Periodic Reporting for period 1 - GEOTRIBE (Generation and Evolution Of Transform-Ridge Interaction and Behavior on Earth)
Période du rapport: 2018-04-01 au 2020-03-31
The work further focused on the locations of new subduction initiation to answer questions such as where new subduction zones preferentially form, where they endure and where they stop living. A study that predicts locations of new subduction zones was published in the Earth and Planetary Science Letters. The models showed that the position of subduction initiation is largely controlled by the strength of the lithosphere and by the length of continental margins. The results of the models were confronted with subduction histories retrieved from plate tectonic reconstructions. Both approaches agree that subduction initiation on Earth is not a random process within the oceans, and more subduction zones stop and die in the vicinity of continental margins compared to subduction initiation. The models also suggest that intra-oceanic subduction initiation is more prevalent during times of supercontinent assembly (e.g. Pangea 220 My ago) compared to more recent continental dispersal.
One of the least understood plate boundaries on Earth are transform faults where two tectonic plates slide past each another. The work analyzed the influence of free deformable surface on the formation of detachment faults and transform boundaries. Advanced numerical methods were implemented and new rheology was developed in the convection code to assess the influence of localization of deformation on plate boundary formation. The models showed that lithospheric strength and deformation history play a key role on the surface tectonics and controls the formation of new shear plate boundaries.