Testing the role of thermo-chemical piles in the generation and continuation of plate tectonics

Informations projet

TEROPPLATE

N° de convention de subvention: 749664

DOI

10.3030/749664

Projet clôturé

Date de signature de la CE 1 Mars 2017

Date de début 1 Février 2018

Date de fin 31 Janvier 2020

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 195 454,80

Contribution de l’UE

€ 195 454,80

Coordonné par

UNIVERSITY OF DURHAM
United Kingdom

Periodic Reporting for period 1 - TEROPPLATE (Testing the role of thermo-chemical piles in the generation and continuation of plate tectonics)

Période du rapport: 2018-02-01 au 2020-01-31

Résumé du contexte et des objectifs généraux du projet

Review of the project

The mechanics of plate tectonics (the movement of the Earth’s surface) is a fundamental scientific question in understanding the recycling of mantle volatiles in processes that affect habitability. The emergence of plate tectonics on Earth set the planet apart from others in our solar system allowing for the propagation of life, yet the fundamentals of how it all began remain unresolved. Present-day geophysical imaging of the deep mantle show anomalous chemical piles thought to originate from the beginnings of Earth. Recently, consensus has been reached that the chemical piles can impact, and be impacted by, plate tectonic processes.

Based largely on geophysical data, two opposing hypotheses dominate the discussion on dynamics at the base of mantle: the large hot anomalies are thermo-chemical in nature; or, alternatively, they are purely thermal plume clusters. The fellowship set out to understand the impact of these chemical piles with mantle convection, and to explore their potential interaction with plate tectonic processes.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

In previous modelling studies, deep chemical heterogeneities have been argued to be essential in developing appropriate present-day plume positions. Here, the work quantified how the chemical composition of large, hot regions in the deep mantle influences the location of rising mantle plumes using numerical 3-D global mantle convection models constrained by 410 million years of palaeo-ocean evolution. State-of-the-art models showed that purely thermal convection can reproduce the observed positions of present-day hotspots. By demonstrating that a lower mantle without large-scale chemical heterogeneities can generate appropriate global dynamics, the power of sinking ocean plates to stir mantle flow and control the thermal evolution of the mantle was illustrated. Because the models with a thermo-chemical anomaly reproduced observed hotspot positions equally well, the work here highlighted that the deep hot anomalies in the mantle are purely passive in global dynamics – regardless of their (thermal or chemical) origin.

A series of invited talks and presentations for the researcher at institutions and conferences allowed for more expertise in understanding chemical piles and mantle dynamics through discussion. An invite to present the findings on the influence of chemical piles on plate tectonic processes as a keynote speaker at SEDI 2018 was a particular highlight and mark of esteem.

In the MSCA application, the researcher outlined that he would like to conduct science outreach in the local prison. In doing so he developed England’s first formal science course behind bars that won numerous awards (and shortlisted for others). Publicity from the project made local and national news. To galvanize the scientific community, the researcher wrote a number of articles on the importance of outreach in prison, as well as co-organised a very successful symposium on STEM in prison.

Returning to the EU, the researcher wanted to expand his ability to design, program, and develop large-scale numerical models using high performance computing gained from doctoral and post-doctoral experiences in Canada. This project successfully allowed the researcher to reintegrate into EU academia and contribute my acquired research skills in both my host department and at numerous other institutions (through invited talks). The expertise of the contributors and the design of the research have provided him with new knowledge and experience in early Earth geophysics and geochemistry, as well as deep mantle dynamics. A particular highlight of this project is the large number of collaborators with European ties that have been cultivated. The strength and legacy of the fellowship lies in these scientific collaborations.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

In summary, the project was to look at large-scale geodynamic models of plate tectonic processes, linking into lower mantle dynamics in the present-day and early Earth. The project has exceeded expectations by managing to produce output for each work package, and producing double the amount of publications described (however, not all have been accepted in the two year time frame of the fellowship).

A summary of the 2-year fellowship can be described as follows:

- three published papers of new work (Tectonics, Geology, and EPSL) and a published review paper;
- three papers in revision and three in preparation;
- eight invited scientific talks;
- 23 conference presentations;
- 24 new collaborators;
- nine students co-supervised;
- setup of host institution as a hub for ASPECT modelling;
- five public talks;
- five magazine articles;
- the development of an award winning education course taught in prison;
- media coverage of science education course;
- organization of ‘Prison Education and STEM Symposium‘ attended by 70 people.

The project has had a hugely successful media campaign, focussing on presenting the new scientific discoveries through invited seminars (6), conferences presentations (22), public lectures (4), and magazine articles (1). The designated outreach program described in TEROPPLATE achieved national success, with the ‘Think Like A Scientist‘ prison education program making national news for its societal impact. Think Like A Scientist won two outreach awards (EGU and BGA) as well as being shortlisted for two Durham University impact awards. A highlight was also being invited to UK Parliament to talk to MPs regarding the prison education program for the STEM for Britain awards.

Awards for Think Like A Scientist: 2020: STEM for Britain Awards shortlisted 2019: Impact and Engagement Award, Durham University shortlisted; Celebrate Excellence, Durham University shortlisted; European Geosciences Union outreach award; British Geophysical Association outreach award.

Media Appearances for Think Like A Scientist: 2019: BBC Radio Newcastle, Metro Newspaper, The I Paper, The Sun, BBC Radio Tees, EGU GeoBlog, Conseris Blog (USA), Northern Echo, Contributor to New South Wales Education Standards Authority.

A number of magazine articles about the course were disseminated (4) as well as a public talk in Durham. Furthermore, the fellowship was used to setup a successful conference on Prison Education and STEM which was hosted alongside the Prisoners’ Education Trust.

As outlined in the proposal, the numerical modelling code ASPECT was to be used for the numerical calculations and the host institution would be setup as a hub for the program in the UK. The introduction of ASPECT to Durham University’s Department of Earth Science has been highly successful, with the Geodynamics and Structural Geology groups now working with the code. Furthermore, Dr Tom Phillips wrote and won a Leverhulme Award that featured usage of ASPECT and the expertise (now established) at Durham.

During the fellowship, the fellow co-supervised PhD student Pavlos Farangitakis in ASPECT modelling, who produced a publication of the work conducted. In addition to Mr Farangitakis, the fellow co-supervised 8 undergraduate students through their final year thesis during the two years at Durham, all using ASPECT (e.g. O. Smith, 2020; Hastie, 2020; Knight, 2019; Bradshaw-Down, 2019; Peel, 2019; Ives, 2019,; Barrett, 2019; Warren, 2018).

Teropplate: Geoscientist magazine front cover and a numerical model of the Earth