Tectonic history along the South Gabon Basin:: Anomalous early post-rift subsidence

An integrated study of the South Gabon Margin (South Atlantic) based on reflection seismic and well data has been performed to quantify tectonic activity. A regional profile crossing the entire basin together with subsidence analysis, highlights important aspects of the post-rift history. The most striking event in the margin evolution appears to be the anomalous extra subsidence during the early post-rift period characterized by high sedimentation rates, equivalent to one third of the syn-rift subsidence. Although the presence of evaporite layers restricts knowledge of the underlying structures essentially composed of pre-rift and syn-rift sequences, the outcome of this post-rift tectonic study has strong implications for the rifting history. The early post-rift subsidence patterns can be related to a high thermal anomaly during the early rifting thermal state of the lithosphere. These findings are highly relevant for petroleum system studies and have implications for hydrocarbon generation. (c) 2007 Elsevier Ltd. All rights reserved.