Geomorphology and architecture of siliciclastic vs. volcaniclastic deep-water channels

Supervisors: Dr. Adam McArthur (Leeds), Prof. Quentin Fisher (Leeds), Prof. Fabiano Gamberi (ISMAR), Alexander Wunderlich (OMV)

Contact email: a.mcarthur@leeds.ac.uk

A PhD studentship to be run under the auspices of the Turbidites Research Group (TRG) in the School of Earth and Environment at the University of Leeds

Highlights

  • Opportunity to undertake field, laboratory and subsurface investigation of stunning datasets from on and offshore New Zealand, Italy and the UK.
  • Join an integrated research group, with links to international research associates and industry.
  • Attend international conferences in Europe, the US and elsewhere.
  • Project sits alongside linked research as part of a larger programme.
  • Opportunities for career development (academia, internships, industry and beyond).
Figure 1. Spectral decomposition image extraction from seismic data across a subsurface area of the Taranaki Basin to be investigated. Here a range of channel types and morphologies are seen, including complex, sinuous forms in the central area and straighter channels from the right fed by submarine volcanoes. Wells penetrating this interval can be used to examine the physical properties of the volcaniclastic sediments. Image courtesy of OMV.

Background

Submarine channels are prevalent across the continental slopes of Earth and are the most important conduits for sediment transfer to the deep-sea. Both on the modern seafloor, in the rock record at outcrop, and in the subsurface submarine channel systems are seen to form intricate networks of incisional and/or aggradational channel complexes. Submarine channels are observed to form in every tectonic setting and are fed from a terrestrial hinterlands or from oceanic volcanic centres. The primary objective of this project is to compare and contrast the geomorphology and resulting stratigraphic architecture and composition of deep-marine channels developed in volcaniclastic and siliciclastic sedimentary systems.

This project will help develop our fundamental understanding of how deep-sea channels behave with different types and volumes of sediment, potentially decoupled from sea-level drivers. The project will also develop an applied understanding of the likely fill and stratigraphic properties of channel complexes imaged in the subsurface, i.e., if they may form good reservoirs for natural resources or present significant geohazards.

This project will benefit from access to a large, industry subsurface dataset (including 3D seismic data, well logs, and core) across an area with numerous deep-marine channel complexes from offshore New Zealand (Fig. 1). Additionally, a seafloor dataset from the Tyrrhenian Sea (including bathymetry, CHIRP, and core data) will allow study of the morphology of volcaniclastic channels (Fig. 2). Fieldwork on volcaniclastic channel fills is possible (Fig. 3) and the successful candidate will work with rock samples to assess the physical properties of volcaniclastic channel fills, but the project is designed to be flexible, and can be adapted to the particular interests of the candidate.

 

Aeolian channels

Figure 2. Oblique view of the seafloor surrounding the Aeolian Island arc. Here seafloor channels may be seen coming from volcanic centres and meeting the continental fed Stromboli Slope Valley, implying a mixing of siliciclastic and volcaniclastic sediment.

Aim and objectives

The primary aim of this project is to analyse a number of examples of siliciclastic and volcaniclastic deep-water channels, to build depositional and architectural models. In addition, the research will involve development and employment of the Deep-Marine Architecture Knowledge Store (DMAKS), a relational database designed and populated by members of Turbidites Research Group at Leeds. Collected data will be used to address research questions (directly as part of this project; see below), but also more widely within the research group to inform modelling of subsurface channel fills, and process-based experimental and numerical modelling of submarine channels. Both fundamental and applied research themes can be investigated as part of the project, and these may include, but are not limited to, any of the following topics and related research questions.

  • What differences are there between the morphology and architecture of siliciclastic and volcaniclastic deep-water channels? Although siliciclastic channel forms and resulting stratigraphic architecture have been well studied (e.g., Mayall and Stewart, 2000; Janocko et al., 2013; Peakall and Sumner, 2015; McArthur and Tek, 2021), their volcaniclastic equivalents have not, particularly in the subsurface. Can geomorphology (planform and cross-sectional) and architecture of the various channel types help us to resolve their formative processes and enable a classification of the channel type and architecture based on their source and sediment type? What can the timing and cyclicity of volcaniclastic channels tell us about generic deep-water channel development, particularly in a setting decoupled from traditional sequence stratigraphic models? What is the anticipated length, size and architectural complexity of the various channel types under the same bounding conditions? To what degree do siliciclastic and volcaniclastic channels display commonalities? What key criteria can be established to help differentiate channel types in the subsurface?
  • Does variability in sediment source and type influence flow processes and reservoir properties? In the absence of terrigenous sediment supply can volcaniclastic systems provide significant quantities of sediment to infill channels? What are the rock properties of volcaniclastic channel fills? Does the mineralogy, diagenesis and potential porosity and permeability differ significantly in the aforementioned channel types? Do volcaniclastic turbidite systems interact with mass-transport deposits in ways similar to their siliciclastic counterparts? Ultimately, do volcaniclastic channel fills present viable reservoirs for resources or carbon capture and storage?
  • Can we improve the application of analogue data for subsurface channel studies? This study will provide data for modelling of channelized deep-marine successions in the subsurface. Can we improve on the population of reservoir modelling workflows in volcaniclastic settings? What geological factors should we consider when selecting analogues for channelized volcaniclastic subsurface deposits?
Mohakatino outcrop
Figure 3. Spectacular outcrops of the Mohakatino Formation volcaniclastic turbidite sequence, onshore Taranaki, North Island, New Zealand. Such exposures allow detailed field mapping, sedimentary logging and collection of samples for further study.

Methodology

Three principle methods shall will be applied to answer the above questions:

  • A comparative study of modern submarine channels and ancient channel fills in volcanic provinces researching data from published literature. The data will be organised and stored in a relational database (DMAKS) and it will provide analogues for the study datasets. This will involve evaluating hierarchy of channel elements and integrating high-resolution modern bathymetry and 3D seismic volumes with outcrop-derived studies.
  • High resolution bathymetry, CHIRP data, and core samples from the Tyrrhenian Sea will be used to classify the geomorphology of modern volcanically sourced submarine channels. This will provide insights to seafloor elements of active channels, flow processes, sediment transport capacity, sediment type and potential distribution.
  • The preservation potential, stratigraphic architecture, spatiotemporal evolution, heterogeneity, and rock properties of volcaniclastic channel complexes will be studied with industry data. Including 3D seismic datasets, well logs, cuttings, and core analysis and interpretation from the Taranaki Basin, offshore New Zealand.
  • Potential for fieldwork in New Zealand, Italy, or the UK to characterise the detail and lateral relationships of lithofacies and stratigraphic architecture of deep-water volcaniclastic systems (Fig. 4).
Volcaniclastic channel fill
Figure 4. Volcaniclastic channel fill example from Baja California, Mexico. Pumice clasts mark an inverse graded bed, formed by complicated flow processes, different to that of siliciclastic turbidity currents.

Potential for high-impact outcome

This project faces earth science, environment, and volcanology themes, whilst aiming to provide applied outcomes in geohazards, natural resources and geosolutions (e.g. carbon capture and storage [CCS]). The project will benefit from expert supervisors, including from industrial (OMV) and government agencies (ISMAR – the Italian marine sciences research institute), from which the candidate can benefit by interaction with key stakeholders, and enjoy placements and training in industry. This interaction will contribute to the development of scientific, policy, and industrial solutions for the national and global scale problems we face in coming decades. Specifically, understanding how subsurface reservoirs perform, both for energy, including geothermal, or as a host for CCS, and with implications for marine geohazards, including eruptions, landsliding, and tsunamis. The successful candidate will also benefit from access to a large, cutting edge, multidisciplinary dataset, required to understand the complex interactions within the submarine Earth system.

 

Eligibility

Applicants should have a BSc degree (or equivalent) in geology, earth sciences, geophysics or a similar discipline. An MSc or MGeol in applied geoscience (or similar) would be an advantage. Experience of using GIS and seismic interpretation software would be useful, though is not essential. Skills in field-based geological data collection and field sedimentology and stratigraphy are desirable.

 

Training

The successful applicant will work within the inter-disciplinary Turbidites Research Group, which is part of the wider Sedimentology Group at the School of Earth and Environment, University of Leeds. The TRG has a number of on-going research projects related to deep-marine clastic sedimentology via field studies, physical and numerical modelling, and seismic studies. The project will provide specialist scientific training, as appropriate, in: (i) morphometric analysis of landscape features with a range of software (e.g. ArcGIS, Matlab or Python); ii) geological interpretation of seismic datasets using a range of software (e.g. Petrel, Paleoscan); (iii) relational-database theory and practice (e.g. MySQL); (iv) statistical analysis of large datasets; and potentially field-based techniques for the sedimentological and architectural analysis of clastic successions. The mixed pure- and applied-science nature of this research project will enable the candidate to consider a future career in either academia or industry.

In addition, the candidate will have access to a broad spectrum of training workshops provided by the Faculty that include an extensive range of training workshops in statistics, through to managing your degree, to preparing for your viva (http://www.emeskillstraining.leeds.ac.uk). The successful candidate will be strongly encouraged and supported to publish the outcomes of their research in leading international journals and present results at leading international conferences.

 

CASE Partner

This research has been agreed as a “Partnership Project” (a CASE project) with OMV, a multinational integrated energy and petrochemical company. The project aligns with an existing collaboration between Leeds and OMV to investigate submarine channels for a better characterization of subsurface sedimentary successions.

 

Recommended Reading

Gamberi, F. and Marani, M. (2007). Downstream evolution of the Stromboli Slope Valley (southeastern Tyrrhenian Sea). Marine Geology 243: 180-199. https://doi.org/10.1016/j.margeo.2007.05.006

Janocko, M., Nemec, W., Henriksen, S. and Warchol, M. (2013). The diversity of deep-water sinuous channel belts and slope valley-fill complexes. Marine and Petroleum Geology 41: 7-34. https://doi.org/10.1016/j.marpetgeo.2012.06.012

Mayall, M. and Stewart, I. (2000). The architecture of turbidite slope channels. In: GCSSEPM Foundation 20th Annual Research Conference, Deep-Water Reservoirs of the World. 578-586. https://doi.org/10.5724/gcs.00.15.0578

McArthur, A. D. and Tek, D. E. (2021). Controls on the origin and evolution of deep-ocean trench-axial channels. Geology 49: 883-888. https://doi.org/10.1130/G48612.1

Peakall, J. and Sumner, E. J. (2015). Submarine channel flow processes and deposits: A process-product perspective. Geomorphology 244: 95-120. https://doi.org/10.1016/j.geomorph.2015.03.005

Shumaker, L. E., Sharman, G. R., King, P. R. and Graham, S. A. (2018). The source is in the sink: Deep-water deposition by a submarine volcanic arc, Taranaki Basin, New Zealand. Sedimentology 65: 2506-2530. https://doi.org/10.1111/sed.12475

Tek, D.E., McArthur, A.D., Poyatos‐Moré, M., Colombera, L., Patacci, M., Craven, B. and McCaffrey, W.D. (2021). Relating seafloor geomorphology to subsurface architecture: How mass‐transport deposits and knickpoint‐zones build the stratigraphy of the deep‐water Hikurangi Channel. Sedimentology. https://doi.org/10.1111/sed.12890

 

Further Information

For more information about this project and related TRG activities contact:

Adam McArthur a.mcarthur@leeds.ac.uk, http://trg.leeds.ac.uk/