The standard Late Devonian conodont zonation between the top of the Upper marginifera Zone and the earliest Carboniferous Siphonodella sulcata Zone is revised to replace the former velifer , styriacus , and costatus zonal groups, which were based primarily on genera other than Palmatolepis , and to eliminate a hiatus above the Upper costatus Zone. The changes were enabled by a new phylogenetic model of Palmatolepis , by range extensions that bridge former gaps between the records of some Palmatolepis taxa, and by further taxonomic revisions of some double-rowed Bispathodus taxa. Basing the standard zonation on conodonts of primarily pelagic biofacies permits construction of parallel, alternative zonations for shallower water biofacies and estimation of phylogenetically more precise zonal timespans.

Abstract Chrono-, litho- and biostratigraphy across the Devonian–Carboniferous transition are reviewed to provide a precise time framework for the global Hangenberg Crisis and for the current search for a revised basal Carboniferous Global Stratotype Section and Point (GSSP). The outer shelf deposits of the Rhenish Massif (Germany) form a lithological standard. Pre- (main Wocklum Limestone), lower (top Wocklum Limestone/Drewer Sandstone to Hangenberg Black Shale), middle (Hangenberg Shale/Sandstone), upper (Stockum Limestone), and post-crisis (Hangenberg Limestone) deposits are defined. Combined with the conodont, ammonoid and miospore zonations and eustatic trends, this succession can be correlated internationally. The contemporaneous successions of the Ardennes serve as a reference for shallow shelf settings. The positive and negative aspects of five options for a redefined Devonian–Carboniferous boundary level are discussed: (1) base of the black shale (main extinction level, base of Bispathodus costatus–Protognathodus kockeli Interregnum and LN Zone), (2) sequence boundary (widespread unconformities) or glacial and regressive peak (base of Hangenberg Sandstone), (3) base of the kockeli Zone and of initial postglacial transgression (base of lower Stockum Limestone), (4) entry of Siphonodella ( Eosiphonodella ) sulcata (base of upper Stockum Limestone), and (5) base of post-crisis interval (base of Hangenberg Limestone), at approximately the poorly correlated current GSSP level. Due to homonymy, Siphonodella ( Siphonodella ) hassi Ji, 1985 is renamed as Siphonodella ( Siphonodella ) jii nom. nov. Consequently, the mid-lower Tournaisian S. ( S .) hassi Zone (previous Upper S. ( S. ) duplicata Zone) becomes the S. ( S. ) jii Zone.

Abstract The late Famennian mass extinction has been associated with a worldwide anoxic event evidenced at many sites by the accumulation of organic-rich shales starting prior to the Devonian–Carboniferous (D/C) boundary. Environmental reconstructions are hampered by the fact that only a few D/C boundary sections exist in carbonate facies. One of these is the Palaeozoic Steinberg section, Eastern Alps, Austria. Based on detailed geochemical investigations and correlation with previously investigated sections, we propose a succession of events from the late Famennian to the Tournaisian. Both the low total rare earth element (REE) contents and the normalized REE distribution patterns indicate low terrigenous input from the praesulcata Zone to the typicus Zone. The δ 13 C, δ 18 O, δ 34 S and total organic content (TOC) show a shift towards higher values, which correlates well with the late Famennian isotopic trends that are related to a period of active ocean circulation, cooling and increased productivity. Two isotopic shifts are present in the section: the older isotopic shift of the δ 13 C values is situated at the level of the Lower to Middle praesulcata Zone, while the younger one is found at the level of the Upper praesulcata Zone. In the sulcata Zone, a sharp decrease in δ 18 O values and a shift in the Ce anomaly follow. Concomitantly, a drop in the δ 13 C and δ 34 S values, highly variable TOC values, and the main and secondary element concentrations are interpreted to be related to a drop in primary productivity, with the recovery continuing in the crenulata Zone. In this context, the variations towards lower CaO, Sr, Rb and Ba values probably correlate with biomass variations and a transition from cooler towards warmer conditions.

Abstract Boundaries for all the Devonian series and stages have now been proposed by the Subcommission on Devonian Stratigraphy (SDS) of the International Commission on Stratigraphy (ICS) and have been ratified by the International Union of Geological Sciences (IUGS). A summary of these decisions is given. All the defined Global Stratigraphic Section and Points (GSSPs) are in the marine realm, and in pelagic facies. Much work is still needed to correlate the new boundaries into neritic and terrestrial facies.