THIN · Lithosphere THINning During Subduction Initiation
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2020-09-01 → 2022-08-31
- EU contribution
- €212,934
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Lithosphere THINning During Subduction Initiation
The formation of new subduction zones is a fundamental process of the solid Earth that controls the motion of the tectonic plates, and therefore the formation of volcanoes and earthquakes around the globe. Despite its importance, this process is still poorly understood. The THIN project, as originally submitted in September 2020, aimed at studying the deformation in the mantle section of ophiolites to reconstruct the nature, style, and kinematics of the tectonic processes associated with the formation of a new subduction zone. This main aim, was achievable by using a set of techniques such as: paleomagnetism, magnetic fabric, field structural geology, and an innovative magnetite geochronology method. Having the project started soon after the outbreak of the COVID-19 pandemic, the primary fieldwork in the Sultanate of Oman could not be carried out due to travel restrictions imposed by the Oman authorities to non-residents. Because of this, the original project was substantially revised in terms of main objectives and study area. The alternative project that have been carried out in the end, addressed another key question of global plate tectonics: what happens when a spreading ridge ceases its activity? The revised THIN project aimed at studying the deformation of the upper mantle and lower crustal section of the Troodos Ophiolite of Cyprus to understand the tectonic processes associated with the demise of a spreading ridge. The topics investigated by the revised THIN project are relevant to the society, as ore deposits are typically extracted from ophiolites for economic exploitation. Ore deposits, primarily copper and chrome, are formed in the oceanic crust and mantle, respectively, during the accretion of new crust at a spreading ridge. Ophiolites are pieces of oceanic lithosphere that have been uplifted above sea level. Hence, understanding how a spreading ridge preserved in an ophiolite like Troodos ends its activity and is eventually disrupted by tectonic processes is fundamental to predict if, where, and how much ore deposits were formed at that specific spreading ridge.
Data: CORDIS, © European Union
Project objective
The initial foundering of lithosphere into the upper mantle, known as subduction initiation, is one of the key, most intriguing, and least understood processes of the solid Earth’s cycle. Despite being a relatively ephemeral phenomenon only lasting a few million years, subduction initiation is paramount to understand the driving forces of plate tectonics. The study of subduction initiation processes has mainly focused on supra-subduction zone ophiolites, which are emerged relics of oceanic lithosphere originally formed above a nascent subduction zone. Geological evidence from these ophiolites strongly suggest that subduction initiation causes extreme thinning of the rocks located above the incipient subduction zone; yet, the origin and main features of this process cannot be investigated directly in modern active systems. The main objective of this project is to investigate the tectonic processes triggered by a nascent subduction zone to fully untangle the complex and still poorly understood process of subduction initiation. The proposed research will analyse for the first time the deformation in the mantle section of one of the best preserved and most complete ophiolites of the world (the Semail ophiolite of Oman) to ultimately unveil the mechanism(s) aiding lithosphere thinning during subduction initiation. THIN will use a combination of paleomagnetic, magnetic fabric, structural geological, and geochronological techniques to reconstruct the tectonic rotations in the mantle section of the Oman ophiolite and ultimately produce a four-dimensional (three dimensions over time) model of deformation that will shed key lights on one of the most fundamental geological processes for our planet.
Original text from CORDIS.
Participants
- THE UNIVERSITY OF BIRMINGHAM · BirminghamCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union