Here, we also focus on presenting state-of-the-art approaches and current challenges, aligned with the upcoming PAGES Special Issue: “The Time-Integrated Matrix for Earth Sciences” (TIMES). The recently launched TIMES initiative is an ambitious international community effort that, over the next ten years, aims to recalibrate global climate records from the last 100 million years on a unified, accurate, and precise timeline.
This session is organized by the International Subcommission on Stratigraphic Classification (ISSC) of the International Commission on Stratigraphy (ICS) and is open to the Earth science community at large
Orals: Wed, 6 May, 14:00–17:35 | Room -2.20
Age models for many sediment records are imprecise at best and inaccurate at worst, hindering our ability to closely compare different proxy records, track variations in regional responses to climate change, and understand how Earth’s climate sensitivity changed through time. We must tackle the challenge of imprecise age models if we are to make significant advances in paleoclimatic reconstructions and near-future climate projections. A coordinated, global, cross-disciplinary research network is required to address the immense challenges of establishing accurate age calibrations for sedimentary records covering the past 100 million years of Earth's climate history.
We have launched an international, coordinated effort to revise, recalibrate, and synchronize the dating tools available to paleoclimatologists – i.e., local and regional information obtained from chemo-, bio- and magnetostratigraphy, as well as radioisotopic geochronology – by unifying these approaches with astrochronology. Synchronizing proxy data at orbital-scale resolution is critical as it allows for detailed reconstructions of climate variability and for resolving the sequence of events in climate-relevant processes over millions of years in the past. Our nascent initiative, the Time-Integrated Matrix for Earth Sciences (TIMES) program, will facilitate the interaction of the climate proxy and modeling communities with the timescale-generating community and astronomers, to deliver highly synchronized, accurate, and precise timelines for these sedimentary climate records.
We will share insights from our Kickoff Workshop in August 2025, at which the TIMES working group began defining key components of a Science Plan for the first five-year long phase of TIMES. We invite further involvement of members of the timescale- and proxy-generating communities, as well as climate modelers, to contribute to our efforts to tackle this colossal scientific challenge as we build our inclusive international collaboration.
How to cite: Kasbohm, J., Westerhold, T., Lam, A., Hönisch, B., Drury, A. J., and Tangunan, D.: Launching TIMES: A Time-Integrated Matrix for Earth Sciences, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14840, https://doi.org/10.5194/egusphere-egu26-14840, 2026.
The Earth's calendar, the geological timescale, provides guidance on periods and events of the past measured in thousands to millions of years. The Time Integrated Matrix for Earth Sciences (TIMES) initiative aims to create an accurate, comprehensive timeline of climatic events from the past 100 million years. The main tool for synchronizing and placing all the targeted geological records on an extremely precise and accurate timeline will be astronomical tuning. It has also improved other stratigraphic methods and is key to calibrating the Geological Time Scale. The International Commission on Stratigraphy (ICS), a body of the International Union of Geological Sciences, functions as the supervisory authority that ratifies Global Stratotype Sections and Points (GSSPs). GSSPs mark the starting point of a stage, which is a unit of rock strata representing a specific interval of geological time, forming part of the fundamental chronostratigraphic hierarchy of the Geological Times Scale. It seems logical that the efforts of TIMES and the ICS should be combined to create synergy with the goal to construct the ultimate Geologic Time Scale for the past 100 million years. How can this synergy be achieved? Here we will present how the TIMES objectives can help to refine GSSP ages and calibrate ages of events within stages more accurately by providing a detailed age model (astrochronology) for the interval between the base and top of a stage by using the cycles as astronomically dated astrochronozones. Combining astronomy and geology, from the present day back to 100 million years ago, can provide an accurate and precise dated framework with an unprecedented level of detail. This temporal framework will provide the base for the ultimate geological time scale, help to improve other numerical and relative dating methods and, importantly, synchronize archives of regional and global change.
How to cite: Westerhold, T., Erba, E., Hilgen, F., Kasbohm, J., Jurikova, H., and Henderson, C. M.: The ultimate Geologic Time Scale for the past 100 million years – approaches to synergy between the Time Integrated Matrix for Earth Sciences initiative and the International Commission on Stratigraphy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3026, https://doi.org/10.5194/egusphere-egu26-3026, 2026.
The TIMES (Time Integrated Matrix for Earth Sciences) community is composed of over 300 scientists worldwide with a common goal of building an accurate timescale for the last 100 million years of Earth’s history (Westerhold et al. 2024). By generating an improved timeline of events, we can better comprehend the forcings and feedback mechanisms controlling the Earth-climate system. This effort is essential as the consequences of human‑induced climate change are ongoing and unavoidable, with significantly varying impacts across regions, environments, and communities. To achieve this goal we need a broad set of global perspectives, scientific specialties, regional datasets, and proxy methods; moreover, we must support the people who conduct Earth Science research – the TIMES Community.
Here, we present the results of a benchmark survey distributed to the TIMES mailing list during the first hybrid Kickoff Workshop which took place in Washington D.C., USA in August 2025. The survey was designed to gauge the demographics, values, interests, and agreements of the TIMES community near its inception and use those results to create a living roadmap towards a more globally inclusive scientific community. From the collected data, we underscore the current imbalances in the TIMES community and identify a starting point that centers the values, interests, aspirations and community commitments of TIMES. We call on every member of the TIMES initiative and invite the geoscience community to join us in shaping this roadmap of who we are and what we aspire to become.
How to cite: Villa, A., Sepúlveda, J., Śliwińska, K., Kasbohm, J., Woodhouse, A., and Sibert, E.: Strengthening the TIMES Community: Who we are and what we want to become, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20946, https://doi.org/10.5194/egusphere-egu26-20946, 2026.
For the construction of age models of sedimentary sections, biostratigraphy remains a crucial tool. The emergence of astrochronology, and the ever-growing need for higher-resolution reconstructions of paleoclimate and paleoceanography now stimulates the biostratigraphic community to tie biostratigraphic zonations to astrochronological cycles (104–105 years). This foremost requires that the biostratigraphic community assesses the accuracy of the ages of microfossil ranges to that kind of temporal scale, and to what extent these are synchronous at such short timescales. This implies a review and revisit of previously published microfossils records, and perhaps the generation of new records. Over the past five years, I have been working towards a complete, open-access, FAIR, and iteratively updateable stratigraphic database for dinoflagellate cysts. Knowing that stratigraphic ranges of dinoflagellate cysts show considerable diachroneity (which creates uncertainty but also may represent a paleoceanographic signal) and that many taxa are provincial, the need arose for the development of regional calibrated dinoflagellate cyst stratigraphies. In other words: DINOSTRAT shows the stratigraphic range of taxa is per region. The continuously evolving stratigraphic framework over the past decades necessitated going back to original sources to avoid inherited errors, apply synonymy and recalibrate sequences to state-of-the-art time scales. Data entry in DINOSTRAT is in two ways. Sites from which stratigraphic ranges of dinocysts were published were added, with their modern geographic coordinates, age span and through that, their paleolatitudinal pathway. A qualification of the dinocyst-independent age control was added (other biostratigraphy, magnetostratigraphy, astrochronology). Then, for each site, the stratigraphic positions of first and last occurrences of dinocyst taxa relative to the independent age control were added. A lookup-file then calculates from that stratigraphic position the age, which enables future updating of the data. The paleolatitude of that age at that site is interpolated, creating regional context for that stratigraphic range. The database has multiple entries per taxa, creating a way of evaluating its regional synchroneity. DINOSTRAT now has at least best-guess ranges of all dinocyst taxa (over 18000 entries for ~6000 taxa), as well as regional calibrations of the mostly used stratigraphic taxa. Range charts can be plotted for all sites that were entered, as well as range charts per species, genus and on suprageneric level. The result is a holistic and still-augmented image of regional calibration of dinoflagellate cyst ranges, towards full application for the next-generation Geologic Time Scale. It shows which taxa are particularly synchronous and useful as biostratigrapic tool, and where. Output from DINOSTRAT is interactively coupled to the open taxonomic database palsys.org, that contains the species descriptions and images of dinoflagellate cysts. I will present the database structure and opportunities it creates, providing quality control of dinocyst biostratigraphic data.
How to cite: Bijl, P.: DINOSTRAT: towards accurate and complete regional calibration of the stratigraphic ranges of all organic-walled dinoflagellate cysts, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2975, https://doi.org/10.5194/egusphere-egu26-2975, 2026.
Changes in Earth’s orbit and axial tilt affect the distribution of solar radiation across the planet’s surface, influencing climate and leaving recognizable imprints in sedimentary layers over time. These recurring patterns, known as Milankovitch cycles, arise from gravitational interactions with other bodies in the Solar System. Their preservation in stratigraphic records allows the construction of continuous and precise age–depth models based on astronomical orbital cycles, helping to compensate for the discontinuities and uncertainties associated with other absolute dating methods.
In this study, we examine several tens of stratigraphic records spanning 40–100 Ma to establish and refine astronomical time scales by extracting signals related to Earth’s orbital eccentricity. We apply our newly released tool, AstroGeoFit (https://www.astrogeo.eu/astrogeofit/), which accommodates flexible time-varying sedimentation rates within stratigraphic sequences and quantifies associated uncertainties by combining genetic algorithm optimization with Bayesian approaches.
Beyond improving age–depth models at the scale of individual sections or cores, our results contribute towards a more systematic reconstruction of Earth’s eccentricity evolution from 40 to 100 Ma, derived primarily from stratigraphic records, providing intrinsic geological insights into the behavior of planetary orbits in deep time.
How to cite: Wu, Y., Laskar, J., Westerhold, T., Thibault, N., Sultanov, A., Hara, N., and Bujons, P.: AstroGeoFit in action. Towards an Eccentricity-Based Astronomical Time Scale for 40–100 Ma, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13244, https://doi.org/10.5194/egusphere-egu26-13244, 2026.
Sedimentary successions preserve the imprint of climatic, geochemical, and ecological change across Earth history, yet extracting high–precision temporal information from these archives remains a central challenge for integrated stratigraphy. Classical astrochronologic approaches typically resolve time only to the scale of precession, limiting our ability to interrogate the rates and durations of environmental perturbations that shaped the geological past.
High–resolution X–ray fluorescence (XRF) core scanning potentially offers an opportunity to overcome these constraints by providing 20–30 elemental series at ~0.2 mm spacing across intervals spanning numerous Milankovitch cycles. These multidimensional datasets capture coherent astronomical pacing signals embedded within chemically diverse sedimentary components, opening the door to a new generation of stratigraphic tools.
Here, we present a multidimensional cyclostratigraphic framework designed to advance the stratigraphic and paleoenvironmental toolbox. Our new cyclostratographic algorithm, AstroComb, employs a probabilistic, covariance–based approach to detect Milankovitch periodicities across multiple elemental series and to quantify uncertainty in inferred sedimentation accumulation rates. Building on such lower–resolution astrochronologic models, we present a second algorithm, ProBE4T (pronounced "Pro Beat"), which integrates these astronomical constraints with lithotype–specific sedimentation behaviour, inferred through unsupervised clustering of elemental and mineralogical estimates and Bayesian inversion under total–duration constraints. This probabilistic workflow distributes time across sedimentary successions at the resolution of the geochemical data itself and explicitly tests the hypothesis that chemically distinct lithotypes accumulate at distinct rates, thereby extending age–model refinement beyond the conventional precession limit.
The resulting age–depth models reveal substantial heterogeneity in time recorded per unit thickness, enabling precise temporal localization of paleoenvironmental signals, such as rapid climatic events, shifts in geochemical cycling, and changes in oceanic redox structure applicable from the Archean to the Holocene. By leveraging the full multidimensionality of XRF data and embedding probabilistic inference at each step, this approach expands the range of sedimentary archives amenable to high–resolution sediment accumulation rate determination and provides a generalizable methodology for integrating geochemical, lithological, and astronomical information.
The resulting age–depth models reveal substantial heterogeneity in time recorded per unit thickness, enabling precise temporal localization of paleoenvironmental signals, including rapid climatic events, shifts in geochemical cycling, and changes in oceanic redox structure, from the Archean to the Holocene. By leveraging the full multidimensionality of XRF data and embedding probabilistic inference at each step, this approach expands the range of sedimentary archives amenable to high–resolution sediment accumulation rate determination and provides a generalizable methodology for integrating geochemical, lithological, and astronomical information. The ProBE4T framework enhances our ability to explore temporal variability with uncertainties in sedimentary archives, opening new avenues for investigating climatic, geochemical, and ecological change at finer temporal scales across Earth history.
How to cite: Dahl, T. W., Fernandes, I., Mosegaard, K., and Sørensen, A. L.: Multidimensional XRF–informed Cyclostratigraphy for High–Resolution Geological Time Modelling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17547, https://doi.org/10.5194/egusphere-egu26-17547, 2026.
North Atlantic DeepWater (NADW), the return flow component of the Atlantic Meridional Overturning Circulation (AMOC), is a major inter-hemispheric ocean water mass with strong climate effects but the evolution of its source components on million-year timescales is poorly known. Today, two major NADW components that flow southward over volcanic ridges to the east and west of Iceland are associated with distinct contourite drift systems that are forming off the coast of Greenland and on the eastern flank of the Reykjanes (mid-Atlantic) Ridge. Here we provide direct records of the early history of this drift sedimentation based on cores collected during International Ocean Discovery Programme (IODP) Expeditions 395C and 395. We find rapid acceleration of drift deposition linked to the eastern component of NADW, known as Iceland–Scotland Overflow Water at 3.6 million years ago (Ma). In contrast, the Denmark Strait Overflow Water feeding the western Eirik Drift has been persistent since the Late Miocene. These observations constrain the long-term evolution of the two NADW components, revealing their contrasting independent histories and allowing their links with climatic events such as Northern Hemisphere cooling at 3.6Ma, to be assessed.
How to cite: Sinnesael, M. and Karatsolis, B. T. and the Expedition 395 Scientists: Onset of strong Iceland-Scotland overflow water 3.6 million years ago, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9577, https://doi.org/10.5194/egusphere-egu26-9577, 2026.
Radiocarbon chronologies for Arctic Ocean sediments remain widely debated due to low sedimentation rates, bioturbation, poorly constrained marine reservoir ages, and the presence of authigenic carbonate that can bias radiocarbon measurements. This debate is particularly critical for sediments overlying a regionally extensive glaciomarine diamict in the central Arctic Ocean, where radiocarbon ages approach the practical dating limit and interpretations range from Marine Isotope Stage (MIS) 3 to MIS 5.
Here we assess the reliability of Arctic radiocarbon chronologies by integrating new and published calcareous nannofossil assemblage data from the North Atlantic, Nordic Seas, and central Arctic Ocean with existing radiocarbon and oxygen isotope constraints. We focus on two key nannofossil bioevents: (i) the transition from assemblages dominated by Gephyrocapsa spp. to dominance by Gephyrocapsa huxleyi, and (ii) the Holocene abundance peak of Coccolithus pelagicus. These assemblage-based events are defined by relative abundance changes rather than first or last occurrences, making them less sensitive to sediment mixing over centimeter scales.
Our results show that the timing and stratigraphic ordering of these bioevents are broadly consistent across sub-Arctic and Arctic sites when evaluated against independent age controls. In particular, the Gephyrocapsa spp.–G. huxleyi transition occurs in sediments younger than MIS 4 in well-dated Nordic Seas records and is consistently observed above the Arctic last diamict interval, supporting a post-MIS 5 age for overlying sediments. While radiocarbon ages in Arctic cores display considerable scatter, likely reflecting mixing and diagenetic effects, the agreement between biostratigraphic markers and radiocarbon-based age estimates in multiple cores indicates that radiocarbon chronologies retain substantial utility when interpreted alongside independent stratigraphic constraints.
This study highlights the value of combining radiocarbon dating with calcareous nannofossil biostratigraphy to improve confidence in Arctic sediment chronologies and provides a refined framework for interpreting late Pleistocene and Holocene paleoceanographic records from the Arctic Ocean.
How to cite: Razmjooei, M. J., Spielhagen, R., Bauch, H., Vermassen, F., Jakobsson, M., and O’Regan, M.: Reassessing Radiocarbon Chronologies in Arctic Ocean Sediments Using Calcareous Nannofossil Bioevents, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7043, https://doi.org/10.5194/egusphere-egu26-7043, 2026.
The Late Jurassic–Early Cretaceous represents a time span characterized by several unstandardized stages and includes the only Mesozoic system boundary still lacking a formal GSSP—the Jurassic/Cretaceous (J/K) boundary. Recent research has concentrated largely on continuous deep-marine Tethyan successions, yielding major advances in the calibration of pelagic bioevents. However, correlating these pelagic zonation schemes with those derived from neritic settings remains challenging.
Biostratigraphic evidence from marginal carbonate successions that contain fossils from both platform and basinal facies offers a critical bridge between these contrasting depositional realms. Such Upper Jurassic–Lower Cretaceous carbonates are extensively exposed in the Pontides, where they occur in association with coeval shallow- and deep-marine deposits. This study synthesizes biostratigraphic data from 17 stratigraphic sections across the Pontides Carbonate Platform (PCP), incorporating fossils representing a range of environments, including benthic and planktonic foraminifera, calpionellids, algae, microencrusters, and crinoids, and documenting 139 bioevent datums.
To address facies-dependent local biohorizons and to integrate datums from unrelated lineages and biofacies, the dataset is analyzed using Graphic Correlation (GC) and Unitary Association (UA) techniques. These methods yield a Composite Standard Reference Section (CSRS) and a set of UA Zones. GC produces facies-independent tie lines and requires only a sufficient number of shared taxa to establish reliable correlations with the CSRS. In contrast, the UA approach relies on complete fossil assemblages to define unique UA Zones, substantially reducing the lateral continuity of its subdivisions. While GC evaluates the superpositional ordering of calibrated bioevents, UA identifies discrete “maximal fossil assemblages” without resolving the internal ordering of their biohorizons, making GC more compatible with contemporary GSSP protocols.
Correlation of the Pontides CSRS with the Geological Time Scale clarifies the relative stratigraphic positions of both shallow- and deep-marine bioevents with respect to the Oxfordian–Hauterivian stage boundaries. The Tithonian/Berriasian (T/B) and Berriasian/Valanginian (B/V) boundaries are currently considered candidates for the J/K boundary and are distinguishable in pelagic sections through characteristic calpionellid bioevents. Equivalent synchronous bioevents in shallow-marine deposits, however, are lacking. The elevated origination rates during the Berriasian produce clusters of bioevents around the T/B boundary, providing stratigraphic brackets for both pelagic and neritic successions. In contrast, several last occurrences in neritic facies offer only weak constraints on the B/V boundary. Declining species richness from the mid-Berriasian onward reflects a broader trend of falling sea level from the Late Tithonian through the Valanginian, which suppressed shallow-marine carbonate production and contributed to widespread platform drowning during the Valanginian–Hauterivian in the northern Tethyan margin. This extinction-dominated interval further complicates identification of reliable origination datums within neritic environments.
How to cite: Atasoy, S. G., Altıner, D., and Özkan-Altıner, S.: Chronostratigraphic calibration of shallow and deep marine bioevents by quantitative biostratigraphy across the last unratified system boundary of the Mesozoic: A synthesis from the Pontides Carbonate Platform, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1210, https://doi.org/10.5194/egusphere-egu26-1210, 2026.
The Early–Middle Jurassic was a pivotal interval in Earth history, encompassing the expansion of calcifying plankton, the diversification of dinosaurs, and major evolutionary turnovers. This period was marked by profound changes in continental and oceanic configurations, the emplacement of large igneous provinces, and major environmental perturbations. These included the collapse of shallow-marine carbonate platforms, first- and second-order mass extinctions, episodes of eutrophication and marine anoxia, and major disruption to the global carbon cycle. Over recent decades, research has focused primarily on the causes and consequences of major Jurassic crises, such as the Triassic–Jurassic boundary, the Pliensbachian–Toarcian transition, the Toarcian Oceanic Anoxic Event and the Bajocian crisis. However, this emphasis has often overshadowed inter-crisis time intervals that shaped the broader background environmental conditions of the Early–Middle Jurassic. Although advances in modelling and geochemical proxy application have improved our understanding of the overall environmental states, atmospheric CO2 levels, and temperature, important gaps and unresolved questions remain. Studies often focus on individual events, thus limiting a comprehensive understanding of the Earth system and its long-term evolution. How far can these events be explored without losing sight of the broader context? Here, we present a new multiproxy, multi-million-year record of environmental, climatic, atmospheric CO2 proxies derived from globally distributed marine sites spanning the Toarcian–Aalenian and Bathonian–Callovian time intervals. This compilation allow us to reconstruct conditions before, during and after the major crises and discuss the triggering mechanisms, and place these events within a broader environemental and climatic framework.
How to cite: Fantasia, A., Jurikova, H., Adatte, T., Spangenberg, J. E., Mattioli, E., Bodin, S., Hesselbo, S. P., Thibault, N., Gavillet, L., Suan, G., and Letulle, T.: Filling gaps in the geological record – Early–Middle Jurassic climate and environmental dynamics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17265, https://doi.org/10.5194/egusphere-egu26-17265, 2026.
The Devonian was marked by numerous ocean anoxic events, many of which are associated with sea-level fluctuations, carbon-cycle perturbations, and faunal turnovers. Yet the mechanisms driving these events and the factors controlling their recurrence remain poorly understood and strongly debated. Growing evidence suggests that astronomical forcing influenced the timing and pacing of Late Devonian anoxic events, most notably through the ~100‑kyr eccentricity (e.g., Kellwasser Crisis) and ~2.4‑Myr grand‑eccentricity (e.g., Annulata, Dasberg, Hangenberg events) Milankovitch cycles. Earlier events, however, remain largely understudied despite their importance in contributing to protracted environmental stress and their resemblance to later, more severe extinction events. We present evidence from the Early to Middle Devonian Oued Ferkla section, which spans the global Daleje, Choteč, Kačák, and pumilio events. New high‑resolution geochemical analyses (XRF) show strong variability in total detrital input and redox-sensitive elements, suggesting distinct shifts in the hydrological cycle and depositional environment. Cyclostratigraphic analysis of the detrital signal reveals strong astronomical control by precession, obliquity, and eccentricity, confirming visual identification of lithological patterns identified on the field. An ~18-Myr floating astrochronology was constructed by tuning to the 405-kyr long eccentricity metronome and placed into global context using δ13Ccarb chemostratigraphy. A conspicuous ~6-Myr cycle was identified that appears to exert primary control on the timing of the anoxic events investigated here. While the Daleje, Choteč, and Kačák event intervals are characterized by stark increases in total detrital input, paced by local ~6‑Myr maxima, the pumilio events occur around a minimum of this long‑period cycle and show only minimal, coarse detrital input. These observations suggest that the recurrence of Early to Middle Devonian anoxic events was paced by a previously unrecognized ~6-Myr astronomical cycle, hinting at the possible role of long-period Milankovitch cycles in shaping Paleozoic climate variability.
How to cite: Huygh, J., Talih, A., Omar, H., Boukhalfa, D., Gérard, J., Sablon, L., Arts, M., El Hassani, A., Crucifix, M., and Da Silva, A.-C.: Astronomical pacing of Early to Middle Devonian anoxic events at multi‑Myr timescales (Oued Ferkla, SE Morocco), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12790, https://doi.org/10.5194/egusphere-egu26-12790, 2026.
The early Cambrian represents a critical interval in Earth’s history, marked by rapid biological innovation and major perturbations in global carbon cycle. However, the timing and relationships among these processes remain poorly constrained due to fossil provincialism, diachronous bioevents, and inadequate high-precision geochronology. The Tiout section (Anti-Atlas, Morocco) provides a unique opportunity to address these challenges, preserving a continuous 1205-m-thick succession with multiple volcanic ash beds, the lowest occurrence (LO) of trilobites, and a refined biostratigraphy in West Gondwana. We integrate high-resolution δ¹³Ccarb stratigraphy, elemental geochemistry, U–Pb geochronology and biostratigrahy within a Bayesian astrochronological age-depth model to provide numerical ages for carbon isotope excursions and biotic events. The new δ¹³Ccarb record from Tiout documents multiple global excursions, including the termination of the Shiyantou Carbon Isotope Excursion (SHICE), the excursions II and III, and the Early Atdabanian/Repinaella Zone Excursion (EAREZE or excursion IV). The EAREZE peaks below the LO of trilobites and is dated at 520.046 ± 0.097 Ma, providing the first direct numerical calibration of this excursion within a single stratigraphic record bracketed by two ash beds. These results establish a robust, multi-proxy framework that synchronizes global carbon cycle records with the onset of trilobite radiation, and positions Tiout as a candidate reference section for the Global Stratotype Section and Point (GSSP) of Cambrian Series 2.
How to cite: Pas, D., Sinnesael, M., Mghazli, K., Jamart, V., Geyer, G., Landing, E., Youbi, N., Ounar, J., Omar, H., Ahmed Boumehdi, M., Huygh, J. J. C., Da Silva, A.-C., and Daley, A.: Integrated stratigraphy and Bayesian age modelling at Tiout (Anti-Atlas, Morocco) constrain early Cambrian δ¹³C excursions and trilobite radiation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5680, https://doi.org/10.5194/egusphere-egu26-5680, 2026.
Posters on site: Tue, 5 May, 08:30–10:15 | Hall X3
A fundamental task in stratigraphy is to understand how observations in the depth-domain translate to geological age. Initial depth-to-age conversions typically rely on stratigraphic control points (tie-points) with numerical ages, either via directly dating volcanic ash-layers or via identifying other geological events, such as magnetic reversals, first/last occurrences of fossils, or isotopic excursions, that have been calibrated to numerical time through correlation with radioisotopic dating or astrochronological methods. How the associated observational and calibration uncertainties are accommodated and propagated in the construction of age-depth models, largely depends on the statistical approaches used. Establishing accurate age-depth models is a multidisciplinary effort upon which many disciplines across the Earth Sciences depend. It is also an evolving science and therefore the critical evaluation of published age models (chronologies) should be a straightforward and routine step for anyone studying Earth’s history. As part of the Time Integrated Matrix for Earth Sciences (TIMES) community initiative, the members of Working Group 9 (Age Model Assessment and Data Processing) aim to review best practices and develop guidelines for standardized, reproducible, and community-driven approaches for constructing and assessing age models. A key need is improving the reproducibility, accuracy, and transparency of comparisons among marine and terrestrial sediment archives, as well as across different biogeographical regions. Important steps towards this goal, in line with the FAIR principles, include:
- Establishing standardized approaches for reporting, propagating, and visualizing age-depth model uncertainty across different stratigraphic datasets, making data, metadata, and methodologies findable and accessible to the broader scientific community.
- Defining clear protocols for consistent storage of original age-depth model data, including uncertainties and associated metadata, so that datasets are interoperable across different platforms and disciplines, and can be reused effectively.
- Providing transparent documentation of workflows for age-depth model construction, to promote critical assessment and reproducibility of published chronologies, and to ensure that workflows are accessible for reuse in future research efforts.
At the meeting, we will present these objectives in detail and extend the invitation to join WG9.
How to cite: Henderiks, J., Tangunan, D. N., Si, W., and Trayler, R. B.: Towards community guidelines for best practices in age model assessment and data processing, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10935, https://doi.org/10.5194/egusphere-egu26-10935, 2026.
The Phanerozoic Eon is characterized by profound biological, climatic, and tectonic changes that are recorded in the stratigraphic record through both fossil successions and physical Earth-system signals. Index fossils play a central role in defining and correlating stratigraphic boundaries, yet their distribution and stratigraphic significance are often presented separately from the broader chronostratigraphic framework. This contribution presents the 2025 Phanerozoic Index Fossil Timescale, a reference chart designed to integrate key biostratigraphic markers with formally defined stage boundaries throughout the Phanerozoic.
The chart compiles approximately 70 globally significant index fossil taxa representing major fossil groups, including trilobites, graptolites, conodonts, ammonoids, planktonic foraminifera, and calcareous nannofossils. These taxa are directly linked to Global Boundary Stratotype Sections and Points (GSSPs) and calibrated using the most recent (2024/12) International Chronostratigraphic Chart. In addition to fossil first and last appearances, the reference chart incorporates complementary stratigraphic criteria such as magnetic polarity reversals, stable isotope excursions, geochemical anomalies, and major climatic transitions.
By combining biological and non-biological stratigraphic markers within a single visual framework, the timescale provides an integrated view of Phanerozoic biostratigraphy and chronostratigraphy. The chart is intended to serve both as a practical research reference for stratigraphic correlation and as an academic teaching tool that illustrates the temporal distribution of index fossils and the evolution of life through deep time. This integrated approach highlights the multidisciplinary foundations of modern stratigraphy and facilitates cross-disciplinary communication within the geosciences.
How to cite: Kaminski, M. A. and Korin, A.: The 2025 Phanerozoic Index Fossil Timescale: An Academic Teaching Tool for Paleontology and Stratigraphy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8978, https://doi.org/10.5194/egusphere-egu26-8978, 2026.
The Lower Cretaceous sediments of the central Lower Saxony Basin (LSB) are primarily composed of thick, CaCO₃-poor mudstones and siltstones. These deposits exhibit a continuous increase in CaCO₃ content during the Albian–Cenomanian interval, culminating in chalky deposits in the upper Cenomanian. The sedimentary system is predominantly controlled by two contrasting processes: carbonate production and the input of fine-grained siliciclastics from the hinterland.
This study presents a 1,500-meter composite stratigraphic record spanning the late Berriasian to the middle Turonian, derived from 14 drill cores. All cores are located in the Hannover area, which served as the depocenter of the LSB during the Early to mid-Cretaceous. In addition to a published long-term carbon isotope stratigraphy (Bornemann et al., 2023), we generated high-resolution CaCO₃ and total organic carbon (TOC) data. Our objective was to evaluate whether the lithostratigraphic units can be clearly differentiated from adjacent units based on these parameters.
As a case study, we revisit the lithostratigraphic subdivision of the Albian – Cenomanian transition using CaCO₃ and TOC, but also X-ray fluorescence core scanning data from the Anderten 1 and 2 cores.
References:
Bornemann, A., Erbacher, J., Blumenberg, M., Voigt, S., 2023. A first high-resolution carbon isotope stratigraphy from the Boreal (NW Germany) for the Berriasian to Coniacian interval—implications for the timing of the Aptian–Albian boundary. Front. Earth Sci. 11, 1173319. https://doi.org/10.3389/feart.2023.1173319
How to cite: Bornemann, A., Blumenberg, M., Kollaske, T., and Erbacher, J.: Deciphering the Cretaceous Lower Saxony Basin: Lithostratigraphic and geochemical insights from a 1,500-m composite record, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10523, https://doi.org/10.5194/egusphere-egu26-10523, 2026.
The Paleocene-Eocene Thermal Maximum (PETM) represents a short (ca.100 - 200 k years) but intense warming episode that resulted in a significant perturbation in the Earth’s climate and carbon cycle 56 million years ago.
The Arabian Platform occupies an important low latitude site for recording this episode, however, there are limited geochemical and sedimentological records of the PETM from this region. High-resolution sampling and integrated approaches are necessary to understand how low latitude, shallow marine deposits respond to abrupt climate change such as the PETM. To address this gap in the records, we integrate sedimentological and stable isotope data with global stratigraphic models to document the depositional and sedimentological changes across the Paleocene-Eocene interval within the Muthaymimah Formation (UAE) and establish the first high-resolution chemostratigraphic record of the PETM from the Arabian Platform
We focus on two chronologically well-constrained stratigraphic sections, the Qarn El Barr outcrop in the central region of Sharjah Emirate and the Mundassah outcrop southeast of Al Ain city, Abu Dhabi Emirate. The Paleocene/Eocene boundary is located between the biozones NP 9a and NP 9b using the Calcareous nannoplankton biozonation scheme.
We examined 49 samples from Qarn El Barr stratigraphic section and 495 samples from the Mundassah stratigraphic section. This data has enabled us to more accurately identify the Paleocene-Eocene transition in the UAE.
We performed stable Carbon (δ13C) and Oxygen (δ18O) isotope analysis on bulk carbonate across both sections. The timing and position of the PETM in both sections was established by preliminary stable isotope analysis of the sediments. Subsequent high-resolution stable isotope analysis confirms this signal, documenting the first record of the PETM in the UAE. Our δ13C stratigraphy reveals a 2.5‰ negative excursion, consistent with the published negative carbon excursions for the PETM in shallow marine environments elsewhere. We further explore temperature changes and faunal turnover within this interval.
Interestingly, field observations do not show any dramatic changes in the sedimentological characteristics: At the Qarn El Barr outcrop the PETM is located near the top of the thin-bedded grey marls, just below the transition to a yellow marly unit, while in Mundassah section, the PETM is located at a thin-bedded wackestone interval above a calciturbidite horizon and thin-bedded mudstone. We integrate our nannoplankton and geochemical records with these sedimentological observations to shed new light on the PETM environments in the UAE.
How to cite: Al Ali, A., Whittaker, A., Price, G., Abdelghany, O., Faris, M., Davies, M., Reynolds, R., and Abu Saima, M.: Tracing Ancient Warmth: Stable Isotope and Sedimentological Insights into the PETM of the Muthaymimah Formation, United Arab Emirates, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21472, https://doi.org/10.5194/egusphere-egu26-21472, 2026.
The Eocene–Oligocene Transition (EOT, aprox. 34.5 Ma) represents a major shift from greenhouse to icehouse conditions, with major effects on ocean circulation, sedimentation and biotic communities. The continuous successions in the Eastern Carpathians (Romania), within the Vrancea Nappe, Paratethys, provide an excellent archive to investigate the interaction between global and regional changes. This study integrates sedimentological observations, calcareous nannofossil biostratigraphy and stable isotope (δ¹³C, δ¹⁸O) data to document environmental changes across the Eocene-Oligocene Transition.
Sedimentological analysis is used to characterise lithofacies, depositional processes and redox conditions, with particular attention to the transition from Upper Eocene turbiditic systems to Lower Oligocene hemipelagic deposits. Calcareous nannofossil biostratigraphy provides a high-resolution age framework and allows the assessment of changes in assemblage composition, diversity and the occurrence of Paratethyan endemic taxa. Geochemical investigations include stable isotope analyses (δ¹³C, δ¹⁸O) and bulk geochemical parameters (e.g., TOC, CaCO₃) to track variations in carbon cycling, water-mass properties and depositional environments.
This study aims to integrate sedimentological, palaeontological and geochemical datasets to create a multi-proxy stratigraphic framework for the EOT in the Eastern Carpathians and it will place regional environmental evolution within the context of global climatic events. The results will contribute to a better understanding of how basin restriction, tectonics and palaeogeography can modify the local response to major climate transitions.
How to cite: Baboș, T. and Melinte-Dobrinescu, M.: A multi-proxy stratigraphic approach to the Eocene-Oligocene Transition in the Paratethyan Realm, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7568, https://doi.org/10.5194/egusphere-egu26-7568, 2026.
Assessments by the Intergovernmental Panel on Climate Change (IPCC) indicate that the Earth is experiencing steady warming and that urgent mitigation measures are required. However, climate model simulations continue to show considerable diversity, and discrepancies remain between observational records and model outputs, highlighting the need for improved model validation. Paleoenvironmental data from multiple geological time slices represent an effective means of testing model performance, yet global reconstructions of sea-surface temperature and salinity have largely been restricted to the CLIMAP project for the Last Glacial Maximum.
The Pliocene epoch (≈2.6–5.3 Ma) has emerged as a crucial warm-period analog for future Earth conditions. Despite atmospheric CO₂ concentrations similar to modern values, global temperatures were 2–3°C higher, accompanied by dynamic ice-sheet behavior and transitions in dominant climate-variability periodicities. Comparative studies of Pliocene paleo–oceanographic data and climate simulations have been advanced by the USGS-led PRISM project, focusing primarily on the 3.0–3.3 Ma interval.
Recent geological evidence from IODP Expeditions 318 (Wilkes Land) and 379 (Amundsen Sea) indicates that earlier Pliocene intervals experienced even warmer conditions. Our preliminary work, based on astronomically tuned, high-resolution chronostratigraphic correlations, further suggests distinct responses of the East and West Antarctic Ice Sheets during this time.
We therefore propose a new Pliocene CLIMAP-style initiative grounded in a highly accurate astronomically tuned timescale, aimed at generating improved global paleoceanographic reconstructions to enhance next-generation climate model validation.
How to cite: Iwai, M., Horikawa, K., Kuwano, D., Haneda, Y., and Matsuzaki, K.: Toward a Plio CLIMAP Project: Enhanced Astronomical Chronologies and Global Paleoceanographic Mapping of the Pliocene, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16648, https://doi.org/10.5194/egusphere-egu26-16648, 2026.
IODP Expeditions 395 and 395C drilled six sites on and adjacent to three major sediment drift bodies—the Gardar, Bjørn, and Erik Drifts—in the North Atlantic Ocean along an east–west transect at ~60°N, south of Iceland (Parnell-Turner et al., 2025). The development of high-resolution age models is essential for robust palaeoenvironmental reconstructions from these sedimentary archives. This study reports progress in constructing astronomically-tuned Pleistocene age models for sedimentary sequences recovered during IODP Expedition 395 east of the Reykjanes Ridge.
As an initial step, magnetic susceptibility records from the newly drilled sites were compared with reference records from ODP Leg 162, with particular emphasis on sites within the Bjørn (ODP Site 984) and Gardar (ODP Site 983) Drifts. Individual glacial–interglacial cycles were identified and correlated across sites, providing a stratigraphic framework for age-model development.
Pleistocene sedimentation rates derived from the new age models for the Bjørn and Gardar Drift records reveal distinct spatial patterns. ODP Site 984 and IODP Site U1554, both located on the Bjørn Drift, exhibit remarkably similar sedimentation rates. In contrast, ODP Site 983 and IODP Site U1564 on the Gardar Drift show substantial divergence. This difference may suggest more spatially homogeneous sedimentation on the Bjørn Drift and greater regional variability on the Gardar Drift, potentially reflecting contrasting ocean current dynamics.
Despite these differences, both drift systems exhibit common large-scale features, including a pronounced decrease in sedimentation rates between ~850-900 ka. Such shared signals possibly reflect basin-wide oceanographic or climatic processes and provide insight into large-scale changes in sediment transport and circulation across the North Atlantic.
Parnell-Turner, R.E., Briais, A., LeVay, L.J., and the Expedition 395 Scientists, 2025. Reykjanes Mantle Convection and Climate. Proceedings of the International Ocean Discovery Program, 395: College Station, TX (International Ocean Discovery Program). https://doi.org/10.14379/iodp.proc.395.2025
How to cite: Weisser, O., Sinnesael, M., Hemming, S., Jasper, C., Karatsolis, B. T., Hochmuth, K., Di Chiara, A., Satolli, S., Parnell‑Turner, R., Briais, A., and LeVay, L. and the Expedition 395 Scientists: Astronomical Tuning of Pleistocene Sediments from North Atlantic Drift Deposits recovered by IODP Expedition 395, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13112, https://doi.org/10.5194/egusphere-egu26-13112, 2026.
Stratigraphic logs are the fundamental interface between geological observation and scientific interpretation. They are a crucial tool which enables scientists to transform field observations of outcrops or boreholes into a graphical representation. Despite their importance, the creation of these logs is a significant bottleneck in geological workflows and lack reproducibility. Manual digitisation of logs can be an extremely time-consuming and tedious process, and often results in highly specialised outputs that are not easily understood between different geoscience communities. The limited range of existing tools for digitisation of stratigraphic logs are typically tailored to specific fields and applications, with many unable to provide core functions such as automatic legend creation, and commonly involve a steep learning curve for the user.
We present stratapy: a new Python package which we have developed to be an accessible tool for rapid, high-quality log digitisation. The package enables scientists across a range of disciplines within the geosciences (e.g., sedimentology, geology and volcanology) to efficiently generate publication-quality stratigraphic logs with basic text- or spreadsheet-based inputs, from three lines of code. The package caters to non-programmers while being highly customisable in both style and function, incorporating standardised lithological patterns and curated geological features and symbols. Easy to change parameters (e.g. grain-size axes, legend configuration) enable more tailored visualisation of logs for a multidisciplinary audience. Furthermore, automatic correlation with the chronostratigraphic column and precise sample location markers, as well as built-in multi-panel visualisation and stratigraphically correlated logs provides enhanced functionality for more complex figures.
With applications in research, industry and education & outreach, stratapy creates a standardised framework for log illustration and digitisation, streamlining scientific workflows, improving the quality of stratigraphic logs, and contributing towards improved uptake of digital practices in the geosciences.
How to cite: Alexander, R., Smith, J., and Antoniou, C.: stratapy: a Novel Tool for Automated Stratigraphic Log Visualisation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18130, https://doi.org/10.5194/egusphere-egu26-18130, 2026.
Earth’s orbit varies due to gravitational interactions within the solar system, leading to cyclical changes in the distribution of incoming solar radiation. This astronomical forcing drives long-term climate variability, which in turn influences sediment production, transport, and accumulation. In the sedimentary record, these processes may be expressed as rhythmic lithological alternations, such as limestone–marl alternations (LMAs), that can potentially be linked to orbital climate cycles. Cyclostratigraphy aims to identify and interpret such cyclic patterns in sedimentary successions to estimate sedimentation rates and reconstruct geological time. However, diagenetic processes can modify, obscure, or even generate cyclic patterns independent of external environmental forcing.
A method to assess the extent of diagenetic alteration is the vector length method (Nohl et al., 2021), which quantifies differences in elemental ratios between lithological couplets. This approach can be transferred to (1) test for diagenetic overprint, and (2) assess variability in accumulation rates or sediment condensation.
IODP Site U1410 is characterised by rhythmic alternations of nannofossil ooze and clay-rich nannofossil ooze, which have previously been interpreted as dilution cycles. However, observed changes in Al/Ti ratios between the two lithologies indicate that the terrigenous input varies not only in amount but also in composition and source, adding further nuance. By comparing the results with common cyclostratigraphic analyses, we aim to assess the reliability of astronomically derived age models and improve estimates of the temporal resolution preserved in the geological record.
How to cite: Aschauer, S., De Vleeschouwer, D., and Nohl, T.: An update for understanding geological time, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5659, https://doi.org/10.5194/egusphere-egu26-5659, 2026.
Posters virtual: Tue, 5 May, 14:00–18:00 | vPoster spot 3
EGU26-10337 | Posters virtual | VPS26
ArtPOP - Automated RecogniTion of Palynomorphs and Organic sedimentary ParticlesTue, 05 May, 14:42–14:45 (CEST) vPoster spot 3
The traditional workflow in palynology begins with the removal of rock minerals through acid digestion and heavy liquid separation, followed by mounting the organic residue on a glass slide, and analysing it under a transmitted light microscope. Using the microscope, palynologists manually identify and assign the observed particles to predefined categories within a designated counting area on each slide. Counting typically continues until a target number of particles has been reached (often between 200 to 300).
Beyond the commonly analysed palynomorphs such as pollen, spores, and dinoflagellate cysts, palynological slides may also contain a diverse range of acid resistant organic sedimentary particles, including freshwater algae, phytoclasts, amorphous organic matter, and many others. Examining the full spectrum of these particles is known as palynofacies analysis. It is one of the most powerful methods for reconstructing depositional environments in sedimentary rocks, as it relies on the distribution and relative abundances of these particles.
However, traditional counting methods for palynological and palynofacies analysis present several limitations. The counting area is rarely defined with precision, making it difficult to reproduce analyses. As a result, if any annotations need to be corrected, the entire counting workflow must be repeated. A particularly challenging aspect is the objective estimation of particles such as amorphous organic matter or phytoclasts, which are always fragmented and do not exist as discrete entities. Moreover, identification accuracy can vary substantially between analysts depending on experience, introducing challenges for reproducibility, comparability, and integration across datasets.
Digitizing palynological slides offers a promising opportunity to reduce subjectivity and personal bias by enabling particle annotation directly on high resolution digital images. This approach also supports iterative analysis, allowing annotations to be updated or refined without repeating the microscopy workflow. Through the ArtPOP project, we aim to develop objective, widely applicable annotation tool that enhance the robustness of paleoenvironmental reconstructions and facilitate integration across diverse palynological datasets. In this presentation, we provide an overview of challenges and advantages associated with digitizing the palynological workflow. We also present our preliminary results of the AI-augmented annotation of selected sedimentary particles.
How to cite: Śliwińska, K. K. and Andrianov, N.: ArtPOP - Automated RecogniTion of Palynomorphs and Organic sedimentary Particles , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10337, https://doi.org/10.5194/egusphere-egu26-10337, 2026.
