Subduction initiation at magma-poor rifted margins: an atlantic perspective
Subduction initiation is a key turning point in the Wilson cycle. How it unfolds remains a glaring unknown in our understanding of the evolution of the Earth’s oceans and mountain belts. Tectonic inheritance acquired at passive margins imposes a major control on how subduction zones may form and propagate in Atlantic-type oceans. In particular, magma-poor rifted margins seem to share characteristics that may localize compressional deformation and lithospheric rupture. The southern North Atlantic represents a unique natural laboratory to investigate the main factors that control the early stages of passive margin reactivation, prior to the onset of subduction. This project aims to study the role of inherited structures on the reactivation of passive margins using qualitative and quantitative constraints derived from examples along the southern North Atlantic rifted margins, coupled with geodynamic models of subduction initiation. The study region encompasses a number of reactivated magma-poor rifted margins that preserve different stages of the Wilson cycle, including: 1) the pristine Newfoundland margin; 2) an incipient, dormant, subduction zone in the western Bay of Biscay; and 3) an example of passive margin reactivation in Western Iberia. We will first map different styles and stages of margin reactivation along the studied Atlantic margins. Direct observations will be used to constrain kinematic reconstructions of the spatial and temporal evolution of these margins from rift to drift to reactivation. The identified key parameters that control reactivation will then be tested and explored using numerical geodynamic models. The action will involve an experienced international and multi-disciplinary team that will work closely together to further enhance our understanding of the Earth system. This opportunity will also provide the candidate with a new set of opportunities to boost her career and to develop strong coordination and leadership skills.