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  1. Article ; Online: Slow response of the gas hydrate system to ridge erosion and sea-level rise

    Kroeger, K. F. / Crutchley, Gareth J. / Pecher, I. A.

    Insights from double BSRs on the southern Hikurangi margin (New Zealand)

    2023  

    Abstract: We analyse reflection seismic profiles across the outer accretionary wedge at the convergent New Zealand Hikurangi margin. We identify several, in some case stacked, bottom simulating reflections (BSRs). We interpret these multiple BSRs to record changes ...

    Abstract We analyse reflection seismic profiles across the outer accretionary wedge at the convergent New Zealand Hikurangi margin. We identify several, in some case stacked, bottom simulating reflections (BSRs). We interpret these multiple BSRs to record changes in gas hydrate stability. With the aid of gas hydrate systems modelling, we identify two geological drivers that affect gas hydrate stability: (1.) rapid sedimentation in trough basins and (2.) uplift and erosion of thrust ridges. Rapid sedimentation in trough basins buries gas hydrates that formed above the former base of gas hydrate stability (BGHS). Locally, we observe a remnant BSR from this process, likely due to residual gas and possibly gas hydrate. The combined effects of uplift and erosion, in contrast, result in the preservation of a remnant BSR within the gas hydrate stability zone, whilst a new BSR forms locally at the present-day BGHS. However, the limited occurrence of double BSRs in seismic data and the model both suggest that the formation of a deeper BSR is limited by gas supply. Formation of significant gas hydrate at this deeper level only occurs in areas of focused gas migration. This slow formation of gas hydrate also has implications for the response to glacio-eustatic sea-level rise: gas hydrates are more likely to accumulate above the BGHS corresponding to the last glacial maximum, whereas only small amounts formed above the deeper present-day BGHS. Hence, future bottom water warming will, at least initially, not lead to significant methane release from dissociating gas hydrates in deep water.
    Subject code 550
    Language English
    Publisher Elsevier
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Revised Storegga Slide reconstruction reveals two major submarine landslides 12,000 years apart

    Karstens, Jens / Haflidason, Haflidi / Berndt, Christian / Crutchley, Gareth J.

    2023  

    Abstract: The Storegga Slide is the largest known exposed submarine landslide in the world, which triggered a tsunami that inundated the coasts of northern Europe ~8,150 years ago. Previous studies suggested the removal of 50–70 m of sediment from the northern ... ...

    Abstract The Storegga Slide is the largest known exposed submarine landslide in the world, which triggered a tsunami that inundated the coasts of northern Europe ~8,150 years ago. Previous studies suggested the removal of 50–70 m of sediment from the northern slide scar segment, contributing half of the total slide volume of up to 3200 km³. However, new sediment echosounder profiles and sedimentological constraints show that most material within the northern Storegga slide scar had already failed ~20,000 years ago, at the end of the Last Glacial Maximum. We refer to this previously undetected slope failure as the Nyegga Slide. In our revised slope failure reconstruction, the Nyegga Slide removed more than 35 m of sediments that were previously attributed to the tsunamigenic Storegga Slide. This implies that large slope failures at the mid-Norwegian margin occur more frequently than previously thought, indicating a higher tsunami hazard for the North Atlantic.
    Subject code 550
    Language English
    Publishing date 2023-02-28
    Publisher Springer
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Conference proceedings ; Online: Extensional faulting around Kolumbo Volcano, Aegean Sea – investigating local stress fields, fault relay structures and volcanism

    Crutchley, Gareth J. / Karstens, Jens / Preine, J. / Hübscher, C. / Kühn, M. / Fossen, H.

    2023  

    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Conference proceedings ; Online: Normal faulting around Kolumbo Volcano - exploring relationships between stress fields and volcanism

    Crutchley, Gareth J. / Karstens, Jens / Preine, J. / Hübscher, C. / Fossen, H. / Kühn, Michel

    2023  

    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Conference proceedings ; Online: Seismic imaging of the submarine Kolumbo Volcanic Chain reveals its volcano-tectonic evolution and link to Santorini

    Preine, J. / Hübscher, C. / Karstens, Jens / Crutchley, Gareth J. / Nomikou, P.

    2023  

    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Conference proceedings ; Online: From Eruptions to Reflections

    Preine, J. / Hübscher, C. / Karstens, Jens / Crutchley, Gareth J. / Nomikou, P.

    Seismic imaging of submarine volcanoes, their plumbing system and eruptive products at the Christiana-Santorini-Kolumbo Volcanic Field

    2023  

    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Conference proceedings ; Online: Seismic imaging of the submarine Kolumbo Volcanic Chain

    Preine, J. / Hübscher, C. / Karstens, Jens / Crutchley, Gareth J. / Nomikou, P.

    2023  

    Publishing country de
    Document type Conference proceedings ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Extensional Faulting Around Kolumbo Volcano, Aegean Sea — Relationships Between Local Stress Fields, Fault Relay Ramps, and Volcanism

    Crutchley, Gareth J. / Karstens, Jens / Preine, Jonas / Hübscher, Christian / Fossen, Haakon / Kühn, Michel

    2023  

    Abstract: The Christiana‐Santorini‐Kolumbo (CSK) volcanic field has hosted more than 100 explosive eruptions in the past 250,000 years, including the 1650 CE eruption of Kolumbo Volcano. Previous studies have established a link between regional tectonics and ... ...

    Abstract The Christiana‐Santorini‐Kolumbo (CSK) volcanic field has hosted more than 100 explosive eruptions in the past 250,000 years, including the 1650 CE eruption of Kolumbo Volcano. Previous studies have established a link between regional tectonics and volcanism in the CSK volcanic field. While 2D seismic reflection data have given valuable insight into regional faulting, detailed fault zone characterization has been precluded by the sparsely spaced profiles. Using 3D seismic reflection data around Kolumbo Volcano, we provide the first 3D characterization of fault zones in the CSK volcanic field. Beneath the volcano's northwestern flank, and farther to the northwest, normal faults are predominantly NE‐SW trending, with mean fault trends between 044° and 049°. Normal faults beneath the southeastern flank are slightly more north‐oriented, with mean fault trends between 028° and 038°. Our detailed fault zone analysis reveals clear NW‐SE directed extension around the volcano, consistent with published focal mechanisms from microseismicity. The Kolumbo Fault Zone, ∼6 km northwest of Kolumbo Volcano, is characterized by distinct relay ramps between major overstepping normal faults. Regional 2D seismic profiles reveal a previously undocumented volcanic cone directly above the fault zone. Magma ascent to this cone has likely exploited enhanced vertical permeability associated with distributed deformation within a relay ramp. We suggest that fault relay structures may play an important role, over a range of spatial scales, in focusing magma ascent within the CSK volcanic field. Plain Language Summary In the last 250,000 years, more than 100 explosive eruptions have occurred in the “Christiana‐Santorini‐Kolumbo” volcanic field in the Aegean Sea. Eruptions like these represent a serious natural hazard for the region. In this study, we explored how tectonic processes are related to volcanic activity. We did this by studying tectonic deformation around the submarine Kolumbo Volcano, which last erupted violently in 1650 CE. We ...
    Subject code 550
    Language English
    Publishing date 2023-10-18
    Publisher AGU (American Geophysical Union)
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Both Longitudinal and Transverse Extension Controlling Gas Migration Through Submarine Anticlinal Ridges, New Zealand's Southern Hikurangi Margin

    Crutchley, Gareth J. / Hillman, J. I. T. / Kroeger, Karsten F. / Watson, Sally J. / Turco, F. / Mountjoy, J. / Davy, Bryan / Woelz, S.

    Journal of Geophysical Research: Solid Earth. 2023 June, v. 128, no. 6 p.e2022JB026279-

    2023  

    Abstract: Sub‐seabed fluid flow, gas hydrate accumulation and seafloor methane seepage are tightly interwoven processes with implications for marine biodiversity, ocean chemistry and seafloor stability. We combine long‐offset seismic reflection data with high‐ ... ...

    Abstract Sub‐seabed fluid flow, gas hydrate accumulation and seafloor methane seepage are tightly interwoven processes with implications for marine biodiversity, ocean chemistry and seafloor stability. We combine long‐offset seismic reflection data with high‐resolution seismic data to investigate shallow structural deformation and its relationship to focused gas migration and hydrate accumulation in the southern Hikurangi subduction wedge. Anticlines, effective traps for focusing free gas, are characterized by both normal faults and vertical zones of hydraulic fracturing within the hydrate stability zone. The normal faults form as a result of sediment layer folding and gravitational collapse of ridges during uplift. We document both longitudinal (ridge‐parallel) and transverse (ridge‐perpendicular) extensional structures (normal faults and elongated hydraulic fracture zones) in the sub‐seafloor of anticlinal ridges. Intriguingly, gas flow through ridges close to the deformation front of the wedge exploits longitudinal structures, while ridges further inboard are characterized by gas flow along transverse structures. This highlights pronounced changes in the shallow deformation of ridges in different parts of the wedge, associated with a switching of the least and intermediate principal stress directions. It is critical to understand these shallow stress fields because they control fluid flow patterns and methane seepage out of the seafloor.
    Keywords biodiversity ; chemistry ; deformation ; gas hydrate ; geophysics ; hydraulic fracturing ; methane ; research ; sediments ; seepage ; subduction ; New Zealand
    Language English
    Dates of publication 2023-06
    Publishing place John Wiley & Sons, Ltd
    Document type Article ; Online
    Note JOURNAL ARTICLE
    ISSN 2169-9313
    DOI 10.1029/2022JB026279
    Database NAL-Catalogue (AGRICOLA)

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  10. Article ; Online: Investigating the role of faults in fluid migration and gas hydrate formation along the southern Hikurangi Margin, New Zealand

    Hillman, Jess I. T. / Crutchley, Gareth J. / Kroeger, Karsten F.

    2020  

    Abstract: The Hikurangi Margin off the east coast of the North Island (Te Ika-a-Māui) is a tectonically active subduction zone and the location of New Zealand’s largest gas hydrate province. Faults are internally complex volumetric zones that may play a ... ...

    Abstract The Hikurangi Margin off the east coast of the North Island (Te Ika-a-Māui) is a tectonically active subduction zone and the location of New Zealand’s largest gas hydrate province. Faults are internally complex volumetric zones that may play a significant role in the migration of fluids beneath the seafloor. The combined processes of deformation and fluid migration result in the formation of concentrated hydrate accumulations along accretionary ridges. It is not fully understood to what extent faults control fluid migration along the Hikurangi Margin, and whether deep-seated thrust faults provide a pathway for thermogenic gas to migrate up from sources at depth. Using 2D models based on seismic data from the region we investigated the role of thrust faults in facilitating fluid migration and contributing to the formation of concentrated gas hydrates. By altering permeability properties of the fault zones in these transient state models we can determine whether faults are required to act as fluid flow pathways. In this study we focus on two study sites offshore southern Wairarapa, using realistic yet simplified fault geometries derived from 2D seismic lines. The results of these models allow us to start to disentangle the complex relationship between fault zone structure, permeability, geometry, fluid migration and gas hydrate formation. Based on the model outputs we propose that faults act as primary pathways facilitating fluid migration and are critical in the formation of concentrated gas hydrate deposits.
    Subject code 550
    Language English
    Publishing date 2020-03-07
    Publisher Springer
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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