Project highlights

  • interpretation of state of the art regional seismic data and local 3D datasets
  • imaging both margins of mini-oceans, revealing the symmetry of rifting
  • comparison with Galicia (Spain), the site of Birmingham-proposed IODP drilling and a NSF/NERC 3D volume (Birmingham is the UK lead).

Overview

The breakup of continents to form ocean basins is a first order tectonic process.  Key discussions centre on the mechanism for hyper-extension of the crust, thinning it from ~ 30 km to zero, the role of detachment faulting and mantle serpentinization in mantle unroofing, and the symmetry/asymmetry throughout the rifting process.  Studies at rifted margins such as Galicia (west of Spain) see the final result on one side of the ocean and so cannot address these crucial questions, but studies across V-shaped rifts (e.g. Porcupine Basin) can address the effect of increasing extension by using different sections across the basin to reveal the structure at different stages in the rifting process, in effect using the spatial variation as a proxy for temporal evolution, and studies across narrow failed oceans (Rockall Trough) can address the asymmetry of final breakup, as both sides of the “ocean” are still geographically close and imaged by the same seismic surveys.

The project will build on previous work on the crustal structure of the Porcupine Basin (using older reflection and refraction data: Reston et al., 2004; Prada et al., 2018), and on the tectonic evolution of the Galicia margin as revealed by an NSF-NERC funded 3D seismic volume (Lymer et al., 2019) by comparing the Galicia rifted margin west of Spain to the failed rifts of the Porcupine Basin and Rockall Trough (both west of Ireland), both of which have been extended to crustal separation and likely mantle unroofing without forming a fully-fledged ocean basin.  Both Porcupine and Rockall are covered by extensive recent 2D seismic survey kindly donated for this study by the Irish Petroleum Affairs Division (Figure 1).  Preliminary work has focused on the postrift section but has shown that the data is of excellent quality, with clear image of faulting and of crustal structure.

The study of rifting to breakup has strong connections to ongoing work at the Galicia margin, where the NSF-NERC 3D volume (at Birmingham) underpinned the Birmingham-led IODP Proposal 943-Full (Reston et al., 2018), which is currently awaiting scheduling.

Host

University of Birmingham

Theme

  • Dynamic Earth

Supervisors

Project investigator

  • Tim Reston, University of Birmingham

 

Co-investigators

  • Steve Jones, University of Birmingham
  • Rob Hardy, Tonnta, Dublin, Ireland

How to apply

Methodology

The project will focus on the interpretation and reconstruction of state-of-the-art 2D and 3D seismic data to reveal the tectonic evolution of these basins and by implication of mature rifted margins.  Software to use will include Kingdom Suite (interpretation), 3D Move (structural analysis and reconstruction), and Globe Claritas (selective reprocessing where necessary). The results will be integrated with the result of IODP drilling west of Galicia, likely to take place in 2022 at the end of the second year of the project.   Depending on other Birmingham participation in the cruise, the DR could apply to participate on the cruise.

Training and skills

The student will take part in the seismic processing courses offered in conjunction with this project, will learn interpretation and reconstruction techniques (Kingdom and Move software) as well as courses in figure draughting, presentation skills, and suitable courses in other areas.

Partners and collaboration

The Irish Petroleum Affairs Division (PAD), and Petroleum Infrastructure Programme (PIP).  PAD commissioned the data and have given us permission to work on it.  PIP is a consortium of industry partners exploring offshore Ireland that can both contribute data to this study and make use of results.

Rob Hardy (Tonnta, Dublin) has overseen the reprocessing of the data collected for PAD and is a long-term collaborator of Jones and Reston.

Proponents of IODP Proposal 943-Full (Galicia margin: Reston et al., 2018) from six countries and 15 different institutes.  The project will be running when Galicia is drilled, probably in summer 2023 and results will be integrated with those of drilling.

Further details

Applications need to be submitted via the University of Birmingham postgraduate portal, https://sits.bham.ac.uk/lpages/LES068.htm, by midnight 11.01.2021. Please first check whether the primary supervisor is within Geography, Earth and Environmental Sciences, or in Biosciences, and click on the corresponding PhD program on the application page.

This application should include

  • a brief cover letter, CV, and the contact details for at least two referees
  • a CENTA application form
  • the supervisor and title of the project you are applying for under the Research Information section of the application form.

Referee’s will be invited to submit their references once you submit your application, but we strongly encourage applicants to ensure referees are aware of your submission and expecting a reference request from us. Students are also encouraged to visit and explore the additional information available on the CENTA website.

Possible timeline

Year 1

Literature review. Initial inspection and interpretation of regional data defining areas for detailed study.   Identification of data for selective reprocessing; training in seismic processing.

Year 2

Focused interpretation and reconstruction using 3D MOVE, and selective reprocessing of data especially in the vicinity of industry drillsites to enhance well-seismic correlation.  Participation if possible in IODP drilling expedition.  Attendance at international conference.

Year 3

Finalisation of the interpretation, incorporating structural restoration of the data.  Attendance at international conference. Publication of results and write-up.

Further reading

Lymer, G.,  Cresswell, D.,  Reston, TJ., Bull, JM, Sawyer,  DS, Morgan, JK, Stevenson, C, Causer, A.,  Minshull, TA,  Shillington, DJ,  2019. The development of detachment faulting and asymmetry during 3D continental breakup.  Earth Planetary Science Letters, v 515, p 90-99

McDermott, K, Reston TJ, 2015.  To see, or not to see? Rifted margin extension. Geology, 43, 967–970

Prada M, Watremez L, O’Reilly B, Minshull TA, Chen C, Reston TJ, Shannon P, Klaeschen D, Wagner G, Gaw V, 2017. Crustal strain-dependent serpentinisation in the Porcupine Basin, offshore Ireland. Earth and Planetary Science Letters,  474, 148-159

Reston, TJ, Gaw, V, Pennell, J, Klaeschen, D, Stubenrauch, A, Walker, I, Extreme crustal thinning in the south Porcupine Basin and the nature of the Porcupine Median High: Implications for the formation of non-volcanic rifted margins. J Geol Soc London, 161, 783-798, 2004

Reston TJ et al., 2018.  The case for scientific drilling west of Galicia, Spain.  IODP Proposal 943-Full (available from Tim Reston on request – see below)

COVID-19

The project is entirely computer-based using data that is already available at Birmingham and all activities within Birmingham can be undertaken within our existing Covid-safe guidelines.