The Stac Fada Member of the Stoer Group, within the Torridonian succession of NW Scotland, is a melt-rich, impact-related deposit that has not been conclusively correlated with any known impact structure. However, a gravity low approximately 50 km east of the preserved Stac Fada Member outcrops has recently been proposed as the associated impact site. We investigate the location of the impact structure through a provenance study of detrital zircon and apatite in five samples from the Stoer Group. Our zircon U–Pb data are dominated by Archaean grains (> 2.5 Ga), consistent with earlier interpretations that the detritus was largely derived from local Lewisian Gneiss Complex, whereas the apatite data (the first for the Stoer Group) display a single major peak at c. 1.7 Ga, consistent with regional Laxfordian metamorphism. The almost complete absence of Archaean-aged apatite is best explained by later heating of the > 2.5 Ga Lewisian basement (the likely source region) above the closure temperature of the apatite U–Pb system (c. 375–450°C). The U–Pb age distributions for zircon and apatite show no significant variation with stratigraphic height. This may be interpreted as evidence that there was no major change in provenance during the course of deposition of the Stoer Group or, if there was any significant change, the different source regions were characterized by similar apatite and zircon U–Pb age populations. Consequently, the new data do not provide independent constraints on the location of the structure associated with the Stac Fada Member impact event.

Álvaro et al. (2018) argued that at least six species of Acadoparadoxides described from the lower–middle Cambrian boundary interval successions in the Anti-Atlas of Morocco all belong to Acadoparadoxides mureroensis (Sdzuy, 1958), which was first described from the Iberian Chains, Spain. Their study is based entirely on a morphometric analysis, which ignores the stratigraphic occurrences of particular morphotypes, deformation-related compaction of individual sclerites and their original relief, and thus underestimates some of the earlier described differences between these species. Their synonymization of a number of named Acadoparadoxides species is based on the morphometric approach that they rely on to distinguish between a number of congeneric species. A morphometric approach as applied by Álvaro et al. will lead to an apparent synonymy based on sclerites of similar taxa. Thus, morphometric study must be complemented by an analysis of which morphologically distinctive sclerites (i.e. cranidia and pygidia) are stratigraphically associated, and evaluation of which measurements are more critical to distinguishing sclerites that may represent distinct taxa, and the recognition of related character sets. Apart from demonstrating problems in the conclusion of Álvaro et al., our more inclusive approach of morphologic and stratigraphic analysis works to reassert the diagnostic characters and differences between six earlier named species of Acadoparadoxides. Our conclusions also emphasize the taxonomic problems associated with the identification and morphological variation of A. mureroensis owing to tectonic deformation of its topotype material and to questionable taxonomic assignment of Acadoparadoxides specimens from the Iberian sections.

The lithostratigraphic characteristics of the iconic Blue Lias Formation of southern Britain are influenced by sedimentation rates and stratigraphic gaps. Evidence for regular sedimentary cycles is reassessed using logs of magnetic susceptibility from four sites as an inverse proxy for carbonate content. Standard spectral analysis, including allowing for false discovery rates, demonstrates several scales of regular cyclicity in depth. Bayesian probability spectra provide independent confirmation of at least one scale of regular cyclicity at all sites. The frequency ratios between the different scales of cyclicity are consistent with astronomical forcing of climate at the periods of the short eccentricity, obliquity and precession cycles. Using local tuned time scales, 62 ammonite biohorizons have minimum durations of 0.7 to 276 ka, with 94% of them <41 ka. The duration of the Hettangian Stage is ≥2.9 Ma according to data from the West Somerset and Devon/Dorset coasts individually, increasing to ≥3.7 Ma when combined with data from Glamorgan and Warwickshire. A composite time scale, constructed using the tuned time scales plus correlated biohorizon limits treated as time lines, allows for the integration of local stratigraphic gaps. This approach yields an improved duration for the Hettangian Stage of ≥4.1 Ma, a figure that is about twice that suggested in recent time scales.

The Late Triassic deposits of the Sichuan Basin, southwestern China are significant for hosting abundant and diverse fossil assemblages including plants (containing spores and pollen), bivalves and insects. However, the Late Triassic palaeoecological variations are still poorly documented in this region. Here we present results from a palynological study from the Upper Triassic Xujiahe Formation in Hechuan of Chongqing, southern Sichuan Basin. The palynological analysis revealed a well-preserved terrestrial palynoflora of high diversity, comprising 184 species in 75 genera of spores and pollen. Three palynological assemblages were recognized, reflecting terrestrial successions throughout the entire interval with significant changes in the vegetation. Cycads/bennettites/ginkgophytes and conifers show an increasing trend into younger deposits, while ferns and lycopsids decrease in relative abundance. The Late Triassic vegetation underwent changes from lowland fern forest to a mixed forest with more canopy trees. We applied the Spore-pollen Morphological Group (SMG) method and Sporomorph EcoGroup (SEG) model to interpret the palaeoclimate features. The results reveal that the lower part of the Xujiahe Formation was deposited under relatively warm and humid conditions with an overall cooling and drying trend from latest Norian to Rhaetian time, accompanied by a general decrease of ferns and simultaneous increase of gymnosperms, and a decline in diversity of miospores. This study presents data on variations within the terrestrial ecosystem prior to the end-Triassic extinction event in the Sichuan Basin, and therefore provides important information for understanding the changes in the vegetation preceding the end-Triassic event.

The Datong pluton, the largest early Palaeozoic granitoid in the Western Kunlun Orogenic Belt (WKOB) in NW China, is a typical appinite-granite complex. It consists of diorites, quartz diorites, monzodiorites, quartz monzodiorites, monzonites, quartz monzonites, syenites, granodiorites and monzogranites. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb dating yielded crystallization ages of 459 ± 3 Ma for the quartz monzonites and 452 ± 5 Ma for the monzogranites (Late Ordovician). The rocks possess a wide range of SiO2 (56.0–73.4 wt %), MgO (0.17–4.55 wt %) and Mg no. (25–60), with high K2O (2.83–5.29 wt %) contents, exhibiting high-K calc-alkaline to shoshonitic traits. They are characterized by enrichments in large-ion lithophile elements (LILEs) and light rare Earth elements (LREEs), as well as depletions in high-field-strength elements (HFSEs). The rocks have initial 87Sr/86Sr ratios of 0.7086–0.7185, negative εNd(t) values of –3.72 to –1.79 and εHf(t) values vary from –1.6 to +4.7. These features are modelled to show that they were most likely derived from an enriched lithospheric mantle source and that fractional crystallization with minor crustal contamination was involved in their petrogenetic process. Considering the distribution and chronology of the Palaeozoic intrusions – such as Kegang, Bulong, Qiukesu, Yierba, North Kudi, Dongbake, Buya, Ayilixi and Warengzilafu granitoid plutons with ages of c. 420–530 Ma – in conjunction with the Palaeozoic metamorphic overprinting in the WKOB, we propose a divergent double-subduction model to explain the destruction of the Proto-Tethys Ocean and suggest that the Datong pluton was likely emplaced in a post-collisional setting following the termination of subduction in response to slab break-off.

Based on seven measured sections from Svalbard, the marine strata of the Permian Kapp Starostin Formation are arranged into seven transgressive–regressive sequences (TR1–TR7) of c. 4–5 Ma average duration, each bound by a maximum regressive surface. Facies, including heterozoan-dominated limestones, spiculitic cherts, sandstones, siltstones and shales, record deposition within inner, middle and outer shelf areas. The lowermost sequence, TR1, comprises most of the basal Vøringen Member, which records a transgression across the Gipshuken Formation following a hiatus of unknown duration. Temperate to cold, storm-dominated facies established in inner to middle shelf areas between the latest Artinskian and Kungurian. Prolonged deepening during sequences TR2 and TR3 was succeeded by a long-term shallowing-upward trend that lasted until the latest Permian (TR4–TR7). A major depocentre existed in central and western Spitsbergen while to the north, Dickson Land remained a shallow platform, leading to a shallow homoclinal ramp in NE Spitsbergen and Nordaustlandet. The Middle Permian extinction (late Capitanian) is recorded near the base of TR6 in deeper parts of the basin only; elsewhere this sequence is not recorded. Likewise the youngest sequence, TR7, extending to the upper formational contact of latest Permian age, is found only in the basin depocentre. Comparison with age-equivalent strata in the Sverdrup Basin of Canada reveals a remarkably similar depositional history, with, for example, two (third-order) sea-level cycles recorded in the Late Permian of both regions, in keeping with the global record. Sequence stratigraphy may therefore be a powerful correlative tool for onshore and offshore Permian deposits across NW Pangaea.

The Mesaoria (Mesarya) Basin exemplifies multi-stage basin development within a regional setting of diachronous continental collision. The Plio-Pleistocene represented a period of major sediment accumulation between two topographic highs, the Kyrenia Range in the north and the Troodos Massif in the south. During Pliocene time, open-marine marls and chalks of the Nicosia (Lefkoşa) Formation accumulated in a shelf setting. The Early Pleistocene period was characterized by a relative fall in sea level and a change to shallower-water bioclastic deposition of the Athalassa (Gürpınar) Formation. The northern margin of the basin was approximately delineated by the E–W neotectonic Ovgos (Dar Dere) fault zone. A carbonate ramp system formed directly to the south of this structural feature. During Early Pleistocene time, the basin evolved from an open-marine shelf to semi-enclosed lagoons with deltaic deposits, and finally to a non-marine aeolian setting, flanked by the rising Kyrenia Range to the north. Synthesis of geological evidence from the Mesaoria (Mesarya) Basin as a whole, including outcrop and borehole evidence from the south, adjacent to the Troodos Massif, indicates that the Pliocene – Early Pleistocene represented a relatively quiescent period. This intervened between Late Miocene – earliest Pleistocene southward thrusting–folding of the Kyrenia Range and Pleistocene intense surface uplift of both the Kyrenia Range and the Troodos Massif. The basin development reflects flexurally controlled collapse during Late Miocene – earliest Pliocene time related to southward thrusting, followed by strike-slip during westward tectonic escape of Anatolia, and finally regional uplift controlled by under-thrusting of continental crust from the south, as collision progressed.

Strata exposed near Tabbowa Tank, Tabbowa Basin, western Sri Lanka have yielded the first representatives of the distinctive Permian Glossopteris flora from that country. The assemblage includes gymnosperm foliage attributable to Glossopteris raniganjensis, roots referable to Vertebraria australis, seeds assigned to Samaropsis sp., sphenophyte axes (Paracalamites australis) and foliage (Sphenophyllum emarginatum), and fern foliage (Dichotomopteris lindleyi). This small macroflora is interpreted to be of probable Lopingian (late Permian) age based on comparisons with the fossil floras of Peninsula India. Several Glossopteris leaves in the assemblage bear evidence of terrestrial arthropod interactions including hole feeding, margin feeding, possible lamina skeletonization, piercing-and-sucking damage and oviposition scarring. The newly identified onshore Permian strata necessitate re-evaluation of current models explaining the evolution of the adjacent offshore Mannar Basin. Previously considered to have begun subsiding and accumulating sediment during Jurassic time, we propose that the Mannar Basin may have initiated as part of a pan-Gondwanan extensional phase during late Palaeozoic – Triassic time. We interpret the basal, as yet unsampled, seismically reflective strata of this basin to be probable organic-rich continental strata of Lopingian age, equivalent to those recorded in the Tabbowa Basin, and similar to the Permian coal-bearing successions in the rift basins of eastern India and Antarctica. Such continental fossiliferous strata are particularly significant as potential source rocks for recently identified natural gas resources in the Mannar Basin.

Cone-in-cone (CIC) and beef (BF) carbonate lenses ornament detachment zone faults underlying Triassic growth basins on Edgeøya. Field relationships place CIC and BF growth as during early diagenesis and a transition from hydroplastic to a later brittle-style of faulting that is marked by coarser calcite veining. Deformation is constrained to have occurred at <300 m depth. Multiple models exist for CIC formation. For the Edgeøya example, textural analysis of thin-sections suggests that small tensile fractures and carbonate shell fragments nucleated development of calcite aggregates with CIC and BF morphology within unconsolidated to poorly consolidated sediment to form asymmetric antitaxial tensile aggregates subparallel to bedding and fault surfaces. The conical forms result from differential growth on stepped, cleavage-parallel faces of fibres facing host sediment, with preferential inclusion incorporation at inner corners. The preferred directions of calcite growth are attributed to local stresses and seepage flow associated with pore pressure gradients. Substantial framboidal pyrite in the sediments represents an early phase of microbially driven sulphate reduction, which may have induced calcite mineralization. The transition to brittle-style faulting was marked by development of deformation twins in CIC/BF fibres, and a transition to coarse, blocky calcite growth in relay arrays of steeply oriented microveins. This indicates local fault-related stresses substantially changed during shallow diagenesis and lithification, an evolution attributed to changing pore pressures, seepage forces and material moduli. Calcite mineralizations at Edgeøya track the very significant changes in mechanical properties and stress states that occur during synlithification deformation at very shallow crustal levels.

Spinosaurus aegyptiacus was probably the largest predatory dinosaur of the Cretaceous period. A new study shows that it was a semiaquatic hunter. The function of Spinosaurus’ huge dorsal ‘sail’ remains unsolved, however. Three hypotheses have been proposed: (1) thermoregulation; (2) humpback storage; or (3) display. According to our alternative hypothesis, the submerged sail would have improved manoeuvrability and provided the hydrodynamic fulcrum for powerful neck and tail movements such as those made by sailfish or thresher sharks when stunning or injuring prey. Finally, it could have been employed as a screen for encircling prey underwater.

The Oligocene sedimentary succession in the eastern North Sea is revised and re-interpreted by applying new state-of-the-art reflection seismic data integrated with new bio- and Sr-stratigraphy data from three key wells in the study area. The Oligocene succession in the eastern North Sea is divided into four transgressive–regressive (T-R) sequences, characterized by non-accretional and/or aggradational transgressive systems tracts and prograding regressive systems tracts. Detailed studies of three wells, including biostratigraphy and Sr analysis, constrain the age relationships between the T-R sequences. Internal clinoform geometry indicates that the sediments were sourced from the present southern Norwegian mainland to the north of the depositional area. The direction of progradation shifted from being SE-directed in the earliest Rupelian (early Oligocene) to S- and SW-directed during Chattian time (late Oligocene). Rapid basin subsidence is indicated by the development of non-accretionary transgressive systems tracts, with subsequent progradation into water depths of hundreds of metres. The creation of accommodation space was out of phase relative to eustatic sea-level changes, and mainly controlled by regional-scale differential vertical movements where uplift and exposure of landmasses of the hinterland (southern Norway) occurred concurrently with basin subsidence. Halokinesis had an intra-basinal influence on the main sediment transport direction, but probably did not contribute much in creation of accommodation space.

In this study, two angular unconformities are found and analysed for the first time in the Mesozoic–Cenozoic succession in the northwestern segment of the Zagros fold–thrust belt (ZFTB) in the Kurdistan Region. The first unconformity exists between Lower Cretaceous and Paleocene–Eocene rocks and the second between the Campanian Shiranish Formation and the Maastrichtian Tanjero Formation. Each of these unconformities is found in two different localities in the Zagros Imbricate Zone (i.e. the highly deformed zone immediately SW of the Zagros Suture) of the ZFTB of the Kurdistan Region near the border with Iran. The study uses recent geological mapping, structural and stratigraphic analyses in addition to using previous biozonation of the stratigraphic units that bound the two unconformities. The first unconformity was initiated with obduction of the ophiolite and Lower Cretaceous radiolarite onto the passive margin of the Arabian plate. This unconformity formed during an early phase of the Zagros orogeny, which is associated with the developing of a foreland basin, and resulted in the folding of the radiolarites and their uplift to form high-relief land. The erosion of this high-relief land resulted in the formation of the Paleocene–Eocene Red Bed Series and their deposition on the folded radiolarite. The timing of the deformation that caused this unconformity is hard to determine; however, its stratigraphic position may suggest that it possibly is related to post-Cenomanian movements. The second unconformity is between the tilted Campanian Shiranish Formation (hemipelagite) and Tanjero Formation (500 m of conglomerate in the more proximal area). These unconformities indicate that deformation and uplift of the sedimentary units was variable during ophiolite obduction in this part of the ZFTB. We argue that deformation, ophiolite obduction and collision are likely to have varied in space and time along the c. 2000 km long ZFTB.