Palynological and paleoenvironmental analyses of the Miocene sediments of Gap-1 well in the onshore Niger Delta Basin.

A comprehensive palynological investigation has been carried out for Gap-1 well penetrating the Agbada Formation in the Niger Delta Basin. The identification of shaly-sandstone, shale, mudstone, and clayey-sandstone lithofacies units and the delineation of four (4) informal palynological biozones (GI, GII, GIII, and GIV), correlating with the P670, P680, and P720Niger Delta pollen zonations, suggested the Early to Middle Miocene age for the investigated Gap-1 well in the Agbada Formation. The interpretation for the common to the relatively abundant occurrence of land-derived palynomorphs such as Verrucatosporites sp., Laevigatosporites sp, Zonocostites ramonae, Sapotaceae, as well as the occurrence of dinoflagellate cysts, Pediastrum sp, amongst others, as a fluvial-dominated delta to shallow marine environment within a humid climate is confirmed.