CaboFrio

Potential Source-Rocks

Base of Atlantic-Type Divergent Margin

In the Cabo Frio offshore area, as illustrated on this Canvas autotrace, the potential lacustrine source rocks (SR), equivalent to the lacustrine clays of the Lagoa Feia formation, are located below the Aptian evaporites or associated salt welds (caused by lateral and/or vertical salt flowage) and above the volcanic sub-aerial crust (post breakup lava flows, colored in violet). Thus, we can say the more likely generating petroleum sub-system is located at the base of the Atlantic-type divergent margin, between the SDRs and the salt interval. The geometry of the SDRs, as well as, that of the potential source-rocks are quite deformed due to the seismic pitfall induced by the lateral changes of velocity interval caused by the thickness variation of the salt interval (in addition the continuous increasing of the water depth must, also, be taken into account). Obviously, the alternative potential Cretaceous marine source are immature. The burial of such organic intervals is insufficient. On the other hand, contrariwise to the Angola offshore, in this offshore there is any Tertiary uplift.