Sedimentary response to tectonism in the Campanian–Maastrichtian succession, Anambra Basin, Southeastern Nigeria

✍ Scribed by G.C. Obi; C.O. Okogbue

• Book ID: 104019789
• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 614 KB
• Volume: 38
• Category: Article
• ISSN: 1464-343X
• DOI: 10.1016/j.jafrearsci.2003.05.001

✦ Synopsis

The study of facies stacking patterns and sedimentary deformation structures in the Enugu-Okigwe area of the Anambra Basin provides understanding of the nature and role of tectonics in the Campanian-Maastrichtian sedimentation. The Anambra Basin-fill contains four third-order sedimentary cycles that document pulses of basin subsidence. Each cycle contains the well-defined three-part vertical succession of facies that typifies incised valley fills. Superimposition of the incised valleys and the proximal fluviatile-distal marine character of depositional systems within each valley sequence, suggest that the Anambra Basin subsided asymmetrically at least three times during the Campanian-Maastrichtian period.

Further evidence for the episodic subsidence is the occurrence of seismically-induced soft-sediment deformation structures including soft-sediment folding and faulting, overturned cross-bedding and load structures, at three stratigraphic levels near and below the sequence boundaries. The appearance of the soft-sediment deformation structures is closely timed with the early phase of each episode of tectonic uplift of the Abakaliki region to the east of the Anambra Basin.