The Dobrudzha Coalfield in northeast Bulgaria has coal-bearing deposits ranging from latest Namurian to early Stephanian age (late Bashkirian to Moscovian age). Palynology of the coals in the upper Makedonka, Krupen and Gurkovo formations has been used to identify major changes in the vegetation during late Westphalian and early Stephanian times. The palynomorphs were grouped in two different ways (according to general morphotype and according to parent plant group) and stratigraphical trends in the two sets of groups used to identify vegetation change through the succession. Detrended Correspondence Analysis was also used to identify ecological relationships between the palynofloras. In the upper Makedonka and Krupen formations, lycophyte spores mostly comprise 15–25 % of the palynofloras in the thicker seams, but in the thinner coals they can represent up to 55 %. Of the other plant groups, ferns are the most abundant, representing 31–69 % in the thicker seams, 12–41 % in the thinner seams. This suggests that the arborescent lycophytes were mainly restricted to pioneer vegetation in these upland areas, and were replaced by ferns as the peat substrates became better developed, suggesting better-drained conditions. The thinner seams also have a noticeable component of sphenophyll spores, indicating significant areas of open conditions allowing colonization by these scrambling plants. In the Gurkovo Formation coals, lycophytes form an even smaller part of the palynological spectra, usually less than 10 % and in only one sample just over 25 %; fern spores make up 43–57 % of the palynofloras. This is in contrast to the palynofloras reported from contemporaneous clastic deposits in South Wales, most of which consist mostly of 34–60 % lycophyte spores and 14–34 % fern spores. Even more marked is the difference from the contemporaneous coals formed in lowland settings in the USA, which have mostly > 50 % lycophyte spores. This evidence suggests that the timing of the decline in abundance of arborescent lycophytes varied according to elevation above sea-level. In lowland coastal settings, the lycophytes remained dominant until middle–late Cantabrian times, but in more inland areas they were progressively replaced mainly by arborescent ferns during late Westphalian times.

The Tianshan orogen is divided into the Northern, Central and Southern Tianshan tectonic zones by the northern and southern sutures on both sides of the Central Tianshan Tectonic Zone. The eastern segment of the Central Tianshan Tectonic Zone is characterized by the presence of numerous Precambrian metamorphic blocks and is unconformably overlain by Ordovician–Silurian and late Palaeozoic strata. The Precambrian Kumishi and Pargantag metamorphic blocks are the largest older blocks in the eastern segment of the Central Tianshan Tectonic Zone, consisting mainly of metamorphic granitoids and sedimentary rocks in greenschist to amphibolite facies. There are two major lithological assemblages of the metamorphic granitoids: (1) quartz dioritic gneisses, and (2) granodioritic–monzogranitic gneisses with a minor amount of tonalitic and syenogranitic gneisses in both the Kumishi and Pargantag blocks. The quartz dioritic gneisses are characterized by low Sr/Ce (<5.3) and Sr/Y (<28), relatively high Mg no. (51.0–57.0), K2O (2.65–4.04 wt %) contents and εNd(t) values (−2.37–5.84), and negative Nb and Zr–Hf anomalies, as well as relatively flat chondrite-normalized REE patterns with slightly negative Eu anomalies, suggesting that the quartz dioritic gneisses were derived from partial melting of a depleted mantle source enriched by fluids and sedimentary melts from the subducted slab. However, most of granitic gneiss samples display high K2O contents, low Al2O3/(FeO* + MgO + TiO2) values, and relatively flat chondrite-normalized REE patterns with intensively negative Eu anomalies. Integrated low εNd(t) values and older TDM model ages suggest that crustal materials played a significant role in the petrogenesis of these granitoid gneisses and that they were mainly derived from the partial melting of calc-alkaline mafic to intermediate rocks in the crust. Also, variations in geochemical features between the Kumishi–Gangou and Pargantag regions, such as Zr and Hf, may reflect geographic variability in the development of coeval granitic magmas. Tectonic discrimination for granitoid, using trace elements, together with Nd isotopic data, demonstrates that these granitoid gneisses in the eastern segment of the Central Tianshan Tectonic Zone formed in a continental margin arc during late Mesoproterozoic times.

The Global Stratotype Section and Point (GSSP) for Stage 2 of the Ordovician System, now the Floian Stage and approximately equivalent to the lower and middle Arenig of England and Wales, is defined by the first appearance datum (FAD) of the graptolite Tetragraptus approximatus in the Diabasbrottet Quarry section at Mount Hunneberg, Sweden. One of the issues this raises is how to correlate the base of Stage 2 at the GSSP with areas and successions that do not contain a correlative graptolite fauna. The distinctive Cymatiogalea messaoudensis–Stelliferidium trifidum acritarch assemblage is present in the upper Tremadocian Araneograptus murrayi Graptolite Biozone of NW England and ranges across the Tremadocian–Stage 2 boundary there (the Tremadoc–Arenig boundary of Anglo-Welsh nomenclature). It also occurs widely at other high southern Ordovician palaeolatitudes around the margin of Gondwana, being reported from Ireland, Wales, the Isle of Man, Belgium, Germany, Spain and Turkey, and may also be present in Bohemia and Argentina (Eastern Cordillera). It therefore has the potential to contribute towards the recognition and correlation of the base of Stage 2 in those areas. Of particular interest are the First Appearance Datums of various taxa within the stratigraphical range of the messaoudensis–trifidum assemblage, notably that of Aureotesta clathrata simplex, which is considered to be close to the base of Stage 2 in NW England.

Elements of the messaoudensis–trifidum assemblage also occur in Baltica, the palaeoplate on which the GSSP for the base of Stage 2 is located. However, many of the taxa used to subdivide the messaoudensis–trifidum assemblage around Gondwana have not been recorded from Baltica and may be restricted palaeobiogeographically to the Gondwanan margin. Furthermore, acritarch microfloras have not been reported from the Diabasbrottet Quarry section itself, and there are hiatuses across the base of Stage 2 in the two sections from Baltica considered in this paper. Hence, direct correlation of the base of Stage 2 between the GSSP and other sections using acritarchs is not yet possible. Nevertheless, some taxa, for example the genera Peteinosphaeridium and Rhopaliophora, are shown to have FADs at similar stratigraphical levels in the late Tremadocian Stage of both Baltica and Gondwana, and therefore have the potential to correlate time slices in the late Tremadocian Stage between palaeoplates.

In one of the higher nappes of the Caledonides of Troms, northern Norway, rare thin dykes of calcite marble lie subparallel to the axial surfaces of folds in multilayered marble beds. The dykes emanate from pure calcite marble layers mostly in or close to the hinge zones of these flat-lying, tight to sub-isoclinal, F3 folds. In many cases, they appear to penetrate along the axial surfaces of these same folds, and there is an up to 10° angular disparity between dyke orientation and axial surfaces. The dykes are considered to have originated, and been expelled, from parent calcite marble layers either at or shortly after the peak of amphibolite-facies metamorphism between the D2 and D3 deformation phases of the Scandian orogeny. The dykes display a dyke-parallel, dark grey to white, colour banding, the origin of which is uncertain at present. In thin-section, an equigranular texture is dominated by 2–3 mm, equant, unstrained, calcite grains with straight boundaries and low-T twin lamellae, denoting a late-stage recrystallization. A weak, oblique, calcite grain-shape orientation fabric curves into a dyke-parallel alignment along the finer-grained margins, reflecting the simple-shear deformation imposed on the host rock. Regarding the initiation of these marble dykes, it seems likely that a combination of P–T conditions and possibly partial melting processes was conducive to generating extreme ductility/superplasticity, at least locally, and that this led to the sudden expulsion of a partially molten carbonate aggregate which had momentarily attained a critical pressure and intruded preferentially along available, transient fractures prior to the imposition of the D3 simple-shear regime.

The amethyst geodes observed in the tholeiitic basaltic flow from the Triz quarry at Ametista do Sul (Rio Grande do Sul, Brazil) show particular wall-layering infillings with, from the outside inwards, celadonite, chalcedony, fine-grained quartz and large-sized amethyst crystals. The primary fluid inclusions analysed in the amethyst crystals yield a 152 to 238 °C crystallization temperature range. The amethyst geodes are always located in the massive, fracture-free, basaltic part of the lava flows and surrounded by a limited wall-lining alteration halo, the thickness of which depends on the geode radius. The geochemical balances calculated from fresh to altered basalt in the geode environment indicate that the amount of SiO2 released from the alteration halo is always sufficient to produce the siliceous rims in the geodes without requirement for extraneous silica supply. The results point to a volcanic origin for the amethyst geode infillings through basalt ‘autoalteration’ by authigenic high temperature hydrothermal fluids. These fluids can originate from (1) unmixing of volatile coumpounds from melt through pressure release, (2) cooling to supercritical hydrous fluids with ‘autoalteration’ of the surrounding basalt and (3) migration of the residual hot fluids from the basalt to the geodic cavities through the pressure gradient between the geodic cavity and the rock.

δ13Corg and TOC data are presented from the upper spiralis Biozone (Telychian, Llandovery, Silurian) through to the upper Sheinwoodian (Wenlock, Silurian) of the Banwy River section, Wales. In laminated hemipelagites from the Telychian, δ13Corg values rise through the upper lapworthi Biozone to a maximum in the lower insectus Biozone after which they decline slightly. The most conspicuous feature of the δ13Corg curve is the prolonged positive excursion in the Sheinwoodian, commencing in the upper murchisoni Biozone and ending in strata yielding Monograptus flexilis. This Sheinwoodian positive δ13C excursion in the Banwy River section correlates precisely with that recognized in the East Baltic. The interval with the highest δ13Corg values also records the highest TOC values, suggesting that for the Sheinwoodian at least burial of carbon may have contributed to the positive δ13C excursion. Bioturbated strata yield very low TOC values; whether the δ13Corg values from these beds reflect a primary signal or the result of biostratinomic or diagenetic modification is uncertain.

The uppermost Llandovery to lower Wenlock Coralliferous ‘Group’ in SW Pembrokeshire is here redefined as a single formation with two members. The Coralliferous Formation is approximately 150 m thick and comprises a basal unit of granule- to pebble-grade rudite beds, the Renney Slip Member, overlain by interbedded mudstones and fine sandstones of the Deadman's Bay Member. The Renney Slip Member lies unconformably above the Skomer Volcanic Group and includes 12.4 m of coarse grained, granule- and pebble-rich rudites, with beds up to 0.94 m thick. Three lithofacies are recognized within this unit: coarse, granule-rich rudite beds are interpreted as a variety of mass flow deposits, some of which have been reworked in a marine environment; thick sandstones with planar and ripple lamination are shoreface to offshore transition zone deposits; silty mudstones interbedded with very fine grained sandstones represent marine offshore deposits, formed largely below mean storm wave base. These facies associations, and abundant bioturbation, indicate an environment with a strong marine influence, and a proximal source of coarse grained sediment. The Renney Slip Member is reinterpreted in the context of a fan delta depositional model. At least seven cycles of deposition are recognized, each showing an upwards-fining pattern, representing deposition from fan delta, shoreface–transition zone to open marine environments. These patterns of deposition are attributed to localized tectonic movements causing variations in relative sea level. At the time the Renney Slip Member was deposited, the southern Welsh Basin margin is interpreted as a fault-block extensional margin, with the landmass of Pretannia to the south. Though fan-delta deposition took place southwards against the uplifted footwall of the Wenall Fault, the basin margin lay to the south of the Ritec Fault.

As an example of microstructural and magnetic fabric evolution, and geochemistry of mafic dykes during a subsequent orogenic overprint, a major Mesoproterozoic dyke complex in Scandinavia, the Västerbotten complex of the Central Scandinavian Dolerite Group, is traced westwards into the crystalline nappes of the early Phanerozoic Caledonian orogen. Using geophysical, field, microscopic, magnetic and geochemical information, dykes and sills are characterized, and their overprint during Caledonian orogeny documented. The Västerbotten complex is composed of sets of dykes, trending NE–SW, NW–SE and WNW–ESE, respectively. Similar dykes are exposed in allochthonous positions (Lower and Middle allochthons) in the Caledonian fold-and-thrust belt. The autochthonous dykes are generally undeformed and retain both their primary texture and mineralogy. Chilled margins are well preserved. In the Caledonian Lower and Middle allochthons, similar dykes in crystalline basement rocks are progressively faulted and sheared when proceeding from the marginal to the interior parts of the orogen. Dyke margins are more likely to be sheared than the interior parts of dykes. In the Lower Allochthon, under very low- and low-grade metamorphic conditions, dykes are distinctly less competent than granitic host rocks. Thick dykes are more competent than gneisses; thin dykes do not show such competence contrasts. In the Middle Allochthon, metre-scale dykes with patches of altered plagioclase phenocrysts can still be discerned in low-strain domains. Highly sheared dykes are drawn out to thin layers of centimetre thickness. Dykes are deformed together with the crystalline country rocks under greenschist-grade metamorphic conditions without major competence contrasts. Magnetic fabrics show an evolution similar to the silicate mineral fabrics. The magnetic fabrics in the dykes are transformed successively from ferromagnetic–magmatic in the Autochthon to ferromagnetic deformational in the Lower Allochthon and, finally, paramagnetic deformational in the Middle Allochthon. As a consequence, the magnetic susceptibility decreases for several orders of magnitude. Geochemically, the dykes are dominantly sub-alkaline basalts typical for continental tholeiites and can be distinguished from the Neoproterozoic dykes in the Särv-Nappe equivalents (highest part of the Middle Allochthon), which show a more MORB-like (E-MORB) magmatic signature. Preliminary age information from a dyke in the Lower Allochthon of the Børgefjell area and the Middle Allochthon is consistent with the assumption that these dykes are time equivalent with the Central Scandinavian Dolerite Group. Therefore, the studied dykes may represent an extension of the Västerbotten complex or a new complex of the Central Scandinavian Dolerite Group. According to section restorations, the Caledonian allochthons were situated further WNW relative to their present position, and, originally, the mafic dykes cut across all of the Fennoscandian lithosphere, at least to the present Atlantic margin and the earlier passive margin of the Baltica terrane. As a consequence, these dykes may provide a link for pre-Caledonian and pre-Grenvillian plate reconstructions.

The hot springs that emerge at 46 °C in the centre of Bath Spa, Somerset, are unique in the UK. The four other thermal springs in Britain are also sourced in the Carboniferous Limestone, but they emerge at significantly lower temperatures (20 to 28 °C). Bath is situated in a region of low geothermal gradient (about 20 °C/km depth) in a geological setting that seems an unlikely place for hot springs. Why then are these the only hot springs in Britain, and why are they confined to such a small (20 × 80 m) area? The explanation presented here involves a sequence of geological events involving Triassic dissolution and Pleistocene permafrost that is unique to central Bath.

Rapakivi granites and several small leucogabbroic and gabbroic bodies are located in the Rangnim Massif, North Korea. The largest batholith in the Myohyang Mountains covers an area of 300 km2 and was intruded into Precambrian metamorphosed rocks. It has a SHRIMP U–Pb zircon weighted mean 207Pb/206Pb age of 1861 ± 7 Ma. The country rocks of rapakivi granites are Neoarchaean orthogneisses and Palaeo-Mesoproterozoic graphite-bearing metasedimentary rocks of granulite facies, and they are similar to those of the rapakivi granites and anorthosites exposed in South Korea and in the North China Craton. We conclude that the three massifs in the Korean Peninsula commonly record an identical Palaeo-Mesoproterozoic anorogenic magmatic event, indicating that they have a common Precambrian basement with the North China Craton.

A phylogenetic analysis of Jurassic irregular echinoids is realized to explore the origin and early evolution of this important subset of echinoids. The phylogeny is based on 39 characters and considers data from apical system architecture, the corona including tuberculation and spines, Aristotle's lantern, and general test shape. Results corroborate the monophyly of Irregularia, and clarify the phylogenetic interrelationships existing between the main groups of irregular echinoids. Specializations of the Aristotle's lantern, spines, tubercles and phyllodes constitute the apomorphies for different taxa, as for the whole of Irregularia. The phylogenetic signal yielded by these characters highlights the importance of the environmental context of the origin and diversification of irregular echinoids. The definition of ‘irregularity’ is re-examined, rejecting exocyclism and characters of the apical system as appropriate synapomorphies, and stressing the importance of other characters, particularly the high density and small size of tubercles and spines. A new clade name, Infraclypeidae [P], and phylocode designations (stem-based diagnoses) are proposed for the clades Irregularia, Eognathostomata, Microstomata, Neognathostomata and Atelostomata. Other groupings formerly used (Pygasteroida, Galeropygidae and Menopygidae) are considered paraphyletic.

Ion microprobe (SIMS) dating shows that three plutonic rock bodies representative of the major, ∼15 000 km2, late tectonic (late-D3), plutonic rock series in the Central Iberian Zone of the Hercynian belt in west-central Iberia have indistinguishable zircon crystallization ages. Ledrada biotite granite and Colmenar cordierite-bearing biotite granite show gradual transitions in field appearance, petrography and chemistry and have statistically indistinguishable weighted average ages of 306.8 ± 1.9(2σ) Ma and 306.5 ± 1.5(2σ) Ma, respectively, which indicates that they originated during a single event involving a heterogeneous magma which notably varied in Al-content. The third rock body, Navahermosa meta-gabbronorite, has a weighted average zircon crystallization age of 305.6 ± 1.4(2σ) Ma, statistically indistinguishable (variance analysis, F-test, α = 0.05) from the granites. Zircon crystals in the gabbronoritic rock are anhedral, skeletal, millimetre-sized and partake in main magmatic textures, whereas the zircon grains in the granites are of more common appearance, much smaller, usually euhedral and enclosed in main magmatic crystals. As gestation times of granitic zircon, the time between zircon crystallization and magmatic intrusion, may be up to 5 Myr, the crystallization age of the gabbronoritic zircon may be the best estimate of the time of emplacement of the magmatic complex. Our study indicates co-existence of basic and silicic magmas in the Hercynian crustal section at c. 306 Ma, suggesting common genetic control. The two granitic rocks carry inherited zircon ranging from c. 1300 to 330 Ma, indicating that pre-Hercynian basement rocks of Proterozoic to Palaeozoic age contributed to the granitic magma.

Jaw fragments bearing teeth from the Barremian of Boca do Chapim (Lisboa e Setubal Province, Portugal), originally considered as crocodilian and identified as Suchosaurus girardi by Sauvage, are redescribed and referred to the spinosaurid dinosaur Baryonyx, on the basis of comparison with Baryonyx walkeri, from the Barremian of England. This extends the geographical distribution of this unusual theropod genus to Portugal.

Baryonyx appears to have been a frequent component of Early Cretaceous dinosaur assemblages in the Iberian region, which may have formed a biogeographical ‘stepping-stone’ for baryonychine dispersal between Europe and Africa.

The Gushan diorite pluton, located at the northern margin of the North China block, was emplaced during Middle Devonian times (SHRIMP U–Pb zircon age of 390 ± 5 Ma). Rocks from the pluton are characterized by low SiO2 and high alkali contents, and they show monzodiorite compositions in a total alkali v. silica (TAS) plot. They exhibit light REE-enrichment, no to slightly positive Eu anomalies, strong depletion in Rb, Th, U, Nb, Ta, P, Zr, Hf and Ti, enrichment in Ba, K and Sr, low contents of Y and Yb, and high Sr/Y ratios. They have a relatively narrow range of isotopic compositions with initial 87Sr/86Sr ratios of ∼ 0.7050, εNd(T) values of −9.5 to −7.5 and zircon εHf(T) values from −11.8 to −5.8. These features are remarkably similar to another Middle Devonian intrusion, the Shuiquangou syenitic complex at the northern margin of the North China block. These similarities suggest that the two intrusions probably have a common origin. They were considered to be derived from a type I enriched mantle, ultimately with some involvement of ancient lower crustal components, and were likely emplaced in a back-arc extension environment related to southward subduction of the Palaeo-Asian oceanic plate or during the cessation of the subduction. Aluminium-in-hornblende barometry studies of the Middle Devonian Gushan pluton yielded emplacement depths of about 18 km. Combined with previous geobarometry results on the Carboniferous plutons within the Inner Mongolia Palaeo-uplift on the northern margin of the North China block, it is inferred that the uplift and exhumation of the plutons within the Inner Mongolia Palaeo-uplift during Middle Devonian to Late Carboniferous times were not as distinct as those during Late Carboniferous to Early Jurassic times, and the strong uplift and exhumation of the Inner Mongolia Palaeo-uplift were achieved during Late Carboniferous to Early Jurassic times.

Protector Shoal, the northernmost and most silicic volcano of the South Sandwich arc, erupted dacite–rhyolite pumice in 1962. We report geochemical data for a new suite of samples dredged from the volcano. Geochemically, the dredge and 1962 samples form four distinct magma groups that cannot have been related to each other, and are unlikely to have been related to a single basaltic parent, by fractional crystallization. Instead, the silicic rocks are more likely to have been generated by partial melting of basaltic lower crust within the arc. Trace element and Sr–Nd isotope data indicate that the silicic volcanics have compositions that are more similar to the volcanic arc than the oceanic basement formed at a back-arc spreading centre, and volcanic arc basalts are considered to be the likely source for the silicic magmas. The South Sandwich Islands are one of several intra-oceanic arcs (Tonga–Kermadec, Izu–Bonin) that have: (1) significant amounts of compositionally bimodal mafic–silicic volcanic products and (2) 6.0–6.5 km s−1P-wave velocity layers in their mid-crusts that have been imaged by wide-angle seismic surveys and interpreted as intermediate-silicic plutons. Geochemical and volume considerations indicate that both the silicic volcanics and plutonic layers were generated by partial melting of basaltic arc crust, representing an early stage in the fractionation of oceanic basalt to form continental crust.

Determination of zircon ages as well as geochemical and Sm–Nd isotope systematics of granitoids in the Khetri Copper Belt of the Aravalli mountains, NW India, constrain the late Palaeoproterozoic crustal evolution of the Aravalli craton. The plutons are typical A-type within-plate granites, derived from melts generated in an extensional tectonic environment. They display REE and multi-element patterns characterized by steep LREE-enriched and almost flat HREE profiles and distinct negative anomalies for Sr, P and Ti. Initial εNd values range from −1.3 to −6.2 and correspond to crustal sources with mean crustal residence ages of 2.5 to 2.1 Ga. A lower mafic crustal anatectic origin is envisaged for these granitoids, and the heterogeneous εNd(t) values are inferred to have been acquired from the magma source region. Zircon Pb–Pb evaporation and U–Pb ages indicate widespread rift-related A-type magmatism at 1711–1660 Ma in the northern Delhi belt and also suggest a discrete older magmatic event at around 1800 Ma. The emplacement ages of the compositionally distinct A-type granitoid plutons, and virtually coeval granulite metamorphism and exhumation in another segment of the Aravalli mountains, further signify that part of the Aravalli crust evolved during a widespread extensional event in late Palaeoproterozoic time.