ALBERT

Description: Sedimentary basins represent geological archives. Accordingly, 3D basin models that integrate geological and geophysical observations can be used to reproduce not only their present-day structural configuration and distribution of physical properties, but also their evolution including the subsidence history. For example, the thickness of deposited sediments reflects the amount of subsidence caused by the sediment load. The corresponding load-dependent vertical movements (called isostatic subsidence) can be sequentially subtracted from the total subsidence in order to reconstruct past depth configurations. Another aspect of basin subsidence is caused by thermal processes that can also be approximated by studying the present-day basin configuration. If the basin formation is related to lithospheric stretching and thinning, it initially involves a thermal disturbance due to which the geothermal gradient is increased by an amount depending on the observed strain. After stretching has ceased, the lithosphere starts cooling down and approaches a thermal equilibrium. This cooling process is accompanied by an increase in rock density and related thermal subsidence, which can also be assessed. By calculating the two subsidence components for certain stratigraphic intervals, the corresponding temporal changes in water depths (paleobathymetries) can be reconstructed for our understanding of subsidence dynamics. This research methodology was applied to the conjugate passive continental margins of Africa and Argentina in order to analyse and compare the evolution of sedimentary basins after the formation of the South Atlantic. This study mainly focussed on the Argentinian Colorado Basin because of its complex evolution and economic resource potential.

Description: Petroleum systems located at passive continental margins received increasing attention in the last decade mainly because of deep- and ultra‐deep-water hydrocarbon exploration and production. The high risks associated with these settings originate mainly from the poor understanding of inherent geodynamic processes. The new priority program SAMPLE (South Atlantic Margin Processes and Links with onshore Evolution), established by the German Science Foundation in 2009 for a total duration of 6 years, addresses a number of open questions related to continental breakup and post‐breakup evolution of passive continental margins. 27 sub‐projects take advantage of the exceptional conditions of the South Atlantic as a prime “Geo‐archive.” The regional focus is set on the conjugate margins located east of Brazil and Argentina on one side and west of Angola, Namibia and South Africa on the other (Figure 1) as well as on the Walvis Ridge and the present‐day hotspot of Tristan da Cunha. The economic relevance of the program is demonstrated by support from several petroleum companies, but the main goal is research on fundamental processes behind the evolution of passive continental margins.