Fundamental to our understanding of the Earth is the theory of plate tectonics. This predicts that throughout the Earth’s history the continents have converged to form large continental assemblies and subsequently broken apart and dispersed. It is hypothesised that continents cyclically converge and disperse. Since the Precambrian, ~600 million years ago, there have been two supercontinents: Gondwana and the younger Pangea. Within the continents today are large circular sedimentary basins that contain a sedimentary record spanning from the break-up of Gondwana till present. These ‘cratonic’ basins provide a unique archive of the past, yet surprisingly, how they formed remains an open question. In this proposed fellowship I will test the hypothesis that they are a fundamental aspect of the tectonic cycle of supercontentent dispersal. The aim is to explore the relationship between cratonic basin formation and lithosphere destabilisation due to continental break-up. I will explore the coupling between the surface processes of erosion and deposition, and the lithosphere and mantle interaction below. I will develop laboratory experiments of fluid flow and a complimentary numerical model of that couples surface erosion and sedimentation with upper mantle convection. Using this combined approach I will explore the relationship between intra-continental subsidence and mantle convection.
Cratonic basins are found on every continent but their potential for hydrocarbon production is not fully understood. Very old cratonic basins have been preserved with sedimentary accumulations of up to 3 billion years . Such an extraordinary sedimentary archive allows insights into continent behaviour and mantle convection in ancient times. These are the only long-lived records of movement of the Earth’s deep interior. Therefore to understand the formation of cratonic basins is a fundamental problem and relates directly to the wider question of long-term stability of continental platform.
Fields of science
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