New Permo-Carboniferous geochemical data from central Thailand: implication for a volcanic arc model

Current ideas and models of geotectonic reconstructions of Southeast Asia are reviewed and new data on Late Carboniferous through Middle Permian tuffites and sills from central Thailand are presented in the light of the problems of Southeast Asian palaeogeography. The volcanic rocks of quartz-keratophyric to spilitic composition are associated with platform carbonates and deep basin sediments. Their geochemistry and the character of the accompanying sediments suggest the existence of a Late Palaeozoic volcanic arc separating a subduction zone in the west from a back arc basin to the east. The geotectonic frame of Southeast Asia is explained in terms of repeated accretion of volcanic arcs by the Late Palaeozoic subduction zone along the northern Tethys margin

Palaeoecological and possible evolutionary effects of early Namurian (Serpukhovian, Carboniferous) glacioeustatic cyclicity

Early Namurian (Serpukhovian, Carboniferous), sedimentary cycles in the Throckley and Rowlands Gill boreholes, near Newcastle upon Tyne, UK, consist of fossiliferous limestones overlain by (usually unfossiliferous) black mudstone, followed by sandstones and often by thin coal seams. Sedimentological and regional geological evidence suggests that the largest are high-amplitude cycles, probably of glacioeustatic origin. 13C (bulk organic matter) delineates marine and non-marine conditions because of the large difference between terrestrial and marine 13C, and indicates that full marine salinity was only intermittent and resulted from glacioeustatic marine transgression superimposed on a background of inundation by freshwater from large rivers, which killed off the marine biota. Palynology suggests that plant groups, including ferns and putative pteridosperms, were affected by changing sea level, and that there is a theoretical possibility of connection between cyclicity and the first appearance of walchiacean conifer-like monosaccate pollen such as Potonieisporites. Long-term terrestrial and marine increasing 13C (organic) may reflect the onset of major glaciation in Gondwana, as there is evidence to suggest that the two are coeval, but no specific mechanism can be suggested to link the trends

Insight into tube-building behaviour and palaeoecology of some agglutinating worms from the Upper Devonian of Nevada, USA

Agglutinated worm tubes from the Upper Devonian of the Devils Gate section in Nevada, USA are reported for the first time, filling a major gap in their Palaeozoic fossil record. Two small (5 mm and 6.7 mm in length) tubes are composed entirely of tentaculitid shells, and one large tube (55 mm in length) is formed from particles including ostracode carapaces, echinoderm ossicles, tentaculitid shells and putative bryozoan fragments aligned perpendicularly to the tube’s long axis. The tubes, in particular the large one have a cylindrical, curved and tapering tube morphology that is very similar to that of modern agglutinating polychaetes of the families Terebellidae and Pectinariidae. The large tube is dominated by objects that fall within a certain size-range, and although built from different types of particles, echinoderm ossicles are prevalent in the posterior part, whereas ostracode carapaces dominate in the middle and anterior parts of the tube. Tentaculitid shells are relatively rare in the large tube, despite being abundant in the surrounding host deposit. The faunal assemblage composing the tube suggests that the worm animal was rather specific in its selection of particles with a certain morphology. This is common behaviour amongst many modern agglutinating terebellid and pectinariid polychaetes. The preservation of such fragile tubes was enhanced by rapid burial, likely caused by gravity flow of sediment in a deep-slope setting

Foraminiferal-based paleobiogeographic reconstructions in the Carboniferous of Iran and its implications for the Neo-Tethys opening time : a synthesis

The biogeographic distribution of foraminifers and their belonging to either the southern or northern margins of the Paleo-Tethys are used here for paleogeographic reconstructions of Iran during the Carboniferous. Lower Carboniferous foraminiferal assemblages from northern and central Iran show a cosmopolitan character and affinities to both the southern and northern borders of the Paleo-Tethys. Hence, in the Early Carboniferous Iran occupied an intermediate southern latitude position, forming part of Gondwana. This conclusion is consistent with the Late Ordovician to Early Carboniferous drift history of Iran based on paleomagnetic data. In the Late Carboniferous, the foraminiferal affinities of northern and central Iran with the northern part of Paleo-Tethys suggest that Iran separated from Gondwana and moved northwards to a lower latitude. This separation is also evidenced by the Upper Carboniferous coal-bearing sandstones of the Sardar Formation and sandstones with high degree of chemical weathering, which would indicate warm and humid conditions. Considering the composition of foraminiferal fauna along with the evidence of magmatic activities in northwest Iran, it can be inferred that the commencement of the Neo-Tethys opening and continental break-up in Iran occurred sometime in the Late Carboniferous, which contradicts the previous claims that the separation of Iran from Gondwana occurred in Permian and/or Triassic times

A Latest Carboniferous Warming Spike Recorded by a Fusulinid-Rich Bioherm in Timor Leste: Implications for East Gondwana Deglaciation

During the late Paleozoic and early Mesozoic Timor lay in the northern part of the north–south East Gondwana rift system along which the western margin of Australia later developed. Discovery of a latest Gzhelian bioherm in the central highlands of Timor Leste has implications for latest Carboniferous–earliest Permian climate history and deglaciation in basins further south in the rift system. Limestone outcrop of the Maubisse Formation near the village of Kulau is recognized as a bioherm with a massive lower unit, including reef framework at the base, and a bedded grainstone upper unit. The bioherm developed on a basalt substrate in warm shallow-water, as indicated by photozoan assemblages in the massive lower unit. Foraminifera belonging to 17 genera are recorded from the bioherm. These include representatives of the families Biseriamminidae, Biwaellidae, Bradyinidae, Cornuspiridae, Lasiodiscidae, Palaeotextulariidae, Pseudotaxidae, Ozawainellidae, Schubertellidae, Schwagerinidae, Staffellidae and Textrataxidae. Twenty-one species have been referred to known types and 12 species are left in open nomenclature. The assemblage probably belongs within the uppermost Gzhelian Schwagerina robusta–Ultradaixina bosbytauensis Zone although a possible lowest Asselian correlation cannot be excluded. The bioherm is the oldest carbonate unit so far recorded from the Maubisse Formation, and the oldest sedimentary unit biostratigraphically dated in Timor. The dominantly heterozoan composition of the skeletal component of the limestone (except for the basal photozoan assemblage) and the taxonomic diversity of the larger foraminifera suggest a subtropical environment consistent with a paleolatitude of about 40° S. The late Pennsylvanian was a time of glaciation that in Australia is represented by a significant stratigraphic hiatus in basins to the south of Timor in the East Gondwana rift system. The development of the Kulau bioherm during the latest Gzhelian may have coincided with a global warming spike that led to rapid melting of continental ice sheets and a substantial influx of glacigene sediment (alternating diamictite and mudstone) in the southern basins

Equatorial Shelf of the Palaeozoic Supercontinent – Cradle of the Adriatic Carbonate Platform

During the Carboniferous and Permian, several carbonate platforms existed along the eastern coast of the supercontinent Pangaea. Croatian Palaeozoic carbonate sediments were produced in this “carbonate factory”. The dominant skeletal carbonate producers were calcareous algae, with assistance from foraminifera, molluscs, brachiopods and crinoids. Sporadically, reef structures were built by calcisponges, bryozoans, algal and cyanobacterial encrusters. Variscan and post-Variscan tectonic events strongly influenced the platform existence through uplift and deposition of molasse sediments, while a global catastrophe at the Permian/Triassic boundary only changed the biotic carbonate producers. A significant input of terrestrial material during the Lower Triassic, due to uplift and/or global regression, altered the mode of sedimentation along the shallow Palaeotethyan shelves. Platforms were partly restored during the Middle and Upper Triassic, and existed with short interruptions till the Middle Eocene

New data on the incertae sedis biota and foraminifera of the mid-Famennian Baelen Member (Late Devonian, eastern Belgium)

The Baelen mud mounds in eastern Belgium represent a local member of the mid-Famennian Souverain-Pré Formation (an important carbonate interval within the Condroz Sandstone Group). The lower part of this member contains silty bioclastic wackestones and packstones that are particularly rich in the problematical algae Serrisinella and Dreesenullella. Plurilocular foraminifera (Septabrunsiina and Baelenia) and rare solitary rugose corals (Neaxon? sp.) occur within crinoidal grainstones (tempestites) interfingering with the latter bioclastic wacke-/packstones and red-stained stromatactoid spiculitic mudstones (carbonate mound core facies). Although Serrisinella is quite common in other mid- and late Famennian limestones, of Belgium, Dreesenulella is almost endemic of the Baelen Member. Both genera apparently inhabited the muddy sediment-water interface, constituting meadows probably in zones of intermittently strong bottom currents. The taxonomic similarities between Dreesenulella and Saccamminopsis are discussed, as well as their possible affinities with the Xenophophyrea and Kokomiacea. Moreover, the first stages of the Septabrunsiina–Baelenia foraminiferal lineage are analysed in detail. The taxonomic and palaoecological positioning of Serrissinella and Dreesenulella adds to the discussion about the palaeobathymetry of the Baelen mud mounds and corroborates sedimentological evidence for their relatively shallow carbonate ramp depositional setting

Evolution and Geological Significance of Larger Benthic Foraminifera

Evolution and Geological Significance of Larger Benthic Foraminifera is a unique, comprehensive reference work on the larger benthic foraminifera. This second edition is substantially revised, including extensive re-analysis of the most recent work on Cenozoic forms. It provides documentation of the biostratigraphic ranges and paleoecological significance of the larger foraminifera, which is essential for understanding many major oil-bearing sedimentary basins. In addition, it offers a palaeogeographic interpretation of the shallow marine late Paleozoic to Cenozoic world. Marcelle K. BouDagher-Fadel collects and significantly adds to the information already published on the larger benthic foraminifera. New research in the Far East, the Middle East, South Africa, Tibet and the Americas has provided fresh insights into the evolution and palaeographic significance of these vital reef-forming forms. With the aid of new and precise biostratigraphic dating, she presents revised phylogenies and ranges of the larger foraminifera. The book is illustrated throughout, with examples of different families and groups at the generic levels. Key species are discussed and their biostratigraphic ranges are depicted in comparative charts, which can be found a

Magnetostratigraphy of the Lower Carboniferous

Geomagnetic polarity reversals studied by magnetostratigraphy have been described well in the Cenozoic and Mesozoic, unfortunately, there are still many data gaps in the Palaeozoic where the magnetostratigraphic record is not easy to correlate or is unknown. One of those is during the Carboniferous System. The magnetostratigraphy of Carboniferous rocks is quite complicated, since overprints produced during the Kiaman Superchron (late Carboniferous-mid Permian) tend to be the strongest components and primary remanence very weak or completely overprinted. This study focused on sediments from S. Cumbria, in North-West England. The studied limestones were on the western edge of the Craven Basin and the NE fringe of the Irish Sea Basin. Two localities in South Cumbria were sampled, the Martin Limestone Formation in Meathop Quarry (50 m profile) and Urswick Limestone Fm in Trowbarrow Quarry (183m) together covering the lower and upper Visean, with a gap in the middle Visean. The sedimentation rate is approx. 30 kyrs/m. Detailed profiles were hand sampled at ~one-meter intervals, conducted with magnetic susceptibility sampling at ~25 centimetres intervals. For paleomagnetic measurements, most samples were thermally demagnetized up to 300-400°C and then AF (alternating field) demagnetization was used. This best differentiated the original magnetic signal from the later Kiaman overprint, and limited thermal alteration. For the time correlation, biostratigraphy using foraminifera was used for Meathop Quarry and carbon isotopes for Trowbarrow Quarry. Results show a Carboniferous dual polarity magnetisation clearly distinguished from the younger Kiaman component. The first detailed magnetostratigraphy through a part of the Visean is presented. The dominant carrier of remanence is magnetite at Meathop Quarry (over 40% of samples) with 7 reversals. At Trowbarrow Quarry, magnetite is dominant in the reversed polarity samples (50% of samples) and hematite for normal polarity samples (over 35% of samples), showing 18 reversals. These results fill a gap in magnetostratigraphic research provding the first detailed magnetostratigraphic study of the Lower Carboniferous in Europe

CARBONIFEROUS FORAMINIFERAL PALEOBIOGEOGRAPHY IN TURKEY AND ITS IMPLICATIONS FOR PLATE TECTONIC RECONSTRUCTIONS

Four foraminiferal paleobiogeographic realms are distinguished in the Carboniferous – North Paleotethyan, Perigondwanian, Siberian and North American. The Carboniferous foraminiferal faunas of both the Istanbul and Anatolide-Tauride zones distinctly differ from both Cimmerian terranes (Central Afghanistan, Qiangtang) and Libya and Egypt of the Perigondwana Realm and show close relation to the North Paleotethyan Realm, especially to the Fennosarmatian Province of southeastern Laurussia (Moesian and Scythian platforms) or to the Central Asiatic Province. A model that best fits with available evidence is that the Anatolide-Tauride Zone was either a part or located close to Laurasia in Carboniferous. The Istanbul Zone represents an equivalent of the Rhenohercynian Zone of the Central Europe and can not be compared with Intra-Alpine or south Variscan terranes which may be correlated with the Anatolide-Tauride Zone. Later, in the Permian, the Anatolide -Tauride Zone may has been separated from the Eurasian mainland by the Karakaya back-arc ocean.&nbsp