Tectono-sedimentary evolution of the Suriname margin in the cretaceous: A sequence-stratigraphic framework

The offshore margins of Guyana, Suriname, and French Guyana (the “Guyanas Equatorial Margin”) have become the focus of active hydrocarbon exploration over the last decade, with significant energy resources discovered since 2015 along both the Guyana and Suriname segments of the margin. Those discoveries are mainly associated with the Late Cretaceous series of the Guyana-Suriname Basin and they shed light to a rare situation where stratigraphic traps are particularly successful. To date, the tectono-stratigraphic evolution of the area has been primarily examined at margin-scale through seismic refraction, rare borehole data and sparse, regional long offset multichannel 2D seismic datasets. In this paper we combine the results from newly acquired high-resolution well data, 2D/3D seismic interpretation and 3D seismic geomorphology, to build a robust and consistent sequence stratigraphic framework and address the evolution of Cretaceous sedimentary landscapes offshore Suriname, with a particular emphasis on the Late Cretaceous strata. The Suriname margin displays a very specific overall sequence stratigraphic evolution marked by four main phases each characterized by distinct sedimentary fluxes and related overall geometries: 1) a margin initiation phase, 2) an aggrading phase, 3) a backstepping phase and 4) a forestepping phase. The Suriname basin initiated in the Early/Mid Jurassic after the emplacement of thick Early Jurassic volcanic series attributed to the Sierra-Leone (or Bahamas) Hotspot (phase 1). This localized early magmatic activity led to two very different configurations: a typical Volcanic Passive Margin in the east along the western border of the Demerara Plateau and a transform segment to the west (essentially along the Guyana margin). The following phase (phase 2) is characterized by the establishment of a Late Jurassic to Early Cretaceous mixed clastic‑carbonate platform with an overall aggradational stacking pattern observed until the Early Aptian. Phase 3 started by significant backstepping, that culminated during the Cenomanian-Turonian transition, coeval with widespread organic-rich marine shale deposition. This overall transgression occurred in four steps: (B) late Early Aptian flooding followed by renewed margin progradation; (C) Early Albian flooding and (D) Late Albian to Cenomanian flooding above the break-up unconformity and (E) the maximum backstep at the Cenomanian-Turonian boundary. This long-term transgressive trend is interpre