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Artiom LOPAREV

Crustal geometries, palaeogeographic evolution and history of the terrigenous accumulation of the basins of the passive margin of the Guiana Craton

Supervisors:
Delphine Rouby and Dominique Chardon
GET, Geosciences Environnement Toulouse, France

Major Results

We established the impact of the superimoposition of the Central and Equatorial Atlantic rifting on the necking style variability along the passive margin of the Guiana Shield, as well as its the long-term stratigraphic architecture and paleogeographical evolution.

Abstract

The superimoposition of the Central and Equatorial Atlantic successive rifts resulted in a high variability of the necking style along the passive margin of the Guiana Shield showing alternating transform, oblique and divergent segments. This complex and diachronous lithospheric thinning pattern with narrow transform/oblique segments and wide divergent segment resulted in very different subsidence evolutions, preservation pattern, sedimentary systems and stratigraphic architectures along the margin.

Nevertheless, the evolution of the craton drainage pattern significantly impacted the stratigraphic architectures further enhanced this variability with the Berbice and Orinoco River feeding the western margin since the late Cretaceous and late Oligocene respectively and the modern Amazon River system fed the eastern margin since the Late Miocene.

Summary of the main crustal structure characteristics of the margin segments.
Values are dip width of the crustal domains in km except for the oceanic crust for which the thickness in TWT in seconds is indicated.
GS: Guiana/Suriname; FOZ: Foz do Amazonas; DEM: Demerara plateau

PhD Thesis: Géométries crustales, évolution paléogéographique et histoire de l’accumulation terrigène des bassins de la marge passive du Craton Guyanais.

Artiom Loparev. Géométries crustales, évolution paléogéographique et histoire de l’accumulation terrigène des bassins de la marge passive du Craton Guyanais. Université Toulouse 3 Paul Sabatier, 2020

keywords: rifting diachrone, marge passive, bilan d’accumulation terrigène, érosion cratonique, paléo-géographie, géodynamique