The Early Jurassic represents a critical interval in Earth’s history, characterized by significant ecosystem perturbations both on land and in oceans. Huge releases of greenhouse gas (e.g., CO2, CH4) by large scale of volcanic eruptions are generally assumed to cause significant increases in temperature during the Triassic-Jurassic transition (TJT) and Toarcian Oceanic Anoxic Event (T-OAE). However, terrestrial environmental responses to the climate perturbations on land, e.g., type and intensity of continental weathering, during these two hyperthermal events are still unclear. Here, we present a continuous lacustrine succession from the Chuxiong Basin in Yunnan Province, China, through the analysis of an approximately 1800 meter core. By integration of sedimentological, paleontological, geochemical, and astronomical data, we have established a chronology spanning about 21 million years from the Rhaetian (Late Triassic) to the Aalenian (late Early Jurassic), calibrated by the long eccentricity cycles. Distinct negative carbon isotope excursions and peaks in sedimentary Hg abundance, confirm significant volcanism during both the TJT and T-OAE. However, the Chemical Index of Alteration (CIA) and clay mineral data show opposing responses for the two events, indicating increasing and decreasing (or constant) chemical weathering intensity during TJT and T-OAE, respectively. Therefore, we proposed that these event-specific chemical weathering variations imply responses of volcanism-induced hydrological changes at different latitudes during these events.

Two-hundred-million years ago, the emission of an estimated 100,000 Gt of CO2 during pulsed eruptions in the Central Atlantic Magmatic Province had dire consequences for the biosphere and resulted in the end-Triassic extinction. The exact causes for the extinction of organisms remain enigmatic, but a complex and drawn-out scenario is emerging that is in line with the pulsed activity in the CAMP. Palynological assemblages obtained from the immediate extinction interval from multiple locations exhibit a remarkable darkening of pollen and spores that is at odds with simple thermal maturation during burial. Here, we investigate this latest Triassic “dark zone”, using the Palynomorph Darkening Index (PDI) obtained from trilete fern spores in the Schandelah-1 core (North Germany) and Classopollis pollen in drill cores from Denmark (Stenlille-4), the United Kingdom (ICDP Prees-2), and Luxemburg (Elvange). Coinciding with a collapse of forest vegetation and the spread of a pioneer fern vegetation, the fern spores’ PDI reaches peak darkness in the uppermost Triletes Beds from Germany and equivalents elsewhere. This darkening event is mimicked in highest PDI values in Classopollis from the upper Lilstock Formation in the Prees-2 core and equivalent beds in the Elvange and Stenlille-4 cores. Controlled heating experiments of Lycopodium spores followed by PDI analyses suggest that latest Triassic darkening of palynomorphs is consistent with frequent surface fires carried in fern savannahs. The ensuing extreme soil erosion during wetter intervals resulted in mass removal of charred organic material in coastal sediments. The impact of continental-scale wildfires during the height of the end-Triassic mass-extinction suggests intense climate change exerting heat stress on vegetation as a major factor in the collapse of terrestrial ecosystems.

Two areas in Sweden are currently being investigated by the Swedish geological survey as possible sites for geological storage of CO2. One of them is in the Baltic Basin south of Gotland, where Cambrian sandstone from the Faludden Member (Borgholm Formation) has been recognized as a suitable storage reservoir. The Faludden reservoir is a well-sorted, fine- and medium-grained quartz arenite with high porosity and permeability. Here, we report new results obtained from scanning electron microscope analyses of the secondary mineralogy of the Faludden sandstone and implications for its CO2 storage potential. Our study shows that there are several phases of secondary mineralization in the sandstone, which to a varying degree affects the interaction with injection and storage of CO2. The results provide information on the diagenetic history of the reservoir and assessment of depth-related P-T mineralizations. The most common secondary mineralization is a patchy carbonate cement. The patches, embedding several detrital grains, are round to irregular with individual diameters of up to 5 mm. The carbonate is mostly dolomite with microscale variations towards more Mn- and Fe-rich compositions. Calcite is also present, especially in connection to occasional microfractures. In general, patchy cementation is favorable for CO2 storage since it can prevent compaction, while still allowing a relatively high porosity and permeability. Quartz cement in the Faludden sandstone is limited to scattered occurrences of fringed overgrowths at the edges of detrital quartz grains. However, we observe that the amount of secondary quartz is increasing with depth in the Baltic Basin. Subcropping lower Cambrian sandstone beds, such as the När and Viklau sandstone members are often more or less completely cemented with quartz. Thus, the process of secondary quartz mineralization is an important factor to consider when assessing the optimal depth range for CO2 storage in the basin. Other secondary minerals in the Faludden sandstone include pyrite, apatite, iron(titanium)oxides and small amounts of clay minerals (illite and kaolinite). In some samples there is evidence of dissolution of both quartz cement and dolomite, introducing a secondary microporosity. This study confirms that the sandstone from the Faludden Member is a suitable reservoir rock for CO2 storage. A thorough understanding of geological processes, including reservoir diagenesis, is essential for predicting the physiochemical interactions between the injected CO2 and the reservoir rock.

Despite often being referred to as a 'coolhouse climate', the climate during the Miocene (23.03- 5.33 Ma) was overall humid, warm and temperate. It was paced by orbitally driven cooler periods (the Oligocene-Miocene Transition and Mi-events) overprinted by a climatic optimum. Global cooling during the Late Miocene brought more arid conditions with climate seasonality, which varied across western Eurasia. Sedimentary archives from onshore Denmark comprise shallow marine siliciclastic deposits and discrete brown coal layers. Hence, they allow us to infer past climates and environments using both marine and terrestrial fossils. The backbone for Miocene stratigraphy and palaeoclimate reconstruction in the eastern North Sea Basin (present-day Denmark) is the Sander (Sdr.) Vium sediment core, which penetrates a shallow marine succession and spans an interval from c. 22 to 8 Ma. Here, we present an improved age model for the core. During the Miocene, forested lowlands predominated in the eastern North Sea Basin. Coastal areas included rich riparian landscapes and delta areas of lignite-forming swamp forest. Compilations of existing proxy records (pollen, spores, leaves, plant fragments and the organic biomarkers alkenones and membrane lipids) collectively show that the climate here was warm and moist during the Early and Middle Miocene, while the Late Miocene was characterised by climate cooling and modernisation of the vegetation. The interval preceding the Miocene Climatic Optimum was already warm and moist, and the onset was not characterised by a significant increase in temperature and precipitation. Instead, the palynoflora indicates homogeneous vegetation and only a weak signal of warming shown by a minor increase of, for example, sabaloid palms and Mastixiaceae.

AbstractThe long-term effects of the Central Atlantic Magmatic Province, a large igneous province connected to the end-Triassic mass-extinction (201.5 Ma), remain largely elusive. Here, we document the persistence of volcanic-induced mercury (Hg) pollution and its effects on the biosphere for ~1.3 million years after the extinction event. In sediments recovered in Germany (Schandelah-1 core), we record not only high abundances of malformed fern spores at the Triassic-Jurassic boundary, but also during the lower Jurassic Hettangian, indicating repeated vegetation disturbance and stress that was eccentricity-forced. Crucially, these abundances correspond to increases in sedimentary Hg-concentrations. Hg-isotope ratios (δ202Hg, Δ199Hg) suggest a volcanic source of Hg-enrichment at the Triassic-Jurassic boundary but a terrestrial source for the early Jurassic peaks. We conclude that volcanically injected Hg across the extinction was repeatedly remobilized from coastal wetlands and hinterland areas during eccentricity-forced phases of severe hydrological upheaval and erosion, focusing Hg-pollution in the Central European Basin.

Over long stretches of the north-east coast of Qeqertarsuaq (Disko), the sediments in the Nuussuaq Basin and their relations to the volcanic rocks are concealed beneath numerous landslides. Two cores south of Qullissat drilled by Falconbridge Ltd in 1994, targeting a native-iron-bearing igneous body assumed to be a sill, present well-preserved sections through the hidden succession. We have dated the sediments in the cores palynologically. The lower part comprises 115 m of deltaic deposits, including coal seams, of the Cretaceous Atane Formation, Qilakitsoq Member (late Turonian to early Coniacian age), which has not been recorded on Disko before. The two cores and five short coastal cliff sections are mutually correlatable and correlate further to the coal seams earlier mined at Qullissat; the coals are hereby dated for the first time. The Cretaceous rocks are overlain by 15 m of marine deposits, mainly mudstones, of the Danian Eqalulik Formation, with a hiatus of c. 24 million years. The igneous body of native-iron-bearing basaltic andesite has a thick, red-oxidised, vesiculated and brecciated top zone and is interpreted as a subaerial lava flow belonging to the Asuk Member of the Vaigat Formation. The flow has run perhaps up to 20 km from the eruption site to the sea, where it ponded and attained a thickness of 138 m, the thickest lava flow in the West Greenland Basalt Group. The flow is overlain by 22 m of non-marine sandstones and mudstones of the Atanikerluk Formation. The core correlation indicates the existence of a fault with c. 90 m vertical displacement between the two drill sites. The structural relations of the various parts of the Atane Formation along the north-east coast of Disko necessitate the assumption of another hidden, prevolcanic fault south of Qullissaaqqat.

Since 1976 more than 25,000 Arctic sediment samples have been processed for their palynological, nannofossil, or microfossil content at the Geological Survey of Greenland (GGU) and the Geological Survey of Denmark (DGU); both institutes are now merged into the Geological Survey of Denmark and Greenland (GEUS). The samples represent nearly all ages from the Neoproterozoic to the Neogene, though dominated by the Mesozoic. A large proportion of the samples were processed for palynomorphs. Up to ten slides have been produced for each palynological sample and usually one slide is produced for each nannofossil and microfossil sample, making the GEUS collection one of the largest Arctic slide collections with more than 200,000 slides. All type specimens and some specimens illustrated in publications listed here have been assigned MGUH numbers ( Museum Geologica Universitas Hafniensis) and are housed in the type collection of the Geological Museum of the University of Copenhagen, now part of the Natural History Museum of Denmark.

Cymatiosphaera hymenosynypha Morbey 1975, previously recorded from the Rhaetian Westbury Formation in the United Kingdom, occurs in Triassic-Jurassic boundary strata from Denmark. From the present study it is clear that this small, finely reticulate, ellipsoidal, two-layered palynomorph is not a prasinophyte, but a dinoflagellate cyst with a combination apical/intercalary archaeopyle (type tAtI) which involves three apical plates plus one intercalary plate. This cavate cyst is morphologically similar but not identical to Valvaeodinium hanneae Piasecki 2001 from the uppermost Bathonian to lower Callovian of East Greenland, and it is therefore here transferred to Valvaeodinium, as Valvaeodinium hymenosynypha (Morbey) Lindstrom comb. nov. The appearance of Valvaeodinium hymenosynypha in Rhaetian strata in the Danish Basin suggests that the lineage of cavate Valvaeodinium cysts originated in the Late Triassic alongside a chorate species of the genus. Valvaeodinium hymenosynypha seems to have survived just barely past the end-Triassic mass extinction as it is also present in the earliest Hettangian.

The long-term effects of the Central Atlantic Magmatic Province (CAMP), a large igneous province connected to the end-Triassic mass-extinction (201.5 Ma), remain largely elusive. Here, we document the persistence of volcanic-induced mercury pollution and its effects on the biosphere for 2 million years after the extinction event. In sediments recovered in Germany (Schandelah-1 core), we record not only high abundances of malformed fern spores at the Triassic-Jurassic boundary, but also during the Hettangian, indicating repeated vegetation disturbance and environmental stress that was eccentricity forced. Crucially, these abundances correspond to spikes in sedimentary Hg concentrations. Hg-isotope ratios (δ202Hg, Δ199Hg) indicate a volcanic source at the Triassic-Jurassic boundary but a terrestrial source for the early Jurassic peaks. We conclude that Hg injected by CAMP across the extinction was repeatedly remobilized from coastal wetlands and hinterland areas during eccentricity-forced phases of severe hydrological upheaval and erosion, focusing Hg-pollution in shallow marine basins.

The Late Jurassic–Early Cretaceous interval represents a prolonged marine deoxygenation period particularly in the Boreal–Arctic basins, the controlling factors of which remain poorly understood. Two drill cores totalling >450 m cover the Kimmeridgian–Barremian succession in contrasting locations in an evolving half-graben system (basin centre and near the footwall crest) in Wollaston Forland, NE Greenland; they provide an exceptional c. 20 myr long window into palaeoenvironmental development and changes in redox conditions within a detailed tectonostratigraphic framework. Synthesis of a multidisciplinary dataset including sedimentology, inorganic geochemistry and previously published organic geochemistry indicates that, despite continuous black mudstone accumulation from the Kimmeridgian to the Ryazanian, seafloor anoxia was intermittent in the Kimmeridgian, whereas more sustained anoxia or euxinia occurred in the middle Volgian–early Ryazanian. Correlation to reported contemporaneous successions along the Greenland margin indicates that protracted rifting and generation of localized seafloor topography were among the major drivers both of seafloor deoxygenation and current funnelling and amplification during the Jurassic–Cretaceous transition. Consequently, distribution of seaway current activity and dysoxia, anoxia and euxinia varied spatially, allowing fully oxygenated and anoxic pockets to coexist. Supplementary material : A facies table, summary of geochemistry data, geochemistry raw data and a sedimentological log from Store Koldewey are available at https://doi.org/10.6084/m9.figshare.c.6442539

For hundreds of millions of years wildfire has influenced, and been influenced by, plant evolution, biogeochemical cycling, and climate. Wildfire has even been implicated as one of the causative agents of mass extinctions. The deep time geologic record offers demonstrated, but underdeveloped, potential to advance knowledge on the role of wildfire in the Earth system. Herein, we present and discuss the geologic history of wildfire and methods for its reconstruction. We argue that application of the numeric approaches to wildfire reconstruction often used in Quaternary studies would advance understanding of deep time wildfire. Application of numeric methods increases statistical rigour, with the intent of reducing bias and increasing accuracy. For example, numeric methods offer a means to robustly calibrate the provenance and taphonomy of particles used to reconstruct wildfire, and to quantify uncertainties. Statistical methods should be used to assess the fidelity of new chemical proxies of wildfire, such as the types, amounts, distributions, and isotope signatures of polycyclic aromatic hydrocarbons, to represent source area and fuel type.

Disturbances in terrestrial vegetation across the end-Triassic mass-extinction (ETME) and earliest Jurassic (-201.5-201.3 Ma) have previously been linked to carbon cycle perturbations induced by the Central Atlantic Magmatic Province. Large-scale volcanic degassing has been proposed to have affected the terrestrial realm through various mechanisms. However, the effects of long-term "super greenhouse" climate variability on vegetation dynamics following the mass-extinction remain poorly understood. Based on a 10-million-year long multi-proxy record of northern Germany (Schandelah-1, Germany, paleolatitude of -41 degrees N) spanning the late Rhaetian to the Sinemurian (-201.5-190.8 Ma), we aim to assess mechanistic links between carbon cycle perturbations, climate change, and vegetation dynamics. Based on a high-resolution palynofloral record a two-phased extinction emerges, confirming extinction patterns seen in other studies. The first phase is associated with a decline in arborescent conifers, coinciding with a negative carbon isotope excursion and an influx of aquatic palynomorphs. Following this decline, we find a stepwise rise of ferns at the cost of trees during the latest Rhaetian, culminating with the extinction of tree taxa at the Triassic-Jurassic boundary. The rise in ferns is accompanied by an increase in reworked organic matter and charcoal, suggestive of erosion and wildfires. Furthermore, the Hettangian (201.3-199.3 Ma) vegetation in NW Europe shows evidence of long-term disturbance reflected by the periodic resurgence of fern taxa, similarly accompanied by increases in reworking and charcoal. This periodicity is linked to the 405-kyr eccentricity cycle indicating a biome that responded to astronomically induced variability in hydrology. A transition into an apparently more stable biome starts during the early Sinemurian, where palynofloral assemblages become dominated by bisaccate pollen taxa, mainly derived from conifers. The ETME was clearly forced by the effects of volcanogenic emissions, such as SO2, CO2 and other pollutants, acting on both short (0.1-10 kyrs) and long timescales (10-100 kyrs). In contrast, charcoal and detrital input indicators show that the disturbances during the Hettangian were driven by periodic shifts in the regional hydrological regime. This was forced by the effects of orbital insolation variation and potentially exacerbated by increased atmospheric pCO2. The cyclic progression of ecosystem disturbance was similar to that of the ETME and only recovered during the early Sinemurian. Atmospheric pCO2 remained elevated after CAMP-activity had subsided due to a collapse of terrestrial biomass and carbonate producers. This inability to store carbon on long timescales could therefore have impeded global recovery.

The end-Triassic mass extinction (ETME; c. 201.6 Ma), one of the so-called “big-five” mass extinctions in the Phanerozoic era, is associated with widespread marine anoxia, ocean acidification, global warming, carbon cycle perturbations (δ13C) and an extinction of diverse marine and terrestrial groups. This extinction is frequently linked to the volcanic activity in the Central Atlantic Magmatic Province (CAMP) which is often cited to explain e.g., the correlative negative carbon excursions across many sections, mutagenesis of land plants by Hg-toxicity, and enrichment of Hg/TOC. Despite this, the exact identification of a volcanic signal in many of these sections is not well constrained. In this study we present high-precision platinum group element (PGE: Ir, Ru, Pt, Pd) and Re data for the Triassic-Jurassic boundary succession at the Kuhjoch section (Austria). These are the first results from our new analytical setup using high-pressure asher digestion, isotope dilution and multi-collector inductively-coupled plasma mass spectrometry for precise determination in low concentration (e.g. ppt) samples such as sediments. The PGE and Re concentrations and patterns vary significantly with stratigraphy. The c. 13 m of clayey sediments above the onset of the extinction (marked by the c. 16 cm thick T-bed) show pronounced enrichment in Pt, Pd and Ir concentrations relative to the under- and overlying carbonate dominated stratigraphy. Their PGE patterns are non-chondritic with Pd/Ir and Pt/Ir similar to CAMP basalts. Normalised for lithology (Al2O3), however, there are no significant variations in Pt, Pd and Ir values below, within and above the clayey sediments. Re and Ru are, however, depleted compared to the other PGEs in the clayey interval, something also observed in some CAMP basalts. One possibility is therefore to interpret the PGE-rich, clayey sediments, including the main extinction interval in the basal portion, as recording increased weathering of CAMP basalts. As the PGE enrichment increases up through the T-bed, this could show that the onset of CAMP weathering and mass extinction would have therefore coincided. However, further work is needed to identify the relative role of CAMP volatile emission during volcanic activity versus post-eruption weathering of basalts.

<p>The Central Atlantic Magmatic Province (CAMP) eruptions are generally regarded as the main driver of major environmental change and mass-extinction across the Triassic-Jurassic (T-J) boundary (~201.3 Ma). CAMP emissions have been invoked as the main trigger for the formation of abnormal pollen and spores during the end-Triassic crisis that may have led to forest dieback and proliferation of pioneer species. Proposed scenarios include extensive climate change leading to wildfire activity, acid rain, and increased UV-B radiation due to ozone depletion. More recently, volcanogenic mercury (Hg) has been implicated in the occurrence of mutations in fern spores. However, Hg-dynamics in deep-time remain poorly understood and require further examination. Here, we explore a new long-term (Rhaetian to Sinemurian) bulk Hg-concentration record combined with Hg-isotope data to understand the link between floral turnovers and the Hg-cycle.</p> <p>Shallow marine sediments sampled from the Schandelah-1 core in northern Germany contain a record of cyclical shifts in malformed fern spores coinciding with fluctuations in carbon isotopes, increased levels of weathering, and Hg-enrichments. Similarly, increased mutagenic spore abundances with accompanying Hg-isotope records confirm the volcanogenic origin of Hg at the T-J boundary, showing a sharp positive excursion in mass-independent fractionation (MIF) of odd-numbered Hg-isotopes. Hettangian cyclicity is clearly reflected in the Hg-isotopic signals, showing positive excursions in mass-dependent/independent fractionation records (d<sup>202</sup>Hg and D<sup>199</sup>Hg) during periods of sedimentary Hg-enrichment. In addition, the Hettangian Hg-isotopic signature clearly deviates from Rhaetian signatures, which hints at climate-controlled mechanisms being responsible. Atmospheric Hg-loading via volcanism can explain the synchronous enrichments of Hg concentrations at the T-J boundary interval in multiple sites across the globe. In contrast, the origin of this periodic Hg-loading is more difficult to pinpoint, but it becomes clear that Hg is showing shifts in speciation and closely tied to terrestrial vegetation development. Orbitally induced changes to the regional hydrological regime, resulting in increased wildfire activity, monsoonal intensity, and soil erosion, potentially redistributed Hg stored in soil and/or bedrock reservoirs causing a shift to more mobile Hg-species. Overall, this shows a more dominant role of climate-induced Hg-remobilisation, rather than direct volcanic emissions, to disturbance in terrestrial vegetation.</p>

<p>Palynology is widely used in both academic and industrial research for correlation and interpretation of subsurface geology on both local and regional scales. While most data gathering tools for the subsurface have undergone major technological developments during the last decades, palynological research has, apart from the use of more advanced microscopes, remained virtually unchanged and can be quite time consuming when large data sets are required. With increasing demand for faster, more high resolution and more detailed palynological analyses from the continuously developing technological industry as well as the academic science community, palynology is at risk of being left behind.</p> <p>The answer could lie in adopting strategies of digitalisation and Artificial Intelligence (AI) originally developed for medical research. The technology of scanning microscope slides into a digital high-resolution image has already been developed, and AI software specifically developed for palynology can be utilised to examine the digital images and detect, identify and quantify the fossil content.</p> <p>In this project we have designed and developed an AI software for clustering and classification of microfossils based on deep-learning based algorithms for detection of palynomorphs and algorithms based on autoencoders for extracting features predictive of different fossil types. The AI is trained to recognize and identify fossils from different angles, preservation levels and fragmentation stages, as well as partially obscured or folded specimens. The AI can then analyse specimens for morphological parameters such as texture, shape and/or RGB/HSV values and use these parameters to categorize the specimen into clusters. The clustering has many applications, e.g., identifying morphological variations within taxa and recognizing variations in colour and preservation related to reworking or caving during the drilling process. The project also explores the advantages and disadvantages of working with digitally scanned palynological slides and the use of AI software recognition. The project will establish if the digital scans of the palynological samples have the resolution needed to be used for quantitative analyses and develop a preparation process to reliably produce the best digital samples possible.</p>

The Upper Triassic-Lower Jurassic succession in the Danish Basin is penetrated by many deep wells that were drilled during former hydrocarbon exploration campaigns, but it is today targeted for geothermal energy and storage of CO2. The Stenlille salt dome on Sj & UAELIG;lland sandstones of the Gassum Formation, sealed by the overlying Fjerritslev Formation mudstones, has been used for decades as a seasonal storage for natural gas. With its comprehensive dataset of seismics, geophysical well logs and conventional core data from 20 wells, the Stenlille succession serves as a model for other salt domes currently being evaluated as potential CO2 storage sites in the basin. Over the last decade the cored Triassic-Jurassic boundary succession has contributed to the understanding of environmental and palynological events during the end-Triassic mass extinction. Core, sidewall core and cutting samples from several of the closely situated Stenlille wells are here used to establish a high-resolution palynostratigraphic zonation scheme covering the entire Rhaetian to Sinemurian succession by integrating new analyses with previously published data. The palynological dataset has allowed the recognition of nine formally described spore-pollen zones, of which eight are new, while two previously described dinoflagellate cyst zones are subdivided into three informal subzones each. The palynological zonation is integrated with a sequence stratigraphic framework and will form the basis for the dating of future well sections in the Danish Basin and other basins and for correlation to outcrops. The large palynological dataset further shows that the vegetation around the Danish Basin was remarkably stable during the early to middle Rhaetian, but that events related to the emplacement of the Central Atlantic Magmatic Province accelerated ecosystem changes for c. 175 ky in the late Rhaetian and earliest Hettangian, including & SIM;25 ky of successional recovery before the terrestrial ecosystem had again stabilised.

<p>Large-scale volcanic activity during the formation of large igneous provinces (LIPs) were contemporaneous with almost every mass extinction event in Earth’s history, and LIP activity is believed to have caused or contributed to at least three, if not all, Big Five mass extinctions. However, compared to the marine fossil record, the effects of the volcanism on the terrestrial plant record is still poorly understood. Extinctions in the animal record during major biotic crises in Earth history are not mirrored by comparable major changes in land plants. Despite being sedentary organisms land plants have evolved adaptations to cope with adverse changes in the environment which may provide autecological advantages compared to animals. Despite their remarkable resilience, land plant communities were still affected in multiple ways during LIP-induced extinction events. During the end-Triassic mass extinction (201.56–201.36 million years ago) emissions of greenhouse gases, sulfur dioxide and aerosols, halocarbons, polycyclic aromatic hydrocarbons, Hg and heavy metals from magmatic activity, as well as sea-level changes, during the emplacement of the Central Atlantic Magmatic Province (CAMP) are considered to have severely stressed land plants. This is exemplified by major changes in ecosystem structure in palynological records, a rise in microscopic charcoal abundance indicating increased wildfire activity, enhanced reworking of palynomorphs indicating increased soil erosion, acid rain damages on macroplant leaves, and increased abundances of abnormal spores and pollen indicating mutagenesis from Hg-toxicity and/or ozone layer depletion. Several of these land plant responses have also been observed during other extinction events contemporaneous to LIP activity. Here, we compare and discuss some of the changes in common between different biotic crises to evaluate whether there is a common pattern or not.</p>

The Wandel Sea Basin in North Greenland was part of the epicontinental Boreal Sea in Triassic time. The basin formed the western margin of the northernmost Atlantic elongated sea connecting southwards with basins along the conjugate Greenland-Norwegian margins. A multidisciplinary dataset including sedimentology, biostratigraphy, organic geochemistry and sedimentary provenance, allow to document its basin evolution. The Wandel Sea Basin was transgressed in the Dienerian with marine deposition prevailing until the Norian. Sediments were mainly sourced from the Greenlandic Caledonian basement and deposited on a 100 km wide shallow marine shelf during the Early Triassic. In Middle Triassic, oil-prone mudstones formed in oxygen-depleted deep shelf settings, including eastern Wandel Sea Basin. Detrital zircon U-Pb ages show that by Carnian times, the >1000 km wide, Uralian-sourced, deltaic shelf had prograded westward across the Barents Sea reaching the eastern north Greenland and de facto nearly closed the northernmost Atlantic Sea.

Terrestrial ecosystems are integral components of global carbon budgets and modulators of Earth’s climate. Emplacement of large igneous provinces (LIPs) is implicated in almost every mass extinction and smaller biotic crises in Earth’s history, but the effects of these and other large-scale magmatic events on terrestrial ecosystems are poorly understood. Palynology, the study of fossilized pollen and spores, offer a means to robustly reconstruct the types and abundance of plants growing on the landscape and their response to Earth crises, permitting predictions of the response of terrestrial vegetation to future perturbations. We review existing palynological literature to explore the direct and cumulative impacts of large-scale magmatism, such as LIP-forming events, on terrestrial vegetation composition and dynamics over geological time.