Evaluating the segmented post-rift stratigraphic architecture of the Guyanas continental margin

Segmentation of the Guyanas continental margin South America is inherited from dual-phase Mesozoic rifting history controlling first-order post-rift sedimentary architecture. The divided into two segments by a transform marginal plateau (TMP), Demerara Rise, Central and Equatorial Atlantic domains. This paper investigates heterogeneities in systems at mega-regional scale (>1000 km). Re-sampling seven key exploration wells scientific boreholes provides new data (189 analysed samples) that have been used to build high-resolution stratigraphic framework using multiple biostratigraphic techniques integrated with organic geochemistry refine timing 10 surfaces three megasequences. results calibrate interpretation margin-scale two-dimensional seismic reflection dataset, megasequence isochore maps, structural restorations gross depositional environment maps time intervals evolution. Our findings revise dating basal succession drilled A2-1 well, indicating oldest sequence penetrated along late Tithonian age (previously Callovian). Early carbonate platform sediments passively infilled subcircular-shaped basement topography controlled underlying structure thinned crust. Barremian–Aptian Atlantic, caused folding thrusting resulting major uplift, gravitational collapse, transpressional structures peneplanation up 1 km sediment capped regional angular Base Albian Unconformity. led segmentation formation TMP, where unconformities developed during intra Late base Cenomanian. These are synchronous oceanic crust accretion offshore French Guiana Demerara–Guinea transform, respectively. A marine connection between demonstrated middle times, coinciding deposition organic-rich source rock Canje Formation (average total carbon 4.21%). variably truncated Middle Campanian Refining within context evolution impacts understanding petroleum system elements. Supplementary material : Photographs sandstone petrography thin sections (Fig. S1); calcareous nannofossil plates S2); palynology reports for FG2-1 S3); taxonomy description species; sample table (Table distribution charts S2) available https://doi.org/10.6084/m9.figshare.c.5280490