Aberdeen University Featured PhD Programmes
University of Dundee Featured PhD Programmes
University of Kent Featured PhD Programmes
University of Southampton Featured PhD Programmes
Cardiff University Featured PhD Programmes

Unravelling the mysteries of plate tectonics


Project Description

Plate tectonics is the most unifying and revolutionary theory in Earth sciences. However, 50 years after its formulation fundamental questions about how plate tectonics works still remain unanswered. In particular, the formation of new subduction zones (whereby one tectonic plate starts to sink underneath another one) is poorly understood. Current models suggest that subduction can either initiate spontaneously due to gravitational instability, or be induced by external tectonic forces. In the last decade ophiolites (emerged relics of ancient oceanic lithosphere) have been crucial to study subduction initiation processes. Most ophiolites, in fact, form during subduction initiation above an incipient subduction zone. A recent work in the Oman ophiolite (Guilmette et al., 2018) used the time lag between the formation of the ophiolitic crust and the formation of the metamorphic layer found at its base to discriminate between forced and spontaneous subduction initiation. These metamorphic rocks, known as metamorphic sole, are key to constrain the age of subduction initiation as they form during the initial moment of subduction development. A substantial difference between the ages of ophiolitic crust and metamorphic sole would indicate a forced subduction initiation, while similar ages would suggest a spontaneous subduction initiation.

The primary aim of this project is to reconstruct the style (spontaneous vs. forced) of a past, major subduction initiation event to understand the possible mechanisms and causes behind the inception of a subduction zone. The ideal natural laboratory to study subduction initiation processes is an ophiolite belt running for hundreds of kilometers from the Alps in northern Italy to the Dinarides and Hellenides in the Balkan Peninsula. These ophiolites are relics of oceanic lithosphere formed during, and as a result of a major subduction initiation event occurred within the Neotethys Ocean during the Jurassic. Available geochronological ages from both the crust and metamorphic sole of the Balkan ophiolites are similar, suggesting a spontaneous subduction initiation. However, ages from the ophiolitic crust are sparse and those from the metamorphic sole used Ar39-Ar40 method, which does not date the actual metamorphism but rather the cooling occurring after it. Obtaining new ages from these ophiolites is key to better understand one of the major subduction initiation events of the Earth’s history.

Funding Notes

CENTA studentships are for 3.5 years and are funded by the Natural Environment Research Council (NERC). In addition to the full payment of their tuition fees, successful candidates will receive the following financial support.
• Annual stipend, set at £15,009 for 2019/20
• Research training support grant (RTSG) of £8,000

References

Allerton, S. and Vine, F.J., 1987. Spreading structure of the Troodos ophiolite, Cyprus: Some paleomagnetic constraints. Geology, 15(7), pp.593-597.
Guilmette, C., Smit, M.A., van Hinsbergen, D.J., Gürer, D., Corfu, F., Charette, B., Maffione, M., Rabeau, O. and Savard, D., 2018. Forced subduction initiation recorded in the sole and crust of the Semail Ophiolite of Oman. Nature Geoscience, 11(9), 688-691.
Maffione, M. and van Hinsbergen, D.J., 2018. Reconstructing plate boundaries in the Jurassic neo‐Tethys from the east and west Vardar ophiolites (Greece and Serbia). Tectonics, 37(3), 858-887.
Maffione, M., Thieulot, C., Van Hinsbergen, D.J., Morris, A., Plümper, O. and Spakman, W., 2015. Dynamics of intraoceanic subduction initiation: 1. Oceanic detachment fault inversion and the formation of supra‐subduction zone ophiolites. Geochemistry, Geophysics, Geosystems, 16(6), 1753-1770.
Stern, R.J. and Gerya, T., 2018. Subduction initiation in nature and models: A review. Tectonophysics, 746, 173-198.
Stern, R.J., Reagan, M., Ishizuka, O., Ohara, Y. and Whattam, S., 2012. To understand subduction initiation, study forearc crust: To understand forearc crust, study ophiolites. Lithosphere, 4(6), 469-483.
Stern, R.J., 2004. Subduction initiation: spontaneous and induced. Earth and Planetary Science Letters, 226(3-4), 275-292.
van Hinsbergen, D.J., Peters, K., Maffione, M., Spakman, W., Guilmette, C., Thieulot, C., Plümper, O., Gürer, D., Brouwer, F.M., Aldanmaz, E. and Kaymakcı, N., 2015. Dynamics of intraoceanic subduction initiation: 2. Suprasubduction zone ophiolite formation and metamorphic sole exhumation in context of absolute plate motions. Geochemistry, Geophysics, Geosystems, 16(6), 1771-1785.
Wakabayashi, J. and Dilek, Y., 2003. What constitutes ‘emplacement’of an ophiolite?: Mechanisms and relationship to subduction initiation and formation of metamorphic soles. Geological Society, London, Special Publications, 218(1), 427-447.

Related Subjects

Email Now

Insert previous message below for editing? 
You haven’t included a message. Providing a specific message means universities will take your enquiry more seriously and helps them provide the information you need.
Why not add a message here
* required field
Send a copy to me for my own records.

Your enquiry has been emailed successfully





FindAPhD. Copyright 2005-2019
All rights reserved.