Development history of the southern terminus of the Central Atlantic; Guyana–Suriname case study

Abstract

The study focuses on the offshore Guyana–Suriname–French Guiana region. It draws from seismic, well, gravimetric and magnetic data. They indicate that the continental break-up along the western margin of the Demerara Plateau took place during the Callovian–Oxfordian, associated with the Central Atlantic opening, and accommodated by normal faults. The continental break-up in the SE offshore Guyana accommodated by strike-slip faults was coeval. The continental break-up along the NE and eastern margins of the Demerara Plateau took place during the late Aptian–Albian, associated with the opening of the Equatorial Atlantic, and accommodated by dextral strike-slip and normal faults, respectively.Different spreading vectors of the Central and Equatorial Atlantic required development of the Accommodation Block during the late Aptian/Albian–Paleocene in their contact region, and in the region between the Central Atlantic and its southernmost portion represented by the Offshore Guyana Block, which were separated from each other by the opening Equatorial Atlantic. Its role was to accommodate for about 20° mismatch between the Central and Equatorial Atlantic spreading vectors, which has decreased from the late Aptian/Albian to Paleocene down to 0°.Differential movements between the Central and Equatorial Atlantic oceans were also accommodated by strike-slip faults of the Guyana continental margin, some active until the Paleocene.Supplementary material:Extended methods and discussion chapters are available at http://www.geolsoc.org.uk/SUP18875

Transform margins: development, controls and petroleum systems – an introduction

“…They include the transform margins associated with the Gettysburg-Tarfaya transform fault system (Nemčok et al 2005 and references therein) and Cobequid-Chedabucto -Gibraltar transform fault (1) the Sierra Leone and Northern Demerara faults that have divided the Central Atlantic from the Equatorial Atlantic since Albian time (e.g. Loncke et al 2015;Nemčok et al 2015a and references therein); (2) the Pernambuco and Fernando Poo faults that divided the Equatorial Atlantic from the South Atlantic since Albian time (Rosendahl et al 2005;Nemčok et al 2012bNemčok et al , 2015a and references therein); and (3) the Falklands and Agulhas transform faults (Edwards 2013, pers. comm.…”

“…The larger-scale example comes from the study of Nemčok et al (2015a). It documents that the stress field controlling the initial development of the transform fault system in initiating the Equatorial Atlantic developed a right-stepping system of ENE -WSW dextral strike-slip fault zones.…”

“…Utilizing a plate reconstruction technique and reflection seismic interpretation, Reeves et al (2016) also study the role of multiple tectonic events on the breakup geometry. Nemčok et al (2015a) document a role of wrench faulting in control of the ocean segment terminus. Focusing on the spatial and temporal development of the two competing rift zones trying to control the continental breakup, Sinha et al (2015) discuss the role of the transform fault in the release of the microcontinent from the overlap region between the two zones.…”

Overpressure evolution controlled by spatial and temporal changes in the sedimentation rate: Insights from a basin modelling study in offshore Suriname

“…The sedimentary history of the basin reflects its tectonic evolution (Figure 2). The Central Atlantic rift phase is represented by syn‐rift fill sediments, which are composed of volcanic rocks, evaporites and siliciclasitc sediments (Berrangé & Dearnley, 1975; Crawford et al., 1985; Nemčok et al., 2016; Reuber et al., 2016). It is overlain by Jurassic sediments of the Central Atlantic drift phase composed of evaporite and fluvio‐deltaic to shallow marine siliciclastic deposits (Crawford et al., 1985; Reuber et al., 2016; Staatsolie, 2015).…”

Superimposed Rifting at the Junction of the Central and Equatorial Atlantic: Formation of the Passive Margin of the Guiana Shield

“…Moreover, the two rift systems had contrasted opening modes: the CAR system had lower obliquity (extension direction at a high angle to the margin trend) and velocity than the EAR (Brune et al, 2016(Brune et al, , 2018. The CAR developed contemporaneously with magmatism (Basile et al, 2020;Museur et al, 2020;Nemčok et al, 2016;Reuber et al, 2016), which is not the case for the EAR (e.g., Greenroyd et al, 2008;Loncke et al, 2009). The mid-Cretaceous (ca.…”