Early Palaeozoic crinoids are known only patchily from the British Isles except for accumulations at starfish beds. A single, exquisitely preserved crinoid is reported from the Telychian (Llandovery, Silurian) of the Pysgotwr Grits Formation of the Llangurig area, Powys, mid-Wales. This sedimentary succession is turbiditic in origin and poorly fossiliferous. The crinoid is a diplobathrid camerate, Euptychocrinus longipinnulus sp. nov., preserved as an external mould without counterpart. It has a high, shuttlecock-like crown; a conical, unsculptured cup; low infrabasals; a pair of long, slender, feather-like arms on each ray, each bearing numerous long pinnules; and a heteromorphic column. Most previous reports of this genus have been from the Upper Ordovician – lower Silurian series of Laurentia; uncertainly, it is described from the Upper Ordovician deposits of Morocco (Gondwana). Euptychocrinus longipinnulus is the first Avalonian occurrence. The beautiful preservation of the arms, including cover plates of pinnules, contrasts with the proxistele, which is a series of ‘broken sticks’. This crinoid responded to an adverse environmental fluctuation, probably a turbidity current, by autotomizing the stem, but it was carried downslope and buried alive.

A new foraminiferal subzone (Cf5α or MFZ12α) in between the classical foraminiferal zonal biozones is characterized by the first occurrence of Archaediscus at concavus stage, primitive species of Pojarkovella, as well as the first Endothyranopsis s.s. This interval is represented in England, France and Morocco (in the western Palaeotethys) and in South China, and more widely in Iran (in the eastern Palaeotethys), where it is partly similar to the MFZ11B subzone defined by previous authors. The position of this new biozone within the Livian or Holkerian substages suggests that it has to be considered as part of the middle Viséan substage. We therefore propose the abandonment of the notation MFZ11B, which includes lower Viséan rocks, and the subdivision of the middle Viséan zones MFZ12 and Cf5 into two subzones MFZ12α or Cf5α, and MFZ12β or Cf5β, with the latter subzone containing the classical Livian–Holkerian foraminiferal guides Pojarkovella nibelis and Koskinotextularia. Furthermore, the lower Viséan MFZ11 zone can be subdivided in most Palaeotethyan basins into three subzones: a lower MFZ11α subzone (characterized by the first occurrence of Uralodiscus rotundus, as well as most species of Glomodiscus); a middle MFZ11β subzone (characterized by the first occurrence of Archaediscus at involutus stage and Conilidiscus); and an upper MFZ11γ subzone (characterized by the first occurrence of Nodosarchaediscus, Consobrinellopsis and Lituotubella).

Obtaining geochemical profiles using X-ray fluorescent (XRF) techniques has become a standard procedure in many sediment core studies. The resulting datasets are not only important tools for palaeoclimatic and palaeoceanographic reconstructions, but also for stratigraphic correlation. The International Ocean Discovery Program (IODP) has therefore recently introduced shipboard application of a handheld XRF device, making geochemical data directly available to the science party. In all XRF scanning techniques, the physical properties of wet core halves cause substantial analytical deviations. In order to obtain estimates of element concentrations (e.g. for quantitative analyses of fluxes or mass-balance calculations), a calibration of the scanning data is required. We test whether results from the handheld XRF analysis on discrete samples are suitable for calibrating scanning data. Log-ratios with Ca as a common denominator were calculated. The comparison between the handheld device and conventional measurements show that the latter provide high-quality data describing Al, Si, K, Ca, Ti, Mn, Fe, Zn, Rb and Sr content (R2 compared with conventional measurements: ln(Al/Ca) = 0.99, ln(Si/Ca) = 0.98, ln(K/Ca) = 0.99, ln(Ti/Ca) = 0.99, ln(Mn/Ca) = 0.99, ln(Fe/Ca) = 0.99, ln(Zn/Ca) = 0.99 and ln(Sr/Ca) = 0.99). Our results imply that discrete measurements using the shipboard handheld analyser are suitable for the calibration of XRF scanning data. Our test was performed on downcore sediments from IODP Expedition 355 that display a wide variety of lithologies of both terrestrial and marine origin. The implication is that our findings are valid on a general scale and that shipboard handheld XRF analysis on discrete samples should be used for calibrating XRF scanning data.

Analysis of the distribution of detrital zircon grains is one of the few parameters by which Precambrian palaeogeography may be interpreted. However, the break-up of Pangea and the subsequent dispersal of some of its fragments around the Indian Ocean demonstrate that zircon analysis alone may be misleading, since zircons indicate their original derivation and not their subsequent plate-tectonic pathways. Based on analysis of Precambrian–Ordovician zircon distributions, the presence of microcontinents and separating oceans in the north Gondwanan realm has been rejected in favour of an undivided pre-Variscan continental northwards extension of Africa to include Iberia, Armorica and neighbouring southern European terranes, based on analysis of Precambrian–Ordovician zircon distribution. However, contrasting views, indicating the presence of three peri-Gondwanan oceans with complete Wilson cycles, are reinforced here by a critical reappraisal of the significance of that Variscan area detrital zircon record together with a comparison of the evolution of the present-day Indian Ocean, indicating that Iberia, Armorica and other terranes were each separate from the main Gondwanan craton during the early Palaeozoic Era.

Aeolian dust input exerts significant influence on oceanic biogeochemical cycles and further potentially controls atmospheric CO2 concentrations. However, the possible link between long-term aeolian dust supply and primary productivity in the western North Pacific remains poorly understood. Here, we present a comprehensive study of major and trace elements and total organic carbon (TOC) concentrations of sediments from Integrated Ocean Drilling Program (IODP) Site U1430 in the southern Japan Sea, in order to reconstruct oceanic palaeoproductivity evolution and test its possible link to Asian dust input since 4 Ma. Palaeoproductivity proxies indicate remarkable increases in productivity at ∼3–2 Ma followed by high-frequency oscillations in productivity since 1.2 Ma. We suggest that higher dust-derived iron supply from Central Asia at 3–2 Ma, which was likely driven by the growth of the Northern Hemisphere ice sheets, could account for enhanced primary productivity and export production in the Japan Sea. Such increased oceanic palaeoproductivity could enhance organic carbon burial, which might contribute to the decrease in atmospheric CO2 concentrations, and provide a positive feedback to the global cooling. However, the Tsushima Warm Current (TSWC) intrusion via the southern Tsushima Strait, which was controlled by glacioeustatic sea level changes, has been the principal cause of the rapid changes in primary productivity and benthic redox condition since 1.2 Ma, regardless of continuously increased Asian dust input.

Situated between the North China Craton to the east and the Tarim Craton to the west, the northern Alxa area in westernmost Inner Mongolia in China occupies a key location for interpreting the late-stage tectonic evolution of the southern Central Asian Orogenic Belt. New LA-ICP-MS zircon U–Pb dating results reveal 282.2 ± 3.9 Ma gabbros and 216.3 ± 3.2 Ma granites from the Yagan metamorphic core complex in northern Alxa, NW China. The gabbros are characterized by low contents of Si, Na, K, Ti and P and high contents of Mg, Ca, Al and Fe. These gabbros have arc geochemical signatures with relative enrichments in large ion lithophile elements and depletions in high field strength elements, as well as negative εNd(t) (−0.91 to −0.54) and positive εHf(t) (2.59 to 6.37) values. These features indicate that a depleted mantle magma source metasomatized by subduction fluids/melts and contaminated by crustal materials was involved in the processes of magma migration and emplacement. The granites show high-K calc-alkaline and metaluminous to weakly peraluminous affinities, similar to A-type granites. They have positive εNd(t) (1.55 to 1.99) and εHf(t) (5.03 to 7.64) values. These features suggest that the granites were derived from the mixing of mantle and crustal sources and formed in a postcollisional tectonic setting. Considering previous studies, we infer that the final closure of the Palaeo-Asian Ocean in the central part of the southern Central Asian Orogenic Belt occurred in late Permian to Early–Middle Triassic times.

The Arctic is warming faster than anywhere else of comparable size on Earth, impacting global climate feedbacks and the Arctic biota. However, a warm Arctic is not novel. The Late Cretaceous fossil record of the region enables a detailed reconstruction of polar environmental conditions, and a thriving extinct ecosystem, during a previous 'hothouse’ global climate. Using leaf form (physiognomy) and tree ring characteristics we reconstruct Cenomanian to Coniacian polar thermal and hydrological regimes over an average annual cycle at eight locations in NE Russia and northern Alaska. A new high spatial resolution (∼1 km) WorldClim2 calibration of the Climate Leaf Analysis Multivariate Program (CLAMP) yields results similar to, but often slightly warmer than, previous analyses, but also provides more detailed insights into the hydrological regime through the return of annual and seasonal vapour pressure deficit (VPD), potential evapotranspiration (PET) estimates and soil moisture, as well as new thermal overviews through measures of thermicity and growing degree days. The new results confirm the overall warmth of the region, particularly close to the Arctic Ocean, but reveal strong local differences that may be related to palaeoelevation in the Okhotsk–Chukotka Volcanogenic Belt in NE Russia. While rainfall estimates have large uncertainties due to year-round wet soils in most locations, new measures of VPD and PET show persistent high humidity, but with notably drier summers at all the Arctic sites.

Whole-rock and Sr–Nd–Pb isotopic composition data, zircon Hf isotopic data and zircon U–Pb ages were obtained for the Late Triassic porphyries in the Zhongdian arc, eastern Tibet. These porphyries are intermediate and metaluminous and are enriched in large ion lithophile elements and depleted in high field strength elements. Moreover, they have weak negative Eu anomalies, high Sr and Ba contents, and high Sr/Y ratios. Different mineral geothermobarometers suggest that the porphyries in the Zhongdian arc crystallized at c. 640–829 °C and pressures of 2.1–2.8 kbar at depths shallower than 8 km. The porphyries have a calculated water content of 4.47–4.94 wt % and a relatively high magmatic oxygen fugacity. These porphyries were emplaced mainly at 230–203 Ma with a peak at 218–215 Ma. The Sr–Nd–Pb–Hf isotope data suggest that the porphyries in the Zhongdian arc were derived from a mixed melt of 50–65 % asthenospheric mantle and 35–50 % eclogite from the western Yangtze lower crust that experienced low-degree partial melting of 2–10 %. Subsequent fractional crystallization resulted in the decreasing trends of the major- and trace-element contents. The high Sr/Y and La/Yb values are the result of the low degree of partial melting of the western Yangtze lower crust rather than fractional crystallization, because no linear relationship was noted between Sr/Y or La/Yb and SiO2. The mixed melts from the lower crust and asthenospheric mantle provided a fertile magma source, and subsequent fractional crystallization under the favourable magmatic conditions of high water content and high oxidation state resulted in the formation of the porphyry Cu–Au deposits.

We investigated the Sakar unit metamorphic rocks of the Sakar–Strandzha zone in Bulgaria, using 40Ar/39Ar dating of amphibole from the polymetamorphic basement and white mica in the overlying upper Permian metasedimentary rocks of the Paleokastro Formation. The amphibole and white mica revealed plateau ages of 140.50 ± 1.75 Ma and 126.19 ± 1.29 Ma, respectively, indicating an Early Cretaceous cooling history of the regional amphibolite-facies metamorphism to greenschist-facies conditions. Similar metamorphic grades and cooling histories of the Sakar unit share evidence with the nearby Rhodope Massif for the northern Aegean region-wide early Alpine tectonometamorphic event.

The Daheyan region, situated in the SW of the Bogda Mountains in eastern Tianshan, is important for understanding the accretionary history of the Central Asian Orogenic Belt. We investigated Carboniferous intrusions from the Daheyan area, SW Bogda Mountains, obtaining new zircon U–Pb ages, whole-rock geochemical data and Hf isotope data for these intrusions. Zircon U–Pb dating indicates that syenogranite, diorite, granodiorite and monzonite of the Daheyan intrusions were all formed during late Carboniferous (311–303 Ma) magmatism. The syenogranite has geochemical characteristics of A-type granites that were mainly sourced from melting of juvenile crust. In comparison, the low-Mg-number diorite intrusion, with tholeiite and metaluminous features, was derived from young crust and mixed some mantle materials. The granodiorite and monzonite are both I-type granites, and are both sourced from the melting of juvenile crust. Based on a comprehensive analysis of previous geochronological, geochemical and isotopic data of magmatic and sedimentary rocks in the Bogda–Harlik belt, we consider that late Carboniferous intrusive rocks of the Bogda Mountains formed in an intra-arc extension related to a continent-based arc setting.

A new stratigraphic survey of the pyroclastic deposits blanketing Pompeii ruins shows departures from prior reconstruction of the events that occurred inside the town during the two main phases (pumice fallout and pyroclastic density currents) of the ad 79 Vesuvius eruption. We document the depth and distribution of subaerial erosion surfaces in the upper part of the pyroclastic sequence, formed during two short-lived breaks occurring in the course of the second phase of the eruption. These pauses could explain why 50% of the victims were found in the streets during the pyroclastic density currents phase.

International Ocean Discovery Program Expedition 355 drilled Sites U1456 and U1457 in Laxmi Basin (eastern Arabian Sea) to document the impact of the South Asian monsoon on weathering and erosion of the Himalaya. We revised the chronostratigraphic framework for these sites using a combination of biostratigraphy, magnetostratigraphy and strontium isotope stratigraphy. The sedimentary section at the two sites is similar and we divided it into six units bounded by unconformities or emplaced as a mass-transport deposit (MTD). Unit 1 underlies the MTD, and is of early–middle Miocene age at Site U1456 and early Paleocene age at Site U1457. An unconformity (U1) created by emplacement of the MTD (unit 2) during the late Miocene Epoch (at c. 9.83–9.69 Ma) separates units 1 and 2 and is identified by a marked change in lithology. Unit 3 consists of hemipelagic sediment with thin interbeds of graded sandstone of late Miocene age, separated from unit 4 by a second unconformity (U2) of 0.5–0.9 Myr duration. Unit 4 consists of upper Miocene interbedded mudstone and sandstone and hemipelagic chalk deposited between c. 8 and 6 Ma. A c. 1.4–1.6 Myr hiatus (U3) encompasses the Miocene–Pliocene boundary and separates unit 4 from unit 5. Unit 5 includes upper Pliocene – lower Pleistocene siliciclastic sediment that is separated from unit 6 by a c. 0.45 Myr hiatus (U4) in the lower Pleistocene sediments. Unit 6 includes a thick package of rapidly deposited Pleistocene sand and mud overlain by predominantly hemipelagic sediment deposited since c. 1.2 Ma.

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.