Recent sedimentology and ocean dynamics of the Western Nigerian continental shelf and coastline

✍ Scribed by A.E Ihenyen

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 465 KB
• Volume: 36
• Category: Article
• ISSN: 1464-343X
• DOI: 10.1016/s0899-5362(02)00153-7

✦ Synopsis

The Western Nigerian continental shelf lies approximately between longitudes 2°42 0 and 5°00 0 E. It is a relatively gently sloping and narrow shelf, incised by two canyons, Avon and Mahin. The beaches between longitudes 2°42 0 and 4°30 0 E are sandy while Mahin Mud Beach is further to the east. The western sand deposits extend about 12 km offshore and are separated into two coastparallel sand bodies by a narrow dark grey silt-mud facies, 1-2 km wide. Lekki lagoon is situated inland of the sandy beach-barrier systems near Lagos. This low energy tidal and freshwater lagoon is slowly silting up with river sediment; bottom sediment characteristics reflect influence of both fluvial transport and weak tidal current patterns. Mahin Mud Beach is starved of sand due to a lack of longshore drift as a result of the two canyons siphoning off arenaceous material. It is thus highly vulnerable to erosion and flooding. The two coast-parallel sand bodies in the west, combined with four preserved drowned coral reef systems, suggest that the post-Pleistocene sea level rise along the Western Nigerian shelf was punctuated by a number of sea level stillstands.