TITLE:
Depositional Facies and Sequence Stratigraphic Study in Parts of Benin (Dahomey) Basin SW Nigeria: Implications on the Re-Interpretation of Tertiary Sedimentary Successions
AUTHORS:
Solomon O. Olabode, Muraina Z. Mohammed
KEYWORDS:
Depositional Facies, Sequence Stratigraphy, Benin (Dahomey) Basin, Ilaro Formation, Coastal Plain Sands/Benin Formation
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.2,
February
29,
2016
ABSTRACT: Detailed fieldwork in parts of the
Benin (Dahomey) Basin SW, Nigeria has allowed the recognition of sedimentary
successions deposited in different continental depositional environments
interpreted as fluvial sedimentation characterised by abandoned channels and
subaerial exposure features. The lithofacies recognisedare:conglomerates,
debris flow deposits, very coarse grained sandstone, ferruginous cross bedded
sandstone, siltstone, shale/clay and massive sand. The lithofacies wereinterpreted in terms of sequence
stratigraphic elements with the recognition of sequence boundaries
characterised by distinct facies dislocations and subaerial exposures. Four
depositional sequences (DS I to DS IV) were identified. Depositional sequences
(DS I) exhibited a complete regressive–transgressive cycle comprising LST, TST
and HST, while DS II to DS IVwereincomplete comprising of sediments
interpreted as LST deposits. On the basis of the depositional facies andsequence stratigraphic elements, the
sediments in the area of study are interpreted as predominantly ofIlaro Formation while fewer exposures
are sediments of the Coastal Plain Sands/Benin
Formation. This observation suggests a re-interpretation of the Tertiary
sedimentary successions, which hitherto recognised all the sediments in the
area of study as Coastal Plain Sands.