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Major structural elements of the Suriname-Guyana Basin include the active and non-active transfer zones, the syn-rift grabens underlying the shelf, the shelf itself and a deep marine basin.
The Jurassic graben system had a strike of approximately 60° to the coast. This rift system was later cut (Albian onwards) by several major transcurrent faults, along which South America and Africa drifted apart. No stretching preceded the latter phase and thermal subsidence is less well expressed. The low thermal subsidence, combined with a large supply of clastics from the shield resulted in a sand rich shelf, which from the Eocene onwards, built out into the deep-water domain.
The major expression of Lower Cretaceous compression is the folded and faulted Demerara Plateau, a scarcely explored, old (Jurassic-Lower Cretaceous) basin. Following the uplift, large volumes of Early Cretaceous sediments were eroded to form a regionally extensive erosion surface, the Aptian –Albian unconformity.
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The main architectural elements of the basin are illustrated in this regional composite seismic section, which stretches from the shelf to the Demerara Plateau. Note the length of the profile as well as the time scale (down to 9 seconds).
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The northwest-southeast oriented section stretches from the deep basin offshore Suriname into French Guiana, where the FG2-1 well was drilled. This well encountered excellent reservoir rocks but a lack of structural closure. Highlighted in the westernmost part of this section are growth faults and toe thrusts, which form part of an Aptian-Albian delta system (see opportunities). The delta marks the western flank of the plateau and was deposited by rivers that once ran between northwestern South America and western Africa, prior to their separation.
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