The common observation that smaller particle-size fractions of sedimentary rocks yield younger K-Ar apparent ages than the larger particle-size fractions of the same stratigraphic age was analyzed with the aid of the 40Ar/40K ratio from 14 stratigraphically and regionally different sections. Estimation of the loss of radiogenic 40Ar from varied clay-rich size fractions was based on two models: a relationship between particle size and the 40Ar/40K ratio, and a theoretical diffusional loss from spherical particles. The differences between the two models and reconciliation of their results are discussed. For the smallest fractions (up to <0.5 μm), percent-wise losses of 40Ar from the spherical particles model increase from Upper Carboniferous and Permian (38±10%), to Late Triassic (47±10%), and to Miocene and Late Neogene (65±8%). This trend suggests that escape of 40Ar from the smaller particles in older sediments decreased or even stopped after deposition of the sedimentary sections.

The large 40Ar losses derived from small 40Ar/40K ratios in the younger Tertiary sediments, indicate that addition of K to the small fractions is, at least in part, responsible for the young K-Ar apparent ages in geologically different settings. In several 102–103 m thick sections, authigenic illite in the <0.1 to <2 μm fractions yields young K-Ar apparent ages resulting from simultaneous 40Ar production and release during clay authigenesis. In a production and loss model, a first-order escape-rate parameter (e) was estimated at 0.2 × 10−8 to 4 × 10−8 y−1, depending on the K-Ar apparent age of the size fractions and the stratigraphic age of the section. The limitations and uncertainties of the methods of evaluating diagenetic 40Ar losses from fine clay particles are discussed.

Columnar-jointed tuffs (bentonites) are located below the Lower Carboniferous Tideswell Dale Sill, Derbyshire, in an abandoned quarry. There are three zones of prismatic joints, columnar joints (∼60 cm thick and mean column width of 4.1 cm) and massive, conchoidally fractured rock sequentially from the dolerite contact downwards. The rocks are very fine-grained (1–10 µm) and consist mainly of sanidine, interlayered illite/smectite, and hematite, with minor quartz, apatite, montmorillonite, anatase and detrital minerals. High K2O and Fe2O3, low Na2O and low MgO are interpreted as due to alteration of felsic volcanic ash. The bentonite was contact-metamorphosed by the sill to temperatures of c. 300 °C. The progression of fracture geometries, thermal considerations and application of theories of column formation indicate that columns formed downwards away from the sill, due to prograde contact metamorphism of the originally clay-rich bentonite. The formation of columnar fracture networks by shrinkage due to igneous heating may have implications for the effectiveness of bentonite as a barrier for disposal of high-level radioactive waste. Regional dimensions include documenting widespread felsic explosive volcanism and inferring a Triassic oxidation event from palaeomagnetic data.

The Longmu Co–Shuanghu suture zone, which divides the Qiangtang terrane into the northern and southern Qiangtang blocks, is regarded as a key locality in reconstructing the evolutionary history of the Palaeo-Tethys Ocean and the break-up of Gondwana. However, although low-temperature – high-pressure metamorphic rocks and ophiolites have been documented within the Longmu Co–Shuanghu suture zone, it remains unclear whether it is an in situ suture zone and represents the relic of the main Palaeo-Tethys Ocean. The uncertainty stems mainly from the limited systematic studies of the provenance, palaeontological evidence and depositional settings of strata on either side of the Longmu Co–Shuanghu suture zone (i.e. northern and southern Qiangtang blocks). Here we report new detrital zircon U–Pb ages and palaeontological data from Lower Carboniferous strata (Riwanchaka Formation) of the northern Qiangtang block, central Tibet. The Riwanchaka Formation contains warm-climate biota with Cathaysian affinities. Provenance analysis reveals that the formation has detrital zircon spectra similar to those from strata of the Yangtze Plate, and it contains a large proportion of zircons with ages (~360 Ma) similar to the timing of synsedimentary magmatic arc activity, implying an active continental margin setting associated with northward subduction of the Palaeo-Tethyan oceanic lithosphere. Conversely, the Carboniferous–Permian strata from the southern Qiangtang block contain cool-water faunas of Gondwanan affinity and exhibit minimum zircon crystallization ages that are markedly older than their depositional ages, suggesting a passive continental margin setting. The differences in provenance, palaeontological assemblages and depositional settings of the Carboniferous to Permian strata either side of the Longmu Co–Shuanghu suture zone indicate the existence of an ancient ocean between the northern and southern Qiangtang blocks. Combining the new findings with previous studies on high-pressure metamorphic rocks, arc magmatism and ophiolites, we support the interpretation that the Longmu Co–Shuanghu suture zone is an in situ suture zone that represents the main suture of the Palaeo-Tethys Ocean.

Ramsay Heatley Traquair, the eminent Victorian Scottish palaeoichthyologist and museum curator, procured an extensive collection of Palaeozoic fishes from across Scotland with the help of local miners and quarrymen. One very productive locality near Edinburgh was Loanhead. Traquair described numerous fossil fish from this Serpukhovian site, including four lungfish taxa: Ctenodus interruptus, Sagenodus quinquecostatus, Uronemus splendens and Ctenodus angustulus. The first three are now quite well known, but the fourth was only briefly described and never figured. It is based entirely on tooth plates, which are unusual both in their very small size and the arrangement of the tooth ridges. They lack the diagnostic characters of Ctenodus tooth plates and are here renamed Clackodus angustulus. A further taxon, Conchopoma sp., has recently been identified. Represented by a spade-shaped parasphenoid and denticulated jaw elements, it is the earliest known occurrence of the genus, extending its range into the Mississippian. A sixth taxon may be represented by an isolated parasphenoid bearing an anterior process, previously only seen in Devonian lungfish. The presence of up to six lungfish taxa at a single locality is unprecedented in the Carboniferous and indicates that the high level of lungfish diversity encountered in the Tournaisian of the Scottish Borders continued throughout the Mississippian, adding to the growing evidence that post-Devonian lungfish evolution was not as limited as previously proposed. This may have been due to changes in tooth plate growth, enabling greater variation in dentition and diet. In most Devonian taxa, tooth plate growth can be explained by comparison with that in extant forms, but analysis of Carboniferous tooth plates suggest growth was different in many taxa, possibly based on more than one pioneer tooth, allowing for novel patterns of tooth ridges and different types of teeth to develop on the same plate.

The Carboniferous in Britain is diverse and this is reflected in the clay mineral assemblages. Several factors affecting the assemblages are identified including climate, rates of weathering and erosion, source rocks in the hinterland, preservation of palaeosols, whether the source rocks are nearby or distant, sorting during transportation, the presence of altered volcanic ash-falls in the depositional environment and the extent of burial diagenesis. There are temporal and geographic variations in the clay mineral assemblages in the mudrocks as a result of these controls. There are also clay-rich rocks that differ from the normal mudrocks and a knowledge of the clay mineralogy of these is a necessary prerequisite to a full understanding of their origins. Mudrocks falling in this category, and described below, include bauxitic clays, flint clays, fragmental clay rocks, tonsteins and K-bentonites and various palaeosols.

The distribution and origin of clay minerals in Carboniferous sandstone reservoir rocks, onshore and offshore UK, is reviewed using both published and unpublished sources. The clay mineralogy for many of the Carboniferous reservoir sands tends to be similar, with the detrital clays predominantly illitic whereas the diagenetic clay assemblages are dominated by kaolin with usually lesser amounts of illite. The main exception to this pattern is found in the Dinantian sandstones of the Clair Basin where significant amounts of smectite are present. Three stages of diagenetic kaolin formation are widely recognized. Firstly eogenetic and/or telogenetic kaolinite; secondly mesogenetic kaolin; and thirdly the partial or complete transformation of kaolinite to dickite during deep burial. In addition to the formation of diagenetic clay phases, the sandstone reservoirs also display a complex diagenetic history involving cementation and dissolution processes. These have affected the reservoir properties of the sandstones but the depositional facies architecture still exerts a major recognizable influence on reservoir porosity-permeability characteristics. The abundance of kaolin cements shows no clear correlation with variations in porosity and permeability for Carboniferous reservoirs. Pore- filling smectite affects reservoir porosity and permeability in the Dinantian of the Clair Field, and could be a potential source of serious reservoir damage arising from swelling.

This study describes the occurrences of sulfate minerals in mines of the Czech part of the Upper Silesian Basin. This mineralization originates from the oxidation of Fe disulfides contained in the coal matrix and enclosing sediments. The oxidation occurs in the presence of formational brines and chemotrophic bacteria. The brines have a pH between 6.3 and 8.5 and total solute content of up to 300 g/l. They are rich in Na, Ca, K, Mg, Ba and Sr and Cl– is the major anion. The minerals of the pickeringite–halotrichite series with coexisting magnesiocopiapite are formed primarily in drier places and areas where the water is only slightly mineralized. In more humid places where the brines are more concentrated, a diverse assemblage of up to 20 different sulfates are found (e.g. natrojarosite, sideronatrite, metasideronatrite, tamarugite, magnesiocopiapite, bílinite, starkeyite, blödite, rozenite and siderotil). These sulfates are accompanied by halite, sulfur, goethite and a number of phases of uncertain identity, such as sulfates containing Sr and REE. This is an example of mineral paragenesis formed by weathering in a saline evaporite environment, which is extremely rare in Europe but is found in arid regions elsewhere (e.g. in the Atacama Desert in Chile).

The Silbergrube Aplite (SA) in the Hagendorf-Pleystein Pegmatite District, near Waidhaus, Germany, is a mildly peraluminous NW-SE directed leucogranite dyke. It occurs in association with quartz dykes and aplitic metamorphic mobilizates in the NE Bavarian crystalline basement. The SA differs from other aplitic mobilizates in the region in having a less well developed strain-related mineral orientation and in containing only minor amounts of garnet and tourmaline. The aplitic metamorphic mobilizates and the SA are chemically and mmeralogically almost identical and yield the same age of formation of ∼302 Ma (stage I). The age of formation of the Hagendorf pegmatites seemingly post-dates the emplacement of the SA. The SA was emplaced at the boundary between fine-grained biotite granites and metamorphic country rocks within a zone of structural weakness, favouring the formation of disseminated late magmatic to hydrothermal mineralization of Li-bearing Fe-Mn phosphates (stages II and III). Brittle deformation along this zone was conducive to the faultbound Fe-Mn-Ca phosphates. Mineral telescoping is evident from the presence of Fe2+, Fe3+ and Mn2+ phosphates in fissures and vugs in a texturally highly variable host-rock environment (stage IV). This intimate intergrowth of phosphate minerals reflects contrasting physical and chemical conditions prevailing in a near-surface/ shallow epithermal S-deficient phosphate system (stage IV), similar to what is known from Cu-Au epithermal systems. The most recent mineral assemblages that formed under predominantly oxidizing conditions are correlated with the subtropical weathering during the Neogene which resulted in the formation of a peneplain truncating the SA and its country rocks (stage V). The SA is the root zone of the felsic aplitic-pegmatitic mobilizates in this region and is overprinted by an epithermal phosphate system.

Stan Wood was an exceptional fossil collector who, over a collecting career of more than 40 years, provided British palaeontology with an abundance and variety of new Carboniferous fossils, the like of which had not been collected since Victorian times. So, what made him a great collector? Here, with the help of Stan's family, his friends and colleagues, we try to provide the answer. There is no single factor that stands out, but a complex mixture of innate and learned behaviours that together produced a unique talent. Although he acquired an Open University degree in geology, Stan was largely self-taught as a collector and, in doing so, became an accomplished and confident field geologist. He was naturally curious, persistent and very observant, with a photographic memory. He was tough, very strong and enjoyed hard physical work. He was congenial, unorthodox and a calculated risk taker. He asked questions, tested ideas and had a healthy disregard for authority. He was systematic, kept detailed records and shared his discoveries. He not only loved collecting fossils but, in the process, discovered in himself the essential qualities of a true scientist.

Ten new early actinopterygian taxa are described from material collected from five North Lanarkshire coal shale tips in the Midland Valley of Scotland. The newly described taxa include Rhadinichthys? ornatocephalum, Rhadinichthys glabrolepis, Pseudogonatodus aurulentum, Pseudohaplolepis argentatum, Rhadinichthys? plumosum and Lanarkichthys gardineri. Also included are the haplolepids Blairolepis wallacei, Parahaplolepis poppaea, Braccohaplolepis fenestratum and Andrewsolepis lochlani. Additional information was also obtained for a further two named species, Rhadinichthys monensis Egerton and Rhadinichthys grossarti Traquair. The material used for this study was obtained from finely laminated slabs of carbonaceous shale containing incomplete and disarticulated specimens, including isolated skull dermal elements and scales preserved en masse. Using this information, the dermal skull bones of a number of taxa were reconstructed and illustrated in dorsal and lateral views. Furthermore, morphological characteristics of the skull roof of each taxon was used to obtain an appropriate dataset, in order to undertake non-vigorous phylogenic analyses to demonstrate possible relationships between the various groups within the assemblage. In addition, ossified endocranial remains from specimens of Rhadinichthys monensis were examined.

The Mississippian volcano-sedimentary complex in the Toca da Moura – Cabrela areas represents remnants of intra-volcanic marine sedimentary basins, formed during the collision between the Ossa Morena Zone with the South Portuguese Zone. These rock units are unconformably overlain by the Pennsylvanian intramontane coal-bearing Santa Susana Basin. Vitrinite reflectance determinations from rocks of these two basins indicate two episodes of thermal maturation. During the first episode, the Toca da Moura – Cabrela volcano-sedimentary complexes attained high maturation levels, equivalent to anthracite coal rank (3.0–3.5% Roran), which pre-dates the middle Moscovian Santa Susana Basin. The Santa Susana Basin attained moderate maturation levels equivalent to bituminous coal rank (1.35–1.5% Roran) recording a second episode of thermal maturation. Here, peak thermal conditions did not overprint the first maturation episode. The observed effects of magmatic intrusion on the thermal maturity and the lack of any increase in vitrinite reflectance with depth through c. 400 m of section in borehole SDJ-1 indicate high geothermal gradients during the first maturation episode. A contemporaneous magmatic event associated with the c. 335–320 Ma Cuba-Alvito Gabbros/Diorites of the Beja Massif was the possible cause for the high geothermal gradients postulated for the first maturation episode. Burial under a post-upper Moscovian sedimentary cover was the most likely process to account for the maturation levels determined for the Santa Susana Basin and for the second episode of thermal maturation.

Geochemical studies on Upper Carboniferous marine bands showed that marked enrichment in redox-sensitive trace elements (uranium (U), vanadium (V), molybdenum (Mo)) mostly occur if they contain Goniatites. Goniatites indicate deposition in relatively distal and deep marine environments. In contrast, Westphalian marine bands found in the Netherlands predominantly show a Lingula facies, indicating deposition in a nearshore environment. These Lingula marine bands are mostly lacking significant trace element enrichments. The aim of this paper is to explain the mechanisms causing the differences in geochemical characteristics between distal (Goniatites facies) and proximal (Lingula facies) marine bands. Geochemical analyses (total organic carbon (TOC), sulfur (S), major and trace elements) were carried out on a selection of these marine bands. Furthermore, a comparison was made with some lacustrine bands which broadly show the same sedimentary development as the Lingula marine bands. The results show that the Lingula marine bands, in contrast to the Goniatites and lacustrine bands, are characterised by low organic carbon contents (1 – 2 wt.%). A relatively high input of siliciclastics probably prevented the accumulation of organic-rich layers (dilution effect). In turn, low organic carbon contents most likely prevented the effective scavenging of trace elements. Although the lacustrine bands are characterised by high TOC contents, here the limited availability of trace elements in fresh water forms the best explanation for low trace metal enrichments. Since marine bands form stratigraphically important horizons in the Upper Carboniferous, many attempts have been made to recognise marine bands using well logs (gamma-ray). The results from this study show that using gamma-ray devices (detecting U-enrichments), only marine bands in a Goniatites facies are clearly recognised while Lingula marine bands are not detected.

Epigenetic mineralisations occurring in the former coal-mining district of Limburg predominantly consist of sphalerite, galena, chalcopyrite, quartz, Fe-dolomite/ankerite and calcite. The present note describes siegenite which was collected for the first time from this paragenesis some years ago.

Sedimentological data acquired by thin section petrography is a rich source of information to better understand and interpret depositional environments that are dominated by fine-grained deposits. This study provides an evaluation of the sedimentological and geochemical changes recorded over Upper Viséan to Lower Namurian successions preserved in a core section from a well drilled in the southern part of the Netherlands. Facies analysis and the recognition of microfacies associations allow detailed interpretations of depositional environments. Interpretation of additional geochemical data acquired by portable X-ray fluorescence analyses has resulted in a chemostratigraphic zonation for the core section. The zonation reflects stratigraphic changes in the mineralogy of the sedimentary successions. Integration of the microfacies associations and the chemostratigraphic zonation has led to the identification of three so-called depositional zones, which show the development of depositional settings from Late Viséan to Early Namurian times. Depositional Zone 1 consists of fine-grained turbiditic limestones and mudstones deposited in a distal carbonate ramp setting during Latest Viséan times. The overlying Depositional Zone 2 corresponds to the Geverik Member (Lower Namurian) and is particularly heterogeneous in geochemical and lithological terms: the zone reflects a complex interplay between different parameters such as sediment source, transport mechanisms and oxygen content that are assumed to be governed by fluctuating sea levels and changing depositional environments (from basinal to shallow marine settings). Sandy lenticular mudstones are predominant in the lower part of Depositional Zone 2 and show that sedimentation was via erosive bedload, whilst the common fossiliferous mudstones present within the upper part of the same zone yield evidence for increased endobenthic activity in dysoxic conditions. The successions assigned to Depositional Zone 3 ( = Epen Formation – Namurian) are the products of cyclic sedimentation of a terrestrial sourced delta.

Stigmaria is one of the iconic plant fossils of the Carboniferous and fragments of the narrower parts of the rhizomorph are found in most museum collections. However, very few almost entire specimens have been found and preserved. A new specimen of Stigmaria from Brymbo, North Wales is described and compared with other preserved examples from Europe and North America. The Brymbo specimen shows a large portion of trunk still attached to the large stigmarian base, which is a rare find, and this specimen supports our ideas of how these impressively large casts were formed. Stigmarias were preserved by the deposition of minerals around them following a sediment inundation, which gave sufficient support while the tissues rotted and filled with sediments. Remnants of the outer tissues were compressed to form a thin surrounding coal layer.

Seven new species and one new genus of the family Haplolepidae (Actinopterygii: Palaeonisciformes) are described from new material obtained from the Drumgray coal shales, North Lanarkshire: Westphalian A (Bashkirian): Protohaplolepis isabellae; Protohaplolepis limnades; Protohaplolepis traquairi; Parahaplolepis alexandrae; Parahaplolepis elenae; Pyritocephalus youngii and Millerolepis eleionomae. The discovery of these new taxa increases the number of haplolepid species found in Europe to 16, thus producing a faunal count more than comparable to that of North America. This high concentration of haplolepid remains in limnic deposits is also a strong indication that these fish were not only adapted to a coastal paralic basin, but also well-adapted to a freshwater brackish environment. A comprehensive description of the skull roof morphology, including a short description of some of the larger dermal bones, is given of seven new haplolepid species obtained from the coal shale tips at Wester Bracco and Shotts in North Lanarkshire. In consequence, a revised table of the stratigraphical distribution of the Haplolepidae in Europe is provided. Furthermore, the new genus Millerolepis is assigned to the subfamily Parahaplolepinae and the generic position of the problematic Haplolepis attheyi from Newsham, Northumberland is discussed, with the taxonomic position of Protohaplolepis proposed.

A preliminary summary of the lower Visean to uppermost Moscovian (Carboniferous) conodont succession and biostratigraphy of the Dianzishang section in Zhenning, Guizhou, South China is presented. Eleven conodont zones, in ascending order, can be recognized: Gnathodus praebilineatus, Gnathodus bilineatus, Lochriea ziegleri, Declinognathodus noduliferus, Neognathodus symmetricus, ‘Streptognathodus’ expansus (primitive form), ‘Streptognathodus’ expansus, Mesogondolella donbassica – Mesogondolella clarki, Idiognathodus podolskensis, Swadelina fauna and Idiognathodus swadei zones. The first occurrences of Lochriea ziegleri at the base of the Serpukhovian Stage, Declinognathodus noduliferus noduliferus at the base of the Bashkirian Stage and ‘Streptognathodus’ expansus at the base of the Moscovian Stage are recognized. The definitions of these stage boundaries, as well as that of the base of the Kasimovian Stage are discussed. Correlations with the Naqing section in South China, Russian and North American sections, as well as other important sections in the world, are considered.

An association of diverse hollow spines and dermal denticles (ichthyoliths) from the Carboniferous (Westphalian) of Todmorden, Yorkshire, England are attributed to a new genus of enigmatic shark that may lie close to Listracanthus Newberry & Worthen, 1870. Scanning electron microscopy shows that denticle morphology is highly variable, but forms a morphocline including elongate multi-spined elements as well as robust dome-like stellate denticles and recurved spinose elements. Histological analysis suggests an absence of enameloid. Continuous variation of form between elongate multi-cusped spines to boss-like circular denticles shows that all previously described Palaeozoic species of Listracanthus are probably junior synonyms of the type species L. hystrix Newberry & Worthen, 1870. The status of Listracanthus as a surviving ‘Lilliputian’ taxon after the Permian extinction is questioned. Although the new specimen has affinities with Listracanthus, significant differences in the form of the posterior spines on elongate denticles warrants its placement in the new genus Acanthorhachis gen. nov. The family Listracanthidae is erected to accommodate Listracanthus and Acanthorhachis.

New detailed mapping and related field studies, together with re-assessment of prior investigations, have revealed that three groups of faults, orientated broadly NE, N and NW, have been the primary controls on stratigraphical, structural and geomorphological evolution in the upper Firth of Clyde since their initiation by proto-Variscan stresses in Late Devonian time. Extended control has been achieved through repeated episodic reactivation, during which existing lines of fracture were rejuvenated and others of similar orientation initiated. Movements on two (if not all three) groups of faults persisted until middle Palaeogene time at least. The faults have been augmented by two sets of irregularly distributed, open, plunging folds, broadly N–S and E–W in their axial orientations. Some N–S folds may be attributed to oblique or strike-slip movement on reactivated caledonoid faults, others to intermittent transpression, probably in Namurian–Westphalian times, affecting mainly the northeastern Midland Valley but stretching beyond the massif of the Clyde Lava Plateau to register a weakened presence as far W as the upper Firth. The N–S folds and dextral strike-slip movements on some faults may be far-field expressions of the Uralian Orogeny, whereas earlier, sinistral displacements on NE faults and the development of small, later and less-significant E–W folds may be related to different phases of long-lived Variscan compression from the S.

The Fenestella Shale Formation of Jammu and Kashmir Himalaya comprises latest Viséan or Serpukhovian siliciclastic deposits formed along the southern margins of the Palaeotethys Ocean. A sequence of shallowing upward and deepening upward units indicates changes from shoreface to offshore and deeper shelf conditions, probably controlled by eustatic changes in an otherwise passive depositional system. Some of the finer-grained, shallow marine deposits have yielded fossil floras dominated by sub-arborescent lycopsids (Sublepidodendron, Lepidodendropsis) sphenophytes (Archaeocalamites) and pteridophylls (Nothorhacopteris, Triphyllopteris). The assemblage compares with other Gondwanan floras of this age that have been assigned to the Paraca floral realm, and are taken to indicate relatively warm climatic conditions that existed just prior to the onset of the Carboniferous–Permian ice-age.