ITS5.2/SSP1.13 | Achievements and perspectives in scientific ocean and continental drilling
Achievements and perspectives in scientific ocean and continental drilling
JpGU
Convener: Angelo Camerlenghi | Co-conveners: Cindy Kunkel, Thomas Wiersberg, Jorijntje Henderiks, Norikatsu Akizawa
Orals
| Tue, 16 Apr, 08:30–10:15 (CEST)
 
Room 2.24
Posters on site
| Attendance Tue, 16 Apr, 10:45–12:30 (CEST) | Display Tue, 16 Apr, 08:30–12:30
 
Hall X3
Orals |
Tue, 08:30
Tue, 10:45
Scientific drilling through the International Ocean Discovery Program (IODP) and the International Continental Scientific Drilling Program (ICDP) continues to provide unique opportunities to investigate the workings of the interior of our planet, Earth’s cycles, natural hazards and the distribution of subsurface microbial life. The past and current scientific drilling programs have brought major advances in many interdisciplinary fields of socio-economic relevance, such as climate and ecosystem evolution, palaeoceanography, the deep biosphere, sustainable georesources, deep crustal and tectonic processes, geodynamics and geohazards. This session invites contributions that present and/or review recent scientific results from deep Earth sampling and monitoring through ocean and continental drilling projects. Furthermore, we encourage contributions that outline perspectives and visions for future drilling projects, in particular projects using a multi-platform approach, and present research originated from the use of scientific drilling legacy data.

Orals: Tue, 16 Apr | Room 2.24

The oral presentations are given in a hybrid format supported by a Zoom meeting featuring on-site and virtual presentations. The button to access the Zoom meeting appears just before the time block starts.
Chairpersons: Angelo Camerlenghi, Cindy Kunkel
08:30–08:35
08:35–08:55
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EGU24-3380
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ITS5.2/SSP1.13
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solicited
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On-site presentation
Cédric M. John

Core data is pivotal for understanding our planet’s past, present, and future. Despite this richness, extracting meaningful insights from core description poses significant challenges due to the inherent complexity and variability of the data, the amount of existing material, and the subjectivity of the interpreter. IODP (and the preceding programs) offers a rich, well labelled source of core images that can be used in machine learning and deep learning.

Focusing largely (but not exclusively) on carbonate rocks, characterized by their heterogeneity at all observational scales, I will discuss how my research group and I have pioneered the application of deep-learning computer vision to geological core interpretation. This technology transcends the traditional, tedious manual interpretations of cores, offering a rapid, and often more accurate, alternative for delineating depositional environments and sequence stratigraphy. Convolutional neural networks (CNNs) form the backbone of our approach, enabling us to process core data with unprecedented efficiency. I will show that these sophisticated models, when correctly trained and fed with substantial datasets, serve as invaluable tools for geologists, outpacing conventional methods in speed without compromising on precision.

Our early work was centred on transfer learning, an AI approach that adapts pre-existing models to new data. I will show that this remains one of the best way to train classification algorithms for geological dataset. But we also worked on generative algorithms that fill gaps in our sampling of core imagery: for instance, we use Generative Adversarial Networks (GANs) to transform the resistivity images from formation micro scanners into representations mirroring actual core photographs, thus enhancing the interpretability for geologists irrespective of their background in downhole tools.

We tackle the often-limiting factor of dataset size in two ways. First, we recourse to generative AI to oversample our training set. Second, we also explore semi-supervised learning techniques.  I will demonstrate that we successfully train models on core deformation images from IODP with minimal labelled data, achieving accuracy on par with, if not exceeding, that of transfer learning models.

None of our achievements would have been possible without the recourse to IODP data. Hence, this presentation serves as a clear illustration of the value of legacy IODP data for future geoscientists.

How to cite: John, C. M.: Legacy IODP Cores Data in the Era of Big Data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3380, https://doi.org/10.5194/egusphere-egu24-3380, 2024.

08:55–09:05
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EGU24-13796
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ITS5.2/SSP1.13
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On-site presentation
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Gary Acton, Laurel Childress, and Vincent Percuoco

We use the LIMS With LithologY (LILY) database compiled by Childress et al. (https://zenodo.org/records/8408297) to examine relationships between physical properties and the lithology of marine drill cores collected by the International Ocean Discovery Program (IODP) and its precursor program between 2009 and 2019. Within LILY, lithologic information such as the principal lithologic name and the major and minor lithologic modifiers, along with other metadata, have been added to each of the more than 34 million observations from the standard data available in IODP’s LIMS Database, which is accessible through the LIMS Online Reports (LORE) portal (web.iodp.tamu.edu/LORE/). The ability to compare and combine descriptive lithologic information across expeditions and to integrate these descriptions with multisensor track and discrete sample measurements allows for a wealth of scientific investigation not possible under the original data structure. One of the obvious values of LILY is the ability to characterize the basic physical, chemical, and magnetic properties of different lithologies from a very large number of observations. As an example of this, we compute grain densities for all available lithologies using the Moisture and Density (MAD) density data from over 24,000 measurements. Once the grain densities are known, then the bulk densities can be used to determine porosity. This is important because besides the over 24,000 MAD bulk densities, there are 3.7 million gamma ray attenuation (GRA) bulk densities measured by the Whole Round Multi-Sensor Logger (WRMSL). Comparison of MAD and GRA bulk densities permits biases in the GRA density dataset to be corrected. These corrected GRA bulk densities are then used to compute a new high-resolution porosity dataset (https://zenodo.org/records/10001855). We further merge this large bulk density and porosity dataset with the P-wave velocity data from a P-wave Logger that is part of WRMSL, a P-wave Caliper, and P-wave Bayonets to characterize lithologic-dependent relationships between density, porosity, and P-wave velocity.

How to cite: Acton, G., Childress, L., and Percuoco, V.: Using the LIMS with Lithology (LILY) Database to Probe IODP Density, Porosity, and P-Wave Velocity Data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13796, https://doi.org/10.5194/egusphere-egu24-13796, 2024.

09:05–09:15
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EGU24-18764
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ITS5.2/SSP1.13
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ECS
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Highlight
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On-site presentation
Robert Lehmann, Michaela Aehnelt, Thomas Grelle, Carlos Lehne, and Kai Uwe Totsche

Core-drilling and groundwater well operation in topographic recharge areas have been rarely applied for groundwater quality monitoring or ecosystem exploration, simply due to lacking of productive water bodies in up to >100 m thick aeration zones. The scarcity of observers and data, and neglection in modelling opposes our efforts to unravel the role of thick hillslope aeration zones for services like water provision, water purification and biogeochemical cycling (Lehmann & Totsche, 2020). To fundamentally understand how groundwater quality comes about as a function of inputs and how climate and land use change will affect this quality, we concentrate our investigations on the soil-aeration zone-phreatic zone continuum in topographic highs. From our Hainich Critical Zone Exploratory in central Germany, we present methods and workflows for low-impact scientific drilling and construction of monitoring wells optimized for representative sampling of the total mobile inventory (Lehmann et al. 2021), and results from the analysis of drill cores, borehole geophysical data and multi-year environmental monitoring data. We found that transient (fluid) flow patterns contribute to groundwater quality dynamics, whereby overall aeration zone-phreatic zone-interactions cause quality fluctuations even in deep and isolated habitats. Results from recent drilling campaigns (2023) comprise the detection of narrow oxic zones (fractures, flow paths) also within mudstone-dominated strata (anoxic aquifer-storeys) and weathering-induced hydrofacies differences that indicate further complexity of habitat structures and ecosystem functioning across recharge(-discharge) zones.

 

 

References:

Lehmann, R., Totsche, K. U. (2020). Multi-directional flow dynamics shape groundwater quality in sloping bedrock strata. Journal of Hydrology 580, 124291. https://doi.org/10.1016/j.jhydrol.2019.124291

 

Lehmann, K., Lehmann, R., Totsche, K. U. (2021) Event-driven dynamics of the total mobile inventory in undisturbed soil account for significant fluxes of particulate organic carbon. Sci. Total Environ. 756, 143774. https://doi.org/10.1016/j.scitotenv.2020.143774

How to cite: Lehmann, R., Aehnelt, M., Grelle, T., Lehne, C., and Totsche, K. U.: “Looking deep” into shallow ground: scientific drilling and continuous monitoring in recharge areas as a key to the understanding of groundwater quality dynamics and subsurface ecosystem functioning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18764, https://doi.org/10.5194/egusphere-egu24-18764, 2024.

09:15–09:25
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EGU24-15118
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ITS5.2/SSP1.13
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ECS
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On-site presentation
Junjian Li, Eva Caspari, Andrew Greenwood, Simona Pierdominici, Marco Venier, Mattia Pistone, Kim Lemke, György Hetényi, and Luca Ziberna

The Drilling the Ivrea-Verbano zonE (DIVE) project completed its first borehole DT-1B in December 2022, recovering a continuous drill core to 578.5 m depth. The objective of DT-1B is to explore the upper part of the Lower Continental Crust. The 100% core recovery provides an excellent opportunity to integrate downhole geophysical measurements with core observations in rarely drilled lithologies. The primary goal of this integrated study is to characterize the rock mass and constrain the factors that influence seismic velocity variations and the origin of reflectivity in lower crustal rocks. For this purpose, we have collected a comprehensive suite of downhole measurements, comprising of natural gamma ray, magnetic susceptibility, dual laterolog resistivity, single point resistance, mud parameter, full waveform sonic, acoustic and optical televiewer, and vertical seismic profiling data. Complementary bulk density measurements have been performed on 96 core sections with a multi-sensor core logger as well as laboratory ultrasonic velocity and bulk density measurements on 15 selected core samples at ambient conditions. To characterize the rock mass mechanically and structurally, a detailed analysis of the acoustic televiewer data was carried out, which identified several natural and drilling-induced fractures. Natural fractures have two predominant azimuthal orientations: NW to NE and SSE to SE. Their dips range from 10° to 85°, with a higher average dip in the upper section that decreases in the lower section of the borehole. Fractures correlate with an abundance of anomalies in the electrical logs and affect sonic velocities. Due to the impact of fractures on these logs, only natural gamma ray and magnetic susceptibility logs are used for lithological classification of the rock masses, into three distinct clusters by fuzzy c-means clustering. Two of the clusters, 1 and 3, are attributed mainly to felsic metasediments, while cluster 2 is attributed to metamafics identified in the cores. Cluster 1 is characterized by high magnetic susceptibility and natural radiation, while cluster 3 is characterized by low magnetic susceptibility and natural radiation, indicating two distinct groups of metasediments. Concerning the elastic properties, it is expected that the velocities of the metamafics are higher than those of the metasediments. However, a systematic correlation between velocities and lithologies (or clusters) is not observed. To investigate the factors contributing to seismic velocity variations, velocities from core measurements, sonic logging, and vertical seismic profiling are compared. The velocities are consistent across the three scales, with P-wave velocities ranging from 5 to 6 km/s and S-wave velocities around 3 km/s, however, the values are much lower than expected. One reason might be the presence of microcracks, as indicated by the P-wave velocity difference between saturated and dry core samples. Together with the observed impact of fractures on the sonic log data, this suggests that the velocities are governed by brittle deformation at various scales, which explains their low values and overprints the lithological response. Consequently, reflections are expected to be caused by large scale fractures, but lithological reflections may still be observed due to the density contrast between metasediments and metamafics.

How to cite: Li, J., Caspari, E., Greenwood, A., Pierdominici, S., Venier, M., Pistone, M., Lemke, K., Hetényi, G., and Ziberna, L.: Integrated interpretation of downhole geophysical measurements of the Lower Continental Crust in the Ivrea-Verbano Zone (Western Alps, Italy) at the DIVE DT-1B borehole, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15118, https://doi.org/10.5194/egusphere-egu24-15118, 2024.

09:25–09:35
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EGU24-16278
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ITS5.2/SSP1.13
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On-site presentation
Mathias Vinnepand, Christian Zeeden, Thomas Wonik, William Gosling, Anders Noren, Jochem Kück, Simona Pierdominici, Silke Voigt, Mehrdad Sadar-Abadi, Arne Ulfers, Sylvester Danour, Kweku Afrifa, and Stefanie Kaboth-Bahr

Situated within a 1.07 million-year-old meteorite crater, Lake Bosumtwi in Ghana stands as a pivotal location for comprehending fluctuations in the hydro-climatic situation in sub-Sahara West Africa. The region is highly sensitive to climate oscillations due to the movements of the tropical rain belt driven by atmospheric circulation leading to pronounced dry or wet conditions on seasonal to orbital scales. Considering that climatic changes may trigger severe socio-economic crises in this area due to negative impacts on the agricultural sector- especially the cacao farming, a better understanding on the responses of the regional hydro-climatic situation to global warming tendencies is crucial. Recently a robust age-depth model was developed for the lacustrine sequence of Lake Bosumtwi, the only continental record spanning the last million years in West Africa. This provides the unique opportunity to gain detailed insights into the hydroclimatic situation. Yet, the natural gamma radiation (NGR) signal that we interpret as a proxy for terrestrial sediment input throughout the 300 m thick record, triggered by fluvial in wash from the crater rims, shows quasi-cyclic patterns. Based on this along with evidence from additional proxies, we discuss these patterns at Lake Bosumtwi and their relation to orbital forcing including fluctuations in the hydroclimate.

How to cite: Vinnepand, M., Zeeden, C., Wonik, T., Gosling, W., Noren, A., Kück, J., Pierdominici, S., Voigt, S., Sadar-Abadi, M., Ulfers, A., Danour, S., Afrifa, K., and Kaboth-Bahr, S.: A million years of regional hydroclimate oscillations in West Africa reconstructed from Lake Bosumtwi, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16278, https://doi.org/10.5194/egusphere-egu24-16278, 2024.

09:35–09:45
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EGU24-11720
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ITS5.2/SSP1.13
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ECS
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On-site presentation
Jonas Preine, Christian Hübscher, Abigail Metcalfe, Katharina Pank, Adam Woodhouse, Olga Koukousioura, Shun Chiyonobu, Timothy Druitt, Steffen Kutterolf, Paraskevi Nomikou, Thomas Ronge, Sarah Beehte, Miachel Manga, Iona McInsoth, Masako Tominga, Gareth Crutchley, and Jens Karstens and the IODP Expedition 398 Scientists

 

Many hazardous volcanic systems worldwide are located in extensional back-arc systems, where the crust is influenced by pervasive faulting. However, our knowledge about the spatial and temporal relationship between crustal faults and the emplacement of volcanic edifices is immature. Located on the South Aegean Volcanic Arc, the Christiana-Santorini-Kolumbo volcanic field formed in a continental rift zone and represents an ideal natural laboratory to study the structural interaction between volcanism and tectonism. From December 2022 to February 2023, IODP Expedition 398 drilled 12 sites across the volcanic rift system. We will present the results of core-seismic integration of several sites from the rift basins. Two of these drill sites lie on the hanging wall and footwall of the Kolumbo Fault, respectively. This fault strikes parallel to the Kolumbo Volcanic Chain and was previously considered a fault with little vertical offset. However, tephra and biostratigraphic markers identified in recovered cores from IODP Expedition 398 indicate a major vertical offset of >200 m (~260 ms TWT) along this fault. Seismic data reveal that this fault is a major NE-SW-directed normal fault and represents an important structural element of the rift system but subsequent rapid sedimentation of volcanoclastic material buried this fault. The volcanic edifices of the Kolumbo Volcanic Chain formed on the hanging wall of this fault at a distance of approx. 6 km from the surface trace. Adjacent, non-volcanic rift basins show pervasive internal fault zones at a similar distance from the respective basin-bounding faults, indicating that these faults may be the preferred pathway for magma to reach the surface. Our study implies a fundamental tectonic control of the emplacement of volcanoes at the Christiana-Santorini-Kolumbo volcanic field, a process that might be present at other back-arc systems.

How to cite: Preine, J., Hübscher, C., Metcalfe, A., Pank, K., Woodhouse, A., Koukousioura, O., Chiyonobu, S., Druitt, T., Kutterolf, S., Nomikou, P., Ronge, T., Beehte, S., Manga, M., McInsoth, I., Tominga, M., Crutchley, G., and Karstens, J. and the IODP Expedition 398 Scientists: IODP Expedition 398 Reveals a Major Normal Fault along the Kolumbo Volcanic Chain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11720, https://doi.org/10.5194/egusphere-egu24-11720, 2024.

09:45–09:55
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EGU24-3723
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ITS5.2/SSP1.13
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Virtual presentation
Yasuo Yabe, Hiroshi Ogasawara, and Raymond Durrheim

 The ICDP-DSeis (Drilling into Seismogenic zones of M2.0 – M5.5 earthquakes in deep South African gold mines) project recovered rock samples from a fracture zone that hosted the aftershocks of the 2014 Orkney earthquake (M5.5). The fracture zone was formed in an altered lamprophyre dike (Lamprophyre, hereafter) intruded into the Crown Formation (local name of altered basaltic andesite). One of the DSeis holes intersected another dike (named the Onstott dike) ~300 m east of the Lamprophyre. A fissure containing ancient (1.2 Ga) hypersaline brine rich in DOC (dissolved organic carbon) was found in the Onstott dike. The formation and metamorphism of these dikes are discussed in Ogasawara et al. (EGU24). This study describes the frictional properties of Lamprophyre that motivated us to propose a new drilling project PROTEA.

The southern shallowest section of the fault intersected by the DSeis hole did not slip significantly during the Orkney earthquake mainshock, but hosted high aftershock activity. This implies that the fault intersected by the DSeis hole was stable frictionally and decelerated coseismic slip to halt the dynamic propagation of the mainshock rupture. Thereafter, the fault transitioned to an unstable state and produced aftershocks. The recovered rocks revealed the Lamprophyre did not contain any quartz and was rich in talc, biotite, amphibole, and calcite. Loss of drilling water into the fault zone suggested that the pore pressure in the fault zone was low (<6 MPa, water head pressure in the borehole). Consequently, sliding-rate step tests were conducted under wet (saturated, but without pore pressure) condition using the powdered samples to investigate evolution of the frictional property with increasing sliding distance.

 The friction coefficient of Lamprophyre was ~0.3, much lower than that of the Crown Formation (~0.7). The friction coefficients of both lithologies were almost independent of sliding distances. Lamprophyre showed rate-strengthening behavior irrespective of sliding distance. Acoustic emission (AE) activity, which mimics aftershock activity, in the Lamprophyre gouge became higher with increasing sliding distance. This implies a hierarchical evolution of frictional property of Lamprophyre. These experimental results explain the spatial coincidence of the mainshock rupture termination and high aftershock activity.

The weakness of Lamprophyre may enable the formation of a fault in Lamprophyre. However, its rate-strengthening behavior would prevent the nucleation and spontaneous propagation of the rupture on a fault in Lamprophyre. Frictional properties, the stress state, the pore pressure, and/or lithology around the hypocenter should differ from those in the aftershock zone. Therefore, we propose a new drilling project PROTEA (Probing the heart of an earthquake and life in the deep subsurface) to drill a hole targeting the hypocenter and the strong motion source of the Orkney earthquake. It will explore the frictional properties, stress state, pore pressure, and lithology that enabled the nucleation and the initiation of the dynamic rupture, as well as the radiation mechanism of strong motions. PROTEA will drill multiple holes intersecting the Onstott dike, not only to elucidate locality and universality of ecosystems that exist in the fissure brine, but also to investigate the interaction between seismicity and microbial activity.

How to cite: Yabe, Y., Ogasawara, H., and Durrheim, R.: Frictional properties of the fault hosting aftershocks of the 2014 Orkney earthquake (M5.5), South Africa, and proposal of a new drilling project PROTEA to probe the heart of the earthquake, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3723, https://doi.org/10.5194/egusphere-egu24-3723, 2024.

09:55–10:05
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EGU24-16452
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ITS5.2/SSP1.13
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On-site presentation
Gerald Auer, Junichiro Kuroda, Yusuke Kubo, Or Mordecai Bialik, Anna Joy Drury, Beth Christensen, Arisa Seki, Theresa Nohl, Jumpei Yoshioka, Xabier Puentes Jorge, Tamara Hechemer, Jing Lyu, An-Sheng Lee, Natsumi Okutsu, David De Vleeschouwer, Werner E Piller, and Minoru Ikehara

In 2023, the ReCoRD program was initiated by a joint venture of the Kochi Core Center (KCC), Kochi University and the Japan Drilling Earth Science Consortium (J-DESC) as a new workshop type, providing access to IODP cores archived at the KCC in Kochi, Japan. The first ReCoRD workshop, ReC23-01, ”Tracing Intermediate Water Current Changes and Sea Ice Expansion in the Indian Ocean”, was held between the 27th of August and the 5th of September 2023 at the KCC in Kochi. The goals of ReC23-01 were to gather new data to test the hypothesis that the expansion of sea ice around Antarctica impacted water circulation in the Indian Ocean through changes in intermediate water formation and the northward expansion of the Antarctic polar front through the Middle to Late Miocene following the Middle Miocene Climatic Transition (< 13.8 Ma).

During ReC23-01, we targeted a latitudinal transect from the high southern latitudes to the tropical Indian Ocean consisting of 1 DSDP and 2 ODP sites. DSDP Site 266 represents the high-latitude target site located just south of the present-day location of the polar front. Data gathered for Site 266 during ReC23-01 is a new tracer location for ice-rafted debris (IRD) accumulation and changes in the Southern Hemisphere frontal system for the Neogene in the Indian Ocean. ODP Site 752 on the Broken Ridge provides a unique record of mid-latitude intermediate water paths, including SAMW and AAIW originating from the high latitudes and the Tasman Leakage. ODP Site 707 represents a critical end member of the south equatorial current and related Indonesian Intermediate Waters in the tropical Indian Ocean.

The ReC23-01 workshop within the ReCoRD program allowed international research collaborators to fully benefit from the legacy of over 50 years of International Ocean Drilling Research from the Deep Sea Drilling Program (DSDP), Ocean Drilling Program (ODP), and International Ocean Discovery Program (IODP). Combining in-tandem sedimentological core descriptions with existing and new core data provides a unique opportunity to re-investigate and evaluate archived (legacy) core material. In particular, the availability of computer tomography (CT) core images provided critical information in assessing sedimentology and drilling disturbance in older DSDP and ODP core material to gather new data from over 50-year-old cores.

ReC23-01 illustrates how ReCoRD-style workshops can offer a new way to explore research questions that could not be easily addressed by single sea-going expeditions. These workshops provide additional and powerful research opportunities based on legacy core material beyond individual sample and data requests, with large-scale community benefits. For instance, ReC23-01 provided an excellent training opportunity for early career researchers in a shipboard-like setting.

How to cite: Auer, G., Kuroda, J., Kubo, Y., Bialik, O. M., Drury, A. J., Christensen, B., Seki, A., Nohl, T., Yoshioka, J., Puentes Jorge, X., Hechemer, T., Lyu, J., Lee, A.-S., Okutsu, N., De Vleeschouwer, D., Piller, W. E., and Ikehara, M.: ReC23-01 – Initial Results of the first KCC-J-DESC Repository Core Re-Discovery Program (ReCoRD), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16452, https://doi.org/10.5194/egusphere-egu24-16452, 2024.

10:05–10:15
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EGU24-16500
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ITS5.2/SSP1.13
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On-site presentation
Anne Briais, Ross Parnell-Turner, and Leah LeVay and the Expedition 395 Science Party

International Ocean Discovery Program Expeditions 384, 395C and 395 investigated the interactions between variations in the Iceland hotspot activity, ocean crust formation at the Reykjanes Ridge, ocean circulation, and climate in the North Atlantic, and sediment drift deposition on the flanks of the mid-ocean ridge. Variations in crustal production along the Reykjanes Ridge produced V-shaped ridges and troughs located on the flanks of the mid-ocean ridge, and the role of the Iceland hotspot in their generation is debated. Changes in hotspot activity, and therefore in the associated dynamic topography, likely influenced the depth of the oceanic gateways formed by the Greenland-Scotland Ridge between the North Atlantic and the Norwegian and Arctic Seas. Such variations might thus have controlled the strength of cold, deep water currents, and the accumulation rate of sediment drifts on the flanks of the ridge: Björn and Gardar drifts on the eastern flank and Eirik drift to the west. Expeditions 384 in 2020, 395C in 2021, and 395 in 2023 collected cores from a transect of five drill sites along a plate-spreading flowline spanning seafloor ages from 2.8 to 32 Ma and crossing Björn and Gardar drifts on the eastern ridge flank, as well as a sixth site along the eastern Greenland margin crossing Eirik drift. Combined, over 400 m of oceanic basalt and over 5.8 km of sediment core was recovered, including continuous records through key Pleistocene and Pliocene sequences, and a unique record of progressive basalt alteration. Here we present preliminary results of the expedition, featuring new insights into crustal accretion variations through time, constraints on the onset of sedimentation at Björn, Gardar and Eirik contourite drifts, and new records of climatic cycles on thousand-year timescales. These sites also provide a unique view on how crust interacts with fluids and sediment over millions of years, while in-situ samples obtained from the cores yield insights into chemical exchanges and microbial systems in the ocean, sediment, and crust. The vast amount of sediments, basalts and measurements collected during Expeditions 384, 395C and 395 will provide a major advance in our understanding of mantle dynamics and the linked nature of Earth’s interior, oceans, and climate.

How to cite: Briais, A., Parnell-Turner, R., and LeVay, L. and the Expedition 395 Science Party: IODP Expeditions 384/395C/395: Reykjanes Mantle Convection and Climate. Preliminary results, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16500, https://doi.org/10.5194/egusphere-egu24-16500, 2024.

Posters on site: Tue, 16 Apr, 10:45–12:30 | Hall X3

The posters scheduled for on-site presentation are only visible in the poster hall in Vienna. If authors uploaded their presentation files, these files are linked from the abstracts below, but only on the day of the poster session.
Display time: Tue, 16 Apr 08:30–Tue, 16 Apr 12:30
Chairpersons: Thomas Wiersberg, Jorijntje Henderiks
X3.81
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EGU24-1949
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ITS5.2/SSP1.13
Minoru Ikehara, Xavier Crosta, Samuel Jaccard, Tim Naish, and Yasuyuki Nakamura

Proposal 918-pre in the Southern Ocean exists in the current science evaluation system of IODP. Site surveys were completed in 2019. We would like to develop an international research project based on this proposal by conducting new drilling/coring in the IODP3. First, we would like to drill by riserless drilling vessel, but if drilling is not feasible, we plan to consider giant piston coring as an option.

 The Southern Ocean (SO) is a key region that profoundly influences climate variability throughout the Cenozoic. Because the SO redistributes heat, fresh water, carbon, and nutrients around the global ocean it plays a key role in the climate system. The growth of ice sheets in the Antarctic continent and changes in sea ice in the surrounding ocean are important variables in Earth’s climate system. Upwelling of deep waters in the Antarctic Circumpolar Current (ACC), in particular, is a key process of the meridional overturning circulation (MOC) as it constitutes the return path for deeply-sequestered carbon and nutrients towards the surface and hence important in the partitioning of carbon between the ocean and the atmosphere. Furthermore, physical and biogeochemical processes modulate nutrient export through SO-sourced intermediate waters that ventilate 75% of the world’s thermocline, thus playing a vital role in influencing low-latitude productivity and ecosystems.

The western Indian sector of the SO, located at the confluence of the SO overturning cells and the MOC return surface flow, is a key region to document the links/teleconnections between the SO, global ocean/atmospheric circulations and hence climate (Fig. 1). It provides a unique opportunity to obtain exceptionally high-resolution sediment records to document and unravel the interaction and feedbacks between atmosphere, ocean and cryosphere from millennial to orbital-timescales during the late Neogene and Quaternary, focus on past 6 Ma (Fig. 2).

Specifically, the proposal aims to constrain further – (A) past changes in the upwelling and latitudinal position of the ACC; (B) the dynamic controls of circum-Antarctic deep ocean ventilation/overturning circulation; (C) their link to the global ocean circulation; (D) past changes in the sea ice coverage and dust inputs; and (E) their implications for the marine biogeochemical cycles of carbon and nutrients. The anticipated results will elucidate the evolution of the SO carbon cycle, identify potentially dominant physical and biogeochemical mechanisms of change, document past oceanic bipolar teleconnections with global MOC dynamics, and provide constraints on its future evolution in response to anthropogenic warming.

Our scientific objectives relate to Strategic Objective 3 (Earth’s climate system), Strategic Objective 4 (Feedbacks in the Earth system), and Flagship Initiative 1 (Ground truthing future climate change) in the 2050 Science Framework.

How to cite: Ikehara, M., Crosta, X., Jaccard, S., Naish, T., and Nakamura, Y.: Plio-Pleistocene Southern Ocean Paleoceanography: Latitudinal drilling in the Southwestern Indian sector of the Southern Ocean, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1949, https://doi.org/10.5194/egusphere-egu24-1949, 2024.

X3.82
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EGU24-3044
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ITS5.2/SSP1.13
Walter Kurz, Irena Miladinova, Gerald Auer, and Arianna Valentina Del Gaudio

International Ocean Discovery Program (IODP) Expedition 366 recovered cores from three serpentinite mud volcanoes that also contain clasts that originate from the subduction-channel along the Philippine Sea Plate – Pacific Plate boundary. The drilled and sampled mud volcanoes (Yinazao, Fantangisña, and Asùt Tesoru) are located at distances of 55 to 72 km from the Mariana Trench.

In general the recovered cores comprise serpentinite mud with lithic clasts from the underlying forearc lithosphere and from the subducting Pacific plate. This aloows the reconstruction of mass transport processes and geochemical cycling within the forearc, the spatial variability of slab-related fluids within the forearc, and water-rock-reactions in subduction and supra-subduction zone settings, the metamorphic and tectonic history of the subduction channel, and the timing and rates of these processes.

Mafic rock clasts, embedded within a serpentine mud matrix, from the flanks and summits of both Asùt Tesoru and Fantangisña Seamounts were analyzed for reconstruction of their metamorphic and deformational overprint in order to reveal the tectono-metamorphic conditions at the metamorphic peak within the subduction channel and the subsequent low-grade overprint during exhumation.

Several seamounts comprise clasts of lower plate metabasites with different metamorphic overprint (from low-grade greenschist facies to lower blueschist facies). The metabasites are also associated with clasts of fossiliferous carbonates and cherts with different degrees of metamorphic and deformational overprint, that also originated from the Pacific lower Plate. This implies that these rocks were exhumed from different depths within the subduction channel before being regurgated within a serpentinite mud matrix. The blueschist facies metamorphic rocks, being affected by metamorphic pressures in the range of 11 to 13.8 kbar at minimum, were very likely exhumed from greater depth within the subduction channel before being captured by uprising, localized serpentine mud flows, indicating evidence that corner flow is actually taking place along the Mariana convergent margin, and, to our knowledge, this is the first direct evidence of exhumation of high-pressure rocks by corner flow in an active subduction zone. Final exhumation, however, is related to the embedding of the rocks within a serpentinite mud matrix and the buoyant ascent of serpentinite mudflows along forearc fracture zones extending from the plate boundary to the upper plate sea floor.

Biostratigraphic analyses of calcareous nannofossils and planktonic foraminifera from serpentinite mud flows, and intercalated pelagic sediments immediately above the metabasites analysed in this study give an age record of ~ 6.10 Ma (late Miocene, Messinian) to 4.20 Ma (early Pliocene, Zanclean), indicating that the final exhumation of the metabasites occurred during late Miocene times, slightly before 6.10 Ma.

How to cite: Kurz, W., Miladinova, I., Auer, G., and Del Gaudio, A. V.: Exhumation of high-pressure rocks by corner flow and serpentinite mud volcanism – implications from serpentinite mud seamounts along the Mariana convergent margin (IODP Expedition 366), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3044, https://doi.org/10.5194/egusphere-egu24-3044, 2024.

X3.83
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EGU24-3074
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ITS5.2/SSP1.13
Thomas Westerhold, Steve Bohaty, Donald Penman, Ashely Burkett, and Edoardo Dallanave and the Expedition 392 Scientists

The abrupt onset of the Paleocene-Eocene Thermal Maximum (PETM) 56 million years ago represents one of the largest transient greenhouse gas-driven global warming event in the last 100 million years. Caused by a geologically rapid injection of exogenic carbon into the ocean and atmosphere system, the PETM is associated with large-scale ocean acidification. Related widespread dissolution of marine pelagic carbonate deposits, particularly in the early stages of the event, complicates marine paleoclimatic reconstructions and the establishment of robust age models at many sites. Recently, a new deep-sea sediment record spanning the PETM was recovered from the southern Agulhas Plateau in the Southwest Indian Ocean during International Ocean Discovery Program Expedition 392. The uppermost Paleocene/lowermost Eocene interval at Site U1580 was drilled in two parallel holes at 2560 m water depth, and consists of 75‒95% carbonate across the event, with a reduction to 75‒65% at the PETM onset. X-ray fluorescence-derived core scanning elemental data at 5mm and 10mm resolution and an unprecedented high-resolution bulk carbonate stable carbon and oxygen isotope record define a new marine composite reference record for the PETM at this site. The record is comparable to Ocean Drilling Program Site 690 (2914 m water depth) in the Atlantic sector of the Southern Ocean, where the event was first described and is still a primary reference sequence for paleoclimate reconstructions. Unlike Site 690, however, Site U1580 elemental data shows a clear cyclicity throughout the event that can be utilized for cyclostratigraphy. Additionally, the highly resolved bulk carbonate stable carbon isotope record provides a new reference for global correlation, which establishes a new benchmark for the different phases of the PETM. Here we present this new record and discuss the implications for timing and duration of the event, and set the stage for multi-proxy paleoclimate reconstructions spanning the PETM at IODP Site U1580.

How to cite: Westerhold, T., Bohaty, S., Penman, D., Burkett, A., and Dallanave, E. and the Expedition 392 Scientists: A new deep sea reference record for the Paleocene-Eocene Thermal Maximum: IODP Expedition 392 Site U1580 (Agulhas Plateau, Southwest Indian Ocean), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3074, https://doi.org/10.5194/egusphere-egu24-3074, 2024.

X3.84
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EGU24-5974
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ITS5.2/SSP1.13
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Highlight
Mikael Erlström, Jan-Erik Rosberg, Peter Dahlqvist, Carl-Erik Hjerne, and Henning Lorenz

With an aggregated thickness of c.100 m, a porosity of up to 15 % and a permeability above hundred millidarcy, previous studies have assessed the three widely distributed Cambrian sandstone members in the Swedish sector of the Baltic Sea as the most potential CO2-storage candidates in Sweden. Existing models indicate an effective storage capacity between 450–1500 Mt CO2. However, these rough numbers are uncertain as they are related to vintage and partly inadequate data sets, especially regarding physical property values needed for a more certain evaluation of the storage capacity. Hence, as part of a larger screening and evaluation programme, launched by the Swedish government to identify and quantify potential storage sites in Sweden, two scientific core drillings were completed in 2023 on the southernmost part of the island of Gotland in the Baltic Sea. The primary aim was to collect complementary and missing data on the Lower Palaeozoic succession including both caprocks and reservoirs. The scientific evaluations and results of the core drillings on south Gotland will together with geophysical logging of the boreholes, new seismic data and 3D models constitute an essential part in improving the models of the effective storage capacity of the Cambrian reservoirs in the Swedish sector of the Baltic Sea. The coring, monitoring and investigations were managed by the Geological Survey of Sweden and the Swedish national research infrastructure for scientific drilling, “Riksriggen”, operated by the department of Engineering Geology at Lund university. H-dimension triple tube coring (96/61 mm hole/core diameter) was successfully performed with an Atlas Copco CT20C rig. The two wells, Nore-1 and Nore-2, penetrate 470 m of Silurian marlstone and claystone, 85 m of Ordovician argillaceous limestone and 225 m of Cambrian sandstone, siltstone and shale before finishing in the Precambrian crystalline basement of potassium porphyritic granite at 791.5 m and 787.7 m, respectively. The operation managed to reach the set goals despite challenges of over pressured formations and up to metre-thick bentonites. Initial results show a thick, tight, and homogenous caprock and that the Faludden Sandstone, one of the three Cambrian sandstone members, have hydraulic properties that qualifies it as a possible storage reservoir. The preliminary results from the two wells are here presented together with evaluations of drilling performance, monitoring programme, logging and test operations. 

How to cite: Erlström, M., Rosberg, J.-E., Dahlqvist, P., Hjerne, C.-E., and Lorenz, H.: Scientific core drilling of the Lower Palaeozoic succession in the Swedish sector of the Baltic Sea – investigation of the CO2 storage potential, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5974, https://doi.org/10.5194/egusphere-egu24-5974, 2024.

X3.85
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EGU24-7109
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ITS5.2/SSP1.13
Keisuke Ariyoshi and Hiroyuki Matsumoto

We have detected an event of pore pressure changes (hereafter, we refer it to “pore pressure event”) from borehole stations in real time in March 2020 and March 2023, owing to the network developed by connecting three borehole stations to the Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) observatories near the Nankai Trough. Slow earthquake is thought to have longer duration time with smaller stress drop than regular earthquake under the same magnitude. This means that the slow earthquake is more sensitive to external stress perturbation and useful to monitor the processes of stress accumulation and release. However, the pore pressure is also affected by tidal and oceanic fluctuations. To overcome this problem, we use the seafloor pressure gauges of DONET stations nearby boreholes instead of the reference by introducing time lag between them. The obtained results demonstrate the detectability of volumetric strain change for nano-scale. We also investigate the impact of seafloor pressure due to ocean fluctuation on the basis of ocean modelling, which suggests that the decrease of effective normal stress from the onset to the termination of the SSE is explained by Kuroshio meander and may promote updip slip migration, and that the increase of effective normal stress for the short-term ocean fluctuation may terminate the SSE as observed in the Hikurangi subduction zone. The evaluation of the ocean impact is to be applied to a fiber-optic submarine cable, and 50 km-long distributed acoustic sensing (DAS) recordings, where the DAS measurement can be sensitive for hydroacoustic signals in a frequency range from 0.1 to a few tens of Hz.

How to cite: Ariyoshi, K. and Matsumoto, H.: Precise monitoring of subduction plate coupling status on the basis of DONET and borehole data analyses, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7109, https://doi.org/10.5194/egusphere-egu24-7109, 2024.

X3.86
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EGU24-7120
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ITS5.2/SSP1.13
Jun-Ting Lin, Jyh-Jaan Huang, Ken Ikehara, Michael Strasser, Ta-Wei Hsu, Chih-Chieh Su, Yu-Hsun Shao, Yen-Hsi Wu, and Astuko Amano

Megathrust earthquakes in subduction zones, such as the AD 2011 Tohoku-oki earthquake, are known to generate turbidity currents that transport sediment into deep marine trenches, creating distinctive event deposits. These deposits are pivotal in submarine paleoseismology, which seeks to extend earthquake records and assess disaster potentials by meticulously analyzing the spatiotemporal distribution of these deposits through precise distinction and correlation. In our research, over 800 meters of sediment cores from 15 sites along the Japan Trench were collected during the International Ocean Discovery Program (IODP) Expedition 386, focusing on these event deposits to trace earthquake history. Utilizing X-ray Fluorescence Core Scanning (XRF-CS), we performed efficient and non-destructive high-resolution analysis of the chemical characteristics of these deposits. Our methodology integrates XRF-CS data with multivariate statistical techniques, such as Principal Component Analysis (PCA) and Cluster Analysis (CA). This integration enables us to objectively differentiate and correlate event deposits based on their unique chemical properties. Significant discoveries were made at Site M0083, where we detected variations in background sediments and event deposits associated with major historical earthquakes, including the AD 1454 Kyotoku and AD 869 Jogan events. These unique chemical fingerprints were also traced to adjacent trench-fill basins at sites M0089 and M0090, revealing consistent event-stratigraphic sequences across the basins and affirming the efficacy of our chemical-based correlation technique. In our ongoing analysis, we aim to explore the diverse chemical fingerprints of background sediments, turbidite bases, and turbidite tails. This investigation seeks to uncover potential spatial and stratigraphic provenance changes, and includes examining mineral and biogenic compositions, such as clay minerals and smear slides, to elucidate the reasons behind variations in chemical signals. Our findings underscore the effectiveness of combining chemical analysis with statistical methods for event-stratigraphic correlation. This novel approach not only sheds light on provenance changes but also helps establish a detailed spatiotemporal distribution framework for event deposits along the Japan Trench. Moreover, this integrated methodology could inform subsequent sampling strategies by objectively selecting sampling locations based on the chemostratigraphy framework. It also has the potential to be adapted to other research areas that require event-stratigraphic correlation and comprehensive spatiotemporal analysis.

How to cite: Lin, J.-T., Huang, J.-J., Ikehara, K., Strasser, M., Hsu, T.-W., Su, C.-C., Shao, Y.-H., Wu, Y.-H., and Amano, A.: Chemical-Based Event-Stratigraphic Correlation along the Japan Trench by XRF-CS Chemical Fingerprint and Multivariate Statistics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7120, https://doi.org/10.5194/egusphere-egu24-7120, 2024.

X3.87
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EGU24-8374
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ITS5.2/SSP1.13
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ECS
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Rohit Samant, Toni Giorgino, Emilia Jarochowska, and David De Vleeschouwer

The Dynamical Time Warping (DTW) technique has been originally developed for speech recognition in the late 1960s and early 1970s and has more recently been applied in geoscientific studies. One of the key objectives of dtw is to stretch or compress two complementary series locally in order for one series to resemble the other as much as possible. In our project, we aim to correlate industrial and scientific downhole wireline logs from offshore Australia, with the ultimate goal to obtain a regional paleoclimate reconstruction at high spatial resolution (“All around Australia”). Here, we propose a novel way to constrain the alignment of two sedimentary sequences based on a-priori stratigraphic information. Therewith, we provide a means to make dtw calculations less computationally expensive, while still evaluating all possible stratigraphic correlations, even for long time-series.

The “All around Australia” project focuses on the automated correlation of thousands of scientific and industrial time-series. Hence, it is important to speed up the calculations and reduce the computational costs. The global constraint on dtw, also known as the window function, speeds up the calculations by limiting the 2-dimensional space of possible alignments between two time-series. As a case study, IODP Site U1463 (Northwest Shelf of Australia) serves as the reference to which two industrial sites (Finucane-1 and Angel-2) are correlated. Biostratigraphic datums of Site U1463 have few meters of depth uncertainty. Their corresponding depths at the industrial sites are manually determined, albeit with a depth uncertainty that is one order of magnitude higher (so-called “slack”).  These manually determined correlation points are then utilized to create custom-made windows, reflecting a priori knowledge of the large-scale stratigraphy of the studied basin. In this case, the comparison of the computational time and the goodness-of-fit for ‘no-window’ and ‘windowed’ dtw calculations reveals that the quality of the correlation improves and computational time is reduced by 15-20%. Hence, the novel window function is primarily useful for stratigraphers to guide the dtw algorithm in creating warping paths that are stratigraphically more plausible. 

How to cite: Samant, R., Giorgino, T., Jarochowska, E., and De Vleeschouwer, D.: Advantages of DTW windowing function in automated correlation of stratigraphic time series, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8374, https://doi.org/10.5194/egusphere-egu24-8374, 2024.

X3.88
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EGU24-12110
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ITS5.2/SSP1.13
Annalisa Iadanza, Andrea Argnani, Chiara Boschi, Angelo Camerlenghi, Giulia Casalena, Elisabetta Erba, Fabio Florindo, Biagio Giaccio, Hanno Kinkel, Marco Sacchi, Andrea Schleifer, Riccardo Tribuzio, and Paola Vannucchi

In the framework of the Research Infrastructures (RIs), scientific drilling represents a globally ranging, distributed RI that generates a wide variety of subsurface data. The ongoing project “Italian Integrated Environmental Research Infrastructures System (ITINERIS)” aims at building the Italian Hub of RIs in the environmental scientific domain by coordinating a network of national nodes from 22 RIs, including the Italian participation in the European Consortium for Ocean Research Drilling (ECORD) and in the International Continental Scientific Drilling Project (ICDP). The main goal of ITINERIS is to promote cross-disciplinary research in environmental sciences through the use and re-use of existing (or pre-operational) data and services and new observations, and to address scientifically and societally relevant issues.

The impact of ITINERIS on the Italian geoscientists involved in scientific drilling is twofold. First, it will improve the access to both the ECORD and the ICDP infrastructures. This will result in increasing the national participation in terms of proposal writing, drilling expeditions/projects, initiatives to use legacy samples/data, and training activities. Secondly, it will allow to collect and systematize the great amount of data produced by Italian scientists in the past scientific drilling programs (DSDP-ODP-IODP). This will facilitate the data handling and interoperability approach. A thematic digital archive of ECORD/ICDP-related data will be provided within the following thematic areas: micropaleontology, petrology, elemental and isotope geochemistry, paleomagnetism, stratigraphy/lithology, structural geology, borehole geophysics and site survey. This structured and accessible scientific dataset will represent a milestone for further implementation following FAIR data principles and best practices for ongoing and future drilling projects. Further developments of this digital archive might also serve as an additional tool to be integrated within the SPARCs initiative of IODP3.

How to cite: Iadanza, A., Argnani, A., Boschi, C., Camerlenghi, A., Casalena, G., Erba, E., Florindo, F., Giaccio, B., Kinkel, H., Sacchi, M., Schleifer, A., Tribuzio, R., and Vannucchi, P.: A legacy plan and an innovative access framework for the next decades of Italian geoscientists involved in scientific drilling: the role of ECORD/IODP-Italy in the ITINERIS project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12110, https://doi.org/10.5194/egusphere-egu24-12110, 2024.

X3.89
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EGU24-14690
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ITS5.2/SSP1.13
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Highlight
Denise K. Kulhanek, Valentin Zuchuat, Morgan Jones, Jiri Barta, William J. Foster, Wolfram H. Geissler, Sten-Andreas Grundvåg, Henning Lorenz, Sverre Planke, Kim Senger, Grace Shepherd, Kasia K. Sliwinska, Aleksandra Smyrak-Sikora, Lidya G. Tarhan, Madeleine Vickers, Maximilian Weber, Weimu Xu, and Daniel Kramer

The Svalbard archipelago, located in the Norwegian High Arctic, preserves more than 650 million years of near-continuous sedimentary rock records spanning from the Neoproterozoic to the Cenozoic. The polar paleogeographic location of Svalbard in the late Mesozoic and the Cenozoic makes sites in Svalbard unique amongst well-studied temporally equivalent successions from lower paleolatitudes, allowing investigation of the polar amplification climatic effect over geological time. The sedimentary record of Svalbard has been largely controlled by northward drift of constituent geological provinces throughout much of the Phanerozoic and evolving tectono-stratigraphic environments including the influence of several Large Igneous Provinces (LIPs) and global climate fluctuations. 

The SVALCLIME initiative aims to systematically drill and core the sedimentary successions in Svalbard. Two sub-projects currently being evaluated by the ICDP materialized from an international workshop held in Longyearbyen in October 2022. The first is a full ICDP proposal focused on hyperthermals from the Permian to Paleogene (SVALCLIME P2P) and an ICDP-IODP Land to Sea preproposal on hothouse to coldhouse transitions in the late Paleozoic and across the Eocene–Oligocene transition (SVALCLIME Hot2Cold).

The SVALCLIME P2P project aims to investigate the high-resolution Arctic paleoclimate record from 255 to 45 Ma onshore Svalbard that encompasses several Mesozoic and Cenozoic hyperthermal events and the near-field impacts of three LIPs (the Siberian Traps, the High Arctic LIP and the North Atlantic Igneous Province). Our focus will also be on the deep biosphere to uncover the relationship between mineral substrates and taxonomic and metabolic diversity of intraterrestrial microbiomes. We propose to core seven boreholes at three locations (Nordenskiöldfjellet, Botneheia and Kropotkinfjellet), with a cumulative total cored length of ~3.4 km. 

The SVALCLIME Hot2Cold project aims to address global transitions from hothouse to icehouse conditions during the late Paleozoic and the Eocene to Oligocene. In the preproposal we identify suitable drill sites both onshore and offshore to characterize these periods. The Forlandsundet Graben in western Spitsbergen offers an opportunity to decipher the evolution of the Fram Strait and its impact on global oceanographic circulation during the Eocene–Oligocene transition. The Upper Carboniferous to Early Permian syn and post-rift deposits of the Billefjorden Trough will be targeted to investigate >130 cyclothems originating from glacioeustatic sea level fluctuations.

In this contribution, we outline the background and motivation of the SVALCLIME initiative and present the scientific objectives and the proposed drill sites.

How to cite: Kulhanek, D. K., Zuchuat, V., Jones, M., Barta, J., Foster, W. J., Geissler, W. H., Grundvåg, S.-A., Lorenz, H., Planke, S., Senger, K., Shepherd, G., Sliwinska, K. K., Smyrak-Sikora, A., Tarhan, L. G., Vickers, M., Weber, M., Xu, W., and Kramer, D.: SVALCLIME – Targeting deep-time Arctic climate archives of Svalbard, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14690, https://doi.org/10.5194/egusphere-egu24-14690, 2024.

X3.90
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EGU24-17124
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ITS5.2/SSP1.13
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ECS
Bernd Trabi, Andrew Greenwood, and Florian Bleibinhaus

A unique Seismic While Drilling (SWD) experiment, whereby a diamond coring drill rig as the seismic source has been conducted in the Val d’Ossola, Western Alps, Italy. For the SWD experiment 64 3C-sensors are employed in an array at the surface and the vibrational action of coring the rock acts as an active seismic source within the borehole. The maximum offset of the sensor array is 480 m with non-uniform spacing that increases with distance. The drilling operation took place from early October until mid-December 2022 and reached a depth of approximately 580 m. The seismic sensors recorded at a sampling rate of 1 ms, which is more than sufficient for an expected frequency of up to 200 Hz. The proposed SWD experiment is to evaluate the potential and limitations of the SWD method for diamond core drilling commonly utilized in scientific drilling projects with a focus on fundamental developments of the methodology and data processing techniques. Ideally the drill-bit seismic record should produce a seismic image around the bore hole and ahead of the drill bit. First it is important to determine if a signal can be detected, and to what depth, from a diamond core drill bit. In contrast to percussion or reverse circulation drilling, the diamond core drilling method produces a very weak signal. The seismic data is also heavily contaminated by coherent and random noises generated at the drill site, including rig engines, generators and mud-pumps, vehicles, and the movement of equipment. Separation of theses coherent noises using radon transform has thus far failed and other wavefield separation methods are investigated. Using seismic interferometric methods for unknown source positions, we aim to detect the weak signal at known drill bit positions. This is promising especially at drilling depths where the drill-rig and drill-bit wave-fields are spatial or temporal separated from each other, due to their different origins and velocities. Interferograms are obtained using the cross-coherence method, which is applied to the recorded passive seismic data. These are computed from 30sec time windows of the continuous recordings and then stacked into the final interferogram to increase the signal-to-noise ratio. Instead of migration summation, semblance is measured for the interferometric migration process. For the migration process, a constant velocity model is sufficient in this hard-rock environment. The major noise sources that we image are the vibrations of the drill rig and power generator, which appear to mask the weaker signal from the drill bit. In an ongoing second experiment, we utilize grid power, reducing the noise sources to the mud-pumps, rotating string, and rig.

How to cite: Trabi, B., Greenwood, A., and Bleibinhaus, F.: Seismic while drilling with a diamond drill bit in project DIVE DT-1B borehole in the Ivrea-Verbano Zone (Western Alps, Italy), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17124, https://doi.org/10.5194/egusphere-egu24-17124, 2024.

X3.91
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EGU24-19299
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ITS5.2/SSP1.13
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ECS
Giulia Matilde Ferrante, Laura De Santis, Sergio Andò, Robert McKay, Denise Kulhanek, Jenny Gales, Matteo Perrotti, Luca Zurli, Satish Singh, Michele Rebesco, Renata Giulia Lucchi, Tina Van Der Flierdt, Tim Van Peer, and Caterina Morigi

Growing evidence suggests that portions of the Antarctic Ice Sheet (AIS) could cross a tipping point over the next decades due to global warming. The Mid-Pliocene Warm Period (mPWP, 3.3-3 Ma, +2°C) is regarded as one possible geologic analog to the climate of the near future, and paleo-sea level during mPWP interglacials indicates that portions of the AIS were lost at that time. However, due to a lack of ice-proximal data, the timing, magnitude and trigger mechanisms of AIS retreats remain unconstrained. Here, we focus on the Ross Sea, where the IODP Exp. 374 Site U1523 recovered the first Antarctic Plio-Pleistocene record from a current-controlled sediment drift in an environment evolving from ice-proximal to open marine over time. U1523 is located where intrusions of warm deep water and outflows of cold water occur today, controlled mainly by the strength and route of the Antarctic Slope Current. To constrain the relative influence of oceanic currents and AIS dynamics on sediment erosion, transport and deposition across the Plio-Pleistocene transition (3.3-2.6 Ma), we integrate grain size, morpho-mineralogical, magnetic fabric analysis and geophysical logs from site U1523 with the multi-channel seismic line IT94-127A. We complement our dataset with a closeby box core (PNRA ODYSSEA exp., box core 08), that can be regarded as a present day analogue. Here, we present our morpho-mineralogical results on the box core and some specific intervals of the mPWP from site U1523. In particular, we perform single mineral Raman spectroscopy which, together with the entire suite of minerals and their relative abundance, highlight the different depositional environments and the source of the detritus, identifying local vs distant and magmatic vs metamorphic sources. Furthermore, we use the geophysical logs to perform rock physics correlation and we tie them to the seismic line, allowing the analysis to be extrapolated along the shelf.

How to cite: Ferrante, G. M., De Santis, L., Andò, S., McKay, R., Kulhanek, D., Gales, J., Perrotti, M., Zurli, L., Singh, S., Rebesco, M., Lucchi, R. G., Van Der Flierdt, T., Van Peer, T., and Morigi, C.: TriGgeR mechanisms of Antarctic ice sheet INStability across the Plio-pLeistocene trAnsitIoN - GRAINSPLAIN project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19299, https://doi.org/10.5194/egusphere-egu24-19299, 2024.

X3.92
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EGU24-22323
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ITS5.2/SSP1.13
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Highlight
Arne Ulfers, Tina van de Flierdt, Richard Levy, Gavin Dunbar, Huw Horgan, Denise Kulhanek, and Molly Patterson and the SWAIS2C Science Team

The West Antarctic Ice Sheet (WAIS) is currently experiencing accelerated mass loss and contains enough ice to raise global sea levels by up to five meters if it were to melt completely. The objective of the international and interdisciplinary SWAIS2C project (Sensivity of the West Antarctic Ice Sheet to 2 Degrees Celsius of Warming) is to understand 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. The project will drill two deep boreholes beneath the Ross Ice Shelf to obtain sediment sequences from a site close to the grounding line of the Kamb Ice Stream site (KIS-3) and the Crary Ice Rise (CIR). The geological data will be used to improve model-based projections of future sea level contributions from Antarctica and to answer  the overarching question under what climatic conditions the WAIS collapsed in the past.

Here we present an overview of the SWAIS2C project, its’a aims and current progress. In the first season 2023/24, hot water drilling was successfully completed at KIS-3 to penetrate the ~580 m thick Ross Ice Shelf. Oceanographic measurements were taken in the ~55 m ocean cavity beneath the ice shelf, together with videos of the seafloor and ice shelf, and installation of permanent moorings. Gravity and hammer coring yielded 7.6 m of sediment, which have been subsampled for microbiology and geochemistry, and described using field-based x-ray images. The sediments recovered include the longest sediment core from the Siple Cost, measuring 1.92 m.

The sedimentological and drilling experience gained will be of great value for the 2024/25 season, when a team of drillers and scientists will return to KIS-3 for deep drilling with the Antarctic Intermediate Depth Drill (AIDD). A combination of hydraulic piston coring and rotary coring will be used to retrieve a sediment core of up to 200 m below sea floor. Drilling operations will be complemented by geophysical downhole logging with wireline tools from the Leibniz Institute for Applied Geophysics (LIAG) and a logging while tripping system provided by the German Research Centre for Geosciences (GFZ). The inclusion of different methods will allow downhole logging of several parameters over the entire sediment sequence and minimizes the influence of unstable borehole walls on the measurements.

How to cite: Ulfers, A., van de Flierdt, T., Levy, R., Dunbar, G., Horgan, H., Kulhanek, D., and Patterson, M. and the SWAIS2C Science Team: Sensivity of the West Antarctic Ice Sheet to 2° Celsius of Warming. The SWAIS2C project., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22323, https://doi.org/10.5194/egusphere-egu24-22323, 2024.

X3.93
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EGU24-4956
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ITS5.2/SSP1.13
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ECS
An-Sheng Lee, Hsuan-Tien Lin, and Sofia Ya Hsuan Liou

X-ray fluorescence (XRF) core scanning, renowned for its high-resolution, non-destructive, and user-friendly operation, is pivotal in geological research for analyzing chemical, physical, and biological signals. Despite the extensive applications of XRF data for various research purposes, the quantification of this data into specific geological proxies remains challenging due to the inherent non-linearity caused by simple sample pretreatment during core scanning. Leveraging advancements in deep learning, computing power and large-scale scientific drilling programs, our study aims to address this non-linearity by harnessing the often-overlooked raw XRF spectra stored in laboratory databases. We introduce an approach involving self-supervised pretraining on 54,643 spectra from marine sediments in the high-latitude sectors of the Pacific Ocean (cruises SO178, SO264, PS97, PS75, LV29). Our model, underpinned by a deep bidirectional image transformer (ViT-base), is trained to reconstruct heavily masked spectra (75%) with an R2 accuracy of 0.996, demonstrating its proficiency in feature extraction from limited data portions. This foundational model is anticipated to serve as a versatile tool for various downstream geological applications after finetuning with specific labeled data, such as quantifying high-resolution calcium carbonate (CaCO3) and detecting machinery anomalies. Future work includes expanding the spectrum database with diverse materials and machine settings to enhance the model's generalizability, ultimately broadening its applicability beyond core scanning for geological applications to encompass all XRF measurement techniques.

How to cite: Lee, A.-S., Lin, H.-T., and Liou, S. Y. H.: Pretraining Foundation Models: Unleashing the Power of Forgotten Spectra for Advanced Geological Applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4956, https://doi.org/10.5194/egusphere-egu24-4956, 2024.

X3.94
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EGU24-14233
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ITS5.2/SSP1.13
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Hiroshi Ogasawara, Yasuo Yabe, Raymond Durrheim, Musa Manzi, Thomas Kieft, Devan Nisson, Julio Castillo, Alba Gómez-Arias, Bennie Liebenberg, and Team DSeis and PROTEA

The ICDP DSeis project accomplished full-core drilling and borehole-logging of the seismogenic zone of the 2014 M5.5 Orkney earthquake, South Africa. Three NQ-holes (total 1.6 km in length), drilled from 2.9 km depth at the Moab Khotsong gold mine, penetrated mostly intact hard rock, including 2.9 Ga meta-sedimentary and altered andesite (Crown) formations dipping ~20°SE. Subparallel altered gabbroic diorite sills intrude the formations.

After the borehole penetrated the Crown Formation and approached the steeply-dipping planar cluster of earthquake aftershocks, it encountered a potassic lamprophyre dyke several meters thick. The lamprophyre was intact close to the dyke contact, with mineral assemblages of augite, actinolite, and biotite. The talc and calcite content and magnetic susceptibility increased towards the centre of the dyke, while the augite and actinolite content decreased. The lamprophyre rock mass then became brecciated, with a substantial fraction of gouge. The Crown Formation adjacent to the dyke contact was also brecciated. Friction tests made on lamprophyre gouge (which contains about 20 wt% talc) yielded very low friction coefficients, similar to the results of previous wet friction experiments (Yabe et al. EGU 2024).

The DSeis drilling also intersected a non-potassic dyke rich in actinolite and chamosite about 300 m east of the potassic lamprophyre dyke. Whilst this dyke hosted no indications for aftershocks, the extracted brine was more hypersaline and older than any brine previously sampled from deep South African gold mines (Nisson et al., 2023). The hypersaline brine was non-meteoric in composition, with dissolved organic carbon concentrations sufficient to support deep life.

Both dykes show significant spatial variation in composition which we attributed to contamination/assimilation and metamorphism, depending on which formations (~20°SE dip) the dykes cut. We postulate that the localization of aftershocks in ‘streaks’ subparallel to the strata is a result of this compositional heterogeneity.

DSeis has successfully penetrated, sampled, and studied the aftershock sequence on the upper edge of the Orkney earthquake rupture. However, important questions regarding the nucleation and rupture of the earthquake that will only be solved by studying the strong motion source of the mainshock. The proposed PROTEA scientific drilling project aims to probe the Orkney earthquake's strong motion sources (the heart).

The existing DSeis hole, the new PROTEA hole, and the connecting horizontal tunnels at 2.9 km depth will allow us to deploy a 3D distributed acoustic sensing (DAS) network with a vertical span of several hundreds of meters, and a horizontal span of about 1 km. Using both active and passive seismic sources, we expect to image the 3D structure of the reflectors precisely.

Moab Khotsong has offered the team access to borehole cores that have sampled numerous dykes and sills; as well as access to the database of lithology and geological structure mapped on the mining horizons at 2-3 km depth. These data cover a much broader volume than the DSeis and PROTEA projects, and will significantly extend and enhance the interpretation.

Acknowledgements: South African gold mines, related firms, SATREPS, Kakenhi (21224012), ICDP, JSPS Core-to-Core Program, MEXT Kochi Core Center, NSF, DFG, NRF, Ritsumeikan and Kyoto Univs.

How to cite: Ogasawara, H., Yabe, Y., Durrheim, R., Manzi, M., Kieft, T., Nisson, D., Castillo, J., Gómez-Arias, A., Liebenberg, B., and DSeis and PROTEA, T.: From DSeis to PROTEA - Probing the heart of an earthquake, especially the interaction between metasedimentary rocks and mantle-derived intrusions. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14233, https://doi.org/10.5194/egusphere-egu24-14233, 2024.