Figure 4. Simplified “Trajectory Plots”, describing the average basin depositional environment trend of the northern (top) and southern (bottom) basins. Depositional environments in the syn-rift and transitional cycles are rather consistent in these basins, but there is a great variety of mainly shelf to deeper marine environments in the post-rift. The upward trend observed in most basins at the end of the post-rift reflects the additional presence of coastal environments. Note the location of source, reservoir, and seal rock horizons on the trajectory path. Note also the significantly greater variation in the southern basins and the transitional cycle (as represented by a salt sequence in the other basins) that is essentially absent from the Pelotas Basin. The proven presence of a restricted (hypersaline) marine transitional PST in the Sergipe-Alagoas Basin and the similarity of facies in other basins (see trajectory plot) might suggest that it could be present elsewhere.