Tectono-stratigraphic evolution and architecture of the Miocene Rio del Rey basin (Cameroon margin, Gulf of Guinea)
- PDF / 22,565,037 Bytes
- 25 Pages / 595.276 x 790.866 pts Page_size
- 8 Downloads / 173 Views
ORIGINAL PAPER
Tectono‑stratigraphic evolution and architecture of the Miocene Rio del Rey basin (Cameroon margin, Gulf of Guinea) François Mvondo Owono1 · Jacqueline Ntsama Atangana2 · Sébastien Owona1 · Olivier Dauteuil3 · Moussa Nsangou Ngapna1 · François Guillocheau3 · Stéphane Koum1 · Raphael Belinga Essama Boum1 · Marie Joseph Ntamak‑Nida1 Received: 7 May 2019 / Accepted: 27 July 2020 © Geologische Vereinigung e.V. (GV) 2020
Abstract The Rio Del Rey basin located in the Gulf of Guinea is one of the two basins lining the Cameroonian coast. It evolved since the Cenozoic in a tectono-magmatic and seismic complex setting. During the Miocene, this evolution was controlled by tectonics, relative sea level changes, basin filling and mantle dynamics. Two deposit megasequences of second order, MS1 and MS2, were pointed out. MS1 (lower Miocene), aggradational and corresponding to the Isongo turbidites deposited during a period of relative sea level drop registered two sequences of third order differentiated by the degree of channel incision: S1a (Aquitanian–Burdigalian), hardly incised and S1b (Serravallian), moderately incised. A double extension along N–S (Burdigalian) and NE–SW (Serravallian) directions responsible for a set of horsts and grabens, high subsidence and depocentres trending NW–SE affected these sequences. MS2 (middle to upper Miocene), progradational and corresponding to deltaic alternations deposited during a period of creation of available space were controlled by the tilting, wrenching, a second stretching phase and low sedimentary filling. MS2 recorded three cycles of 3rd order: S2a (lower Tortonian), S2b (upper Tortonian) and S2c (Messinian) differentiated by their morphology in ramp for S2a and S2b and slope for S2c. The formation of grabens and horsts and the tilting of the margin coincide with the high activity of the Cameroon volcanic line interpreted as a result of deep mantle dynamics affecting the inner Congo craton lithosphere. This architecture, which differs from those of the other basins of the Gulf of Guinea, partly explains the low oil production of this basin. Keywords Rio del Rey · Cameroon margin · Cameroon volcanic line · Architecture · Miocene · Isongo formation
Introduction Most studies related to sequence architecture of basins were carried out either on classic passive margins or rift and island arc basins (Royden et al. 1987; Zhou et al. 2014;
Zecchin et al. 2015). In the passive margins, especially tectonically stable, the development of sequence architecture is very closely related to climate change, eustatic sea level changes and sediment supply (Posamentier et al. 1988; Jervey 1988; Van Wagoner et al. 1990; Shanley and McCabe
* François Mvondo Owono [email protected]
Raphael Belinga Essama Boum [email protected]
Jacqueline Ntsama Atangana [email protected]
Marie Joseph Ntamak‑Nida ntamaknida@univ‑douala.com
Sébastien Owona owonas@univ‑douala.com
1
Olivier Dauteuil olivier.dauteuil@uni‑rennes1.fr
Department of Earth Sciences
