Basin Evolution

Central Atlantic Rift Phase The petroleum basin history began in the Jurassic, by which time the North Atlantic rift system had progressed southward to the Central Atlantic region. Laurasia separated during this period from Gondwana Land, generating a rift graben along the coast of Suriname-Guyana.
South Atlantic Rift Phase During the Lower Cretaceous, a change in tectonic regime occurred and the African continent rotated counter-clockwise with respect to South America. This resulted in rifting to the south, opening the South Atlantic Ocean, and concomitant compression in the equatorial zone of the margin. This convergence in northeastern South America caused uplift of the Demerara and Guinea Plateaus, where Jurassic rift grabens were inverted, and Jurassic syn-rift and older, intra-cratonic sediments, underwent significant compression. This uplift was followed by major peneplainisation of the entire Suriname-Guyana Basin during the Aptian/Albian.
Equatorial Atlantic Drift Phase The Late Cretaceous is characterized by the release of stress from northeastern South America as the Equatorial Atlantic Drift Phase ensued. Africa and South America drifted largely along transform fault systems, and the South and North Atlantic Oceans were connected. A second passive margin sequence developed along the Suriname margin.
Passive Margin Phase This satellite image, derived from SEASAT radar altimeter measurements, reveals geomorphological features of the present day Atlantic Ocean floor. The seamounts, mid oceanic ridges, megafaults and fracture zones are remnants of Upper Cretaceous rifting. The faults link landforms that were once geographically contiguous: the Demerara Plateau and its conjugate margin counterpart, the Guinea Plateau; The Suriname-Guyana Basin and the Sierra Leone Basin. Since the Upper Cretaceous, the coast of Suriname has remained a passive margin. The basin was, however, affected during the Tertiary by the eastward movement of the Caribbean Plate, which resulted in a series of strike-slip faults parallel to the Surinamese coast. During the Miocene, the Pacific Plate started to under-thrust the South American continent, causing it to tilt to the east. The Amazon River’s lower tributaries consequently shifted to the south, beheading the big rivers that were draining in the Guyana Basin. This meant a change for the Suriname-Guyana basin from a sand dominated system to a clay-dominated system. It also ended the carbonate growth on the shelf due to the mud carried from the present Amazon River mouth along the coast of the Guyanas.