un vaste olistholite. Ce stromatopore est attribué au genreTrupetostromaParks 1936. Il correspond typiquement à l’assemblage n° 3 de stromatopores du Famennien Supérieur — Famennien terminal (= «Strunian») défini parStearn (1987),Stearn, Halim-Dihardja & Nishida (1987). Cet assemblage, limité à l’Europe occidentale et au Kazakhstan, se caractérise par la présence de nombreux clathrodictyidés et l’absence de labéchiidés. Les autres genres qui, dans le the Famennien supérieur — Famennien terminal (= «Strunien») d’Europe occidentale, accompagnentTrupetostroma, sontAmphipora, Anostylostroma, Atelodictyon, Clathrocoilona, Clathrodictyon, Clathrostroma, Gerronostroma, Petridiostroma, Stromatopora. Au cours du Dévonien moyen (Givétien) et supérieur (Frasnien), tous ces genres étaient largement représentés dans les environnements récifaux à la surface du globe terrestre. Ainsi, en Europe occidentale, ces genres correspondent typiquement à des taxons «Lazare» survivant à l’événement Kellwasser, à la limite Frasnien/Famennien, qui a fait disparaître les environnement récifaux de la surface du globe. Si, au niveau générique, la faune de stromatopores du the the Famennien supérieur — Famennien terminal (= «Strunian») apparaît très ubiquiste en Europe occidentale, il faut toutefois souligner l’important endémisme spécifique lié à la reconquête de biotopes dispersés, lorsque les conditions redevinrent favorables au développement récifal. Cet endémisme est analysé à l’aide du coefficient de Jaccard.KurzfassungEine einzelne große Stromatopore, die von einem von uns (D. W.) im sog. „Haupt-Kalkstein“ von Dzikowiec (= Ebersdorf) in den Sudeten Unterschlesiens (Polen) aufgesammelt wurde, wird hier der GattungTrupetostromaParks 1936 zugeordnet. Sie ist typisch für die Stromatoporen-Vergesellschaftung Nr. 3 des oberen bis obersten (= „Strunium“) Famennium, wie sie vonStearn (1987) undStearn, Halim-Dihardja & Nishida (1987) definiert wurde. Diese Vergesellschaftung, die auf das westliche Europa und Kasachstan beschränkt ist, wird von Clathrocytiden dominiert, jedoch ohne Labechiiden. Weitere Gattungen, die zusammen mitTrupetostroma in dieser Vergesellschaftung vorkommen, sindAmphipora, Anostylostroma, Atelodictyon, Clathrocoilona, Clathrodictyon, Clathrostroma, Gerronostroma, Petridiostroma undStromatopora. All diese Gattungen waren im Mittel- und Ober-Devon (Givetium-Frasnium) im globalen Maßstab weit verbreitet, in den Ablagerungen des oberen bis obersten (= „Strunium“) Famennium im westlichen Europa stellen sie typische „Lazarus-Taxa“ dar — eine Folge des Kellwasser-Ereignisses an der Frasne/Famenne-Grenze, das weltweit die Riff-Habitate ausgelöscht hat. Betrachtet man die Stromatoporen-Fauna des westlichen Europa im oberen bis obersten (= „Strunium“) Famennium auf dem Gattungsniveau, ist sie allgegenwärtig; auf dem Artniveau hingegen sind Endemismen auffallend. Dieser Sachverhalt mag darauf hinweisen, daß aufgrund einer Reaktivierung auseinandergerissener Biotope und verbesserten Bedingungen es — lokal — zu erneuten Riff-Entwicklungen kommt. Dieser Endemismus wird analysiert unter Anwendung des Jaccard-Koeffizienten.

Large-sized Early Permian “caninioid” corals from the Karavanke Mountains, Slovenia

Abstract. A new monospecific “caninioid” genus, Preisingerella n. gen., from the lower Permian of the Karavanke Mountains (Southern Alps, Slovenia) is erected. The type species is Preisingerella stegovnikensis n. sp. The new taxon can be differentiated from other Caninia-type genera by its specific ontogeny and features of its dissepimentarium. Corals with such morphology had a wide distribution during the Carboniferous and early Permian, occurring in mostly shallow-water carbonate rocks. The phylogenetic relationships within this group are mostly unclear due to similarities in the adult stages. The earlier stages reveal the main distinguishing features that are decisive for a generic assignment, but these have rarely been well preserved and properly considered. The new taxon is compared with related genera of the Cyathopsidae and species of Caninella Gorskiy, 1938 characterized by lateral dissepiments. Large numbers of specimens of the new species, representing a monospecific assemblage, have been collected from the Born Formation at Mt. Stegovnik. Sedimentological and microfacies characteristics, as well as macro- and microfossil assemblages, underline this correlation. The fusulinoidean assemblage of the Born Formation, with Sphaeroschwagerina carniolica (Kahler and Kahler, 1937), as the predominant species, corresponds to the time span between the Sphaeroschwagerina moelleri-Schwagerina fecunda and Pseudofusulina moelleri zones, indicating a late Asselian to early Sakmarian age in the Southern Urals.