Orals: Tue, 29 Apr | Room 2.24
Scientific ocean drilling has a rich history in the United States, beginning with Project Mohole in 1961. In 1966, the National Science Foundation (NSF) funded the establishment of the Deep Sea Drilling Project (DSDP), which, beginning in 1968, carried out coring expeditions aboard the purpose-built drilling vessel Glomar Challenger, managed by the Scripps Institution of Oceanography. The program became international in 1975 when the Federal Republic of Germany, United Kingdom, France, Japan, and the Soviet Union joined DSDP.
DSDP concluded in 1983 and was succeeded by the Ocean Drilling Program (ODP). The workhorse vessel for ODP (1985-2003) and the subsequent Integrated Ocean Drilling Program (IODP-1; 2003-13) and International Ocean Discovery Program (IODP-2; 2013-24) was the JOIDES Resolution (JR), owned by Siem Offshore and leased and managed by Texas A&M University. Expeditions during IODP-1 and IODP-2 were also implemented by the European Consortium for Ocean Research Drilling using a mission specific platform model, and by Japan aboard the riser-equipped drilling vessel Chikyu.
Because of a long-term decline in available funds, the lease agreement for the JR ended in 2024; thus, for the first time in more than 50 years, the U.S. is without a dedicated platform for scientific ocean drilling. In this presentation we describe U.S. plans for a Subseafloor Sampling Program (S3P) to succeed IODP-2. S3P will follow a mission specific platform approach. Proponents will submit drilling proposals directly to NSF, which will employ a semiannual review panel to evaluate them in the context of the internationally developed guiding document, “2050 Science Framework: Exploring Earth by Scientific Ocean Drilling.” In addition, the U.S. community is developing a list of near and intermediate term science priorities through the FOCUS (“Future Ocean Drilling in the U.S.”) workshop effort.
A newly created Scientific Drilling Coordination Office (SODCO) will identify and procure appropriate platforms for projects that are positively reviewed and selected for drilling; it is hoped that up to two expeditions per year can be implemented. SODCO will also assist the U.S. community through planning and training workshops, pre-drilling activities, support for technological innovation, and science communication and outreach. A robust advisory committee structure will ensure that the U.S. subseafloor sampling effort is open, broad-based, community-driven, and motivated by achieving the highest quality science at acceptable risk.
International collaboration in ocean drilling remains a priority for the U.S. For example, NSF is contributing significant funds toward IODP3/NSF Expedition 501 (New England Shelf Hydrogeology) and will support the participation of around a dozen U.S. scientists. Similarly, the U.S. is interested in providing opportunities for non-U.S. scientists aboard S3P expeditions. The exact mechanisms and policies for mutual participation remain to be developed; the U.S. will take a flexible approach that emphasizes transparency, reciprocity, and the interests of potential partners.
How to cite: Brenner, C. and Johnson, K.: After IODP: The Next Phase of U.S. Scientific Ocean Drilling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14232, https://doi.org/10.5194/egusphere-egu25-14232, 2025.
China has been an active participant in scientific ocean drilling programs over the past decades, significantly contributing to advances in marine science, talent development and technological innovation. With the officially conclusion of the International Ocean Discovery Program (IODP) in 2024, China is gearing up for a new phase of ocean exploration. This presentation will comprehensively review China's achievements in ocean drilling and outline its ambitious future plans.
Under the leadership of the Ministry of Science and Technology and the National Natural Science Foundation of China, a new China Multifunctional Platform (CMP) will be established. The CMP will be jointly operated by the Science Center at Tongji University and the Platform Center at the Guangzhou Marine Geological Survey. It will operate with high flexibility, selectively deploying appropriate drilling ships or subsea drilling rigs such as the DV Meng Xiang for deep-water drilling, the "Haiyang Dizhi Shihao" for shallow-water drilling, and the "Hainiu" for shallow target layer drilling, based on specific scientific goals and drilling requirements.
China's ocean drilling strategy is founded on the principles of openness and inclusivity. Proposals for drilling missions will be solicited globally, evaluated by an international panel of experts, and the best projects will be selected for implementation. In keeping with the tradition of scientific ocean drilling programs, all data and samples collected during China-led expeditions will be shared openly, enabling scientists from around the globe to contribute to groundbreaking research. China's commitment to international cooperation extends to maintaining and expanding partnerships with current IODP members, including the United States, Japan, 14 European countries, Canada (ECORD), Australia and New Zealand (ANZIC), India, and others. By broadening the scope of collaboration, China aims to create opportunities for more countries, particularly developing nations, to engage in ocean drilling and contribute to the collective understanding of our oceans.
How to cite: Tuo, S., Wang, W., and Jian, Z.: China's Scientific Ocean Drilling: Past and Future, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14554, https://doi.org/10.5194/egusphere-egu25-14554, 2025.
The International Ocean Drilling Programme (IODP3)
After decades of unified international programmes, from DSDP to the International Ocean Discovery Program that ended on 30 September 2024, post-2024 scientific ocean drilling initiatives will see a transition from a single international programme operated by independent platform providers to independent ocean drilling programmes.
Through a two-year long process of exchange of views and ambitions, ECORD and Japan agreed to build a joint scientific ocean drilling programme: the International Ocean Drilling Programme - IODP3(IODP-cubed).
IODP3 consists of an international scientific collaboration addressing important questions in Earth, Ocean, Environmental and Life sciences described in the ‘2050 Science Framework: Exploring Earth by Scientific Ocean Drilling, based on the study of rock and/or sediment cores, borehole imaging, in-situ observatory data, and related geophysical imaging obtained from the subseafloor.
IODP3 will adopt a transparent, open, flexible, and international modus operandi, programme-wide standard policies and guidelines, sustainable management, and publicly accessible knowledge-based resources.
IODP3 will implement and fund two types of expeditions: offshore expeditions and Scientific Projects using Ocean Drilling ARChives (SPARCs).
Proposals supporting these expeditions will be submitted through a bottom-up process to the IODP3 Science Office by teams of proponents belonging to the international research community. All proposals will be evaluated by the Science Evaluation Panel (SEP) in a fair, open, and transparent manner, in terms of both scientific excellence and completeness and quality of the site characterization data packages. The Safety and Environment Advisory (SEA) Group will provide independent advice regarding potential safety and environmental issues associated with the proposed IODP3 drill sites.
IODP3 offshore expeditions and SPARCs will be scheduled by the MSP Facility Board (MSP-FB), based on their scientific merit and operational constraints within the limits of the available resources.
Offshore expeditions will be implemented by the IODP3 Operators, the ECORD Science Operator (ESO) and/or JAMSTEC-MarE3, following an expanded Mission Specific Platform (MSP) concept by diversifying drilling and coring technologies and applying them to all drilling environments, as determined by scientific priorities, operational efficiency, and better value for money. The duration of IODP3 expeditions will be flexible and be determined by scientific requirements and available funds.
Land-to-Sea Transects (L2S), requiring scientific drilling at both onshore and offshore sites to be implemented jointly with the International Scientific Continental Drilling Program (ICDP) are one of prime objectives for IODP3.
Scientific Projects using Ocean Drilling ARChives (SPARCs) are international and multidisciplinary projects that have objectives originating from or that are based on ocean drilling archives (i.e. cores, samples, and data from current and past scientific ocean drilling programmes) without new drilling or other operations at sea. Each SPARC will have a funded duration of three years and will receive €300,000 for its implementation.
How to cite: Camoin, G. and Eguchi, N.: The International Ocean Drilling Programme (IODP3), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9036, https://doi.org/10.5194/egusphere-egu25-9036, 2025.
The success of 55+ years of scientific ocean drilling through the International Ocean Discovery Program (IODP) and its predecessors has provided the international scientific ocean drilling (ISOD) community with a wealth of legacy material and data. These physical and digital archives are stored in the three IODP core repositories and several programme databases. Greater utilisation of legacy archives is anticipated as ISOD enters its next phase starting in 2025. For instance, advances in dedicated Earth Science software now make it possible to generate digital representations of cores and use these as a primary data source (e.g., through packages like Code for Ocean Drilling Data, or CODD; Wilkens et al., 2017). There is significant scope for integrating these “virtual cores” and data derived from them following the re-analysis of physical “legacy core” stored in IODP’s core repositories. This integration offers one pathway to increase the capacity and utilisation of legacy material in the future.
The 21st Century Drilling Workshops Project aimed to test best practices for the re-analysis and integration of physical and digital IODP/ODP/DSDP legacy material through four global workshops hosted at all three core repositories. These workshops also tested best practices for training early career researchers in hands-on core analysis. Finally, the linked workshops also addressed the scientific objectives of tracing changes in ice-rafted debris (IRD) and biological responses to shifting Antarctic fronts in the Southern Ocean due to Miocene ice volume variability. To achieve this, the four workshops targeted five sites spread across the Indian, Atlantic and Pacific sectors of the Southern Ocean.
The first workshop was hosted as part of J-DESC’s RECORD ReC23-01 at the Kochi Core Centre (KCC, Japan) in August 2023. Two ECORD MagellanPlus 21st Century Drilling Workshops were held at the Bremen Core Repository (BCR, Germany) in April and November 2024. The final USSSP 21st Century Drilling workshop was held in February 2025 at the Gulf Coast Repository (GCR, USA). RECORD ReC23-01 investigated DSDP Site 266 (Indian Ocean Sector), MagellanPlus Workshop 1 and 2 respectively investigated ODP Site 704 and ODP Sites 1090 and 1092 (Atlantic Ocean Sector), while the USSSP Workshop will investigate a Pacific Sector site. The target sites were carefully chosen to address the scientific objectives while ensuring coverage of sites spanning IODP’s entire history. This approach enabled the workshops to identify potential differences in the analytical requirements of legacy material depending on the age of the cores.
Through the four workshops, we have brought together ~80 researchers (early career to experienced) from a wide range of IODP and non-IODP countries. Though linked by common goals, each workshop had its own specific focus and developed a path tailored toward participant needs and site-specific requirements. By conducting the workshops sequentially, we had the opportunity to evaluate our approaches and adapt them as appropriate. Here, we aim to illustrate initial research highlights alongside several case studies highlighting best practice approaches for investigating digital and physical legacy material to provide powerful research and training opportunities for the next generation researchers engaged with ISOD.
How to cite: Drury, A. J., Auer, G., Christensen, B., Kuroda, J., Kubo, Y., De Vleeschouwer, D., Westerhold, T., Röhl, U., Childress, L., and Ikehara, M. and the 21st Century Drilling Workshops Team Members (in alphabetical order): 21st Century Drilling Workshops Project - Building capacity in the digital domain using scientific ocean drilling legacy material, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13173, https://doi.org/10.5194/egusphere-egu25-13173, 2025.
The Fram Strait gateway connecting the North Atlantic and Arctic Oceans is an area of high importance for understanding relationships between ocean currents and ice sheet dynamics during past climate transitions; such information is valuable for informing predictive models of future global change. IODP Expedition 403 was motivated by the necessity of retrieving continuous, high-resolution depositional sequences containing the record of the paleoceanographic characteristics of the warm, northward flowing West Spitsbergen Current (WSC) and the cryosphere evolution of the paleo-Svalbard Barents Sea Ice Sheet (SBSIS). Over 5.3 km of sediment records were recovered by drilling 7 sites located along the (S to N) pathway of the WSC, and at (E to W) proximal to distal settings relative to the paleo-SBSIS terminus. The initial age models based on paleomagnetic reversals and microfossils indicate the recovery of expanded Pleistocene and Pliocene sequences in the paleo-SBSIS proximal zone, and in the more distal setting, with recovery of 600+ m sequences that extend into to the mid-Pliocene and the early Pliocene/late Miocene. Preliminary comparisons between lithologies and well-established lithofacies from shallow piston cores of the western Svalbard margin, suggest that the Exp403 site records can be used to constrain the history of shelf edge glaciation, paleo-meltwater events, iceberg calving events, and warm periods dominated by persistent bottom water flow. Physical properties data support this tentative conclusion and suggest that orbital patterns and marine isotope stages (MIS) can be depicted in the records from all site locations despite the diagenetic overprint that complicates the identification of primary depositional signals and stratigraphy. We report also about the challenges faced during Exp-403, the last expedition of the RV JOIDES Resolution under the historical ODP/IODP international program.
How to cite: Lucchi, R. G., St John, K. K., and Ronge, T. A. and the IODP Exp-403 Science Party: IODP Expedition 403, Eastern Fram Strait Paleo-Archive: challenges and achievements of the last IODP expedition, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-326, https://doi.org/10.5194/egusphere-egu25-326, 2025.
Understanding the history of the northern Greenland Ice Sheet (NGrIS) and its connection to long-term changes in the Arctic is crucial for assessing glacial instability thresholds and the cryosphere's response to greenhouse gas emissions. To fill knowledge gaps in the evolution of the GrIS and its climate role, IODP Expedition 400 collected sedimentary records from Sites U1603–U1608 along the northwest Greenland margin and into Baffin Bay. These sites recover a range of deep ocean-to-shelf depositional settings and lithofacies which form proximal archives of NGrIS evolution through the late Cenozoic era. Across six sites, 2299 meters of core material were recovered, and wireline logging was conducted at four sites. The expedition targeted high-accumulation contourite drifts within, and below, a well-mapped trough mouth fan system. At Site U1607, deep time objectives were achieved with cores extending to 978 meters below the seafloor, capturing Miocene and late Oligocene sediments. This presentation summarizes the initial results in alignment with the key scientific objectives pursued by the expedition scientists: (1) evaluating near-complete NGrIS deglaciations during the Pleistocene and mid-Pleistocene orbital shifts, (2) examining NGrIS expansion timing and links to Pliocene marine heat transport, and (3) studying climate-ecosystem conditions under higher atmospheric CO2 levels over the past 30 million years. The X400 shipboard results, and the ensuing post-cruise research, will enable the assessment of the forcings—oceanic, atmospheric, orbital, and tectonic—affecting the GrIS over various timescales and improve models of glacial inception and interglacial transitions.
How to cite: Knutz, P. C., Jennings, A., and Childress, L. B. and the IODP Expedition 400 Scientists: Unravelling Greenland Ice Sheet and Arctic climate history over the last 30 Million years – Results from IODP Expedition 400, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20836, https://doi.org/10.5194/egusphere-egu25-20836, 2025.
The West Antarctic Ice Sheet (WAIS) is currently experiencing accelerated mass loss. It contains enough ice to raise global sea levels by up to five meters if completely melted. Yet we do not know under which environmental conditions a total collapse will occur.
Here we present an overview of the SWAIS2C (Sensivity of the West Antarctic Ice Sheet to 2 Degrees Celsius of Warming) project. The project aims to unravel past and present factors influencing WAIS dynamics and to reconstruct WAIS response to warmer temperatures, including those exceeding the +2°C target outlined in the Paris Climate Agreement. SWAIS2C (ICDP project 5072) targets two sites, chosen to obtain geological data close to the centre of the WAIS to improve model-based projections of future sea level contributions from Antarctica. The first site is close to the grounding line of the Kamb Ice Stream site (KIS3) and sensitive to ocean forcing of ice shelf and ice sheet collapse. The second site on the Crary Ice Rise (CIR) demarks a pinning point of the ice shelf and offers a complementary view on processes that can (de)stabilise the WAIS. Data obtained at these sites will enable us to answer the overarching question under which climatic conditions we will lose the WAIS.
In the first two field seasons of the SWAIS2C project in 2023/24 and 2024/25, equipment was traversed more than 800 km across the Ross Ice Shelf to the remote KIS3 field site. Hot water drilling was successfully completed in both years and penetrated ~580 m of ice to provide access to the 55 m deep ocean cavity and seafloor beneath. Oceanographic measurements were made beneath the ice shelf, videos of the seafloor and ice shelf were recorded, and a long-term oceanographic mooring was installed. Gravity and hammer coring during both seasons yielded a total of 9.5 m of unconsolidated diamict sediment, including the longest sediment core from the Siple Cost, measuring 1.92 m. All of the cored material was x-rayed in the field. During each drilling season, one or two cores were extruded in a sterile environment and sampled for microbiology, geochemistry, pore water or ancient DNA work.
Deep drilling was attempted in both years using the Antarctic Intermediate Depth Drill (AIDD). In our first season, Glass Reinforced Epoxy (GRE) formed part of our sea riser. It was chosen for its light weight and thermal properties, but deployment proved challenging. In our second season, we replaced the GRE sea riser with HRQ steel pipe. We successfully lowered the sea riser to the sea floor, which marked a major project milestone. After deploying 450 m of NQ drill string inside the riser, we had to call off operations, just a couple of hours short of retrieving our first sediment core. Our next drilling attempt will be at Crary Ice Rise in 2025/26, where we hope to recover 200 m of sediment core, and perform a range of geophysical surveys.
Deep field work in Antarctica is challenging, but the questions we are trying to answer for humanity are worth it.
How to cite: van de Flierdt, T., Levy, R., Dunbar, G., Horgan, H., Kulhanek, D., Patterson, M., and SWAIS2C Science Team, T.: Sensivity of the West Antarctic Ice Sheet to 2° Celsius of Warming. The SWAIS2C project, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7417, https://doi.org/10.5194/egusphere-egu25-7417, 2025.
Located in the heart of the Tibetan Plateau, Nam Co is a closed lake spanning over 2,000 square kilometers and situated at an elevation exceeding 4,700 meters. The sediment thickness within the lake exceeds 700 meters, providing comprehensive insights into the climate and environmental conditions covering several glacial and interglacial cycles. With the support of the International Continental Scientific Drilling Program (ICDP) and China's Second Tibet Integrated Expedition Project (STEP), the Namcore drilling project aims to achieve: (1) Reconstructing the long-term climate change history across multiple glacial-interglacial stages and elucidating its relationship with global atmospheric circulation patterns; (2) Investigating the evolution and resilience of high-altitude terrestrial and lacustrine ecosystems under glacial and interglacial climate conditions; (3) Understanding the metabolic factors influencing lake sediment microbial communities in various glacial-interglacial environments; (4) Providing fundamental observation data on paleomagnetic changes to simulate the paleomagnetic field prior to the Holocene epoch. Depending on a stable and wind-resistant drilling barge manufactured in China, and a skilled drilling team as well as the long-term used drilling equipment provided by ICDP, the field campaign was successfully conducted from June 6 to July 17 of 2024, resulting in the retrieval of a total length of 950 meters of lake core. The deepest depth reached by the drill exceeded 510 meters. Based on seismic survey data, it is anticipated that the age of the lake core surpasses MIS 13 stage (approximately 550,000 yrs BP). Furthermore, the average resolution achieved is as high as 10 yrs cm-1. A combination of multiple dating methods will be employed in order to establish a robust deposition time series. 14C will be utilized for sediments less than 50,000 yrs BP while OSL and post-IR IRSL method will be employed to date back approximately 200,000 yrs BP. For more older deposits, amino acid racemization (AAR), uranium/thorium ratio (U/Th), cosmic ray Beryllium isotope (10Be/9Be), as well as geomagnetic polarity analysis, thermochronology assessment and cyclic stratigraphy will be integrated to obtain reliable chronological sequences of cores. Proxies will be utilized to indicate climate and environmental changes, such as geochemical indicators, pollen, biomarkers, sedaDNA, environmental magnetic indicators, etc. for reconstructing paleo-temperature, precipitation, water level, vegetation, aquatic biodiversity and other changes in the lake basin. The relationship between these changes and atmospheric circulation changes and glacial activities in the lake basins will be also discussed.
How to cite: Zhu, L., Haberzettl, T., Wang, J., Vogel, H., Clarke, L., Henderson, A., Spiess, V., Ju, J., and Adolph, M.-L.: An over 500,000 years lacustrine core in the high-altitude lake Nam Co of the Tibet Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4722, https://doi.org/10.5194/egusphere-egu25-4722, 2025.
The ICDP project DOVE (Drilling Overdeepened Alpine Valleys) Phase-1 investigates a series of drill cores from glacially overdeepened troughs at several locations along the northern front of the Alps. These basins provide an excellent but yet underexplored archive with regard to the age, extent, and nature of past glaciations. Drilling operations started in 2021 when two sites were drilled in the Northern Alpine foreland. In addition, DOVE analyses included four legacy sites providing a combined 1750 m of cored Quaternary sediment and over 40 m of underlying bedrock cores. A unified characterization of the sedimentary infill of these troughs allowed recognition of various orders of glacial sequences, which were defined by depositional pattern (lithology, sedimentology, geotechnics), wire-line logging data (petrophysics) and seismic data (seismic sequence stratigraphy and facies analysis). Several geochronological methods were employed and luminescence dating proved to allow assigning the glacial sequences to respective marine isotope stages (MIS).
This glacial sequence stratigraphy is interpreted in terms of glacial advance and retreat cycles into basins carved by this or by older glaciations. All drilled overdeepened glacial troughs contain more than one glacial advance-retreat leading to a stacked preserved record of past ice advances. Correlation of the glacial sequence stratigraphy across the northern Alpine arch emphasizes that most sediments were deposited during MIS 6, indicating a strong erosional and depositional pulse during the penultimate glaciation with two-to-three ice advances. Some troughs contain older sequences (i.e. MIS 8) indicating that MIS 6 might have reoccupied pre-existing basins formed by older glaciations. Erosion and infilling patterns during MIS 2 clearly contrast that from MIS 6 and older glacial cycles as many troughs remained underfilled since the Last Glaciation Maximum (LGM) and contain still lakes today. Moreover, it is important to note that during the last glacial cycle, a desynchrony of glaciations has been observed across the Alps, i.e. more extensive glaciation during MIS 4 as well as an earlier onset of the last glacial advance in the western Alps. This can be explained by shifts of the polar front over the North Atlantic that caused different regional maxima of precipitation, which triggered spatial offsets in the timing of past glaciations.
Overall, the overarching pattern emerging from DOVE Phase-1 so far is the dominance of MIS 6-dated sedimentary fills of overdeepenings with older sequences only preserved in a few selected sites. MIS 6 played obviously a key role in landscape evolution along the northern margin of the Alps. This consistent pattern is very surprising and poses the question if it also occurs around the entire Alpine arch, or whether it is restricted to the northern Alpine sections that were covered in DOVE Phase-1. Thus, a prolongation within DOVE Phase-2 is currently planned to comprise four sites in overdeepened troughs in the southern and western areas (Slovenia, Italy, France).
How to cite: Anselmetti, F., Bavec, M., Crouzet, C., Fiebig, M., Gabriel, G., Mencin Gale, E., Monegato, G., Novak, A., Preusser, F., Scardia, G., Valla, P., and Scientific Team, D.: ICDP project DOVE: Drilling Overdeepened Alpine Valleys to decipher (a)synchroneities of glaciations around the Alps, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11809, https://doi.org/10.5194/egusphere-egu25-11809, 2025.
IMMAGE is a Land-2-Sea drilling project designed to recover a complete record of Atlantic-Mediterranean exchange from around 8 million years ago, to its current configuration with a gateway through the Gibraltar Strait. The aim of the project is to evaluate the influence of Mediterranean-Atlantic exchange on local, regional and global climate before, during and after the formation of a salt giant – the Messinian Salinity Crisis (MSC). This is being achieved by targeting Miocene offshore sediments on either side of the Gibraltar Strait with IODP Expedition 401 and recovering Miocene successions from the two precursor connections now exposed on land in southern Spain and northern Morocco with ICDP.
Expedition 401 (December 2023-February 2024) drilled three Atlantic sites (U1385, U1609 and U1610) and one in the Alborán Sea (U1611). The Atlantic sites record strong precessional cyclicity in NGR and XRF data. These records have been astronomically tuned and correlated with Mediterranean Late Miocene-Pliocene sequences that include the MSC. Changes in the character of the Atlantic signals correlate with Mediterranean-Atlantic gateway changes associated with progressive restriction of exchange that led to evaporite precipitation in the Mediterranean and the abrupt termination of the MSC with the Zanclean deluge.
The influence of gateway changes in the Alborán Basin are less obvious. The Messinian sequence recovered from the Site U1611 includes 150 m of near continuous subaqueous sediments through the MSC. Initial sedimentological, faunal and geochemical results suggest during the Miocene the basin was mostly highly stratified with anomalous but not extreme salinity even during the MSC. Sediments deposited by bottom currents which are commonly associated with gateway exchange only occur in the Pliocene. This suggests that the Gibraltar Strait only started functioning as the Mediterranean-Atlantic gateway from 5.33 Ma and that during the Messinian the Mediterranean-Atlantic connection must have been elsewhere. Future ICDP drilling of the fossil gateways through Morocco and Spain are required to identify and characterise this enigmatic gateway.
How to cite: Krijgsman, W., Flecker, R., Ducassou, E., Williams, T., and 401 Science Party, E.: New results from IODP Expedition 401 and their implications for the next phase of IMMAGE Land-2-Sea drilling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11595, https://doi.org/10.5194/egusphere-egu25-11595, 2025.
The Permian witnessed some of the most profound climatic, biotic, and tectonic events in Earth’s history. Global orogeny leading to the assembly of Pangea culminated by middle Permian time, and included multiple orogenic belts in the equatorial Central Pangean Mountains, from the Variscan-Hercynian system in the East to the Ancestral Rocky Mountains in the West. Earth’s penultimate global icehouse peaked in early Permian time, transitioning to full greenhouse conditions by late Permian time, constituting the only example of icehouse collapse on a fully vegetated Earth. The Late Paleozoic Ice Age was the longest and most intense glaciation of the Phanerozoic. Reconstructions of atmospheric composition in the Permian record the lowest CO2 and highest O2 levels of the Phanerozoic, with average CO2 levels comparable to the Quaternary, rapidly warming climate. Fundamental shifts occurred in atmospheric circulation: a global megamonsoon developed, and the tropics became anomalously arid with time. Extreme environments are well documented in the form of voluminous dust deposits, acid-saline lakes and groundwaters, extreme continental temperatures and aridity, and major shifts in biodiversity, ultimately culminating in the largest extinction of Earth history at the Permian-Triassic boundary.
The Deep Dust project seeks to elucidate paleoclimatic conditions and forcings through the Permian at temporal scales ranging from millennia to Milankovitch cycles and beyond by acquiring continuous core in continental lowlands known to harbor stratigraphically complete records dominated by loess and lacustrine strata. Our initial site is in the midcontinental U.S.— the Anadarko Basin (Oklahoma), which harbors a complete continental Permian section from western equatorial Pangaea. We will also address the nature and character of the modern and fossil microbial biosphere, the chemistry of saline lake waters and groundwaters, Mars-analog conditions, and exhumation histories of source regions. Importantly, data from Deep Dust will be integrated with Earth-system modelling. This is crucial for putting the (necessarily local) drill core data into the broader global context and for understanding relevant mechanisms and feedbacks of the Permian Earth system.
How to cite: Feulner, G., Soreghan, G. S., Bedle, H., Benison, K., Bourquin, S., Hamamura, N., Hinnov, L., Moscariello, A., Noren, A., Pfeifer, L., Ramezani, J., Spina, A., and Zeeden, C.: Deep Dust – An ICDP Drilling Project to Probe Continental Climate from the Late-Paleozoic Icehouse to the end-Permian Hothouse, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8251, https://doi.org/10.5194/egusphere-egu25-8251, 2025.
Orbital forcing may be preserved as cyclical variation in acoustic impedance in marine sediments due to paleoclimate-related changes in grain size, sorting and lithology. If seismic images of such deposits have the relevant bandwidth, this cyclicity may be imaged as distinct peaks in the power spectra of the seismic traces. In principle this could allow the application of cyclostratigraphic techniques to seismic data. It is still unclear, however, if in practice the statistical power is high enough to reliably discriminate orbital cyclicity from seismic data alone, and how the false detection rate compares to directly sampled data such as outcrop, drill core or borehole logs.
In this study we compare the discriminatory power for cyclostratigraphic analyses between seismic data and an equivalent borehole log. We develop a method for spectral background estimation that accounts for some of the amplitude and frequency filtering effects inherent to seismic data. We forward model the seismic response using 1-D visco-acoustic full-wavefield seismic modelling that includes the contribution of multiples and seismic absorption, which we combine with Monte Carlo ensemble modelling using sedimentary noise models to quantify the discriminatory power of both seismic and borehole significance testing approaches.
We demonstrate this on two examples: i) a simplified model with constant background velocity, sedimentation rate and known seismic source wavelet, and ii) a real-world example based on ODP Site 1084 (Cape Basin, ODP Leg 175). We observe in both cases that the sensitivity and specificity (related to the true and false detection rates) for the seismic case are strongly dependent on the spectral frequency, compared to the largely frequency-independent results for the borehole cyclostratigraphy. For the ODP Site 1084 example we observe a seismic spectral peak corresponding to 95 kyr eccentricity with an uncalibrated confidence level of >95%. Our Monte Carlo ensemble modelling, however, shows that the false positive rate at this frequency and confidence level is around 25%, compared to around 5% for the equivalent borehole cyclostratigraphy. We also demonstrate eccentricity modulation and bundling analysis (TimeOpt) applied to the seismic data, which can successfully invert for the sedimentation rate for the simplified seismic synthetic example.
Our results suggest that reliably identifying Milanković cyclicity from seismic data is possible but is strongly dependent on the sedimentation rate, the geophysical properties of the subsurface and the spectral frequency in question. Where the age model is known (i.e., from a co-located borehole) and an orbital signal is well-preserved in the acoustic impedance, for typical airgun seismic bandwidths, sedimentation rates around 20 cm ka-1 and seismic velocities around 1600 ms-1 it should be generally possible to identify eccentricity and obliquity cyclicity in seismic data. This opens the door to widespread use of seismic cyclostratigraphy to identify the preservation of cyclicity directly from seismic data, to extrapolate astronomically-tuned age models away from (and below) boreholes and to screen for the preservation of cyclicity prior to drilling. Similar principles could be applied to other methods such as sub-bottom profilers to identify, for example, higher frequency precessional cyclicity.
How to cite: Ford, J., Camerlenghi, A., Rebesco, M., Uenzelmann-Neben, G., and Weigelt, E.: Seismic cyclostratigraphy: hypothesis testing for orbital cyclicity at ODP Site 1084 using seismic reflection data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6556, https://doi.org/10.5194/egusphere-egu25-6556, 2025.
The early Paleogene represents a greenhouse Earth experiencing large-scale global environmental changes after the Cretaceous-Paleogene extinction. Understanding climate and ocean dynamics during this recovery phase is challenging due to the scarcity of continuous, carbonate-rich sedimentary records. The Paleocene interval of International Ocean Discovery Program−International Continental Scientific Drilling Program (IODP-ICDP) Site M0077 from within the Chicxulub crater provides such an archive. Sequence and cyclostratigraphic analyses reveal condensed and rhythmic bedding, transitioning between marl or argillaceous wackestone and foraminiferal packstones. These 5−33-cm-thick cycles document low-amplitude sea-level changes or local environmental shifts in the Chicxulub basin associated with sea level. The cycles exhibit retrogradational, progradational, or aggradational facies stacking patterns, indicative of transgressive, highstand, and shelf margin systems tracts. Progradational packages align with global sea-level events, suggesting a eustatic driver. Cyclostratigraphy on the sediments’ color reflectance reveals 10 cm and 20 cm periodicities, interpreted as 41 k.y. obliquity and 100 k.y. eccentricity signatures. These climate-driven cycles resemble Paleogene hyperthermals, intensifying the hydrologic cycle and erosion of fine-grained siliciclastic sediments in the Chicxulub hinterland. Thereby, hyperthermals correspond to marl or argillaceous wackestone facies. Moreover, sequence boundaries tend to correspond to minima in the 1.2 m.y. obliquity modulation cycle. This longer-term astronomical control on sea level and climate offers insights into potential drivers of eustatic sea-level change in the Paleocene greenhouse world. The phase relationship between sea level and the 1.2 m.y. obliquity cycle indicates increased water storage in continental reservoirs during periods of astronomically suppressed seasonality (i.e., 1.2 m.y. obliquity minima). Thus, the carbonate sedimentological study of the Paleocene Chicxulub sequences provides unique insights into both local and global environmental dynamics.
How to cite: De Vleeschouwer, D., O’Malley, K., Lowery, C. M., Gulick, S. P. S., and Whalen, M. T.: Sequence and cyclostratigraphic analysis of Paleocene carbonate sediments in the Chicxulub impact crater: Implications for sea level change and climate dynamics, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7975, https://doi.org/10.5194/egusphere-egu25-7975, 2025.
To advance the next generation of astronomical solutions, there is a need to establish constraints on the Earth-Moon distance and the related precession and obliquity parameters throughout Earth's history. These constraints can be derived by extracting precise precession and/or obliquity signals from geological records. The recently drilled ICDP BASE cores from the Moodies Group in the Barberton Greenstone Belt (South Africa) provide a unique opportunity to determine an Earth-Moon distance datapoint at 3.2 Ga using cyclostratigraphy. In this study, we present initial cyclostratigraphic results from BASE Site 5A, which represents a relatively deeper and quieter depositional environment with finer-grained sediments compared to other ICDP BASE drill sites. To detect a potential Milanković signal, we performed time-series analyses on a suite of elemental proxies obtained via XRF core scanning, tracing temporal changes in redox conditions and siliciclastic input.
BASE Site 5A reveals superimposed cycles of 4–6 meters and 30–50 meters, visible in both redox-sensitive elements and siliciclastic elemental proxies. However, interpreting this sedimentary cyclicity is challenging due to the absence of radio-isotopic age constraints at this site. Existing U-Pb ages from the Barberton Supergroup suggest extremely high sedimentation rates of approximately 25 to 1000 cm/kyr for the Moodies Group as a whole (Heubeck et al., 2013). Given that Site 5A was selected for its finer-grained sediments, its sedimentation rates may be on the lower end of this range. Additionally, variations in lithology, ranging from sandstones of varying grain sizes to jaspilites and siltstones, complicate sedimentation rate estimates and duration calculations for this interval. Nevertheless, preliminary evolutive time-series analyses (evolutive harmonic analysis, evolutive TimeOpt and eASM) suggest no significant sedimentation rate changes, except near the stratigraphic top of the record. Sedimentation rates estimated by these evolutive analyses range from 35 to 55 cm/kyr, corresponding to a total duration of 820–1300 kyr for the 450-meter-long Site 5A core. Based on these derived sedimentation rates, the 4–6-meter cycles could potentially correspond to precession, while the 30–50-meter cycles may reflect short ~100-kyr eccentricity cycles. However, we emphasize that these interpretations are preliminary and remain inconclusive. At this stage, these results provide only an indication of potential astronomical Milanković forcing, which will require thorough scrutiny against additional sedimentological and statistical analyses before an inference on Earth-Moon distance can be made.
Heubeck, C., Engelhardt, J., Byerly, G. R., Zeh, A., Sell, B., Luber, T., and Lowe, D. R.: Timing of deposition and deformation of the Moodies Group (Barberton Greenstone Belt, South Africa): Very-high-resolution of Archaean surface processes, Precambrian Research, 231, 236–262, https://doi.org/10.1016/j.precamres.2013.03.021, 2013.
How to cite: Wichern, N., Schreiber, D., Gugliotta, M., Heubeck, C., and De Vleeschouwer, D.: Decrypting Milanković-driven sedimentary rhythms in nearshore strata of the Archean Moodies Group, South Africa, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9111, https://doi.org/10.5194/egusphere-egu25-9111, 2025.
After the climatic and environmental context of hominin evolution in East Africa centred the spotlight for decades, West Africa gains increasing interest considering a pan-African early human history. However, long and continuous continental climate records from this area illuminating regional hydroclimatic impacts and differences across Africa are missing. This is a major shortcoming as fundamental offsets in W-E hydroclimates are expectable that may have influenced human dispersal. Here we present the million-year-old hydroclimate record from Lake Bosumtwi in tropical West Africa, suggesting that this area has been strongly impacted by hemispheric system interactions (N-S-Atlantic, 100 ka cycles) and local insolation including half-precession. Comparing our findings with records from tropical East Africa governed by an Indian Ocean signal (20 ka, 400 ka cycles), we can confirm strongly contrasting hydroclimatic trends. To understand the meaning of these, we compare hydroclimatic signals from Lake Bosumtwi and Chew Bahir (tropical East Africa) providing us with important relative (moister-dryer) information with climate model output data delivering mean annual precipitation (MAP) estimates. This reveals striking similarities between the considered geoscientific data and climate models raising confidence that the MAP estimates can be reliably used to infer supported biomes. Whilst modelled MAP at Lake Bosumtwi varies between 1050 mm (wet savannah) and 1550 mm (rainforest), Chew Bahir may have been characterised by thorn to dry savannah conditions (550-750 mm/a). In this context, cross-Africa climate modelling suggests that large W-E savannah corridors supporting migration of large mammals and humans spread during periods, when the differences between MAP at both end-members have been low. In contrast, these corridors are interrupted by conditions supporting rainforests, when δMAP is high. These phases coincide with major steps in the evolution of the mega-fauna and hominins providing us with a basis for discussing new perspectives on climate and human co-evolution scenarios.
How to cite: Vinnepand, M., Kaboth-Bahr, S., Gosling, W., Noren, A., Paknia, M., Wonik, T., Martinez, M., Pierdominici, S., Kück, J., Ulfers, A., Danour, S., Afrifa, K., and Zeeden, C.: A million years of contrasting climate system influences shaped potential hominin habitats across Africa – Novel perspectives from Lake Bosumtwi (Ghana, West Africa), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17257, https://doi.org/10.5194/egusphere-egu25-17257, 2025.
The exploration well GeoLaB-1 will be drilled in February 2025 into the Tromm pluton in the Odenwald (SW Germany) with a maximum depth of 500 m. An only 20-30 cm thin veneer of Quaternary sediments is expected on top of a few m of weathered granite, followed by massive granites and quartz-monzonites until final depth. The drilling plan involves full coring and a comprehensive logging program of the Tromm pluton. Drilling is accompanied by 2D-seismic, gravimetric, geoelectric, and magnetic surveys. The cores will provide basic information about the compositional heterogeneities of the Tromm pluton, particularly their mineralogy, fracture network, hydrothermal alteration, and their microbiology with depth. The focus of the investigations will be on petrography and mineralogy, petrophysical properties, quantitative analysis of fracture networks, the native upper crustal microbiome, hydrochemistry, hydrotesting, and geomechanical modelling. Borehole completion includes implementation of glass fiber optic cables and geophones for later monitoring.
The results will influence the site selection and design for the construction of the GeoLaB research underground infrastructure. Furthermore, it will allow the evaluation of potential future impacts from tunnel construction and laboratory operation.
How to cite: Deon, F., Grimmer, J. C., Mitzscherling, J., Kamrani-mehni, S., Giese, R., Bauer, F., Garipi, X., Seib, L., Dashti, A., Schmidt, N. L., Bahrami Dashtaki, N., Lüth, S., Sass, I., Kohl, T., Rudolph, B., and Kolditz, O.: The GeoLaB-1 well, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15640, https://doi.org/10.5194/egusphere-egu25-15640, 2025.
We report the first results of the International Ocean Discovery Program Expedition 402 in the Tyrrhenian Sea (February 9 to April 8, 2024). Almost 40 years have passed since the discovery of exposed mantle west of Iberia by ODP but key questions remain unanswered, such as the nature of the mantle, whether it is subcontinental or formed by ultraslow seafloor spreading, or how models can explain the apparent lack of melting. Since then, the mantle has only been probed at mid-ocean ridges, because obtaining samples and data from drilling in magma-poor COTs is a major challenge, as the exposed mantle is typically buried under kilometers of sediment.
The Tyrrhenian Basin is the youngest of the western Mediterranean, formed from the Middle Miocene to recent times by continental extension associated with the ESE-SE rollback of the subducting slab and with the migrating Apennine subduction system. The Tyrrhenian is an outstanding location to test COT formation models by drilling because of its thin sedimentary cover, the presence within a few tens of kilometers of the conjugate pair of COT margins, and the availability of high-quality geophysical data suggesting the presence of serpentinized mantle rocks in its center. A surprising key feature of the basin is the lack of seafloor spreading after mantle exhumation, which allows for the first time a close look into the early stages of the exhumation process.
The main objective of the IODP Exp. 402 was to determine the nature of the geological basement in the central part of the Tyrrhenian Basin and in the conjugate margins to the west and east. The objectives included the kinematics of the opening, the deformation mechanisms of the crust and mantle, and the relationship of the melted products to the exhumed mantle.
The samples and data collected during Exp.402 provide an extensive new data set to determine mantle heterogeneity, the nature and history of melt production and impregnation, and the extent and evolution of serpentinization and carbonate formation; to constrain the geometry and timing of deformation that led to mantle exhumation; to study fluid-rock interactions between seawater, sediment, and the serpentinizing mantle; and to constrain geodynamic models of rifting and COT formation.
How to cite: Zitellini, N. and the Exp. 402 Science Party: Tyrrhenian magmatism and mantle exhumation: first results from IODP Exp. 402, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12058, https://doi.org/10.5194/egusphere-egu25-12058, 2025.
We report initial results from the first phase of the ICDP-funded ‘Drilling the Ivrea-Verbano zonE‘ (DIVE) project in Val d’Ossola (northern Italy). Characterized by pronounced geophysical anomalies, the exposed Ivrea-Verbano Zone offers unique opportunities to test geophysical and petrologic models about the lower continental crust (LCC) and its transition to the upper mantle. From October 2022 to April 2024 two boreholes of respectively 578.5 and 909.5 m depth were drilled using continuous diamond double tube wireline coring. Core recovery was ~100% for both boreholes. During and after drilling, geophysical logs were acquired, providing natural and spectral gamma ray, magnetic susceptibility, electrical resistivity (SPR and DLL), spontaneous potential, sonic, acoustic and optic televiewer data. Retrieved rock cores were described and classified by the DIVE drilling project science team and later shipped to the BGR Rock Core Repository in Spandau-Berlin, where core density and magnetic susceptibility were measured with a multi-sensor core logger followed by XRF scans.
Here we summarize core descriptions, initial geochemical results, geophysical logging data, drill hole fluid chemistry and gas compositions, and preliminary microbiological investigations. The two boreholes sampled two fundamentally different compositions of the lower continental crust: one (5071_1_B) mostly consists of metasedimentary rocks and a few amphibolites, and the second hole (5071_1_A) mostly captures a variety of gabbroic rocks with intercalations of granulite facies metasediments, pyroxenite, and intrusive gabbronorite. This is in agreement with the expected structural positions but allow to study the continental lower crust across numerous spatial scales.
In borehole 5071_1_A, several zones of ultramylonites, cataclasites, fault gauges and pseudotachylites were recovered documenting important episodes of semi-brittle behaviour of the LCC after assembly in the Lower Permian. Along the entire drillholes fractures and open cracks were observed and sampled, some of them filled with precipitates of quartz, carbonates, sulfides, graphite, and oxides.
Continuous monitoring of borehole fluids and gases provide evidence of varying gas mixtures including H2, CH4, and CO2, indicating diverse fluid sources and microbial activities in the deep crust. At the current stage, we are evaluating the biotic and abiotic contributions. Some of these open fractures are potentially promising hosts for microbial communities and are currently under investigation. Additional samples for microbiological studies were taken every 20 m from the drillcores and are currently cultivated for further investigations and also analyzed for bulk rock major and trace elements.
The two drillholes of DIVE provide unprecedented details of the variability of lower continental crust. Metasedimentary sections of the drilled LCC are important reservoirs for volatile and radiogenic heat producing elements, while dominantly mafic sections of the lower continental crust are depleted in these elements. Measured seismic velocities and densities are affected by numerous fractures but metasedimentary rocks are uniformly lower in density (2.5-2.8 g/cm3) compared to the mafic section (2.8-3.4 g/cm3) indicating that the lowermost part of the drilled section enters the continental crust–mantle transition zone.
How to cite: Müntener, O., György, H., Andrew, G., Luca, Z., Alberto, Z., Mattia, P., Donato, G., and Marco, V. and the DIVE Drilling Project Science team: From the lower crust towards the crust–mantle transition zone: Initial results from the ICDP DIVE project, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16604, https://doi.org/10.5194/egusphere-egu25-16604, 2025.
The Nankai Trough subduction zone, located off the southern coast of southwestern Japan, has a well-documented history of large Mw > 8 earthquakes and significant tsunamis (e.g., Ando, 1975; Garrett et al., 2016). This region has been the focus of extensive research, including numerous scientific ocean drilling expeditions conducted through the Deep Sea Drilling Project (DSDP), the Ocean Drilling Program (ODP), the Integrated Ocean Drilling Program (IODP), and the International Ocean Discovery Program (IODP).
In this study, we compile all available friction data and shipboard routine X-ray diffraction (XRD) analyses from across the Nankai Trough. Our findings reveal that while individual friction studies show systematic variations related to mineralogy (e.g., Ikari et al., 2018), temperature (e.g., den Hartog et al., 2012), and pore-fluid pressure (e.g., Bedford et al., 2021), only the correlation between friction and clay mineral content is consistently observed across the entire dataset. Specifically, the friction coefficient measured over velocity scales from nanometers per second to millimeters per second generally remains below 0.6, which is lower than the typical ‘Byerlee’ friction value of 0.85 under normal stress conditions below 200 MPa (Byerlee, 1978), and exhibits an inverse correlation with clay mineral content. The rate-and-state friction parameter (a-b) varies significantly between -0.01 and 0.02, showing no clear relationship with clay mineral content. This lack of correlation is likely due to the diverse experimental conditions across different studies. However, it is notable that velocity-weakening behavior becomes less frequent at the higher end of this velocity scale (>10 μm/s), which may help explain the widespread occurrence of slow slip events in the Nankai Trough. In contrast, samples tested at higher velocity scales (centimeters per second to meters per second) display pronounced frictional weakening, with the friction coefficient dropping to very low values (~0.1) once slip velocities exceed 0.1 m/s.
The wide variation in experimental friction data reflects the complex and heterogeneous frictional properties of the Nankai Trough and aligns with the diverse seismic behaviors observed in the region. The dataset compiled in this study serves as a robust basis for constraining the frictional characteristics of the shallow portion of the Nankai Trough subduction zone.
How to cite: Zhang, J., Faulkner, D., Okuda, H., Bedford, J., Ikari, M., Schleicher, A., and Hirose, T.: Synthesis of the laboratory frictional properties of a major shallow subduction zone: the Nankai Trough, offshore SW Japan, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13865, https://doi.org/10.5194/egusphere-egu25-13865, 2025.
IODP Expedition 405 “Tracking Tsunamigenic Slip Across the Japan Trench” (JTRACK) was a challenging but successful 4-month expedition (September 6 to December 24, 2024 – 56 scientists) that revisited and drilled the large co-seismic slip region of the 2011 Mw 9.0 Tohoku-oki earthquake, 12 years after IODP Expedition 343 “JFAST” had done so. One of the expedition’s primary objectives is to evaluate temporal variations in stress state, fluid flow, and physical properties in the thirteen years since the Tohoku-oki earthquake. This will allow an assessment of how faults heal and reload after a major earthquake, and the role of fluids in such processes. The second objective is to investigate the compositional, structural, mechanical, hydrological, and frictional properties of the rocks in and around the shallow plate boundary, to assess the role of each of those components on the plate boundary location and slip behavior, and to understand the long-term evolution of this prism. Two sites were successfully drilled. At Site C0019, located ~8km landward of the trench axis, drilling intersected the frontal prism, décollement, and subducted plate at the JFAST location. Drilling at Site C0026 intersected the sediment sequence and underlying oceanic crust of the incoming Pacific Plate, thus serving as a reference site. Operations consisted of: 1) collecting logging while drilling (LWD) data at C0019 and C0026 from the seafloor to oceanic crust; 2) coring at C0019 through the entire frontal prism, décollement, and oceanic crust, and at C0026 through the incoming sediment sequence; 3) installing temperature sensors in two borehole observatories to characterize fault zone hydrogeology by re-instrumenting the existing observatory in borehole C0019D (JFAST observatory) and the developing and instrumenting a new observatory borehole C0019P (JTRACK observatory). Overall, Expedition 405 was a huge operational success. Under 7 km of water, it successfully recovered cores from multiple shallow hydraulic piston coring system (HPCS) holes at each site, as well as three deep small-diameter rotary core barrel (SD-RCB) holes at Site C0019 to ~950 mbsf and one SD-RBD hole at Site C0026 to ~300 mbsf. Together, the boreholes provide continuous records of the subsurface from the seafloor to the deep sedimentary rocks and mafic volcanic rocks of the oceanic crust, documenting the Pacific oceanic plate as never before. The plate boundary fault zone was drilled and sampled in multiple holes, providing a unique dataset from an active fault zone that constrains its lateral heterogeneity. Measurements and observations made provide key data to evaluate the controls on shallow tsunamigenic slip and the temporal variations in stress and physical properties and conditions that occur following a great subduction zone earthquake. Overall, the range of data gathered during the expedition is vast, encompassing sedimentary and volcanic processes, paleoseismology, paleoclimate and paleo-oceanography, earthquake mechanics, and tectonic processes at convergent margins.
How to cite: Conin, M., Kodaira, S., Fulton, P., Kirkpatrick, J., Regalla, C., Ujiie, K., Okutsu, N., Maeda, L., Toczko, S., and Eguchi, N. and the IODP Expedition 405 Scientists: Preliminary assessment of IODP Expedition 405 JTRACK in the Japan trench: investigating slip and tracking fault healing after a Mw9 earthquake, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16584, https://doi.org/10.5194/egusphere-egu25-16584, 2025.
Posters on site: Tue, 29 Apr, 14:00–15:45 | Hall X3
Based on site-survey work during research expedition M183 (2022), the sea floor drill rig MARUM-MeBo70 was deployed in summer 2023 on the research vessel MARIA S. MERIAN (MSM119) in order to install observatories for the investigation of hydrothermal circulation in young oceanic crust. In-situ heat flow and fluid chemistry had inferred crustal fluid circulation along the ridge flank. The expedition went to the southernmost tip of Reykjanes Ridge – a part of the Mid-Atlantic Ridge. We were able to set two pairs of observatories in 1500 and 1700 m water depth, respectively. At each site two holes with 103 mm diameter were drilled through a 5 to 30 m sediment cover and an additional 5 to 13 m into the underlying ocean crust. The drill string was lifted by one drill pipe before a last prepared rod – the observatory rod - was screwed onto the drill string. The observatory rod sealed the drill pipe from sea water and was equipped with temperature sensors. One type – the injection observatory – also contained a system for releasing a tracer to the base of the borehole where it has contact to the fluid circulation system within the upper ocean crust. The second type – the monitoring observatory – was installed in a distance of a few tens of meters and contained an additional osmo-sampler for sampling the fluids from the upper crustal aquifer the base of the bore hole. The osmo-samplers will be recovered during an upcoming expedition in September 2025 (research expedition M213). This experiment will help to better understand the relevance of hydrothermal circulation in the flanks of ocean ridges for the exchange of elements and heat between the ocean crust and the oceans.
How to cite: Freudenthal, T., Achim, K., Markus, B., and Matthias, Z.: Installation of Borehole Observatories at Reykjanes Ridge with the sea floor drill rig MARUM-MeBo70, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8141, https://doi.org/10.5194/egusphere-egu25-8141, 2025.
With the conclusion of the International Ocean Discovery Program (IODP), the laboratories and instruments of the JOIDES Resolution (JR) are now operational in the newly renovated laboratory space of the Gulf Coast Repository (GCR) at Texas A&M University. The facility is available to academic researchers (U.S. and abroad), as well as commercial customers. This includes individual researchers, small and large research teams, and legacy projects such as Scientific Projects using Ocean Drilling ARChives (SPARCS). The instrumented facility can be used to make new measurements on the over 150 km of core housed at the GCR. Additionally, the facility can process new cores acquired by future scientific ocean drilling coring projects conducted from mission-specific platforms, on cores collected from other coring projects, and on discrete geologic samples. The instrumented GCR maintains an almost identical suite of analytical capabilities as those that were available on the JR. This includes multi-sensor loggers for measuring P-wave velocity, magnetic susceptibility, density, natural gamma ray counts, and color reflectance. Imaging and X-radiography loggers, a superconducting rock magnetometer, microscopes and SEM-EDS, as well as ICP-OES, CHNS, and XRD analysis are also available. The previous GCR instrumentation, including two XRF core scanners and a new hyperspectral scanner remain available. Other peripheral devices, such as a core splitter, allow for the processing of new cores. Workshops, educational and training exercises can also be held at the GCR. To provide long-term viability and equitable access to instrumentation, a user-fee model will support maintenance and repair of instruments and replacement of consumables. Combined with experienced technical and science staff, the instrumented GCR will facilitate new scientific ocean drilling research, training, and outreach opportunities in the onshore environment.
How to cite: Childress, L., Penkrot, M., Crowder, L., and Malone, M.: The Gulf Coast Repository: Instrumented Facility for Analysis of Scientific Ocean Drilling Cores, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10354, https://doi.org/10.5194/egusphere-egu25-10354, 2025.
Since 2004, the U.S. office of the International Ocean Discovery Program (IODP) has utilized the JOIDES Resolution (JR) and its related facilities and scientists to reach out to educators and the general public in efforts to raise awareness and knowledge about the interdisciplinary fields of the program, including climate and ecosystem evolution, palaeoceanography, the deep biosphere, sustainable georesources, deep crustal and tectonic processes, geodynamics and geohazards. Over these past few decades, IODP has strived to not just push the bounds of scientific knowledge, but also make these findings accessible to the public. Towards these goals, the program has hosted the School of Rock (SOR) professional development program – focusing on the training and education of educators – as well as Onboard Outreach Officers (professional education and outreach personnel embedded into expedition science parties). Together, these two programs have generated a vast library of resources – developed through partnerships with shipboard educators and scientists – available to educators worldwide. Topics addressed range from seafloor spreading and plate tectonics, to microbiology and climate change. The materials are easy to filter (e.g. by grade level) to meet the needs of learners in varied settings.
The JR’s Onboard Outreach (OOO) program has also served as a pivotal bridge between the scientific endeavors of the JOIDES Resolution and the public. This program evolved significantly over the past 15 years, leveraging both advancements in technology and changing needs and attitudes towards public outreach. Through the efforts of Outreach Officers, the importance of deep sea ocean drilling has been disseminated to the general public on a global scale.
School of Rock has also served as a fruitful generative vehicle for new ideas, including a community-driven, travelling informal exhibit program, and mechanisms for developing long-lasting relationships between K12 educators and university faculty. Beyond its legacy of a significant body of educational resources, SOR has also impacted how professional development is done by serving as a template for teacher/researcher collaboration and exchange of knowledge — spawning and inspiring new programs such as STEMSEAS and JR Academy (for undergraduate students). In this presentation, we will share highlights of this legacy, plans for the future of scientific ocean drilling education and outreach in a post-JR world, and new efforts to shape the next generation of geoscientists.
How to cite: Cooper, S., White, L., and Thesenga, D.: IODP Education and Outreach: An Enduring Legacy from Two Decades of IODP programming and opportunities in the U.S. and beyond, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14962, https://doi.org/10.5194/egusphere-egu25-14962, 2025.
The oceanic lithosphere cools as it spreads away from the mid-ocean ridges, and subducts into the mantle at the subduction zones. In the context of Earth’s material cycle, quantitative chemical and thermal state of the oceanic lithosphere is desired to be estimated to elucidate material flux into the mantle. As a step toward reconstructing the chemical and thermal state of oceanic lithosphere, we present geochemical data set of mantle xenoliths from petti-spots in the northwestern Pacific, where no seismic anomaly is imaged. The petit-spot-borne mantle xenoliths provide us unique chemical and thermal information avoiding modifications derived from the mantle plumes.
The petit-spot mantle xenoliths include lherzolites, harzburgites, and dunites collected at petit-spot Sites A and B in the northwestern Pacific, using deep-submergence vehicle Shinkai 6500 during four expeditions of YK05-06, YK20-14S, YK21-07S, and YK24-10S. They are small in size ranging from 1 to 5 cm in diameter, except for a lherzolite with 15 cm-long diameter. The peridotites show variation in terms of the presence of spinel and garnet, and degree of melt depletion. Some of the peridotites include fine-grained mineral aggregates, which are broken-down products after pyrope-rich garnets considering their average bulk chemical compositions. Rare-earth elements (REE) of clinopyroxene are evaluated with a one-dimensional, steady-state, decompressional melting model. The results indicate that fractional melting in the garnet-stable region is required before conventional fractional melting in the spinel-stable region. Geothermobarometric pressure-temperature estimation results indicate that the peridotite xenoliths were derived from ~2.5 GPa where asthenosphere/lithosphere boundary is expected based on the geophysical investigations.
Abyssal peridotites recovered from the mid-ocean ridges are known to undergo melting from the garnet-stable region to the spinel-stable region. Thus, depleted spinel dunite/harzburgite layer is expected to be perched atop fertile spinel/garnet harzburgite-lherzolite layers as a melting column in the mid-ocean ridge. Since the petit-spot peridotite xenoliths cover a long range of the oceanic stratigraphy deep down to the lithosphere/asthenosphere boundary, we present more detailed chemical and thermal state of the whole oceanic lithosphere in the presentation. In addition, we attempt to present a perspective vision for future petit-spot drilling.
How to cite: Akizawa, N., Ishikawa, A., Niwa, Y., Alard, O., Greau, Y., Hirano, N., and Machida, S. and the YK20-14S/YK21-07S/YK24-10S scientific teams: Chemical and thermal state of oceanic lithosphere reconstructed by petit-spot mantle xenoliths from the northwestern Pacific, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10999, https://doi.org/10.5194/egusphere-egu25-10999, 2025.
The consolidation state of sediments provides crucial information about the pore pressure in sediments, as well as the loading and unloading history of sedimentary basins. We performed consolidation tests on mudstones and calcareous oozes just below the thick volcaniclastics in the Hellenic Arc Volcanic Field, Greece. These sediments were sampled from the International Ocean Discovery Program (IODP) Expedition 398 in the Christiana, Santorini, and Kolumbo (CSK) volcanic field.
To understand the in-situ stress and pore pressure, we compared the preconsolidation stress (pc) from the consolidation test with the in-situ effective overburden stress (σ’v) calculated from the shipboard bulk density measurement of core samples. The overconsolidation ratio (OCR = pc/σ’v) is used to identify the state of underconsolidation (OCR < 1) or overconsolidation (OCR > 1) at each drill site.
In the IODP Sites U1589, U1590 and U1593 in the Anydros Basin, underconsolidation states were identified in the interval 200-600 m below sea floor (OCR = 0.59 to 0.85). A maximum of 40% of the effective in-situ overburden is supported by the excess pore pressure at 200 mbsf. These underconsolidated intervals are overlain by >200 m of volcaniclastics derived from the Santorini and the Kolumbo volcanoes. Therefore, the rapid sediment supply (0.8-1.0 m/ky) from the submarine volcanoes apparently leads to the excess pore pressure, which can make sedimentary basins unstable.
On the other hand, measurements from IODP Sites U1591 and U1598 in the Christiana Basin, and Sites U1592 and U1599 in the Anafi Basin showed normal consolidation (i.e., OCR = 1) and overconsolidation (OCR =1.27-2.52) states. Sediments which showed overconsolidation are mostly composed of dolomitic mudstones. The effect of cementation is identified from their consolidation curves, implying that the intergranular bonding contributes to the overconsolidation of sediments. In the presentation, the maximum amount of erosion is calculated to explain the overconsolidation states in the Cristiana and Anafi basins.
How to cite: Yoshimoto, T., Yamamoto, Y., Manga, M., Beethe, S., McIntosh, I., Woodhouse, A., Chiyonobu, S., Koukousioura, O., Druitt, T., Kutterolf, S., and Ronge, T. and the IODP Exp. 398 Scientists: Consolidation state of sediments in the Hellenic Arc Volcanic Field, Greece: Evidence for excess pore pressure caused by huge eruptions and mass wasting (IODP Expedition 398), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11443, https://doi.org/10.5194/egusphere-egu25-11443, 2025.
The mixed carbonate-siliciclastic barrier and atoll reef system offshore Belize is the largest modern tropical reef complex in the Atlantic Ocean, highly sensitive to past and future sea-level changes. The deglaciation and increasing temperatures after the Last Glacial Maximum caused a rise in sea level characterized by multiple melt-water pulses and stillstands, which left their characteristic marks in the morphology and growth pattern of the Belize Barrier Reef. Such postglacial sea-level change indicators provide thus critical details to reconstruct how sea level rose from the full glacial to Late Holocene levels. We present a study that was done within the framework of the active IODP proposal “Postglacial Atlantic sea-level and climate reconstruction through drilling the Belize Barrier Reef (BBRdrill)”. To gain better insight into the morphological details, we acquired a high-resolution (1 x 1 m) topographic dataset of the Belize Barrier Reef with a state-of-the-art multibeam bathymetric device. Moreover, by investigating the entire point cloud of sonar reflections, we were even able to visualize the rarely investigated overhanging reef walls in great detail.
Concise morphological features indicating stagnant or slow-change phases were mapped in detail. They comprise elongated ridges at various water depths, indicating reef build-up to past sea level, which are aligned in single or multiple parallel lines, connecting hook-like structures, or complex honeycomb patterns. We hypothesize that older, postglacial and glacial reefs are stacked more or less vertically below the outermost ridge and the wall. The walls contain various erosional notches indicating still stands of sea level causing enhanced erosion in the quasi-vertical structure. This vertical stacking of the barrier reef crests gets affected towards the submarine outflow area of the English Cay Channel, where turbid waters likely challenged reef growth so that the aggradation eventually stopped and reefs drowned forming a reef line deepening towards the channel.
We provide a statistical distribution of features indicative for sea levels over 100 km length of Belize Barrier Reef, indicating the different slow-downs or stillstands of sea levels since the last glacial maximum. Several levels of erosional notches could be mapped at water depths of ~ -60 to -110 m, whereas the single or multiple reef crest occurs within a range of ~ -15 to -40 m water depth relating to sea levels ~13-16 ka and ~8-11 ka, respectively. The bathymetric distribution of notches and reefs suggests also the existence of a vertical tectonic displacement in the reef.
"BBRdrill" proposes to drill these morphological features in order to i) reconstruct the LGM and postglacial sea-level rise in the western Atlantic ii) reconstruct environmental parameters using corals, coralline algae, and cryptic microbialites; iii) elucidate reef paleoecology in relation to postglacial sea-level rise and associated environmental changes; and iv) assess microbial life in a barrier-reef system.
How to cite: Hosmann, S., Fabbri, S. C., Anselmetti, F. S., and Gischler, E.: Morphology of the Belize Barrier Reef as indicators for postglacial Atlantic sea-level changes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11853, https://doi.org/10.5194/egusphere-egu25-11853, 2025.
The Tibetan Plateau is part of a region often referred to as the ‘Third Pole’ because its ice fields are the world’s largest outside the polar regions. Almost one third of the world's population depends on the water supply from the Tibetan Plateau and future climate change will have a large impact on the region, affecting the water cycle, water resources, ecology and the economy. To assess predictive climate model scenarios, it is crucial to improve our understanding of the timing, duration and intensity of past climatic variability and its environmental impact in this sensitive area over long geologic time scales. For this, we use a sequence of lacustrine sediments from the Tibetan Plateau, which was acquired during the drilling campaign for the international ICDP project ‘The Nam Co Drilling Project, Tibet (NamCore)’ that was carried out in June/July 2024. The lake is located 4700 m above sea level, has a maximum depth of approximately 100 m, and covers an area of more than 2000 m2. In contrast to much younger and often incomplete climate archives on the Tibetan Plateau, the sedimentary sequence of Nam Co contains continuous information on climate history with age estimations of more than one million years. The investigation of this sequence will cover several cycles of glacial and interglacial stages.
The LIAG Institute for Applied Geophysics completed geophysical downhole measurements at the drill site in the central area of the lake. This involved multi-tool logging of two boreholes down to a depth of 185 m and 360 m below lake floor, respectively. Preliminary analyses reveal several lithological units that can be characterised by their physical properties. In addition, certain sections exhibit cyclic variations in the sedimentary sequence. This is beneficial for cyclostratigraphy and time series analyses, which in turn can lead to the creation of a robust time-depth scale.
Information on depositional age and lithology will be combined to derive statements on the relationship between aridity and precipitation in the past and to interpret these in the context of global climate development.
How to cite: Ulfers, A., Haberzettl, T., Wang, J., Zhu, L., Clark, L., Henderson, A. C. G., Vogel, H., Ju, J., Adolph, M.-L., Vinnepand, M., Zeeden, C., and NamCore Science Team, T.: Insights into geophysical downhole logging data from the ICDP project ‘The Nam Co Drilling Project, Tibet (NamCore)’, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16325, https://doi.org/10.5194/egusphere-egu25-16325, 2025.
Charles Darwin described in 1842 the island of Bora Bora (Society Islands, Central South Pacific) as key example for a subsiding basaltic oceanic island with related reef development. He recognized that the Bora Bora lagoon developed between an outer barrier reef with a sand apron and an inner fringing reef attached to the shore of the volcanic island. In order to quantify past sea-level and paleoenvironmental changes and island subsidence, the lagoonal sediments were cored in 2024 in the context of the Bora2coring project. Previous shorter cores indicated that the Holocene lagoonal sediments are of a mixed-carbonate-siliciclastic nature: the carbonate fraction is formed in-situ in the shallow-water depositional environment, whereas the siliciclastic fraction originates from the volcanic island. A recent seismic survey documented that below the Holocene sequence, several stacked depositional sequences occur, which must reflect the combined effect of sea-level fluctuations and ongoing island subsidence. To unravel the complex depositional history, a full suite of sedimentological, paleontological, petrophysical and geochemical analysis of the cores are conducted. In addition, samples of recent soil and lagoonal sediment will provide a data set to calibrate the measured proxies from the cores.
A total of 33 m of sediment cores were recovered and spliced into a composite section with a length of 18.2 m. The composite section reveals variable lithologies. A 4.5 m thick Holocene carbonate mud overlays a stiff, red to grey-bluish mottled, carbonate-free clay, forming the next underlying sequence. Coarse-grained carbonate sediments reappear at a depth of 9 m. Below this second carbonate unit, carbonate-free, grey-to-brown clay occurs, with occasional interbeds of white carbonate. Downcore, the clay becomes reddish again.
These sediments will be interpreted in the context of the interplay between sea-level, island subsidence and resulting accommodation space. A permanent connection to the open ocean seems to have existed only during the Holocene. In contrast, the deposition of siliciclastic fines during glacial phases suggests a distal alluvial or even shallow lacustrine depositional environment with no carbonate production within the lagoon. The occurrence of carbonates in 9 m depth indicate an older marine transgression and regression cycle presumably during an interglacial period overlying another glacial sequence.
All the different analyses will eventually merge toward an improved knowledge of island subsidence and the chronology and amplitudes of sea-level changes. The siliciclastic fines will additionally serve as an excellent proxy for hydroclimate-dependent weathering and erosion processes on the island.
How to cite: Felder, M. H., Hosmann, S., Camoin, G., Eisenhauer, A., Gischler, E., De Jonge, C., Kremer, K., Lecchini, D., Milne, G., Vogel, H., and S. Anselmetti, F.: Multiple interglacial sequences in a Darwin-type barrier-reef lagoon: Implications for paleoclimate, sea-level changes and subsidence since the Late-Pleistocene, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16330, https://doi.org/10.5194/egusphere-egu25-16330, 2025.
International Ocean Discovery Program (IODP) Expedition 395 recovered near-continuous sedimentary records from several major contourite drift bodies in the North Atlantic Ocean. These drifts deposits are influenced by deep-water currents, and studying their composition can inform us on past changes in ocean circulation. Drift sedimentation is a dynamic process that can lead to spatial variation in deposition and preservation through time. Here, we correlate on a glacial-interglacial timescale new IODP Expedition 395 records with Ocean Drilling Program (ODP) records previously cored nearby to assess the degree of variability between sites on the same drift body. We correlate IODP Site U1554 with ODP Site 984 for Björn Drift, and IODP Site U1564 with ODP Site 983 for Gardar Drift. Variations in magnetic susceptibility measured on sediment cores show striking resemblances between the paired sites. The clearly expressed glacial-interglacial scale variability enables astronomical tuning of the records. Furthermore, we explore the possibility of using multiple volcanic ash layers as additional markers for stratigraphic correlation. This work will contribute to the construction of high-resolution age models for the Expedition 395 records, as well as to a better understanding of the evolution of Björn and Gardar Drifts through space and time.
How to cite: Sinnesael, M., Irwin, R., Magzoub, A., Parnell-Turner, R., Briais, A., and LeVay, L. and the Expedition 395 Scientists: Plio-Pleistocene Glacial-Interglacial Climate Variability as Recorded in the North-Atlantic Björn and Gardar Drift Sediments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2373, https://doi.org/10.5194/egusphere-egu25-2373, 2025.
