Chemolithoautotrophy, free energy from chemical disequilibria in crustal environments, apparently sustained the last universal common ancestors (LUCAs) of all life. If the LUCAs relied on the reductive Acetyl-CoA metabolic pathway via abundant H2 (e- donor) and bicarbonate (e- acceptor), they were confined to hydrogenous (H2-producing) metalliferous (ultra-)magnesian alkaline hydrothermal (>50°C) systems. The later advent of photoautotrophy provided a new plentiful e- donor (Corg) that allowed early life to exploit Sulfur (S) compounds as an energy source. Here, we report new multiple S-isotope (32S, 33S, 34S; Δ33S) data from authigenic sedimentary sulfides in Eoarchean-Paleoarchean sedimentary rocks from Isua (West Greenland) and South Africa (Barberton) to trace this early metabolic evolution. Our aim is to: (i) pinpoint in time and space when life began to influence the marine S cycle; (ii) follow changes in primary (Corg) production; (iii) model commutations to Eoarchean-Paleoarchean geodynamic regimes; and (iv) experimentally test how Corg is altered. Geodynamic scenarios particular to the Eoarchean-Paleoarchean Earth supported early biodynamic environments in both plate tectonics vs. non-plate tectonic contexts. For example, crust production modulates nutrient supply to the oceans which in turn influences the timing and tempo of metabolic innovation. Bio-geo-dynamic changes in the early Archean set the stage for the eventual emergence of the Eukaryotes.
How to cite: Mojzsis, S. J., Kremer, B., Marin-Carbonne, J., Tackley, P., Heubeck, C., and Timar-Gabor, A.: Tracking the co-evolution of microbial sulfur metabolisms and geodynamics at the Eoarchean - Paleoarchean (3800-3200 Ma) transition, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1220, https://doi.org/10.5194/egusphere-egu25-1220, 2025.
Revealing the characteristics and origins of surface deformation in planetary bodies is fundamental to understanding the biogeodynamic cycle. Investigating how mountains and basins (topography) as well as magmatism (carbon cycling) develop with or without subduction—and therefore, plate tectonics—provides critical insights into the habitability and climate stability of a planet. This study aims to identify tectonic deformation on Venus, specifically describing extensional and shortening features. High-resolution, scaled laboratory experiments combined with structural observations suggest that lithospheric drips (sinking plumes) influence strain distribution and the geometric characteristics of various coronae. Notably, the linear shortening structures observed at the centers of coronae appear to form above downwelling regions, while material pulling results in crustal stretching at the topographic rims. These findings support the hypothesis that multiple geodynamic processes may collectively control coronae formation, with lithospheric drips often overlooked due to the prevalence of plume models. Ultimately, the coexistence of crustal extension/rifting and plate shortening (fold and thrust belt) by lithospheric instabilities offers a possible explanation for clarifying deformation patterns on Venus and earth.
How to cite: Göğüş, O. H., Karagöz, O., Bodur, Ö., Ballı Çetiner, A., and Dinç Göğüş, Ö.: Geodynamics of synconvergent extension on Venus and earth, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9519, https://doi.org/10.5194/egusphere-egu25-9519, 2025.
Explosive volcanoes eject large amounts of ashes in the form of fine-grained glass fragments (shards) during eruption. Depending on their size, degree of vesicularity and composition, pyroclastic glass shards have chemically reactive catalytic surfaces with high surface-to-volume ratios. They are able to adsorb organics, metals, and phosphates, as well as create microenvironments attractive for microbial growth. Pyroclastic material – deposited in both aquatic and terrestrial environments – was abundant on early Earth and some of the first habitats for life may have been glass-rich. Our new sedimentological, geomicrobiological and geochemical-petrological comparative studies (LAICPMS, EMPA, TEM, Raman) aim at evaluating the significance of volcanic glass shards as a substrate and source of nutrients for microbes and as a medium for preservation of biosignatures in the geological record.
Here we show that modern (Holocene) and Paleoarchean volcanic glass shards deposited in aqueous settings (hyaloclasts) preserve evidence of alteration by microbial activity. For example, sub-recent (ca. 0.37 ka; Kaźmierczak & Kempe 2006) shards of island arc basalt composition (containing phenocrysts of the early crystallization process i.e., forsterite olivine, spinel, plagioclase-bytownite, pyroxene) are documented from the alkaline caldera lake Vai Lahi on Niuafo’ou Island, Tonga (Kempe & Kaźmierczak 2012). Analyses by 3D Raman spectroscopy (depth profiling) reveal aragonite and calcite in the entire shard volume with associated carbonaceous matter, as well as spectra of anorthite and olivine.
Most Niuafoʻou shards are coated with a laminated envelope of alternating aragonitic and silicate layers resembling oncoids cortex. Open vesicles and external faces of the shards host an organic matter and mineral assemblage texturally identical to that of the laminated envelope. Two types of alterations are identified in the Niuafo’ou shards: i) pit-like etchings; and, ii) alveolar-spongy textures. Transmission electron microscopy reveals etch-like alterations (weathering or microbial activity?) on shard surfaces to a depth of ca. 2 µm. Elemental compositions of the altered layer point to a mixture of glass and the carbonate-silicate envelope.
Niuafo’ou shards were deposited in water of increased alkalinity that favored silica dissolution and carbonate precipitation. In turn, this leads to the growth of aragonite coatings as well as sizeable stromatolites in the lake. Such habitat is ideal for alkalophilic cyanobacteria that form biofilms and participate in the precipitation of mineral envelopes. Coated by carbonate-silicate, such glass shards can effectively preserve biosignatures even as far back as the Paleoarchean (<3.5 Ga) geologic record.
Kazmierczak, J. & Kempe, S. (2006) Naturwissenschaften 93, 119- 126.
Kempe, S. & Kazmierczak, J. (2012) Life on Earth and Other Planetary Bodies, Springer, 197-234.
How to cite: Kremer, B., Słaby, E., Wirth, R., Krzysztof, O., Maciej, B., Marcin, W., Agata, K., Anja, S., Stephan, K., and Jozef, K.: Volcanic glass shards as a substrate for early life, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12998, https://doi.org/10.5194/egusphere-egu25-12998, 2025.
The long-term climate depend on continental weathering, hydrothermal fluxes, and carbonate sequestration in the oceans, but a coherent explanation is missing. Here, we investigate the role of neritic carbonate accumulation, by plugging a macro-ecological model for shallow-water carbonates onto a combined set of state-of-the-art tectonic, climatic and physiographic reconstructions. Our model introduces and quantifies neritic habitability as a primordial climatic control. Our model confirms the role of deep ocean carbonate habitability -when carbon sources exceed the accumulation capacity of warm water carbonates, expanding carbon storage to the abyss- as a cooling factor, and reveals an unidentified alternative warm regime, controlled by the exceeding capacity of warm-water carbonates to capture Ca2+ and alkalinity fluxes. This regime depletes the oceans of its alkalinity, shoals the carbonate compensation depth, and releases carbon from the deep ocean to the atmosphere. These contrasted regimes, that we refer to as habitability-limited and calcium-limited, largely explain longterm climatic excursions, as revealed by the geological archive.
How to cite: Husson, L. and Salles, T.: Deep time climatic oscillations regulated by shallow-water carbonates, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18229, https://doi.org/10.5194/egusphere-egu25-18229, 2025.
The distribution of plant species richness on earth suggests that tectonic mountain-building and its interaction with climate exert a defining control on species distributions and diversification rates. The two main pathways identified to increase species richness are, first, the broadening of environmental heterogeneity through the creation of new habitats formed by tectonic topography and, second, the disruption of existing landscapes by tectono-geomorphic processes, leading to time-dependent habitat fragmentation and increased allopatric speciation. Here, we resolve the contribution of these two pathways to explain global plant species richness. We build a model for environmental heterogeneity at the 100 km scale based on local richness at the 100 meter scale, which we take to be a function of local climate, and community turnover between 100 m cells based on environmental distance, which we take to be a global function. Each of these functions is calibrated to local field data. These two models can be combined to provide a prediction of species richness due to environmental heterogeneity at the 100 kilometer scale using global topography and climate data. Differencing this prediction from observed richness provides an estimate of the excess richness, which we argue is dominated by tectonic and geomorphic enhancement of allopatric speciation rates. We find that this excess component of richness is nearly always positive and is locally a factor of up to ten above that expected by environmental gradients alone. We conduct a categorical analysis, comparing the excess richness to active tectonic and geomorphic domains and find a close correspondence between the patterns of excess richness and recent tectonic and geomorphic activity. We conclude that high richness areas (biodiversity hotspots) overwhelmingly fall in areas of tectono-geomorphic activity, even after accounting for environmental heterogeneity, supporting the hypothesis that transient, tectono-geomorphic disruption is an important control on speciation rates and the distribution of biodiversity.
How to cite: Willett, S. D., Luo, A., Wang, Y., Wang, Z., and Pellissier, L.: Tectonic Control of Global Plant Biodiversity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10211, https://doi.org/10.5194/egusphere-egu25-10211, 2025.
The rise in species richness from the poles to the tropics, known as the latitudinal diversity gradient (LDG), is one of the most widespread patterns in the distribution of modern ecosystems. Although first documented more than 200 years ago, its origins, evolutionary dynamics, and underlying mechanisms remain unresolved. While geological and climatic changes are recognized as key drivers of biodiversity patterns, the precise causal factors shaping the LDG and their relative contributions to species richness gradients are still debated. Here, we explore how spatiotemporal variations in the physical environment influence the LDG by simulating the global diversification of terrestrial mammals over the past 125 million years using a spatially explicit eco-evolutionary model (gen3sis). This approach allows us to investigate both the mechanisms driving the LDG and broader biodiversification processes in dynamic landscapes, integrating changes in geological, climatic, and surface processes. Our findings indicate that the modern LDG is largely shaped by paleoclimatic and paleogeographic factors, with limited influence from surface processes. This gradient has persisted since the Cretaceous, steepening and stabilizing in width from the early Tertiary. Over deep time, LDG drivers demonstrate a strong influence of tectonic activity on speciation rates. The modeled scenarios also support an "out of the tropics" model in which species primarily originate in the tropics and disperse toward the poles without losing their tropical presence. As a result, the tropics are defined not only as a cradle, fostering the origination of new species, but also as a museum, preserving biodiversity over deep time.
How to cite: Lorcery, M., Husson, L., Salles, T., Lavergne, S., Hagen, O., and Skeels, A.: Biodiversification and the Latitudinal Diversity Gradient over deep time: insights from mechanistic models, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1684, https://doi.org/10.5194/egusphere-egu25-1684, 2025.
Land plants are a major contributor towards global terrestrial biomass which influences atmospheric CO2 and O2 however the amplitude of their contribution has fluctuated throughout the Phanerozoic; partly due to the evolution of plant features and strategies. An extended rise of atmospheric O2 over the Carboniferous and Permian coincides with the rise of large vascular plants which is thought to have increased organic carbon burial rates1. Here, we present one of the first dynamic climate-biogeochemical-vegetation model that allows the assessment of how plant evolution may have played a key role in the rise of the Late Paleozoic oxygen level. We implement a simple rooting evolution parameter and a high net primary productivity strategy of lycophyte paleotropical trees2 to the existing SCION-FLORA model3. The evolution of roots amplifies continental weathering processes and increases overall biomass while the lycophyte tree strategy allows for accelerated biomass accumulation. The two strategies contribute towards the increase of organic carbon burial which leads to a rise in oxygen with lycophyte tree forests playing a much greater role. Without the evolution of lycophyte tree forests, Paleozoic O2 levels cannot be reached suggesting that a quicker accumulation of biomass compared to present day forests was essential.
1. Berner RA. 1999 DOI: 10.1073/pnas.96.20.10955.
2. Cleal CJ, Thomas BA. 2005 Geobiology. DOI: 0.1111/j.1472-4669.2005.00043.x
3. Gurung K, Field KJ et al. 2024 Nat Comms. DOI: 10.1038/s41467-024-46105-1
How to cite: Gurung, K., Hetherington, A. J., and Mills, B. J. W.: Implementing plant evolution into a dynamic vegetation model and its impact on the Phanerozoic biosphere, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11019, https://doi.org/10.5194/egusphere-egu25-11019, 2025.
Biodiversity loss and climate change are interlinked crises with global ecological and societal impacts. Common explanations for how climate shapes biodiversity focus either on spatial scale (whereby more extensive and/or isolated climates promote species richness) or on temporal scale (whereby older, or more stable, climates foster biodiversity). However, these hypotheses overlook the intrinsic link between the spatial and temporal dimensions of climate.
We investigated how spatio-temporal climate changes over deep time may have influenced global patterns of plant diversity through the lens of climate analogues. By compiling global occurrence records for 350,864 vascular plant species, we produced the most comprehensive and precise global map of plant diversity to date. We identified analogues of recent (1851–1989) climate conditions across several geohistorical time periods: the Early Eocene (ca. 50 Ma), the Mid-Pliocene (3.3–3.0 Ma), the Last Glacial Maximum (LGM, 22–18 ka) and the Mid-Holocene (ca. 6 ka). We quantified spatial climate change within temporal periods, temporal change across spatial gradients, and the integrated spatio-temporal dynamics of climate. We evaluated the relative contributions of these metrics in explaining global plant diversity variation and examined the correlations between the spatial and temporal dimensions of climate change.
Our findings extend previous hypotheses by showing that species richness is higher in climatic conditions that were historically more extensive and/or isolated and have remained so through time. We also reveal a previously unrecognized mechanism by which climatic conditions that have undergone geographic expansion and slower movement over deep time tend to harbour higher plant diversity. Moreover, the combination of temperature stability and precipitation variability has facilitated species accumulation in low-latitude regions.
Spatial and temporal dimensions of climate change are thus interconnected, with long-term trends and short-term variability influencing the geography and movement of climate analogues, which in turn shape species richness. By incorporating the spatio-temporal climate changes into models, we can almost completely (> 90%) explain the global patterns of plant diversity today.
How to cite: Li, J. and Prentice, I. C.: How deep-time climate change has influenced the diversity of plants, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3646, https://doi.org/10.5194/egusphere-egu25-3646, 2025.
Since the emergence of life on Earth 2.8 billion years ago, plants have been capitalizing on the C3 photosynthetic pathway. In the world’s grasslands that emerged since the Paleogene, C4 vegetation expanded considerably between 8 and 3 Ma following climatic changes, which heralded profound terrestrial ecosystem changes. However, sparse reconstructions of C4 vegetation in the northeastern Mediterranean region prevent a reconstruction of C3-C4 vegetation dynamics.
We present the first extensive δ13C soil carbonate record for Anatolia (Türkiye) for the last 10 Ma, which we combine with existing records from the Aegean (Greece). Our results show the emergence of C4 vegetation in Anatolian floodplains by 9.9 Ma, which is similar to regions in NW and E Africa. A transition to C4 dominance before ca. 7.1 Ma in Anatolia and potentially the Aegean occurs simultaneous with southern Asia during global Late Miocene Cooling in response to decreasing atmospheric pCO2.However, the patterns of the Anatolian and likely Aegean paleoecosystems are unique due to a rapid and permanent return to C3 dominance at ca. 4.4 Ma. A return to C3 dominance is not observed elsewhere in the world and occurs simultaneously with the disappearance of the open environment-adapted large mammal Pikermian chronofauna. We suggest that a regional warm-to-cold season change in rainfall seasonality toward a Mediterranean-style climate triggered the return of C3 biomass in Anatolia and the vanishing of herbivorous mammal populations of the Old World savannah paleobiome.
How to cite: Meijers, M. J. M., Mikes, T., Rojay, B., Çubukçu, H. E., Aydar, E., Lüdecke, T., and Mulch, A.: Climate change-driven Late Miocene to Pliocene rise and fall of C4 vegetation in Anatolia (Türkiye), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8561, https://doi.org/10.5194/egusphere-egu25-8561, 2025.
It is becoming increasingly well understood that the Earth’s interior and surface evolution is intrinsically interrelated with the evolution of its atmosphere, oceans, landscape and life. This understanding lays down principal foundations of Biogeodynamics – an emerging scientific field that explores the interface of geodynamics, geomorphology, climate, ocean and atmosphere sciences, biology and ecology in order to understand how the evolution of the planetary interiors, surface, atmosphere, ocean, climate, and life is coupled. Despite its strong scientific, educational and societal potential, Biogeodynamics has not been yet fully established as a new discipline. An intrinsically cross-disciplinary character of Biogeodynamics creates organizational, educational and scientific challenges due to the necessity of truly collaborative research and education to efficiently combine scientific knowledge, research tools and training approaches from the very different research fields (such as Earth Sciences, Biology, Ecology, Climate Sciences and Planetology), which evolved independently from each other. To address these challenges, recently approved COST Action EUROBIG (https://www.cost.eu/actions/CA23150/) established the first pan-European Biogeodynamics network, which currently includes >100 scientists from 26 countries. The envisaged EUROBIG networking activities will accelerate the development of Biogeodynamics as a discipline in Europe and worldwide by supporting and linking the relevant communities, facilitating interactions to address the important scientific, methodological, educational, networking and funding challenges of this new field. Here, I will present in short the EUROBIG COST Action, which is open for new participants interested in building, advancing and leading the global Biogeodynamics research community. I will also review some recent advances in computational Biogeodynamics to show why and how the unique Earth's global evolution style - plate tectonics – is coupled to biosphere dynamics thereby accelerating life evolution and controlling biodiversity dynamics. Implications from Biogeodynamics for finding habitable Earth-like exoplanets and for the future dynamics and longevity of human civilization will also be discussed.
How to cite: Gerya, T.: Pan-European Biogeodynamics network EUROBIG: outstanding challenges and opportunities, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7005, https://doi.org/10.5194/egusphere-egu25-7005, 2025.
Quick take: We investigate the conditions behind exoplanetary habitability. We compare how different models (complex physics-based vs. parameterized evolution) estimate the climate of Earth-like planets. We identify which planetary properties are critical to assess habitable conditions, and how that impacts the reliability of parameterized modeling.
Estimating whether an exoplanet is habitable is a complex question that goes far beyond calculating its host star Habitable Zone. In addition to incoming radiation from the star, atmosphere composition, planetary rotation, topography, and ocean/continent layout can all affect surface conditions spatial distribution. Simple parameterized models of those exoplanets allow for testing a large parameter space quickly, while physics-based models are more complex and much more time consuming, only allowing for the modelling of more restricted cases. We wish to test how the limitations of both approaches affect our capacity to assess planetary habitability, given the limited characterization available for exoplanets at present and for the foreseeable future.
We use Earth as a reference case, as the only planet where data is available regarding surface conditions evolution. We present new modeling results from the 3D climate General Circulation Model (GCM) ROCKE3D applied to Earth-like planets, based on atmospheric compositions derived from internal thermal histories and outgassing evolution scenarios consistent with Earth observation. We also compare atmospheric compositions and interior/atmosphere evolution scenarios obtained in a parameterized interior approach to the results of the 2D/3D Earth mantle dynamics model StagYY.
The main properties that we have investigated are variations of length of day, continental vs. oceanic coverage, topography and diverse atmospheric compositions consistent with recorded constraints on the Earth.
We compare average surface temperatures, albedos, precipitations, ice and clouds coverage obtained in both simulations. We then evaluate precipitations, sea surface level, and ice coverage obtained in GCM simulations and compare them to the usual criteria for habitability (such as average temperatures above 273-258 K). Finally, we assess the reasons for discrepancies between the models.
The trend of the variations of average temperature through time (and CO2 abundances) is consistent in parameterized vs. GCM models, making parameterized approaches generally efficient for a broad estimate of average surface conditions. However, perturbations around the reference model result in stronger temperature variations in the GCM due to albedo feedback. The albedo variations can be significant in 3D simulations and are not considered in the parameterized approach. Additionally, spatial variations of local surface conditions are found to be large and dependent on properties that cannot be resolved by parameterized models nor observed for exoplanets. Supercontinent setups result in markedly dryer land than the present-day Earth continental layout. Even models with average temperatures below 273-258 K have significant ice-free ground in all continental setups.
How to cite: Gillmann, C.: The habitability of Earth-like (exo)planets: modelling and limitations., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4476, https://doi.org/10.5194/egusphere-egu25-4476, 2025.
Detecting signatures of life in sedimentary rocks lies in the difficulty of distinguishing them from abiotic signals and interpreting their formational conditions, particularly when working on planetary systems that are different from Earth, such as Mars (Corenblit et al., 2023). Research in this field is booming, thanks to the development and deployment of detection tools either in orbit or on the surface. Mars is of great interest due to its early history comparable to Earth during the Noachian period > 3.7 Ga (Lapôtre, 2022). In addition, traces of favourable environmental conditions for the potential development of life have been found for this period, for example in Gale Crater (Rapin et al., 2023). Among the candidates for searching potential signatures of life, Microbially Induced Sedimentary Structures (MISS, Nora Noffke in 1996) have become a target. MISS are characteristic structures resulting from surface sediment disturbances induced by microbial mats (Schieber et al., 2007; Noffke, 2010). Their formational environments may correlate with early Mars conditions, and their terrestrial study is enriched by their representation in both fossil and modern records (Noffke 2015, 2021). The analogy between two planetary systems relates to the principle of abductive inference, which posits that similar (bio)geomorphological processes will result in similar (bio)geomorphological structures (Corenblit et al., 2019). Therefore, it is crucial to develop a clear conceptual framework for processing observations of modern and fossilized textures, forms, and patterns and for discussing the gradient of distinction between abiotic and biotic modalities (Davies et al., 2016).
Here, we focused on one type of MISS known as “mat cracks”, the biotic equivalent of abiotic structures “mud cracks” (Noffke, 2010). These are well-represented in the field in both fossil and modern records, and they are robustly repeatable under controlled laboratory conditions. They may correspond to ancient Martian environmental systems as attested by polygonal ridges in Gale Crater, which are characteristic of sustained wet/dry cycles (Rapin et al., 2023). The methodology is based on the visual distinction of biotic and abiotic classes of texture, form, and pattern using different visualisation methods such as photogrammetry and expert visual observations, statistical tools and classification with convolutional neural networks (CNNs). For an initial exploration of the mud crack variability, we set up an ex-situ experiment to produce mud cracks with three types of biofilms and three biomass levels according to variables observed in the field, and using 3D picture dataset of the resulting mud cracks. We have demonstrated significant differences between abiotic and biotic classes and between strain and biomass classes. CNN models outperformed the human-blinded classification by refining the diversity of criteria used and observations such as the textures of the sandy matrix. These significant distinctions and the finesse of the classification provided by artificial intelligence allow us to discuss the interest of the information gain in distinguishing potential textures, forms and patterns that are characteristic of MISS in the field where noise, alteration and erosion can be a problem in identifying the origin of signatures, particularly on Mars.
How to cite: Fernandez, L. A., Corenblit, D., Arrignon, F., Boulêtreau, S., Davies, N. S., Ferriol, J., Julien, F., Leflaive, J., Otto, T., Roussel, E., Toumazet, J.-P., and Steiger, J.: Detecting signatures of life on terrestrial and Martian rocks: contribution of microbial mats in the biogeomorphological responses of desiccated sediments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15785, https://doi.org/10.5194/egusphere-egu25-15785, 2025.
Researching large-scale responses of organisms and ecosystems to deep-time perturbations requires a paleogeographic reconstruction of ancient Earth. Deep-time paleogeographic reconstruction rests on the foundations of tectonic modelling. The GPlates suite offers a continuously-developed, open-source solution for the development and interrogation of global tectonic models. These allow the implementation of key components of deep-time ecological research, such as the analysis of geographic ranges, the study of bioregionalization, the spatiotemporal analysis of diversity dynamics, and ecological niche modelling, to mention a few. However, the difficulty of using tectonic models and making fossil occurrence record data interact with them in the R environment, the standard scripting environment for paleoecological research, has been limiting the integration of paleogeographic and paleontological research.
Here we present the R extension package 'rgplates', which provides access to the calculations implemented in the GPlates Web Service and the GPlates desktop application via its command-line interface. Besides the reconstructions of point paleocoordinates, the package allows the access and manipulation of more complex vector features with the popular 'sf' extension. We present the basic feature set of the package and provide examples demonstrating their relevance to paleoecological calculations using occurrence records from the Paleobiology Database, as well as derived reconstruction products, such as digital elevation models and paleoclimatic models. In short, 'rgplates' enables the exploration of various tectonic models and the assessment of how their disagreements propagate to paleoecological inference.
How to cite: Kocsis, Á. T., Cannon, J., Qin, X., Müller, D., Raja, N. B., Williams, S., Zahirovic, S., and Dowding, E. M.: ‘rgplates’: R Interface to Plate Tectonic Models in GPlates, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10843, https://doi.org/10.5194/egusphere-egu25-10843, 2025.
Cretaceous Oceanic Anoxic Event 2 (OAE2) coincided with the emplacement of several large igneous provinces. The rapid exhalation of volcanic CO2 intensified the global climate and accelerated the hydrological cycle. Cyclic variations in marine redox conditions linked to weathering are documented in OAE2 successions, indicating an orbital control on global weathering rates, and thus, marine nutrient availability. However, the impact of the cyclicity varies in intensity, particularly at the end of OAE2, which is characterized by dampened weathering variability. In this conceptual approach, we assess the influence of orbital forcing on global chemical weathering rates under different atmospheric CO2 concentrations and orbital configurations using HadCM3L. We find that with increasing pCO2, chemical weathering rates significantly increase and the influence of changes in obliquity is amplified. This suggests a strong coupling between orbital cyclicity and global weathering fluxes under hot climates, with significant influence on the carbon cycle driven by weathering-derived nutrients.
How to cite: Krewer, C., Hunter, S., Poulton, S. W., Newton, R. J., and Mills, B. J. W.: Influence of orbital cycles on chemical weathering and marine redox conditions under greenhouse climates, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18533, https://doi.org/10.5194/egusphere-egu25-18533, 2025.
The end-Permian event (EPE; c. 252 Ma) resulted in the loss of keystone plant species from humid tropical and high-latitude ecosystems and the extinction of several major insect groups. The subsequent Early to Middle Triassic evinced diminished terrestrial productivity, punctuated by a series of second-order biotic crises that hindered recovery. End-Permian ecosystem collapse resulted in the extirpation of productive wetland ecosystems, the primary carbon sinks on land, represented by the cessation of significant coal formation until the Middle Triassic. The gymnosperm seed fern Dicroidium (Order: Umkomasiales) emerged as the dominant floral component of most known terrestrial ecosystems of the Early Triassic across southern Gondwana and, by the Middle Triassic, was the principal coal-forming plant. Understanding when and how this ecologically important taxon rose to dominance will provide a gauge of ecosystem recovery and carbon sink stabilisation in Gondwana following the worst mass extinction event in Earth’s history.
While there have been many large-scale investigations into Middle Triassic plants and biodiversity, the Early Triassic interval of ecological recovery immediately following the EPE is poorly studied. In addition to examination of the fossil plants themselves, trace fossils of plant–arthropod interactions (PAIs) provide an independent window into assessing terrestrial ecosystem states through geological time. In this context, PAI records can be used for evaluating changes in herbivorous arthropod feeding guilds in the wake of global biotic crises. Here, we investigated three well-preserved early records of Dicroidium from the well-age constrained Lower Triassic strata of the Sydney Basin, Australia (the Skillion, Turimetta Head and Mona Vale). In this study, we: 1, systematically described the Dicroidium species from these localities; 2, interpreted their palaeoenvironmental contexts; 3, compared their diversity and morphological trends over time; and 4, recorded evidence of PAIs.
The floras exhibited a generally low species richness of Dicroidium overall, but an increase in richness and leaf size with increasing time from the EPE. Similarly, Dicroidium leaf fragments from each locality revealed evidence of PAIs (including margin feeding, hole feeding, galling, and oviposition), with the highest proportion of PAIs from the youngest locality. Increasing numbers of PAIs on the dominant plant genus in Gondwanan ecosystems indicate that foundational trophic interactions between plants and arthropods were slowly re-establishing in the early Mesozoic. Given the broadly similar depositional conditions, these changes cannot readily be attributed to differences in local environments. Collectively, our findings evidence the recovery of terrestrial ecosystems and carbon sinks over several millions of years following the worst warming-driven mass extinction in Earth’s history.
How to cite: Turner, H.-A., McLoughlin, S., Sweeney, A., and Mays, C.: Ecosystem recovery after the end-Permian event, Sydney Basin, Australia: Diversity and ecological interactions of the Early Triassic Dicroidium floras, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1062, https://doi.org/10.5194/egusphere-egu25-1062, 2025.
The spatial-temporal climate and environmental effects triggered by the weathering of basaltic magmas after a large igneous province (LIP) eruption are not well known. Here, we present geochemical data from numerous sedimentary sites with a near-global distribution to explore the effects of juvenile basalt weathering of the low-latitude Emeishan large igneous province (E-LIP, ~260 Ma). These data show the weathering of basalt dominantly contributed to siliciclastic materials in proximal basins (> 6 × 106 km2) at a timescale of up to ten million years. Our data thus provide evidence that, besides the gases released during the eruption, release of (metal) elements via weathering of basalt at low latitudes plays a significant role in surface geochemical cycling. The release of these elements likely facilitated the flourishing of tropical wetland flora in southwestern China during the Late Permian, resulting in the widespread formation of coal seams. Moreover, increased erosion rates, sharply reduced Chemical Index of Alteration (CIA), and exponentially increased bulk accumulation rates suggest a shift in the weathering regime of basaltic landscapes under the extreme climate conditions of the Early Triassic. This shift, characterized by intensified physical weathering, enhanced erosion in source areas but limited sediment transport, potentially resulting in the rapid disappearance of basalt weathering records in southwestern China.
How to cite: Ouyang, Q., Shen, J., and Longman, J.: Long-term provenance supply records of the Emeishan large igneous province: implications for the extreme climate of the Early Triassic, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9529, https://doi.org/10.5194/egusphere-egu25-9529, 2025.
The Permian-Triassic transition was marked by severe climatic and environmental disturbances, culminating in the largest mass extinction event since the Phanerozoic era. Volcanic activity, particularly the eruptions associated with the Siberian Traps Large Igneous Province (STLIP), is widely regarded as the primary driver of this ecological crisis. However, it is still unclear about the ecosystem effects by the weathering of the basalt, although the volatile effects by volcanic releasing had been well explored. This study focuses on the Suol section in the Siberian Basin to explore the causal relationship between basalt weathering and climatic-environmental evolution during this critical period, by metal geochemistry, sedimentology, and mineralogical analyses.
Results show that the concentrations of nickel, copper, vanadium, scandium, cobalt, and other metals in sediments near the Permian-Triassic boundary align with the elemental composition of Siberian basalts, confirming that the primary source material originated from basaltic eruptions. Following the volcanic events, the weathering of exposed Siberian basalts continued to influence the metal cycling in the Suol section into the Early Triassic, which yielding higher temperature. Notably, mercury and carbon isotope records recovered swiftly to pre-eruption background levels during the Early Triassic, indicating that volatile components such as mercury and carbon had a short-term impact on the climate and environment. In contrast, the weathering of non-volatile components persisted, resulting in prolonged effects on the regional climate and ecosystem.
These findings highlight a temporal disparity in the release and impact of volatile versus non-volatile components during Siberian volcanic activity. Volatile emissions significantly influenced short-term climatic and environmental conditions, whereas basalt weathering under extremely higher temperature conditions exerted a long-term influence on geochemical cycles and ecosystem dynamics.
How to cite: Zhang, Z. and Shen, J.: Sedimentary records of basalt weathering in the Suol section of Siberia basin during the Permian-Triassic Transition, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9047, https://doi.org/10.5194/egusphere-egu25-9047, 2025.
The weathering of basaltic rocks, especially on volcanic islands, plays a crucial role in global carbon cycling. In these environments, intense precipitation and frequent exposure of fresh rocks accelerate weathering processes, thus favoring the uptake of atmospheric CO2. While most estimates of weathering rates derive from river chemistry, soils and paleosols –the solid residue of protracted interaction between surface waters and the volcanic substrate– remain underexplored. Developed in contact with the atmosphere and incorporated into the geological record once sealed by volcanic deposits, paleosols record valuable environmental information, including the paleoclimatic conditions under which they were formed. In this study, we investigated the geochemistry of paleosols developed in the Azores Archipelago over the past 1 Myr. Precise geochronology of volcanic units bracketing paleosols revealed pulses of fast soil formation during interglacial peaks, and indicates high soil formation rates (3–180 mm kyr-1), similar to modern soil formation rates in tropical volcanic islands. This suggests periods over which the Azores High-pressure system could have been weakened or centered farther to the south of its current position, allowing humid air masses to reach the Azores region. Geochronological evidence suggests high initial formation rates, rapidly decreasing to near zero after ~35 kyr. This might be attributed to a combination of cation depletion and precipitation of stable minerals. Paleosols have generally developed faster on pyroclastic deposits than on lava flows. However, those formed on lava flows required less vertical development to sustain high cation exports due to their higher density. Based on the geochemistry of paleosols and their parental materials, we estimated cation exports (0–2600 t km-2 yr-1) and associated CO2 uptake (0–35 × 106 Mol km-2 yr-1). These estimates generally exceed previous estimates based on the geochemistry of modern rivers in the Eastern Azores, by a factor of up to tenfold. Our results highlight the criticality of precise geochronological control to estimate past weathering and soil formation rates, and that atmospheric CO2 may have experienced short episodes of intense sequestration during interglacial stages, possibly contributing to subsequent cooling events over the past 1 Myr. A preliminary study of U-series geochronology on paleosols of the Azores provided promising results, consistent with our previous Ar geochronology. This is expected to provide a better understanding of the evolution of past weathering rates and consequent CO2 consumption in the Azores and other volcanic settings.
How to cite: Hevia-Cruz, F., Hildenbrand, A., Sheldon, N., Chabaux, F., Marques, F. O., and Carlut, J.: Intense CO2 consumption by pulsed volcano weathering near interglacial peaks in the Azores Archipelago (North Atlantic Region), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3297, https://doi.org/10.5194/egusphere-egu25-3297, 2025.
Volcanic activity plays a pivotal role in Earth’s material cycling and serves as a crucial mechanism in regulating atmospheric CO2 concentrations. During the Late Ordovician–Early Silurian, global volcanic activity was frequent, exerting substantial influences on paleoclimate, paleoceanographic changes, mass extinctions, and the formation of important hydrocarbon source rocks in the Early Paleozoic era. In this study, Hg content, Zr content, Hf content, and Zr/Cr were used to identify volcanic activity; Cu content, Mo content, TOC content, and carbon isotopes were used to determine primary productivity; U/Th, V/Cr, V/(V+Ni), and Ni/Co were used to analyze the redox conditions of the sedimentary environment; chemical index of alteration, Sr content, and Sr/Cu were used to discriminate paleoclimate; and Sr/Ba to discriminate paleosalinity. In the Katian in the Yangtze region, the water body was highly reducing, and at the beginning of the Rhuddanian, the maximum values of all redox indicators appeared, with the maximum values of U/Th reaching 7.99, V/Cr reaching 25.68, V/(V+Ni) reaching 0.89, and Ni/Co reaching 25.15, which meant that the water body was in the strongest period of reductivity at this time. In the middle and late Rhuddanian, U/Th, V/Cr, V/(V+Ni), and Ni/Co all showed a decreasing trend, indicating that the reductivity of the water body gradually weakened. The trend in marine water's reducibility paralleled that of primary productivity, as indicated by Cu, Mo, and TOC content and the δ13C value increasing from the Katian to the beginning of the Rhuddanian, and then starting to decrease, and reached their maximum values at the beginning of the Rhuddanian. Additionally, the frequency and thickness of the bentonite layers were gradually decreasing and thinning from the Wufeng Formation to the Longmaxi Formation, and indicators of volcanic activity intensity, such as Zr content and Hf content, and Zr/Cr ratio exhibited an overall declining trend from the bottom to the top, aligning with the pattern of volcanic activity and the evolution of the sedimentary environment in the Late Ordovician–Early Silurian. The weathering process of volcanic rocks and volcanic ash brought huge amounts of P to the ocean during the Late Ordovician-Early Silurian, accompanied by inputs of N, Fe, Zn, and other vital elements necessary for biological growth and development, triggering the flourishing of marine organisms in the Yangtze Sea, with a rapid increase in biomass and consumption of more oceanic and atmospheric CO2. The original organic carbon sequestered in the Wufeng-Longmaxi Formation in the Yangtze region is about 4582.493 Gt, and the global total original organic carbon sequestered during this period is at least 16131.135 Gt. Volcanic activity enhanced the biological pumping effect, which resulted in the largest organic carbon sequestration in the Early Paleozoic.
How to cite: Xie, H. and Liang, C.: Late Ordovician-Early Silurian global volcanism triggers biological pumping in the Yangtze region driving ocean and climate change, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1320, https://doi.org/10.5194/egusphere-egu25-1320, 2025.
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.
How to cite: He, Q., Lindström, S., Hesselbo, S., Bjerrum, C., Li, M., Yu, J., and Shen, J.: Hydrological cycles perturbation of continental weathering during the Triassic-Jurassic transition and Toarcian Oceanic Anoxic Event, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5049, https://doi.org/10.5194/egusphere-egu25-5049, 2025.
Marginal marine settings – the deltaic, estuarine, and mudflat habitats at the interface of land and sea – offer exceptional taphonomic windows on the rise of eukaryotic ecologies. Organic microfossils from tidally influenced horizons point to pre-Cryogenian origins for major eukaryotic groups, including red algae (Butterfield 2000), putative fungi (Butterfield 2003, 2005), and amoebae (Porter et al. 2003; Dehler et al. 2012). Meanwhile, an absence of comparable records even in those supratidal settings offering exceptional preservation conditions (e.g., in early diagenetic silica) suggests that Precambrian eukaryotes were essentially confined to subaqueous environments. Yet, these windows onto early eukaryotic history are vanishingly rare and temporally restricted. Efforts to place them within a broader record, spanning the Precambrian-Cambrian transition and its Phanerozoic aftermath, have been frustrated by a lack of similar organically preserved biotas from Cambrian marginal marine settings. New ichnofossils and Small Carbonaceous Fossils (SCFs; Butterfield & Harvey, 2012) from mudcracked horizons of the Middle Cambrian Pika Formation (Western Canada) offer a comprehensive view on an early Palaeozoic fauna from a periodically emergent mudflat. The wiwaxiids, priapulids, stem- and crown-annelids, and burrow traces of the Pika biota show that both classic Burgess Shale-type metazoans and ecosystem engineers from modern classes ventured into Cambrian tidally influenced settings, where they coexisted with members of derived living orders. This attests to an early influence of animal ‘pioneer taxa’ on dysoxic, intermittently desiccating marginal habitats. These findings push the limits of metazoan ecological tolerance to dehydration, UV exposure and salinity and redox fluctuations (e.g. Sagasti et al., 2001; Blewett et al., 2022), complementing the Precambrian record to suggest shallow-marine settings as cradles of eukaryotic innovation across the Neoproterozoic-Cambrian boundary.
References
Blewett, T. A., Binning, S. A., Weinrauch, A. M., Ivy, C. M., Rossi, G. S., Borowiec, B. G., ... & Norin, T. (2022). Physiological and behavioural strategies of aquatic animals living in fluctuating environments. Journal of Experimental Biology, 225(9), jeb242503.
Butterfield, N. J. (2000). Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes. Paleobiology, 26(3), 386-404.
Butterfield, N. J. (2005). Probable proterozoic fungi. Paleobiology, 31(1), 165-182.
Butterfield, N. J. (2005). Reconstructing a complex early Neoproterozoic eukaryote, Wynniatt Formation, arctic Canada. Lethaia, 38(2), 155-169.
Butterfield, N. J., & Harvey, T. H. P. (2012). Small carbonaceous fossils (SCFs): a new measure of early Paleozoic paleobiology. Geology, 40(1), 71-74.
Dehler, CM, SM Porter, and JM Timmons (2012) "The Neoproterozoic Earth system revealed from the Chuar Group of Grand Canyon", in JM Timmons and KE Karlstrom, eds., pp. 49–72, Grand Canyon Geology: Two Billion Years of Earth's History. Special Paper no. 489, Geological Society of America, Boulder, Colorado.
Porter, S. M., Meisterfeld, R., & Knoll, A. H. (2003). Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon: a classification guided by modern testate amoebae. Journal of Paleontology, 77(3), 409-429.
Sagasti, A., Schaffner, L. C., & Duffy, J. E. (2001). Effects of periodic hypoxia on mortality, feeding and predation in an estuarine epifaunal community. Journal of Experimental Marine Biology and Ecology, 258(2), 257-283.
How to cite: Mussini, G.: Building the eukaryotic planet: a view from marginal marine settings, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1806, https://doi.org/10.5194/egusphere-egu25-1806, 2025.
Early Cambrian tectonics of eastern Australia was characterised by the transition from a passive margin to a convergent regime with associated development of a volcanic arc system. This interval coincided with the Cambrian Explosion—the geologically sudden appearance of all major animal body plans. In South Australia, lower Cambrian successions in the Stansbury and Arrowie basins are stratigraphic archives that preserve evidence for diverse fossil faunas that flourished along the eastern margin of Gondwana, and the dynamic palaeoenvironments they inhabited. Sandwiched within these marine and marginal marine successions are distal volcanics—key for mapping the tectonically-driven palaeoenvironmental and palaeogeographic evolution of this region.
Proximal and distal volcanics from South Australia (SA) and western New South Wales (NSW) have been CA-TIMS dated to establish precise marker horizons. These dates link distal volcanics with their likely proximal equivalents in South Australia and the Gnalta Shelf in western NSW. In SA, a tuff from the lower part of the Parara Limestone in the SYC 101 drill core in the western Stansbury Basin has been dated to 517.5±0.2 Ma (Castle-Jones et al., in review) which is within error of a CA-TIMS date of 517.41±0.15 Ma from the Marne River Volcanics in the eastern part of the basin (Curtis, in prep.). Tuffs from the Mernmerna Formation in the Arrowie Basin have been dated to 515.38 ± 0.13 Ma (Big Green Tuff), 514.56 ± 0.13 Ma (Third Plain Creek Member), and 514.46 ± 0.13 Ma (Paralana 1B DW1 drill core) (Betts et al., 2018). These ages correspond closely to the 514.96 ±0.14 Ma tuff from Cymbric Vale Formation, western NSW (Betts et al., 2024). The Billy Creek Formation tuff in the Arrowie Basin, dated to 511.87 ±0.14 Ma (Betts et al., 2018), is slightly younger than the Ma Mooracoochie Volcanics in the Warburton Basin to the north (Curtis, in prep.).
Changes in volcanic regime over time accompanied profound changes in basinal palaeogeography, sedimentation and faunal composition in eastern Australia during the early Cambrian. This study shows how geochronology, accompanied by rigorous petrographic, biostratigraphic and geochemical data are important for resolving how tectonic evolution impacted nascent ecosystems along the early Cambrian margin of eastern Australia.
References
Betts, M.J., et al. 2024. First multi-proxy chronostratigraphy of the lower Cambrian Byrd Group, Transantarctic Mountains and correlation within East Gondwana. Gondwana Research 136, 126-141.
Betts, M.J., et al. 2018. Early Cambrian chronostratigraphy and geochronology of South Australia. Earth-Science Reviews 185, 498-543.
Castle-Jones, J., et al. in review. Integrated biostratigraphy, chemostratigraphy and geochronology of the lower Cambrian succession in the western Stansbury Basin, South Australia. Australian Journal of Earth Sciences.
Curtis, S., in prep. The Delamerian Orogen: Insights into a rapidly evolving convergent continental margin from the timing and petrogenesis of igneous rocks. PhD thesis. University of South Australia
How to cite: Jatupohnkhongchai, S., Curtis, S., Castle-Jones, J., Payne, J., R. Paterson, J., A. Brock, G., Milan, L., and J. Betts, M.: Early Cambrian volcanic and palaeoenvironmental evolution of eastern Australia , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14800, https://doi.org/10.5194/egusphere-egu25-14800, 2025.
Revealing the patterns and drivers of diversity in the Cambrian requires an understanding of distribution. On a dynamic Earth with uncertain palaeogeography, the understanding of range and diversity requires novel methodology and approaches. Trilobites, an extremely diverse group of arthropods, underwent important shifts in diversity and morphology throughout the Cambrian. However, the mechanisms driving their global dispersal and diversification during the early Palaeozoic remain inadequately understood. Persistent issues in studying the facilitators of distribution include morphological and life history constraints, e.g. the impact of benthic or pelagic larval stages. This uncertainty is compounded by the limitations of current palaeogeographical reconstructions. To address these issues, the Trilobite Biogeography and Ecology working group (TRiBE) applied a novel approach to geography and reconstructed trilobite biogeographical patterns associated with their initial global radiation from throughout the Cambrian. Using phylobiogeographic methods, with the Paterson et al (2019) phylogeny, we took three approaches to area establishment and compared the resulting patterns. The results, strengthened through robust comparison of area establishment, provide insights into Cambrian trilobite ancestral geographical ranges, the frequency and type of allopatric speciation events, and the connectivity between different regions during this critical phase of euarthropod evolution. Comparison between palaeogeography, climate, and marine connectivity are examined as facilitators of a global trilobite distribution and the specialisation of the group throughout the Cambrian. This study aims to both make comment on the evolutionary success of early euarthropods, but also to highlight the influence of geographical assumptions on interpretation.
How to cite: Dowding, E., Drage, H., Lam, A., Holmes, J., Pates, S., Jordan, K., Collantes, L., Esteve, J., Laibl, L., Lucas, K., Nikolic, M., Rojas, A., Serra, F., and Gabriela Suárez, M.: Range and radiation of Cambrian Trilobites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12000, https://doi.org/10.5194/egusphere-egu25-12000, 2025.
The Permian-Triassic (PTME, ~251.9 Ma) and Triassic-Jurassic (TJME, ~201.3 Ma) mass extinctions, both triggered by large igneous province (LIP) activity, represent two of the most significant extinction events in Earth’s history. Despite this similarity, there were contrasting impacts on land plants. Here, we compile global macrofossil records of Triassic-Jurassic flora and integrate them with lithological climate proxies, the HadCM3L climate model, and vegetation model FLORA to reconstruct vegetation dynamics across the TJME. Our findings suggest that, unlike the significant low latitude plant extinction during the PTME, the TJME coincides with floral compositional turnover and enhanced productivity, particularly in mid- to high- latitudes. High-resolution chemical weathering index, mercury, and plant biomarker records further suggest that global vegetation productivity and biotic weathering was enhanced after the TJME, stabilizing Earth’s temperature and facilitating rapid post-extinction cooling once LIP emissions ceased. This contrasts with the PTME when widespread deforestation trapped the Earth in a prolonged super-greenhouse climate. This study underscores the critical role of vegetation in modulating long-term climate and highlights plant thermal response and adaption as a key control on Earth's sensitivity to warming.
How to cite: Xu, Z., Gurung, K., Farnsworth, A., Wignall, P., Hilton, J., Merdith, A., Hunter, S., Krause, A., Wang, Y., Yu, J., and Mills, B.: Contrasting vegetation and climate regulation at the Permian-Triassic and Triassic-Jurassic hyperthermals, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13043, https://doi.org/10.5194/egusphere-egu25-13043, 2025.
The middle Eocene was marked by long-term global cooling trend, interrupted by a notable
warming event lasting ~500 kyr, the Middle Eocene Climatic Optimum (MECO, ~40 Ma),
characterized by a 4–6°C increase in surface and temperatures, accompanied by a transient rise in
atmospheric pCO2. The MECO event is attracting increasing scientific interest, as it records
temperatures and pCO2 levels that Earth could reach by the end of this century if anthropogenic
greenhouse gas emissions are not reduced. Continental weathering plays a critical role during warm
phases, as it contributes to carbon removal from the atmosphere through silicate hydrolysis.
Analyzing clay and bulk mineralogy in the stratigraphic archives offers valuable insight into past
environmental conditions. The preservation of clay minerals allows for the reconstruction of the
conditions under which they formed, providing clues about continental weathering and geochemical
conditions in the water columns or pore waters (neoformed or transformed) of the sedimentary
environment during climate events. However, bulk and clay mineralogy data that characterize
paleoenvironmental conditions during the MECO, are still insufficiently explored. This study
presents an integrated approach to assess changes in weathering regimes through bulk and clay
mineralogy from the Alano di Piave section, a Neo-Tethys bathyal succession located in NE Italy.
This section, the GSSP of the Bartonian/Priabonian boundary, offers a continuous and well-
preserved record of the MECO interval, well constrained by stable isotope record, making it an
ideal location to study paleoclimatic conditions of this crucial warming event, especially in relation
to continental weathering. Changes in mineralogical assemblages observed in this study reflect the
regional climatic expression of the MECO global warming event. In addition, climatic variations as
derived by our analyses can provide significant information on the marked biotic changes recorded
from this section.
How to cite: Cruciani, G., Sigismondi, S., Giusberti, L., and Luciani, V.: Investigating warm climatic conditions through bulk and clay mineralogy in the AlanoSection (Neo-Tethys) during the Middle Eocene Climatic Optimum (MECO, ~40 Ma), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19148, https://doi.org/10.5194/egusphere-egu25-19148, 2025.
Exploring the dynamical structure of complex systems like Earth’s climate generally requires run- ning simulations over long time scales and for a wide range of initial conditions [1] following a ‘bio- geodynamical approach’. This means that the simulations need to include interactions among the climatic components (in particular, dynamical atmosphere and ocean as in general circulation models, as well as representations of vegetation, sea and continental ice) under different plate tectonic config- urations for deep time modelling. This is hardly achieved using CMIP-like models, because of their high computational costs.
Here, we describe a recently developed biogeodynamical modelling tool that allows for running simulations over multi-millennial time scales within a reasonable amount of CPU-time. Starting from the MITgcm coupled atmosphere-ocean-sea ice setup, we have developed a global ice-sheet model based on the shallow-ice approximation, where in a first step the surface mass balance is computed as in [2]. In a second step, we will adapt the MITgcm land/snow model to properly compute the surface energy balance. The runoff map is obtained by the hydrological model pysheds [3] and takes into account the ice-sheet isostatic correction. These three components are further coupled with the well- known vegetation model BIOME4 [4] and the paleogeographical reconstruction model PANALESIS [5].
Such a coupled setup permits to investigate nonlinear interactions among the climatic components at the global scale. These interactions evolve and balance differently along Earth’s history under the effect of various types of forcing, leading to a wide range of climatic steady states for different paleogeographical reconstruction times, and potentially revealing the presence of tipping mechanisms. Here, we show a present-day validation of this coupled setup against observations and CMIP6-model results, and how we are planning to apply it to selected time frames in deep time.
References
[1] Brunetti and Ragon, Physical Review E 107, 054214 (2023)
[2] Tsai & Ruan, Journal of Glaciology 64,246 (2018)
[3] Bartos, Matt., pysheds: simple and fast watershed delineation in python. (2020)
[4] Kaplan et al., Journal of Geophysical Research 108, 8171 (2003)
[5] Vérard., Geological Magazine 156, 2 (2019)
How to cite: Moinat, L., Franziskakis, F., Vérard, C., Goldberg, D., and Brunetti, M.: Development of a biogeodynamical tool for exploratory paleoclimate modelling , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2266, https://doi.org/10.5194/egusphere-egu25-2266, 2025.
Over the course of the Phanerozoic, Earth’s climate has alternated between greenhouse and icehouse regimes, driven in large part by shifts in continental configurations that influence weathering processes and, consequently, the global climate. Geodynamic factors play a critical role in these shifts, and intermediate-complexity Earth System Models provide an effective means of exploring the associated parameter spaces. These models rely on topographic boundary conditions derived from paleogeographic reconstructions, where elevation and slope significantly affect silicate weathering intensities. However, different methodologies for reconstructing paleogeographies can yield markedly different results. Among these, the digital elevation maps by Scotese and Wright (2018) are widely used, despite notable discrepancies compared to alternative reconstructions.
To evaluate the impact of paleogeographic reconstructions on climate model simulations, we compared the outcomes of PlaSim-GENIE simulations for 45 time slices across the Phanerozoic, using both Paleomap and PANALESIS (Vérard, 2019) digital elevation models (DEMs). These simulations, covering pCO2 levels from 0.25 to 16 times pre-industrial atmospheric concentrations (280 ppm), were used to generate lookup tables for the spatially resolved global carbon cycle model SCION (Mills et al., 2022). This approach allowed us to investigate a broad parameter space of potential drivers for climatic shifts throughout the Phanerozoic.
Preliminary results indicate that incorporating degassing forcing from the PANALESIS paleogeography enables even simple inorganic carbon cycle box models to more closely replicate atmospheric CO2 variations inferred from proxy records. Furthermore, climate simulations using PANALESIS paleogeography within SCION more successfully capture the Hirnantian Glaciation, whereas simulations constrained by PaleoMap reconstructions produce pCO2 levels that are too high to align with the observed glaciation during this period. The identified differences may be related to a more robust treatment of plate boundaries evolution in PANALESIS, which is based on plate tectonic rules.
References
Mills, B. J., Donnadieu, Y., & Goddéris, Y. (2021). Spatial continuous integration of Phanerozoic global biogeochemistry and climate. Gondwana Research, 100, 73-86.
Scotese, C. R., & Wright, N. (2018). PALEOMAP paleodigital elevation models (PaleoDEMS) for the Phanerozoic. Paleomap Proj.
Vérard C. (2019.b). PANALESIS: Towards global synthetic palæogeographies using integration and coupling of manifold models. Geological Magazine, 156 (2), 320-330; doi:10.1017/S0016756817001042.
How to cite: Werner, N., Vérard, C., Brunetti, M., Gerya, T., and Tackley, P.: Evaluating the Impact of Paleogeographic Reconstructions on Phanerozoic Climate Simulations and Carbon Cycle Dynamics, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9324, https://doi.org/10.5194/egusphere-egu25-9324, 2025.
The Messinian Salinity Crisis (MSC, 5.9-5.3 Ma) is recognised as a period of dramatic regional environmental change but it is rarely considered in the interpretation of global environmental change in the late Miocene. Following Shields & Mills (2021), who showed that evaporite deposition has the potential to perturb the global carbon cycle, we investigate the temporal and spatial patterns of global environmental change resulting from the precession-paced extraction of the gypsum preserved until today in the Mediterranean basin in the 3D Earth system model cGENIE. The prescribed evaporite deposition causes a transient atmospheric CO2 draw-down of ~80 ppm and swings in the carbonate saturation state which causes sedimentary dissolution near the carbonate compensation depth, especially in the Pacific and Indian ocean. We compare the simulated model response to proxy records of late Miocene environmental change to test whether the fingerprint of the MCS evaporite deposition can be identified or whether additional buffer mechanisms need to be invoked to explain a more stable carbonate system.
References
Shields, G.A. and Mills, B.J., 2021. Evaporite weathering and deposition as a long-term climate forcing mechanism. Geology, 49(3), pp.299-303.
How to cite: Mills, B., Adloff, M., Monteiro, F., and Flecker, R.: Global impacts of evaporite deposition during the Messinian Salinity Crisis in transient Earth system model simulations , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19755, https://doi.org/10.5194/egusphere-egu25-19755, 2025.
The sulphur (S) cycle is important for determining paleoenvironmental evolution and organic matter enrichment. Compared with research on marine facies, studies on the terrestrial sulphur cycle and its relationship with key geological events, such as volcanic activity or hydrothermal fluids, are more limited. The Fengcheng Formation in the Mahu Sag of the Junggar Basin in northwestern China, which deposited approximately 360m during the Carboniferous to early Permian in an alkaline lake, is an ideal research object for studying the relationship between the terrestrial sulphur cycle and geological events. Therefore, in this work, we identified volcanic activity during the deposition of the Fengcheng Formation and established a link between volcanic activity and the lacustrine alkaline carbon‒sulphur cycle during the Carboniferous‒Permian through petrologic, geochemical, and geophysical data from the MY1 Well in the Mahu Sag. The results revealed that (1) multiple volcanic episodes occurred during the deposition of the Fengcheng Formation, as evidenced by high mercury (Hg) concentrations, high Hg/S ratios, increased sulphate concentrations and large negative pyrite sulphur isotope (δ34Spy) values (ranging to -20.52‰); (2) long-term ferruginous bottom water conditions may have been conducive to the preservation of organic matter; however, sulphate from volcanic activity promoted bacterial sulphate reduction, resulting in intermittent alternating euxinic conditions, as evidenced by iron speciation, molybdenum concentrations, and framboid and euhedral pyrite morphologies, which may have resulted in some consumption of organic matter; and (3) after volcanic activity, the sulphate in the lake water was depleted, and the bottom water system gradually closed and was continuously enriched with δ34Spy. Therefore, volcanic activity appears to have been the key factor controlling the sulphur cycle and organic matter enrichment through increased sulphate fluctuations in the oldest alkaline lake during the deposition of the Fengcheng Formation. This study sheds new light on the sulphur cycle of ancient alkaline lakes and can serve as a reference for organic matter enrichment under different mechanisms in shale.
How to cite: Liang, X., Bychkov, A. Y., Xie, Q., Wang, B., and Zhu, R.: Volcanic impact on terrestrial sulphur cycling during the Carboniferous‒Permian in an alkaline lake in the Junggar Basin, NW China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14655, https://doi.org/10.5194/egusphere-egu25-14655, 2025.
The Paleocene Eocene thermal Maximum (PETM) was a rapid global warming event, which occurred ~ 56 million years ago and lasted for ~200 ka. It is characterized by a massive rapid input of 13C-depleted carbon into the atmosphere and ocean, causing a 2-7‰ negative carbon isotope excursion (CIE). As a result of high atmospheric CO2 levels, high temperatures, and an enhanced hydrological cycle during the PETM, increases in physical and chemical weathering intensity have previously been reconstructed across the globe. Chemical weathering of silicate rocks predominates in humid climates and significantly influences the major and trace element composition of resulting sediments. Numerous studies suggest that the intensified chemical weathering of silicate rocks occurred during the PETM, driven by the warm conditions and enhanced hydrological cycle.
Here we present the first results of elemental geochemical analysis of sediment samples collected from the mid-Norwegian margin during IODP Expedition 396. Our initial results focus on variations in chemical weathering across the PETM as inferred from geochemical proxies.
In the samples examined here, chemical index of alteration (CIA), a proxy for chemical weathering intensity, values show a sharp drop from pre-PETM to mid-PETM. In contrast to other locations, these observations suggest a shift in the intensity of weathering from intermediate to weak and indicates chemical weathering was not intensified during the PETM in our study region. As this is opposite to previous studies, we consider whether changes in sediment provenance may explain these data. However, the provenance discrimination plots (La-Th-Sc ternary diagram Th/Co vs. La/Sc bivariate plot) shows mixed source with no clustering regardless of the time period. This indicates that the sediment source of the Vøring basin did not change at the PETM onset and we suggest that our CIA data truly represent a decrease in the intensity of chemical weathering during the PETM in the Vøring Basin.
How to cite: Sandhya, A. G., Pahnke, K., Longman, J., Frieling, J., and Jones, M. T.: Low chemical weathering intensity in the Vøring Basin during the Paleocene-Eocene Thermal Maximum, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9334, https://doi.org/10.5194/egusphere-egu25-9334, 2025.
Global climate variations (e.g., during glacial-interglacial transitions) induce local climatic effects such as temperature and precipitation changes, significantly impacting the chemical and physical degradation of volcanic islands. Conversely, the weathering of volcanic rock, especially on volcanic islands, consumes CO2, thus impacting its concentration in the atmosphere and consequently the global climate. The Azores Archipelago (Central North Atlantic) is particularly sensitive to climate changes due to its position influenced by regional climatic drivers such as the North Atlantic Oscillation atmospheric system and the oceanic North Atlantic Gyre. Paleosols are key targets to reconstruct paleo-environmental conditions, as they constitute a valuable archive of both paleoclimatic conditions and weathering processes. Recent work on paleosols spanning the past 1 Myr in the Central and Eastern Azores showed pulses of fast soil formation during wet and warm interglacial stages locally promoting intense atmospheric CO2 consumption through weathering. Flores Island, in the Western Azores, is the perfect target to further study rates of weathering and paleosol formation, and document paleoclimate at the regional scale (~600 km separation between Western and Eastern Azores). In this work, K-Ar geochronology of volcanic units under and overlying paleosols was used to precisely constrain their mean ages and formation times. This was complemented with paleoclimatic proxies based on paleosol whole-rock geochemistry, which allowed us to reconstruct Mean Annual Precipitation (MAP) and Mean Annual Air Temperature (MAAT) at the time the paleosols were formed. Our results show two groups of paleosols formed mainly during glacial periods (~ 550 ka, 630-670 ka), in contrast with the Central and Eastern Azores, where paleosols were formed near interglacial peaks. Our MAAT and MAP reconstructions show that mild and wet conditions prevailed in Flores, reaching 21.5°C and 1340 mm yr-1, respectively. These conditions are hotter and drier than current mean annual conditions (17°C and 1716 mm yr-1). However, they show wetter/warmer conditions than those reached around interglacial peaks in the Central and Eastern Azores, consistent with modern climatic differences (wetter/hotter conditions to the west). As paleosol ages between Flores and other Azores islands do not overlap, our data could indicate (1) persistent wet/warm local paleo-conditions in Flores due to its position farther to the north-west compared to the Central and Eastern Azores, closer to the westerlies’ main trend; or (2) a regional warm and wet climate around 550 ka and 650 ka that remains to be investigated in the other parts of the Archipelago and the Atlantic region at a broader scale (e.g., the Canary volcanic archipelago). In any case, our data evidence periods of fast soil formation during glacial stages (10 to 367 mm kyr-1), supposed to be too dry and cold to allow the efficient weathering of the volcanic substrate, according to recent reconstructions in the Central and Eastern Azores. Such intense and fast weathering likely resulted in significant atmospheric CO2 consumption, at least at local scale. Further investigations of paleosols could improve our temporal and spatial resolutions, and consequently our understanding of the feedback between volcanic islands weathering and global climate.
How to cite: Hildenbrand, A., Hevia-Cruz, F., Loiodice, L., and Sheldon, N.: Unexpected intense weathering during glacial periods in the Central North Atlantic as recorded by paleosols from Flores Island (Azores), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6489, https://doi.org/10.5194/egusphere-egu25-6489, 2025.
Clay mineralogy records provide important climate archives of weathering and hydrology through time, but these paleoclimate signals may be obscured by authigenic or diagenetic overprinting. International Ocean Discovery Program Expedition 396 drilled an expanded Paleocene-Eocene Thermal Maximum (PETM) succession from the Modgunn Vent in the Northeast Atlantic Norwegian Continental Margin. The PETM succession here is marked by frequent occurrence of discrete ash beds (centimetre scale) and by thicker ash-rich deposits. Three major lithological units were identified from the Late Paleocene to the Early Eocene in holes U1568A and U1567B: Late Paleocene bioturbated mudstone (Unit VI), laminated mudstone from the PETM onset and earliest PETM body (Unit V), and ash-rich mudstone in the later PETM body (Unit IV). Smectite is the dominant clay mineral throughout the record, with minor components of illite, kaolinite, and quartz. However, the potential transformation of volcanic ash into authigenic smectite after deposition complicates using clay mineralogy as a proxy for paleoclimate and weathering at this site.
We apply X-ray diffraction (XRD) analyses to quantify the bulk mineralogical composition as well as the clay-sized fraction and electron microscopy (SEM/EDX) to characterise the compositional and morphological changes of the clay-sized fraction. These results enable us to investigate the contribution of volcanism to the clay signal in order to discriminate between continental weathering processes given by clay mineralogy and early diagenesis processes by the input of volcaniclastic material. Morphological analysis of smectites indicate the occurrence of both detrital and authigenic types, but the chemical compositions are clustered by lithological unit rather than type. Detrital smectites in all units are montmorillonite-beidellites, and in Units V and VI authigenic smectites resemble the composition of detrital smectites in the same unit – suggesting a precursory relationship. In Unit IV Mg-rich authigenic smectite (cheto type) makes up >95% of the clay-sized fraction and is associated with enhanced in situ alteration of volcanic ash. This record indicates volcanic ash was relatively well preserved in the latest Paleocene and earliest PETM (Units VI and V) and authigenic smectites were mostly derived from detrital smectite and therefore paleoclimate signals are preserved. In the later PETM, a relative increase in volcanic material to background sedimentation – through increased bioturbation and/or volcanic production – significantly influenced the clay fraction due to the formation of ash-derived authigenic smectite. This process overwhelms the percentage of detrital clay in the XRD record and therefore masked any paleoclimate signals in Unit IV.
How to cite: Turton, N., Xu, W., and Pellenard, P.: Assessing volcanic influence on clay minerals as weathering proxies during the Paleocene-Eocene Thermal Maximum from Modgunn Hydrothermal Vent (IODP Expedition 396), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3510, https://doi.org/10.5194/egusphere-egu25-3510, 2025.
Posters virtual: Wed, 30 Apr, 14:00–15:45 | vPoster spot A
EGU25-15990 | ECS | Posters virtual | VPS4
Expanded aerobic iron biogeochemical cycle in the Paleoproterozoic oceans during the ca. 2.22-2.06 Ga Lomagundi EventWed, 30 Apr, 14:00–15:45 (CEST) | vPA.36
The variability of iron (Fe) isotopes during the Paleoproterozoic is a topic of debate due to the complex pathways involved in isotopic fractionation. Similarly, the expansion of ocean oxygenation during the late part of the Great Oxygenation Event (GOE)―the ∼2.22–2.06 Ga Lomagundi Event (LE) that represents Earth’s most pronounced and longest-lived carbon isotope excursion―remains controversial. Here, we present new Fe isotope data on bulk samples from a range of lithologies of the Francevillian Group, Gabon, including marine carbonates, black shales, thin sedimentary pyrite beds, early diagenetic pyrite and carbonate nodules. We also analyse pyritized Francevillian biota that were further combined with data obtained from in situ Fe isotope analyses on early diagenetic pyrite nodules (pyritized Francevillian biota and non-fossil pyrite). The δ56Fe values from this study vary from highly positive values, up to +1.71‰, in non-fossil pyrite nodules, to highly negative values, down to –3.14‰, in pyritized Francevillian biota. The near-to-zero δ56Fe values notably characterize primary carbonates, black shale, thin pyrite beds and carbonate concretions. The near-to-zero δ56Fe values are interpreted to reflect complete oxidation and quantitative removal of dissolved Fe2+ from seawater, in the Paleoproterozoic oceans, followed by complete reduction of Fe3+ in the sediments akin to previously described modern-like Fe biogeochemical cycle which is proposed to have kicked off only from ca. 1.7 Ga. In contrast, positive δ56Fe values are linked to equilibrium isotope fractionation, favoured by the high S/C ratios during early diagenesis, while the negative values reflect the kinetic isotope effect driven by a high organic carbon content of the Francevillian biota. The Francevillian Group massive manganese deposition is devoid of concomitant and significant Fe precipitation in the Francevillian shelf environments which is in stark contrast to early GOE Mn-ore deposits in southern Africa. The data thus suggests that the marine Fe2+ reservoir was already exhausted in the Paleoproterozoic oceans during the late part of the GOE. In this scenario, and considering the observation of Fe-lean Mn deposits, the Paleoproterozoic oceans were likely oxygenated enough to quantitatively oxidize and remove Fe2+ from seawater during the LE. However, extensive oxidation of Fe2+ may have been an important O2 buffer that contributed to maintaining low redox thresholds (e.g., low Eh) in the deep Paleoproterozoic oceans, which ultimately prevented it from reaching oxidizing conditions that require the stability of Mn (oxyhydr)oxides and other elements of similar redox thresholds, i.e., nitrate and selenate. Oxidizing conditions to quantitatively oxidize Mn2+ or to significantly build up a pool of oxyanions stable at much higher redox thresholds (e.g., nitrate and selenate) were only reached in the photic zone where the rate of oxygenic photosynthesis was significantly enhanced as a consequence of intense oxidative weathering during the LE. The findings highlight moderately oxygenated Paleoproterozoic oceans with habitats capable of sustaining complex aerobic ecosystems only restricted in shelf environments during the immediate aftermaths of the GOE.
How to cite: Ajagunjeun, A., Ossa Ossa, F., Kleinhanns, I. C., Marin-Carbonne, J., Hofmann, A., Al Suwaidi, A., and Schoenberg, R.: Expanded aerobic iron biogeochemical cycle in the Paleoproterozoic oceans during the ca. 2.22-2.06 Ga Lomagundi Event, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15990, https://doi.org/10.5194/egusphere-egu25-15990, 2025.
EGU25-14396 | ECS | Posters virtual | VPS4
Supraglacial biological niches as a solution to the Sturtian oxygenation problemWed, 30 Apr, 14:00–15:45 (CEST) | vPA.37
Understanding how climate and biology changed during and after Snowball Earth events - global glaciations which coincided with major shifts in the ocean-atmosphere state - is critical for understanding the evolution of life on Earth. New observations of the Neoproterozoic Sturtian glaciation pose challenges to the Snowball paradigm. Precision geochronology shows that the Sturtian lasted ~56 Myr, and the lack of sulfur-MIF signals observed indicates that the atmosphere remained oxygenated throughout. A source of O2 is required to maintain an oxygenated atmosphere for ~56 Myr, but in the canonical Snowball scenario, primary production shuts down completely. Here, we model the carbon and oxygen cycles during the Snowball to investigate this challenge. We propose that photosynthesis in melt holes on the equatorial glacier surface was sufficiently productive to provide the missing O2 source, and that accumulation of aeolian dust sustained these melt holes and supplied them with nutrients. We argue that primary production was limited by phosphorus availability and photosynthetically active surface area, and show that only a dust-supported supraglacial ecosystem could satisfy both conditions.
How to cite: Minsky, C., Wordsworth, R., and Johnston, D.: Supraglacial biological niches as a solution to the Sturtian oxygenation problem, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14396, https://doi.org/10.5194/egusphere-egu25-14396, 2025.
