Evolution of the Southern Guinea Plateau

Implications on Guinea-Demerara Plateau formation using insights from seismic, subsidence, and gravity data

Jared R. Olyphant, Roy A Johnson, Amanda N. Hughes

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The Guinea Plateau (offshore Guinea) and its conjugate, the Demerara Plateau (offshore French Guiana), comprise two of the most prominent passive continental margins in the Atlantic Ocean. The conjugate plateaus formed as a result of two periods of rifting, the Jurassic opening of the Central Atlantic Ocean and the northward-propagating Cretaceous opening of the Southern Atlantic Ocean. Although several studies are published on the Demerara Plateau that explain the evolution of its multi-rift history and the effect of rifting on its distinct geometry, the Guinea Plateau, and in particular its south-eastern margin, remain relatively unexplored in the literature. Here we present interpretations of the structure and evolution of the Guinea Plateau using recent 2-D and 3-D seismic-reflection data collected at the intersection of the southern and eastern margins. We substantiate our study with calculated subsidence curves at four locations along the southern margin, as well as two 2-D gravity forward models along regional seismic-reflection profiles to estimate stretching factors (β) and crustal thicknesses. We combine our results with previous studies concerning the south-western Guinea margin, and compare them to published interpretations regarding the conjugate margins of the Demerara Plateau. The resolved amounts of rift-related volcanism, listric-style normal faults, and moderate stretching factors suggest that a component of upper-crustal asymmetry (simple shear) and depth-dependent stretching may have persisted at the Demerara-Guinea conjugate margins during Cretaceous rifting of the equatorial segment of the Southern Atlantic Ocean.

Original languageEnglish (US)
Pages (from-to)358-371
Number of pages14
JournalTectonophysics
Volume717
DOIs
StatePublished - Oct 16 2017

Fingerprint

Guinea
subsidence
plateaus
margins
plateau
gravity
gravitation
Atlantic Ocean
rifting
ocean
seismic reflection
French Guiana
Cretaceous
listric fault
crustal thickness
continental shelves
intersections
normal fault
continental margin
volcanism

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

Cite this

Evolution of the Southern Guinea Plateau : Implications on Guinea-Demerara Plateau formation using insights from seismic, subsidence, and gravity data. / Olyphant, Jared R.; Johnson, Roy A; Hughes, Amanda N.

In: Tectonophysics, Vol. 717, 16.10.2017, p. 358-371.

Research output: Contribution to journalArticle

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