OffshoreCongo

Congo Offshore

Point Noire Offshore

On this schematic cross-section of the Congo offshore, we find the same geological elements as in the northern offshore of Angola. Sub-aerial lava-flows, i.e., SDRs, are not illustrated. Probably they are included in the basement. Between the pre-rifting unconformity (PR) and the breakup unconformity, a large rift-type basin was deposited, in which a proven generating petroleum sub-system developed in association with lacustrine shales. Between the breakup unconformity and the salt induced tectonic disharmony (bottom off the salt and salt welds) a significant shaly interval (Pointe Noire and Pointe Indienne shales), with characteristics of potential source-rocks was deposited. Seaward of the Atlantic hinge (prominent basement high bounded by a major west-dipping normal fault zone (Karner et al., 1998), the seismic lines show indication of the margin infra-salt sediments. Do not forget this cross-section is idealized. The seismic lines, as well as, their time-depth conversion suggest a more complex picture, as illustrated by the next Canvas autotrace of a regional depth seismic line.

The presence of a typical lengthened continental Gondwana lithosphere (continental crust) with rift-type basins below an obvious breakup unconformity is not evident on this Canvas autotrace of a depth seismic line shot on the Congo offshore. As we had not access to the original time seismic line, this tentative geological interpretation is, highly, conjectural. In fact, as with wrong interval velocities a time antiform can be transformed in a depth synform, all tentative interpretation of a depth seismic line without, previously, show the time version interpretation is the best way to avoid criticism, but criticism is the basis for any scientific research (K. Popper, 1934).