- Opportunity to work with cutting edge subsurface and outcrop datasets from geologically exciting areas, such as offshore New Zealand
- Join an integrated research group, with links to international research 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)
Rationale: The evolution of tectonic plate boundaries represents a fundamental aspect of the geological cycle. Sedimentation in such areas of active faulting has often been considered to be controlled by structure growth. However, new research from active margins indicates that fault network growth and evolution may be modulated by influxes of sediment (e.g., McArthur et al. 2022). Particularly, in terms of whether strain is distributed across multiple faults or focused on a smaller number of larger faults. Understanding how fault networks grow and evolve is a major question for Earth science, as faults pose significant geohazard potential, in the form of earthquakes, and concomitant land-sliding and tsunamis. The primary objective of this project is to examine subsurface data from active margins to quantify fault distribution and how that varies in the presence or absence of influxes of deep-water sediments.
This project will help develop our fundamental understanding of how geological structures develop in marine environments along active margins. This project will benefit from access to a large subsurface dataset (including seismic, well, and core data) across an active convergent plate margin – the Hikurangi Margin of New Zealand. Particularly exciting is the fact that the data span a geodetic coupling transition, between the southern portion of the margin, which is prone to catastrophic megathrust earthquakes, whilst the north of the margin is experiencing slow-slip events (Wallace and Beavan 2010). Hence, this project provides the opportunity to examine whether faulting in the wedge has developed differently either side of this transition and help assess the associated geohazard risks. Examples from other active margins, such as the outcropping Eocene deep-water fold and thrust belt of the Spanish Pyrenees may provide further insights, but the project is designed to be flexible, and can be adapted to the particular interests of the candidate.
Aim and objectives: The primary aim of this project is to analyse a number of deep-water sedimentary basins and associated structures along active continental margins, to quantify the volumes of sediment delivered to such basins and the response of structure growth. I.e., to quantitatively determine if there is a relationship between sedimentation and fault growth. 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:
- Is there a quantifiable relationship between sediment input and structure growth? Although relationships between sediment delivery and structure evolution have been hinted at from 2D cross-sections (Butler 2019; McArthur et al. 2021), little quantitative research has been done on 3D fault networks at subduction zones.
- Does the style of deformation vary depending upon the sedimentary regime? The structural style and deformation varies along the Hikurangi Margin (e.g., Wallace and Beavan, 2010; McArthur et al. 2019). Numerous reasons have been suggested for this, but does the style of deformation, e.g. distribution of thrusts, back-thrusts, detachment folds etc., vary in relation to the sedimentary system?
- Is fault activity, rupture length and hence associated natural hazards (e.g., earthquakes and tsunamis) modulated in any way by sediment flux? Can we identify areas along active margins that may be more susceptible to catastrophic fault movements, such as those to have devastated coastal communities in Indonesia and Japan? Hence this work may have fundamental implications for Earth science, in understanding the geological evolution of continental margins, but also societal impact for communities on active margins.
Methodology: Four principle methods shall will be applied to answer the above questions:
- Map faults within the overriding plate throughout the Hikurangi Margin 3D seismic volumes, totalling >15,000 km3.
- Using the extracted fault network we will explore fault population statistics.
- Mapping of sedimentary sequences in the Hikurangi Margin 3D data with a view to constraining depositional episodes in relation to structure growth. This will permit investigation of potential sediment-structure interactions.
- Fieldwork to constrain sediment-structure interactions in the exhumed Ainsa Basin in Spain may provide sub-seismic scale examples of sediment-structure interactions.
Potential for high-impact outcome: This project covers a broad scope of Earth science, with themes across structural and sedimentary geology, and aims to provide applied outcomes in geohazard research. The project will benefit from expert supervisors, including from international research institutes (e.g., GNS Science, GEOMAR) and industrial partners (e.g., Schlumberger), from which the candidate will benefit through interaction and potential placements and training. This interaction will contribute to the development of scientific and policy solutions for the global scale problems we face in coming decades.
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 petroleum geoscience (or similar) would be an advantage. Experience of programming (e.g., Python or Matlab) and seismic interpretation software would be useful, though is not essential. Skills in subsurface-based geological data collection and structural geology and stratigraphy are desirable.
Training: The successful applicant will work within the inter-disciplinary Turbidites Research Group (TRG), which is part of the wider 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) statistical analysis of large datasets; and potentially supervised machine learning. 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.