Crutchley, Gareth J., Judith Elger, J. Kuhlmann, J. J. Mountjoy, A. Orpin, A. Georgiopoulou, J. Carey et al. "Investigating the basal shear zone of the submarine Tuaheni Landslide Complex, New Zealand: a core‐log‐seismic integration study." Journal of Geophysical Research: Solid Earth (2021): e2021JB021997.
In a new core-log-seismic integration (CLSI) paper, Crutchley et al. have investigated the basal shear zone of the submarine Tuaheni Landslide Complex, off the East Coast of New Zealand. Understanding the triggers for submarine landslides is something that has been the focus of intense study for many decades. In this paper, the authors make use of a remarkable dataset that includes high-resolution 3D seismic data (from the P-Cable system), sediment core samples (from both the JOIDES Resolution drillship and MARUM’s remote seafloor drillrig MeBo200), and logging-while-drilling data from the JOIDES Resolution. Integrating these diverse datasets is a challenging task, that has required expert input from a range of geoscience disciplines.
Drilling next to the landslide revealed a ∼25 m-thick layer of sediment (from ∼75–95 m below the seafloor) that has strong variations in sediment strength and density. The authors infer that intervals of relatively low strength within this layer developed into the main sliding surface of the landslide. Additionally, results from within the landslide suggest that the process of landslide emplacement has induced a zone of weak sediments closer to the seafloor. The study demonstrates how combining seismic images and drilling data helps to understand submarine landslide processes.
Figure courtesy of Gareth Crutchley, GEOMAR.
Check out the full paper (open access) at the following link:
Elger, Judith, Christian Berndt, Felix Kästner, Simona Pierdominici, Jochem Kück, Bjarne SG Almqvist, Christopher Juhlin, and Henning Lorenz. "Core‐log‐seismic integration in metamorphic rocks and its implication for the regional geology: A case study for the ICDP drilling project COSC‐1, Sweden." Geochemistry, Geophysics, Geosystems 22, no. 3 (2021): e2020GC009376.
Kästner, F., Pierdominici, S., Elger, J., Zappone, A., Kück, J., Berndt, C., 2020. Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: a case study for the COSC-1 borehole, Sweden. Solid Earth 11, 607–626. https://doi.org/10.5194/se-11-607-2020
Kästner, F., Pierdominici, S., Zappone, A., Morales, L.F.G., Schleicher, A.M., Wilke, F.D.H., Berndt, C., 2021a. Cross‐Scale Seismic Anisotropy Analysis in Metamorphic Rocks From the COSC‐1 Borehole in the Scandinavian Caledonides. J. Geophys. Res. Solid Earth 126, e2020JB021154. https://doi.org/10.1029/2020jb021154
Kästner, F., 2021. Core-log-seismic data integration at the COSC-1 borehole in the Central Scandinavian Caledonides.
Kästner, F., Klaeschen, D., Berndt, C., Pierdominici, S., Hedin, P., 2021b. Anisotropic velocity models for (3D) seismic imaging of the Lower Seve Nappe in Jämtland, Sweden. Geophys J Int 228, ggab339-. https://doi.org/10.1093/gji/ggab339
In the true spirit of core-log-seismic integration (CSLI) we conducted a joint project between GFZ-Potsdam and GEOMAR, reanalyzing wire line logs and 3D seismic data and augmenting them with physical property measurements of core samples under in situ pressures in the laboratory. The site for the CLSI study was the COSC-1 borehole in the central Scandinavian Caledonides of Sweden. CLSI in well-stratified sedimentary rocks comes with a lot of challenges. Now, imagine how difficult such a study becomes when you are dealing with metamorphic rocks, where internal impedance contrasts are much more difficult to characterize than they are in sedimentary rocks.
These studies combine data from the COSC-1 borehole with different geophysical measurements to better understand the lithology and structure of the Seve Nappe Complex. Elger et al. show that the combination of these data enables rocks of mafic and sedimentary origin to be distinguished from each other. Geophysical data through the borehole image the change in composition of the rocks, which probably originates from magmatic intrusions that have been overprinted by geological processes, rather than from deformation-induced physical property changes as observed in the KTB borehole. Crucial headway was made for CLSI in metamorphic environments by incorporating anisotropy during seismic processing (Kästner et al.).
Figure courtesy of Judith Elger, GEOMAR.
Check out the full papers at the following links:
Elger et al. 2021:
Kästner et al. 2020:
Kästner et al. 2021a:
Kästner et al. 2021b:
On the 15th and 16th of April, 2021, we will be hosting a virtual workshop on Core-Log-Seismic Integration (CLSI). The workshop will be jointly hosted by GEOMAR, GFZ and AWI. The workshop has 50 registered participants and will include nine invited talks and approximately twelve quick-fire presentations.
The goal of the workshop is to provide a forum for presenting a range of expertise and interest in CLSI and to stimulate discussion between different groups. Additionally, the workshop provides us with the opportunity to formally open the Virtual CLSI Centre and discuss how we can get the best value out of this community initiative.
For more information, please contact one of the workshop organisers. Attendance is open to anyone who is interested. We just request that you register your interest with us, and then we can provide you with more information (including how to join the online meeting).
Professor of Marine Geophysics
Head of Scientific Drilling Working Group
Deputy Head of Geophysics Section