Tectonostratigraphic development in the eastern Lower Congo Basin, offshore Angola, West Africa

As in all Aptian Salt Basins off western Africa, the post-rift evolution of the Lower Congo Basin offshore Angola was greatly influenced by raft tectonics. We suggest that rafting in the Lower Congo Basin took place during relatively short periods (7-10 Ma), characterized by high strain rates separated by longer periods ( 15-35 Ma), characterized by low strain rates. The high strain rate periods are dated as: Aptian-Late Cretaceous, Late Eocene-Late Oligocene and Late Miocene-Recent. With respect to the Tertiary development we have obtained a positive correlation between sedimentary thickness and cumulative stretching, suggesting sedimentary loading as an important driving mechanism for raft tectonics. During the Tertiary two different types of depocentres developed. These are (i) broad first order depocentres governed by regional subsidence and (ii) narrower elongated second order depocentres governed by growth on active faults. Within the study area the depocentres seem to have migrated from the west towards the east. (C) 2001 Elsevier Science Ltd. All rights reserved.