The Zweikofel Formation of the Rattendorf Group in the Carnic Alps (Austria) is 95–102 m thick and consists of a cyclic succession of thin‐ to thick‐bedded fossiliferous limestone and intercalated thin intervals of siliciclastic sediment. The siliciclastic intervals were deposited in a shallow marine nearshore environment. The variety of carbonate facies indicates deposition in a shallow neritic, normal‐saline, low‐ to high‐energy environment. The Zweikofel Formation is characterized by a paracyclic vertical arrangement of facies and represents sedimentary sequences that are not well understood elsewhere in the Tethys. Fusulinids and conodonts from the upper Grenzland and Zweikofel formations in the Carnic Alps clearly suggest that what has been called ‘Sakmarian’ in the Tethys includes both the Sakmarian and Artinskian stages of the Global Time scale. Fusulinids from the lower part of the Zweikofel Formation at Zweikofel closely resemble those of the Grenzland Formation and approximately correlate with the upper part of the Sakmarian and lower part of the Artinskian of the Global Time scale. The upper part of the Zweikofel Formation correlates approximately with the lower‐middle (?) parts of the Artinskian Stage of the Global Time scale. A new regional Hermagorian Stage of the Tethyan scale is proposed between the Asselian and Yakhtashian. The lower boundary of the Hermagorian Stage is proposed to be located at the base of bed 81 in the 1015 section of Darvaz (Tadzhikistan). The boundary between the Hermagorian and Yakhtashian stages is placed at the base of bed 73 in the Zweikofel section at Zweikofel, Carnic Alps. In the Darvaz region, Tadzhikistan, the type area for the Yakhtashian Stage, this boundary has never been precisely defined. The entire fusulinid assemblage of the upper part of the Grenzland and Zweikofel formations reported herein includes 62 species of 18 genera, of which one subgenus and 12 species and subspecies are new. Copyright © 2012 John Wiley & Sons, Ltd.

No abstract

Streptognathodus Pa elements dominate conodont faunas from the proposed Carboniferous-Permian boundary stratotype at Aidaralash Creek, northern Kazakhstan. The phyletic development of this genus provides the means for subdividing the late Gzhelian to early Sakmarian prodeltaic section (Beds 9-37) into six zones. The preferred Global Stratotype Section and Point (GSSP) for the base of the Permian System is 27 m above the base of Bed 19 at the first occurrence of Streptognathodus isolatus Chernykh, Ritter, and Wardlaw, 1996. This arbitrarily chosen point in the evolutionary continuum of nodose streptognathodids is recognizable in basinal rocks elsewhere in the Ural trough (lower part of Bed 16 at Usolka) as well as the cyclic shelf succession of the American Midcontinent (Glenrock Limestone Member of the Red Eagle Limestone).Eight new species of Streptognathodus occur in the Aidaralash collections: S. bellus n. sp., S. costaeflabellus n. sp., S. flexuosus n. sp., S. glenisteri n. sp., S. longilatus n. sp., S. rectangularis n. sp., S. sigmoidalis n. sp., and S. tenuialveus n. sp. In addition, three morphotypes with limited occurrence (S. sp. A-C) are left in open nomenclature. New collections of topotype material from the nearby Tabantal River section permit clarification of S. barskovi (Kozur).

In the recent report of the Task Group to establish a Global Stratotype Section and Point (GSSP) at the K a s i m o v i a n-G z h elian boundary (Villa and Task Group, 2005) and in a series of recent publications (H e c kel et al., 2005; C h e r n y k h, 2005; M e n n i n g et al., 2006; etc.), the conodont species Streptognathodus simulator Ellison, 1941 (regarded as Idiognathodus by some authors), has been proposed as the best index-fossil for the definition of the base of the global

The Sakmarian Stage represents a critical time interval because the Late Paleozoic Ice Age reached its acme during this time. After extensive studies, we herein use the First Appearance Datum (FAD) of the conodont Mesogondolella monstra within the lineage from M. uralensis→M. mons-tra→M. manifesta at Bed 26/3 of the Usolka section in the southern Urals, Russia, as the primary signal for the base-Sakmarian GSSP. The first occurrence of the conodont Sweetognathus binodosus within the lineage from Sw. aff. merrilli→Sw. binodosus is used as an auxiliary marker for the base of the Sakmarian Stage. An extrapolated age for this GSSP is 293.52 ± 0.17 Ma produced by a Monte Carlo simulation based on two ash beds dated by chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-ID-TIMS). The 87 Sr/ 86 Sr isotopic value based on conodont apatite for the base of the Sakmarian Stage is approximately 0.70787. Two minor negative excursions in δ 13 C carb are present at the boundary levels and the upper one is consistent with the GSSP level. The documentation of fusulinaceans, ammonoids, brachiopods and palynology also aid intercontinental and marine-terrestrial correlation. The Usolka section meets the requirements for the GSSP and a monument has been established; correlation with sections in North America and South China is also well documented.