f Basin modelling of the Ghana transform margin: implications for the structural, thermal and hydrocarbon evolution of the Tano Basin

This study explores the structural and thermal evolution of the Ghana transform margin. The main objective is to explore how the opening of the Atlantic Ocean and subsequent interaction with the Mid-Atlantic Ridge (MAR) has affected the margin’s structural and thermal evolution. Two representative evolution scenarios are described: a reference case that neglects the influence of continental break up and a second scenario that does account for a possible heat influx during the passage of the MAR as well as magmatic underplating. These two scenarios have further been analyzed for the implications for the hydrocarbon potential of the region. The scenario analysis builds on a suite of 2D realizations performed with TECMOD2D, a modeling software for automated basin reconstructions. Taking the presently observed stratigraphy as input, the structural and thermal evolution of a basin is automatically reconstructed. This is achieved through the coupling of a lithosphere scale forward model with an inverse algorithm for model parameter optimization. We find that lateral heat transport from the passing MAR in combination with flexure of the lithosphere can explain the observed uplift of the margin. These results were obtained for a broken plate elasticity solution with a relative large value for the effective elastic thickness (Te=15) and necking level (15km). Lateral heat flow from oceanic lithosphere is clearly visible in elevated basement heat flow values up to 50km away from the OCT. This influx of heat does, however, not seem to have significantly affected the maturation history along the margin. Only the deepest sediments close to the OCT show slightly elevated vitrinite reflectances in simulations that account for the passage of the MAR. In conclusion, it appears that that lateral heat transport from the oceanic lithosphere is instrumental for shaping the Ghana transform margin but seems to have only limited control on the maturation history.<br>