Quantified Subsidence/Sedimentation History of the Tarfaya Basin (Cenozoic, Offshore Morocco)

Abstract

The sequence stratigraphic modelling study from the offshore Cenozoic Tarfaya basin located between the Canary Islands and Morocco is mainly performed with seismic and well data in order to assess different possible exploration areas. Results of this study confirm the importance of rapid changes from uplift to subsidence on the Atlantic passive continental margin for the evolution of accommodation space in time. A tectonic active phase in the onshore part of the Aaiun-Tarfaya basin during the Eocene/Oligocene is witnessed by several hiatuses on the shelf and pronounced mass transport complexes in the basin. Seismic interpretation and numerical forward modelling indicate decreased preservation of sediments during these times, possibly because of a combination of multiple slumping and reduced sedimentary input into the system. Input data for sequence stratigraphic forward modelling are calibrated with sedimentary flux rates derived from a GIS-based analysis of the hinterland. The modelled sedimentation rates reflect the regional climatic and tectonic evolution during the Cenozoic in the study area. Especially after a turnover from greenhouse to icehouse conditions in Oligocene times (Séranne, 1999), an increased sedimentary input into the exploration area is observed in the seismic interpretation and verified within the course of sequence stratigraphic modelling.