Late Tournaisian Research Articles

Mississippian (early Late Tournaisian; early Osagean) ammonoids from the Nancy Member of the Borden Formation, northeastern Kentucky

Mississippian (early Late Tournaisian; early Osagean) ammonoids from the Nancy Member of the Borden Formation, northeastern Kentucky

Bryozoan Diversity Dynamics at the Devonian–Carboniferous Transition: Evidence from Transcaucasia

The Devonian–Carboniferous transition was marked by a series of perturbations in the geological and biological evolution. The palaeontological data from Transcaucasia allowed the bryozoan diversity dynamics on the northern Gondwanan margin (southern periphery of the Palaeo-Tethys Ocean) to be documented at this transition. Taxonomic ranges of 43 species, 26 genera, 19 families, and 4 orders were analysed to reveal changes in the total diversity, the number of appearances, the number of disappearances, and the turnover rates per substages. It is established that the bryozoan diversity was rather high in the beginning and the end of the Famennian, as well as in the Late Tournaisian. It declined significantly in the Middle–Late Famennian and the Early Tournaisian due to the combination of the high number of disappearances and the low number of appearances. The turnovers remained strong, and they peaked in the mid-Famennian. These regionally documented diversity changes match the patterns recorded globally and in Southern Siberia. Hypothetically, the Middle–Late Famennian and Early Tournaisian crises established in Transcaucasia were related to the global events (anoxia and mass extinctions), a series of which weakened the bryozoans’ resistivity to negative external influences.

Brachiopods of the Lower Carboniferous Vegamian Formation (Cantabrian Mts, Spain): Part I. Introduction, Linguliformea

The history of the Tournaisian Vegamian Formation of the Cantabrian Mts (Spain) consisting of gray to black shales with a typical quiet-water ("Culm") fauna characterised by Linguliformea and small Rhynchonelliformea, is discussed. After an overview of the faunas studied thus far, an evaluation of the age of the Vegamian Formation is given, concluding to the Tournaisian, mainly middle to late Tournaisian. Also, the environment of deposition is discussed. The linguliform fauna, discussed in this first part, is found mainly in the black, thinly bedded shales. Species of the genera "Lingula ", Lachrymula and Orbiculoidea are described, including the new species Lachrymula truyolsi. The new subfamily Lachrymulinae of the Lingulidae is created for the genera Lachrymula and Trigonoglossa. It is distinguished from the Lingulinae by a relatively thick, subtriangular shell with a distinct pedicle groove and a rugose ornamentation. The rhynchonelliform fauna, occurring mostly in more thickly bedded, often decalcified grayish layers, will be dealt with in a subsequent paper.

The middle–late Tournaisian crisis in conodont diversity: a comparison between Northeast Laurussia and Northeast Siberia

The middle–late Tournaisian (Hastarian–Ivorian) transition is marked by isotopic and sedimentological evidence of climatic cooling and glaciations accompanied by a sea level fall and changes in global ocean circulation. At this time, the extinction among conodonts was followed by its gradual recovery in the late Tournaisian–early Viséan. Siphonodellids, representing an important part of conodont assemblages in the early–middle Tournaisian, became extinct. This study aims to compare conodont diversity dynamics in Northeast Laurussia and Northeast Siberia. The materials used range in paleolatitudinal gradients from 20°N (the north of the Urals and Pechora Craton) up to 45°N (Northeast Siberia), and in paleoclimatic gradient from an equatorial to a warm subtropical climate. The middle and late Tournaisian conodont associations of these regions demonstrate a high similarity in taxonomic composition and diversity dynamics, which may suggest that the glaciation and the following decrease in temperature probably was not the direct cause of conodont extinction; instead, the changes in the food web implied by the carbon isotope compositions of conodont elements and host carbonates could have been the main driver of the crisis in conodont diversity

Re-assessment of ammonoid specimens from the Early Carboniferous Protocanites Beds of the Badenweiler–Lenzkirch Zone (Schwarzwald, Central Variscan Belt): age constraints for a lithostratigraphic key bed

The Protocanites Beds of the Black Forest Massif (Germany) form an important lithostratigraphic key bed, as the index fossils contained in this formation enable correlation within large areas of the internal zone of the central Variscan Belt of Europe. Furthermore, the formation provides significant information on the geodynamic evolution of the Moldanubian Zone. The stratigraphic age of the formation has been a subject of controversy in the past; a Devonian to Viséan age has been proposed. To determine the age of the Protocanites Beds, two ammonoid specimens from the Protocanites Beds of Schönau are re-described here. They belong to Becanites abnobensis and Pericylcus princeps and fix the stratigraphic position of the Protocanites Beds to the early Late Tournaisian.

Richness of Famennian-Tournaisian (Late Devonian-early Carboniferous) bryozoans in shallow areas of Palaeotethys and Palaeoasian oceans

Based on the analysis of data on bryozoan localities in territory of modern Eurasia, changes of the bryozoan richness were calculated in detail for six time slices in the interval from the early Famennian to the late Tournaisian. Highest extinction tempo was observed for the latest Famennian, apparently linked to the Hangenberg Event. However, in the richness of bryozoans during the late-latest Famennian, an abrupt increase in the origination tempo is observed, as well as a slight decrease in the total bryozoan richness at the Devonian-Carboniferous transition. Origination of abundant narrowly specialised bryozoan genera in the orders Trepostomata and Cryptostomata at the end of the Devonian and in the beginning of the Carboniferous was caused by the combined influence of extrinsic and intrinsic factors. An observed increase in the morphological specialisation of bryozoans during the Late Devonian and early Carboniferous coincides with patterns observed in other benthic organisms such as brachiopods and rugose corals. These patterns can be explained by vacation of ecological niches and changes in the structure of the marine biota in the aftermath of the Hangenberg Event.

БИОСТРАТИГРАФИЯ И ЛИТОЛОГИЧЕСКИЕ ОСОБЕННОСТИ НИЖНЕКАМЕННОУГОЛЬНОЙ УРМУГТЭЙУЛЬСКОЙ СВИТЫ (ОРХОНСКИЙ ПРОГИБ, СЕВЕРНАЯ МОНГОЛИЯ)

The results of a biostratigraphic and lithological studies of the terrigenous Carboniferous Urmugteyul Formation in the stratotype area (left bank of the Sharyn-Gol River, Orkhon Trough) are presented in this research paper. Four members are distinguished in the composition of the formation; the first three members are assigned to the Lower Urmugteyul Subformation, the fourth is to the Upper Urmugteyul Subformation. The first palynological studies made it possible to limit the accumulation time of the Lower Urmugteyul Subformation to Late Tournaisian, and the Upper Urmugteyul Subformation to Late Visean. The nature of the structure and lithological features of the section, considered as part of two terrigenous facies associations, as well as the paleontological characteristics and analysis of palynofacies, indicate that the accumulation of the Lower Urmugteyul Subformation occurred in the alluvial-delta plain settings, and the Upper Urmugteyul Subformation is in the shallow shelf basin.

Morphological Evolution of Eurasian Bryozoans during Famennian–Tournaisian

The main trends in the morphological evolution of bryozoans at the Devonian-Carboniferous boundary were established when studying the Late Devonian–Early Mississippian bryozoans of Eurasia. The diversity of vertical colonies increased from Early Famennian to Late Tournaisian. An increase in their strength occurred by growth of the exozonal skeleton due to the growth of vesicular tissue in cystoporates, thickening of the autozooidal walls in trepostomates, complication of polymorphism in cryptostomates, and thickening of the branches in fenestrates. The most rapid evolutionary changes were observed in rhabdomesine bryozoans of the order Cryptostomata, expressed in the change of the spiral arrangement of autozooids to complex one and a high diversity of heterozooids and styles. The development of keels, nodes, superstructures, acanthostyles, and spines in bryozoans provide protection from predators.

Uncovering the hidden diversity of Mississippian crinoids (Crinoidea, Echinodermata) from Poland.

Partial crinoid crowns and aboral cups are reported from the Mississippian of Poland for the first time. Most specimens are partially disarticulated or isolated plates, which prevent identification to genus and species, but regardless these remains indicate a rich diversity of Mississippian crinoids in Poland during the Mississippian, especially during the late Viséan. Lanecrinus? sp. is described from the late Tournaisian of the Dębnik Anticline region. A high crinoid biodiversity occurred during late Viséan of the Holy Cross Mountains, including the camerate crinoids Gilbertsocrinus? sp., Platycrinitidae Indeterminate; one flexible crinoid; and numerous eucladid crinoids, including Cyathocrinites mammillaris (Phillips), three taxa represented by partial cups left in open nomenclature, and numerous additional taxa known only from isolated radial plates, brachial plates, and columnals. To date, the youngest occurrence of Gilbertsocrinus was the early Viséan of the United States, thus the present finding in upper Viséan extends this genus range. Furthermore, the occurrence of Lanecrinus? sp. expands the Western European range of this genus into the Tournaisian. A single partially disarticulated crown, Crinoidea Indeterminate B, is described from the Serpukhovian of the Upper Silesian Coal Basin. In addition, several echinoid test plates and spines are also reported.

Devonian-Carboniferous boundary sections in Iran

Many sections are known from Iran which exhibit sediments across the Devonian-Carboniferous (D-C) boundary. In contrast to the majority of published D-C sections worldwide from pelagic/hemipelagic environments, successions in Iran are mainly composed of shallow-water sediments. Correlation with hemipelagic or pelagic palaeoenvironments remains difficult due to biostratigraphic uncertainties in most sections and/or hiatuses. On the other hand, a limited number of sections dealing with shallow-water facies settings in Iran at this particular time period are known and further research is necessary. Several sections in the Alborz Mountains provide an excellent opportunity to study successions across the D-C boundary in shallow-water facies. In Iran, protognathoids are represented by Protognathodus meischneri and Protognathodus collinsoni. The two biostratigraphically important protognathoids (Protognathodus kuehni and Protognathodus kockeli) were not reported or did not occur for the first time in the Late Tournaisian. Early siphonodellids were described instead. In the frame of an Iranian/German research project, we study different palaeoenvironments to reduce serious palaeoenvironmental and palaeogeographical sampling bias which may limit our knowledge on the Hangenberg Event particularly in shallow-water facies. We present a summary on published D-C sections in Iran (Ghale-Kalaghu, Howz-e-Dorah 1, Howz-e-Dorah 2 and Shahmirzad) and sections which are under study (Mighan, Chelcheli and Khoshyeilagh) at the time of this writing.

Taxonomy and evolution of late Tournaisian and Viséan (early Carboniferous) Heterostrotioninae (Rugosa, Anthozoa) from SE China

Colonial rugose corals with a heterocoral-like septal pattern are diverse and common in the Tournaisian–Viséan (Mississippian) of South China. Numerous species were named in classical works but most of them require systematic revision. Newly collected material allowed eight Heterostrotion species to be recognized (ranging from the upper Tournaisian up to the middle Viséan), including a new species H. huaqiaoense; three Stylostrotion species (middle Viséan), including a new species S. houi and four Polygonaria species (upper Tournaisian and upper Viséan). Heterostrotion as the oldest genus of the Stylostrotionidae probably originated in the western Palaeotethys and migrated to South China during the Tournaisian. The development of the cerioid genus Polygonaria from large-sized Heterostrotion during the late Tournaisian is described. The origin of Stylostrotion is however proposed in the evolution of Heterostrotion by a reduction of the minor septa and the development of a columella during the middle Viséan. Stylostrotion is known only from China, where it seems to have evolved by homeomorphy with Siphonodendron, which only occurred in that area in the late Viséan.http://zoobank.org/urn:lsid:zoobank.org:pub:15F3D222-7027-4771-A8B5-05F024D298A0

The Mississippian (Late Tournaisian) ammonoid Rotopericyclus from the Borden Formation, Kentucky

The Mississippian (Late Tournaisian) ammonoid Rotopericyclus from the Borden Formation, Kentucky

Foraminifera, Radiolaria and Conodont assemblages from the Early Mississipian (late Tournaisian)/Early Pennsylvanian (early Bashkirian) blocks within the Mersin Mélange, southern Turkey: Biochronological and paleogeographical implications

The Mersin Mélange, a sedimentary complex in southern Turkey, includes blocks of various origins within a Late Cretaceous matrix. Two blocks in the Mersin Mélange are herein recognized to be of Carboniferous age. One block (the Kozan Block) is composed of alternating chert and mudstone, and includes radiolarian and conodont assemblages revealing a late Tournaisian (Early Mississippian) age. The other (Keven-West Block) consists of platform carbonate containing abundant foraminifera indicating Bashkirian (Early Pennsylvanian) age. These dates are so far the oldest obtained from the blocks within the Mersin Mélange. A correlation of the lithostratigraphies of blocks in the Mersin Mélange with the coeval Tauride sequences indicates that they correspond to the successions in the Beysehir-Hoyran Nappes. In these nappes, the late Tournaisian is characterized by radiolarian rich chert and mudstone of an open marine environment, whereas the Bashkirian succession represents a shallow water environment with Foraminifera-bearing limestone. The Tournaisian deepening can be ascribed to the opening of a deep marginal basin to the north of the Tauride Platform and uplifting of the northern Tauride-Anatolide Platform margin during the Late Mississippian and Early Pennsylvanian.A shallowing upward sequence started in the Tournaisian with a pelagic sequence followed by platform carbonates of Bashkirian age in the Beysehir-Hoyran Nappes, and could be related to a major glaciation event during late Visean–Serpukhovian resulting in a sea-level drop and deposition of platform carbonates in the Bashkirian. Given the stratigraphic properties of northerly originated nappe packages (Cataloturan, Hadim and Bolkardag) and parautochthonous/autochthonous sequences in Taurides, sedimentation on the Tauride-Anatolide Platform mainly terminated after the Moscovian, except in the Hadim Nappe with sedimentation in a very shallow sea conditions until the end of the Permian. A depositional break corresponding to the Kasimovian–Wordian time interval in these sequences in the Tauride-Anatolide Platform could be related to the effects of both late Paleozoic Gondwanan glaciation and a possible mantle plume occurrence evidenced by the geochemistry of lavas in the Mersin Mélange causing major uplift in the Northern NeoTehys Ocean. However; at the center of the plume, pelagic sequences (e.g., ribbon chert and pelagic limestone) were deposited associated with these lavas due to a progressive developing rift system during the Permian, based on previous studies.

Sedimentologic and paleoclimatic reconstructions of carbonate factory evolution in the Alborz Basin (northern Iran) indicate a global response to Early Carboniferous (Tournaisian) glaciations

The Lower Carboniferous Mobarak Formation records the development of a storm-sensitive pervasive carbonate factory on the southern Paleo-Tethyan passive margin following the opening of the Paleo-Tethys Ocean into the Alborz Basin along the northern margin of Gondwana. Its depositional facies encompass inner ramp peritidal environments, peloidal to crinoidal shoals, storm to fair-weather influenced mid-ramps, proximal to distal shell beds and low energy outer ramps. Sedimentological analyses and foraminiferal biostratigraphy reveal four events affecting carbonate platform evolution in the Alborz Basin during the Lower Carboniferous: (1) A transgression following global temperature rise in the Early Tournaisian (middle Hastarian) caused the formation of thick-bedded argillaceous limestones. This interval correlates with Early Tournaisian nodular to argillaceous limestones in the Moravia Basin (Lisen Formation, Czech Republic), the Dinant Basin (Pont d'Arcole Formation, Belgium), and at the Rhenish Slate Mountains (Lower Alum shale, Germany). (2) Late Hastarian–early Ivorian glaciations previously identified in Southern Gondwana but had not yet recognized in Northern Gondwana were recorded through a sequence boundary. (3) During the Late Tournaisian–Early Visean?, a differential block faulting regime along the basin's margin caused uplift of the westernmost parts of the Alborz Basin and resulted in subsidence in the eastern part of the central basin. This tectonically controlled shift in depositional regime caused vast sub-aerial exposure and brecciation preserved in the top of the Mobarak Formation in the western portion of the Central Alborz Basin. (4) Tectonic activity coinciding with a progressive, multiphase sea level drop caused indirectly by the Viséan and Serpukhovian glaciations phases ultimately led to the stagnation of the carbonate factory. Paleothermometry proxies, the presence of foraminiferal taxa with a northern Paleo-Tethyan affinity and evidence for arid conditions in the terrestrial hinterland place the Alborz Basin at lower latitudes than the approximately 45ο–50ο southern paleolatitude reported thus far.

Ahnetia, a new lignophyte stem from the Lower Carboniferous of southern Algeria

A new taxon of lignophyte is described based on a permineralized stem from the Late Tournaisian (Lower Carboniferous) of the Central Ahnet region, Algeria. It shows similarities with arborescent seed plants described in the Lower Carboniferous of Europe and North America such as Eristophyton waltonii Lacey and Cauloxylon ambiguum Cribbs. However, the primary and secondary vascular system of the stem display an original combination of characters and it is assigned to a new genus: Ahnetia. The preservation of extraxylary tissues (secondary phloem, periderm, cortex) allows formulating hypotheses on the stem's growth potential. The early appearance of a periderm indicates that Ahnetia was capable of significant secondary growth and that the specimen likely represents a young axis of a larger plant. By its Late Tournaisian age, this specimen represents the oldest known occurrence in North Africa of a lignophyte capable of significant secondary growth after the extinction of the progymnosperm Archaeopteris.

The significance of Tournaisian tectonism in the Dublin basin: Implications for basin evolution and zinc-lead mineralization in the Irish Midlands

Recently acquired seismic reflection data, combined with detailed subsurface stratigraphic analysis (core analysis and gamma ray logs) reveal a new view of Lower Carboniferous stratigraphy and tectonism in Ireland. Seismic stratigraphic relationships and stratal thickness variations within Tournaisian units indicates that the Ballinalack High (and associated faulting) was produced by tectonism during the mid to late Tournaisian (Moathill Event, ~348Ma). A second major tectonic event, dominated by regional subsidence (rather than faulting), occurred during the Lower Viséan (Tober Colleen Event, ~345Ma). Each of these tectonic events was associated with major subsidence in the basin, producing strong transgressions within the stratigraphy.We suggest that the Late Tournaisian Moathill Event was responsible for producing the structural setting of the Ballinalack and other Zn-Pb deposits in the Irish Midlands. The suggested earlier timing of fault movement in the basin has implications for arguments about the origin of Irish-type Zn-Pb deposits and the necessity (or not) for having active faulting during mineralization.

Microfacies and carbon isotope records of Mississippian carbonates from the isolated Bama Platform of Youjiang Basin, South China: Possible responses to climate-driven upwelling

Changes in Mississippian global paleogeography derived from the reconfiguration of the continents have been suggested to result in a change in oceanic circulation, carbon cycling, as well as in global cooling. Here, integrated δ13Ccarb chemostratigraphy and foraminiferal biostratigraphy across the Mississippian (late Tournaisian, Visean, early Serpukhovian; MFZ6–MFZ16 foraminiferal biozones) of the Gongchuan section located in the isolated Bama Platform in the Youjiang Basin, South China, are presented. The δ13Ccarb trend shows an abrupt decline during late Visean (Asbian-early Brigantian; MFZ13–14). This decline is also observed in subequatorial western Euramerica, whereas coeval sections in subequatorial eastern Euramerica show consistently elevated δ13C values across the entire Visean. The δ13C decline in western Euramerica and the South China Block (eastern Paleo-Tethys) coincides with a global regression with a suggested glacioeustatic origin, the onset of high-frequency climate and sea-level oscillations, and the closure of the Rheic seaway between Euramerica and Gondwana. We propose a model explaining the divergence of δ13C records resulting from the closure of the Rheic seaway and development of upwelling zones in the western margin of Euramerica and the eastern Paleo-Tethys realm. Quantitative microfacies analysis across the Mississippian succession in the Gongchuan section shows facies-independent disappearance of corals and increased proportion of cortoids and filter-feeding organisms at the onset of the Asbian δ13C decline, which may support an increase in nutrient level that can be expected as a result of upwelling.

Tournaisian 40Ar/39Ar age for alkaline basalts from the Lublin Basin (SE Poland)

The main aim of this study is to define precisely the age of the alkaline basalts occurring within the lowermost part of Carboniferous succession in the northeastern part of LublinBasin(drill core Parczew IG-7 and IG-9; SE Poland). The new, whole-rocks 40 Ar/ 39 Ar data constrain the age of volcanic activity and emplacement of alkaline basalts to the Late Tournaisian (348 ± 0.8 Ma) with possible prolongation to the Middle Visean (338.5 ± 0.7 Ma). The younger age is however of evidently poorer quality than the older one. The new data caused to correlate the volcanic processes occurring within theLublinBasin with alkaline intrusions drilled inNE Poland inside the Paleozoic cover of the East European Platform. They also correspond to the volcanoclastic levels defined in different parts of the Trans European Suture Zone inPoland.

A revised Mississippian lithostratigraphy of County Galway (western Ireland) with an analysis of carbonate lithofacies, biostratigraphy, depositional environments and palaeogeographic reconstructions utilising new borehole data

An integrated study of borehole data and outcrop of Mississippian (late Tournaisian to late Viséan) rocks in Co. (County) Galway, western Ireland has enabled a more detailed geological map and lithostratigraphy to be constructed for the region. Several carbonate formations have been distinguished by microfacies analysis and their precise ages established by micropalaeontological investigations using foraminifers and calcareous algae. In addition, palaeogeographic maps have been constructed for the late Tournaisian, and early to late Viséan intervals in the region. The oldest marine Mississippian (late Tournaisian) deposits are recorded in the south of the study region from the Loughrea/Tynagh area and further south in the Gort Borehole; they belong to the Limerick Province. They comprise the Lower Limestone Shale Group succeeded by the Ballysteen Group, Waulsortian Limestone and Kilbryan Limestone Formations. These rocks were deposited in increasing water depth associated with a transgression that moved northwards across Co. Galway. In the northwest and north of the region, marginal marine and non-marine Tournaisian rocks are developed, with a shoreline located NW of Galway City (Galway High). The central region of Co. Galway has a standard Viséan marine succession that can be directly correlated with the Carrick-on-Shannon succession in counties Leitrim and Roscommon to the northeast and east as far as the River Shannon. It is dominated by shallow-water limestones (Oakport, Ballymore and Croghan Limestone Formations) that formed the Galway-Roscommon Shelf. This facies is laterally equivalent to the Tubber Formation to the south which developed on the Clare-Galway Shelf. In the southeast, basinal facies of the Lucan Formation accumulated in the Athenry Basin throughout much of the Viséan. This basin formed during a phase of extensional tectonics in the early Viséan and was probably connected to the Tynagh Basin to the east. In the late Viséan, shallow-water limestones of the Burren Formation extend across much of the southern part of the region. They are characterized by the presence of rich concentrations of large brachiopod shells and colonial coral horizons which developed in predominantly high-energy conditions. These limestones also exhibit palaeokarstic surfaces and palaeosols which formed during regressive conditions of glacio-eustatically controlled cyclicity. Locally, slightly deeper water, lower energy conditions developed on the shelf with the formation of rare bryozoan-rich mud-mounds. Deep-water basinal facies were maintained in the central and southeastern parts of the region between the two shelves with the persistence of the Lucan Formation. Active syn-sedimentary faulting influenced deposition in the Viséan and interfingering of basinal sediments with slumps and shallow-water shelf carbonates are recognized.

Taxonomy, Biostratigraphy and Palaeobiogeography of the Late Tournaisian rugose corals of north-western Turkey

This article provides the first taxonomic description of Ivorian (Late Tournaisian, Early Carboniferous) rugose coral associations from north-western Turkey (Zonguldak and Bartin). Eleven species belonging to ten genera are described, one species is new. Three biostratigraphic assemblages are recognized. The oldest assemblage includes Cyathaxonia cornu, Cyathoclisia uralensis, ‘Lophophyllum’ konincki and Uralinia multiplex. This corresponds to the RC3 Biozone (early Ivorian). The middle assemblage in characterised by Amplexus coralloides, Sychnoelasma hawbankense and Zaphriphyllum daleki sp. nov. and is correlated with the early late Ivorian RC4α Biozone. The youngest assemblage (RC4β1 Biozone, latest Ivorian) is composed of Corphalia fourmarieri, Corphalia sp. and Amydgalophyllum? sp. These three assemblages have a low specific and generic diversity compared to time-equivalent assemblages but contain genera with a wide distribution in the Palaeotethys Ocean, such as Cyathoclisia, Uralinia and—in a lesser extend—Zaphriphyllum, as well as typically European taxa such as Corphalia and Sychnoelasma. These latter two, identified for the first time outside of Europe, allow associating north-western Turkey with the European Coral Province.