Description du projet
L’évolution géologique des côtes orientales de l’Amérique
Les marges passives, zones où les continents se sont éloignés et ont été séparés par un océan, sont des sources majeures de pétrole et de gaz et des points chauds essentiels de la biodiversité. L’élévation du niveau de la mer, l’augmentation de l’intensité des tempêtes et la perte de sédiments constituent une menace pour ces environnements dont l’évolution est mal comprise en raison de l’absence de modèles combinant l’érosion des sols et le dépôt de sédiments. L’histoire de la marge passive de l’Atlantique dans l’est des États-Unis, qui implique l’exposition de roches autrefois enfouies à la suite de facteurs tels que l’érosion, n’est pas tout à fait claire. En développant un nouveau modèle, le projet STRATASCAPE, financé par l’UE, vise à clarifier cette histoire.
Objectif
Passive continental margins make up many of the world’s densely populated coasts, hold 35% of the world’s largest oil reservoirs, sequester carbon, and are critical biodiversity hotspots. Human populations and infrastructure on passive margins are at risk from sea level rise, increased storm intensity, and sediment starvation. The geologic evolution of passive margins around the world is poorly understood due to a lack of models that couple terrestrial erosion with sediment deposition in the deep marine environment. The Atlantic Passive Margin (APM) of the eastern United States is exceptionally enigmatic; debate centers on how many (if any) pulses of exhumation occurred on the APM since the opening of the Atlantic Ocean 200 million years ago. Yet there has been no attempt to use mechanistic surface process models to extract APM exhumation history. I propose to build a new, coupled model of terrestrial and marine sediment transport and use it to invert the rich deep marine sedimentary record for APM exhumation history. I will develop a new model for continent-scale deep marine seascape and stratigraphy evolution over geologic time, which I will couple with existing models for terrestrial and shallow marine environments. I will validate the new model against an existing small-scale stratigraphy model as well as stratigraphy from the Bay of Biscay and the Ogooué Delta, Gabon. I will use the coupled model to invert the deep marine sedimentary record and resolve APM exhumation history over the past 200 Ma. Inversion results will provide novel constraints on the number, timing, and cause of exhumation pulses, and will be compared against thermochronologic data and geodynamic models. This approach is the first to quantitatively link the development of marine stratigraphy to APM landscape change. The proposed study will unlock the potential of deep marine deposits, the most complete sedimentary archives on Earth, to yield time-resolved records of changes to Earth’s surface.
Champ scientifique
Mots‑clés
Programme(s)
Régime de financement
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinateur
14473 POTSDAM
Allemagne