The Pliensbachian–Toarcian succession of North Yorkshire provides a global reference for the interval incorporating the Toarcian Oceanic Anoxic Event (T-OAE, ∼183 Ma). Major and trace element, carbon stable-isotope (δ13Corg) and total organic carbon (TOC) data for the Dove’s Nest core, drilled close to the classic outcrop sections of the Yorkshire coast, demonstrate geochemical, mineralogical and grain-size trends linked to sea level and climate change in the Cleveland Basin. High-resolution correlation between the core and outcrop enables the integration of data to generate a comprehensive chemostratigraphic record. Palaeoredox proxies (Mo, U, V, TOC/P, DOP and Fe speciation) show a progressive shift from oxic bottom waters in the late Pliensbachian through dysoxic–anoxic conditions in the earliest Toarcian to euxinia during the T-OAE. Anoxia–dysoxia persisted into the middle Toarcian. Elemental and isotope data (Re, Re/Mo, δ34SCAS, δ98Mo and ε205Tl) from the coastal sections evidence global expansion of anoxic and euxinic seafloor area driving drawdown of redox-sensitive metals and sulfate from seawater leading to severe depletion in early Toarcian ocean water. The record of anoxia–euxinia in the Cleveland Basin largely reflects global-scale changes in ocean oxygenation, although metal depletion was temporarily enhanced by periods of local basin restriction. Osmium and Sr isotopes demonstrate a pulse of accelerated weathering accompanying the early Toarcian hyperthermal, coincident with the T-OAE. The combined core and outcrop records evidence local and global environmental change accompanying one of the largest perturbations in the global carbon cycle during the last 200 Ma and a period of major biotic turnover.

The increase in biobased material usage requires the methods of verification to investigate the actual content of biocarbon in such materials, including liquid fuels. The determination of biocarbon in liquid samples using 14C required adaptation of existing sample preparation methods. In this study, both accelerator mass spectrometry (AMS) and liquid scintillation counting (LSC) methods were used to determine the content of 14C in six different liquid fuel blends produced from purely bio-based hydrotreated vegetable oil (HVO) and a 14C-free petrodiesel sample (ON/UF-BC). The results obtained for pure petrodiesel provide background values. The results indicate a good agreement between LSC and AMS, and a linear correlation between the 14C measurement results for blended samples and HVO content affirmed the reproducibility between the two methods. The repeatability of AMS results was tested on 10 aliquots of one of the blends, and the results were deemed reproducible.

Recent research has shown the potential of speleothem δ13C to record a range of environmental processes. Here, we report on 230Th-dated stalagmite δ13C records for southwest Sulawesi, Indonesia, over the last 40,000 yr to investigate the relationship between tropical vegetation productivity and atmospheric methane concentrations. We demonstrate that the Sulawesi stalagmite δ13C record is driven by changes in vegetation productivity and soil respiration and explore the link between soil respiration and tropical methane emissions using HadCM3 and the Sheffield Dynamic Global Vegetation Model. The model indicates that changes in soil respiration are primarily driven by changes in temperature and CO2, in line with our interpretation of stalagmite δ13C. In turn, modelled methane emissions are driven by soil respiration, providing a mechanism that links methane to stalagmite δ13C. This relationship is particularly strong during the last glaciation, indicating a key role for the tropics in controlling atmospheric methane when emissions from high-latitude boreal wetlands were suppressed. With further investigation, the link between δ13C in stalagmites and tropical methane could provide a low-latitude proxy complementary to polar ice core records to improve our understanding of the glacial–interglacial methane budget.

Here, we present the results of carbon isotope and elemental analysis of one-year-old Pinus Sylvestris L. needles collected in 2021 from 10 sampling sites in a highly populated and industrialized area of Poland. The needles were exposed to air pollution for one year. The chemical analysis of the samples was performed using different methods: radiocarbon analysis by accelerator mass spectrometry, stable isotope analysis using isotope ratio mass spectrometry, and elemental analysis by inductively coupled plasma-atomic emission spectroscopy. Variations in the carbon isotopes and elemental composition of pine needles were due to a mixture of carbon dioxide originating from different sources such as households, vehicle traffic, and industrial factories.

Mudstones from the Argiles de Châtillon Formation exposed in the Boulonnais region of Northern France represent a proximal lateral equivalent of the organic-rich Kimmeridge Clay Formation. The Argiles de Châtillon Formation is composed of two subunits that straddle the Kimmeridgian–Tithonian boundary. Each subunit contains an organic-rich interval. The two conspicuous organic-rich intervals have been linked to either periods of high sea level or greenhouse warming. Here, we use palynology to further understand climate and environmental mechanisms that drove organic matter enrichment. We use bulk organic carbon isotope records (δ13Corg) to correlate the Boulonnais sections with those of the Kimmeridge Clay Formation. The palynological results suggest that the stratigraphically lower organic-rich interval (Kimmeridgian) was deposited under suboxic to anoxic stratified conditions. A large-scale climate shift from cooler/humid to warmer/arid conditions marked the Kimmeridgian–Tithonian boundary, influencing organic matter enrichment in the stratigraphically higher organic-rich interval (Tithonian). In contrast with the lower organic-rich interval, there are no indications of stratified conditions for the higher organic-rich interval. Within this thicker organic-rich interval, cyclic variations in amorphous organic matter distribution, total organic carbon and δ13Corg trends on a 2 m scale are observed. They co-occur with fluctuations of the palynological assemblages, indicative of more humid versus arid climate conditions, likely alternating on a ∼100 kyr eccentricity timescale. Our results show that under the most humid phases of these overall arid climate conditions, sulfurization of carbohydrates was the dominant control on organic matter preservation. This climate-controlled process that drives organic matter enrichment in the Tithonian can be recognized on a basin-wide scale.

Determining the biocomponents in liquid fuels using radiocarbon radioisotope (14C) dating requires sample preparation adaptations to the conditions of the Gliwice Radiocarbon and Mass Spectrometry Laboratory. Liquid scintillation counting (LSC), and accelerator mass spectrometry (AMS) were investigated using six samples, including one 14C-free fuel and modern hydrotreated vegetable oil (HVO). For AMS, samples were prepared using tin capsules for liquids for EA combustion and graphitization in an AGE system. For LSC, liquid fuels were prepared by mixing with purified preheated sand and a benzene synthesis line. Benzene resublimation was also tested. IRMS measurements were also conducted for benzene to account for isotopic fractionation. Sample background measurements using both methods showed good performances by both AMS and LSC without resublimation. Comparable results were also obtained for HVO.

The episode of widespread organic carbon deposition marked by peak black shale sedimentation during the Palaeoproterozoic is also reflected in exceptionally abundant graphite deposits of this age. Worldwide anoxic/euxinic sediments were preserved as a deep crustal reservoir of both organic carbon, and sulphur in accompanying pyrite, both commonly >1 wt %. The carbon- and sulphur-rich Palaeoproterozoic crust interacted with mafic magma to cause Ni–Co–Cu–PGE mineralization over the next billion years, and much uranium currently produced is from Mesoproterozoic deposits nucleated upon older Palaeoproterozoic graphite. Palaeoproterozoic carbon deposition has thus left a unique legacy of both graphite deposits and long-term ore deposition.

Throughout the Ediacaran Period, variable water-column redox conditions persisted along productive ocean margins due to a complex interplay between nutrient supply and oceanographic restriction. These changing conditions are considered to have influenced early faunal evolution, with marine anoxia potentially inhibiting the development of the ecological niches necessary for aerobic life forms. To understand this link between oxygenation and evolution, the combined geochemical and palaeontological study of marine sediments is preferable. Located in the Yangtze Gorges region of southern China, lagoonal black shales at Miaohe preserve alga and putative metazoans, including Eoandromeda, a candidate total-group ctenophore, thereby providing one example of where integrated study is possible. We present a multi-proxy investigation into water-column redox variability during deposition of these shales (c. 560–551 Ma). For this interval, reactive iron partitioning indicates persistent water-column anoxia, while trace metal enrichments and other geochemical data suggest temporal fluctuations between ferruginous, euxinic and rare suboxic conditions. Although trace metal and total organic carbon values imply extensive basin restriction, sustained trace metal enrichment and δ15Nsed data indicate periodic access to open-ocean inventories across a shallow-marine sill. Lastly, δ13Corg values of between −35‰ and −40‰ allow at least partial correlation of the shales at Miaohe with Member IV of the Doushantuo Formation. This study provides evidence for fluctuating redox conditions in the lagoonal area of the Yangtze platform during late Ediacaran time. If these low-oxygen environments were regionally characteristic, then the restriction of aerobic fauna to isolated environments can be inferred.

A number of ecological and geochemical transformations occurred during late Ediacaran and early Cambrian time, the effects of which are difficult to overestimate. However, the strong linkage of biostratigraphic and chemostratigraphic methods with lithofacies makes the localization of the Precambrian–Cambrian boundary and its correlation with lithologically contrasting sections highly debatable. We analyse the taxonomy and stratigraphic distribution of small skeletal fossils and trace fossils, the carbonate carbon and oxygen isotope composition, and U–Pb detrital zircon age in the Ediacaran–Cambrian transitional interval of the Irkutsk Cis–Sayans Uplift (southwestern Siberian Platform). This interval (Moty Group) comprises a transgressive succession with red-coloured alluvial to deltaic siliciclastic deposits (Shaman Formation) and overlying shallow-marine carbonates (Irkut Formation). The lower Irkut Formation hosts sporadic and poorly preserved tubular Cambrotubulus fossils, which are known from both the terminal Ediacaran Period (c. 550–541 Ma) and the Terreneuvian Epoch (541–521 Ma), and typical Fortunian trace fossils, including an index ichnotaxon of the Cambrian boundary Treptichnus pedum. The biostratigraphic and carbonate carbon isotope data and U–Pb concordia ages of 531.1 ± 5.2 Ma (mean weighted, 530.6 ± 5.3 Ma) of the five youngest zircon grains from the lower Irkut Formation indicate that at least the shallow-marine carbonates of the upper Moty Group correspond to the Cambrian Stage 2 (c. 529–521 Ma). In the Irkutsk Cis–Sayans Uplift, the Cambrian Period tentatively began before or during the accumulation of the alluvial to deltaic siliciclastic Khuzhir and Shaman formations, and this crucial divide remained unmarked in the palaeontological and isotopic records.

Guided by conodont biostratigraphy and unconformities observed in the field, stable carbon isotopic analysis (δ13Ccarb) was performed on 210 samples from Lower–Middle Ordovician (Tremadocian to Darriwilian) sections and wells in the Tarim Basin, NW China. The δ13C trend in the Tarim Basin sections has three distinct characteristics: (1) from the Tremadocian to the Floian, a positive shift from −1.9 ‰ to −0.2 ‰ is observed near the boundary between the Penglaiba Formation and the Yingshan Formation; (2) from the Floian to the Dapingian, a positive shift in δ13C from −3 ‰ to −0.7 ‰ occurred under large-scale sea-level rise and a change in the sedimentary environment from a restricted platform to an open platform. Changes in the conodont type are also observed in the Tabei region; and (3) from the Dapingian to the Darriwilian, δ13C first decreased and then increased, showing a negative shift at the Dapingian–Darriwilian boundary. During the Floian, δ13C decreased in the study area, while it first decreased and then increased in other regions, which may reflect local sea-level movements in response to isostatic crustal movements. Two types of positive shift were identified at the Floian–Dapingian boundary, which likely show the effects of local factors, including a disconformity, dolomitization, and platform restriction, superimposed on the global signal of the carbon isotope. Some conodont zonations and recurrent negative excursions in Tremadocian, Floian and Dapingian stages appear to be truncated by unconformities, which are accompanied by short-term subaerial exposure due to sea-level fall and local tectonic uplift.

Chemostratigraphic units require consistent definitions and unambiguous names. So-called TOCE (Top of Cambrian Excursion) is used as an uppermost Cambrian δ13Ccarb negative excursion although it was proposed without documentation, is ambiguously defined, and variably correlated into four Laurentian trilobite zones. TOCE, a nihilartikel, is regularly substituted to the exclusion of the earlier named, precisely documented and geochronologically older HERB (Hellnmaria-Red Tops Boundary) Event. HERB allows late Cambrian global correlation; its onset is close to the lowest occurrence of the conodont Eoconodontus notchpeakensis at the base of a proposed replacement (Lawsonian Stage) of Cambrian Stage 10. TOCE must be retired from use and abandoned as a synonym of the HERB Event.

A new carbon isotope record for two high-latitude sedimentary successions that span the Jurassic–Cretaceous boundary interval in the Sverdrup Basin of Arctic Canada is presented. This study, combined with other published Arctic data, shows a large negative isotopic excursion of organic carbon (δ13Corg) of 4‰ (V-PDB) and to a minimum of −30.7‰ in the probable middle Volgian Stage. This is followed by a return to less negative values of c. −27‰. A smaller positive excursion in the Valanginian Stage of c. 2‰, reaching maximum values of −24.6‰, is related to the Weissert Event. The Volgian isotopic trends are consistent with other high-latitude records but do not appear in δ13Ccarb records of Tethyan Tithonian strata. In the absence of any obvious definitive cause for the depleted δ13Corg anomaly, we suggest several possible contributing factors. The Sverdrup Basin and other Arctic areas may have experienced compositional evolution away from open-marine δ13C values during the Volgian Age due to low global or large-scale regional sea levels, and later become effectively coupled to global oceans by Valanginian time when sea level rose. A geologically sudden increase in volcanism may have caused the large negative δ13Corg values seen in the Arctic Volgian records but the lack of precise geochronological age control for the Jurassic–Cretaceous boundary precludes direct comparison with potentially coincident events, such as the Shatsky Rise. This study offers improved correlation constraints and a refined C-isotope curve for the Boreal region throughout latest Jurassic and earliest Cretaceous time.

The Toarcian Oceanic Anoxic Event (T-OAE, c. 182 Ma) represents a major perturbation of the carbon cycle marked by widespread black shale deposition. Consequently, the onset of the T-OAE has been linked to the combined effects of global warming, high productivity, basin restriction and salinity stratification. However, the processes that led to termination of the event remain elusive. Here, we present palynological data from Arctic Siberia (Russia), the Viking Corridor (offshore Norway) and the Yorkshire Coast (UK), all spanning the upper Pliensbachian – upper Toarcian stages. Rather than a ‘dinoflagellate cyst black-out’, as recorded in T-OAE strata of NW Europe, both the Arctic and Viking Corridor records show high abundance and dinoflagellate diversity throughout the T-OAE interval as calibrated by C-isotope records. Significantly, in the Arctic Sea and Viking Corridor, numerous species of the Parvocysta and Phallocysta suites make their first appearance in the lower Toarcian Falciferum Zone much earlier than in Europe, where these key dinoflagellate species appeared suddenly during the Bifrons Zone. Our results indicate migrations of Arctic dinoflagellate species, driven by relative sea-level rise in the Viking Corridor and the establishment of a S-directed circulation from the Arctic Sea into the Tethys Ocean. The results support oceanographic models, but are at odds with some interpretations based on geochemical proxies. The migration of Arctic dinoflagellate species coincides with the end of the T-OAE and marks the arrival of oxygenated, low-salinity Arctic waters, triggering a regime change from persistent euxinia to more dynamic oxygen conditions.

The introduction of agriculture is a key defining element of the Neolithic, yet considerable debate persists concerning the nature and significance of early farming practices in north-west Europe. This paper reviews archaeobotanical evidence from 95 Neolithic sites (c. 4000–2200 cal bc) in Wales, focusing on wild plant exploitation, the range of crops present, and the significance of cereals in subsistence practices. Cereal cultivation practices in Early Neolithic Wales are also examined using cereal grain stable carbon (δ13C) and nitrogen (δ15N) isotope analysis. The Early Neolithic period witnessed the widespread uptake of cereals alongside considerable evidence for continued wild plant exploitation, notably hazelnuts and wild fruits. The possibility that wild plants and woodlands were deliberately managed or altered to promote the growth of certain plants is outlined. Small cereal grain assemblages, with little evidence for chaff and weed seeds, are common in the Early Neolithic, whereas cereal-rich sites are rare. Emmer wheat was the dominant crop in the Early Neolithic, while other cereal types were recorded in small quantities. Cereal nitrogen isotope (δ15N) values from Early Neolithic sites provided little evidence for intensive manuring. We suggest that cultivation conditions may have been less intensive when compared to other areas of Britain and Europe. In the later Neolithic period, there is evidence for a decline in the importance of cereals. Finally, the archaeobotanical and crop isotope data from this study are considered within a wider European context.

In this paper, a record of the 14C and 13C isotope content of atmospheric CO2 for Gliwice is presented for samples collected on a weekly basis in the years 2011–2013. In addition, measurements were performed on the early and late wood from the annual rings of pine trees from five sites located 3–6 km from the atmospheric CO2 sampling point. The concentration of 14C in CO2 samples from the air was much lower relative to the concentration of this isotope in “clean air,” indicating a pronounce Suess effect, with a mean Δ14C lower by ca. 60‰ than Jungfraujoch data when the 15% of the highest differences are excluded, which leads to the FFCO2 estimate of 5.8%. In winter, the main source of fossil CO2 was fuel combustion, as confirmed by significant correlations with air pollutants. In the vegetation seasons, the Δ14C was highly variable due to biogenic influence and more variable winds. The isotopic results were also affected by an additional significant CO2 source for the Gliwice air, which was a closed mine shaft. The Δ14C and δ13C in tree rings did not record a strong Suess effect in the years 2008–2013 in woodland areas around Gliwice city.

Speleothem organic matter can be a powerful tracer for past environmental conditions and karst processes. Carbon isotope measurements (δ13C and 14C) in particular can provide crucial information on the provenance and age of speleothem organic matter, but are challenging due to low concentrations of organic matter in stalagmites. Here, we present a method development study on extraction and isotopic characterization of speleothem organic matter using a rapid procedure with low laboratory contamination risk. An extensive blank assessment allowed us to quantify possible sources of contamination through the entire method. Although blank contamination is consistently low (1.7 ± 0.34 – 4.3 ± 0.86 μg C for the entire procedure), incomplete sample decarbonation poses a still unresolved problem of the method, but can be detected when considering both δ13C and 14C values. We test the method on five stalagmites, showing reproducible results on samples as small as 7 μg C for δ13C and 20 μg C for 14C. Furthermore, we find consistently lower non-purgeable organic carbon (NPOC) 14C values compared to the carbonate 14C over the bomb spike interval in two stalagmites from Yok Balum Cave, Belize, suggesting overprint of a pre-aged or even fossil source of carbon on the organic fraction incorporated by these stalagmites.

Highly resolved, well-dated paleoclimate records from the southern South African coast are needed to contextualize the evolution of the highly diverse extratropical plant communities of the Greater Cape Floristic Region (GCFR) and to assess the environmental impacts on early human hunter-gatherers. We present new speleothem stable oxygen and carbon isotope ratios (δ18Oc and δ13C) from two caves at Pinnacle Point, South Africa, covering the time between 330 and 43 ka. Composite δ18Oc and δ13C records were constructed for Staircase Cave and PP29 by combining all stable isotope analyses into a single time series and smoothing by a 3-point running mean. δ18Oc and δ13C values record changes in rainfall seasonality and the proportions of C3 and C4 plants in the vegetation, respectively. We show that in general increased summer rainfall brought about a wider spread of C4 grasses and retreat of the C3 plant–dominated GCFR communities. The occurrence of summer rainfall on the southern coast of South Africa was linked to total rainfall amounts in the interior region through tropical temperate troughs. These rainfall systems shifted the southern coastal climate toward more summer (winter) rainfall when precession was high (low) and/or the westerlies were in a northern (southern) position.