Modelling and inverting the deep marine sedimentary record to constrain atlantic passive margin landscape evolution
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.