Tidal Channel Depositional Complex of the Cretaceous Yolde Formation of the Gongola Sub-Basin, Northern Benue Trough N. E. Nigeria

Abstract

The facies analysis of the Cretaceous Yolde Formation at Gamajigo village in the Gongola Sub-basin of the Northern Benue Trough indicated fining upward a sequence characterized by the assemblages of five lithofacies that comprises of trough crossbeds, planar crossbeds, massive beds, ripple laminations, and mudstone. This fining upward architecture is defined by trough crossbedded sandstone with erosional contact at base overlain by interbedded sandstone and mudstones often displaying bi-direction paleocurrent patterns and growing mudstones content upwards moving into dominantly mudstones unit. This concurrently demonstrates dissipating energy intensity upwards as such reflecting a tide dominated system clearly of tidal channel depositional complex that most commonly develop in estuaries and tide dominated delta. Though on the account of the presences of Skolithos ichnofacies, a stressed hydrodynamic regime and indicating extension of tidal channel into the open sea may be very likely. This is generally indicative of a tide dominated oceanographic system in the advancing and inundating Cenomanian transgressive sea that define the coastal realm of the Gongola Sub-basin.