Palynology, Paleoenvironment and Stratigraphy Relationship of Tungan Buzu Hill with Adjacent Valley Gwandu Formation, Sokoto Basin, Northwestern Nigeria

Abstract

Palynological study of Tungu Buzum Hill was investigated with a view towards determining the age of the outcrop, compare its miospore content with the adjacent Tungu Buzu Valley of carbonaceous shale, their stratigraphic relationship and paleoenvironment of deposition of the litho-sequence. Field study involved litho-description and logging achieved by noting the rock type, mineralogical composition, bed thickness, texture, sorting, roundness, structure, fossil content and diagenetic effect. Palynological slide preparation involved decarbonisation, digestion, sieving, maceral separation using zinc bromide, mounting on slide and petrographic analysis. The litho-sequence is composed sequentially upward of claystone, siltstone, indurated silty claystone, mudstone and ferruginized ironstone characterized by loadcast, fracture, lithification and bioturbation. Palynologically, the litho-section exhibits few marker forms such as Belskipollis elegans, Peregrinipollis nigericus and Retibrevitricolporites obodoensis depictive of early Miocene age. The paleoenvironment was deduced based on the occurrence of peridinacean forms such as Andalusiella sp., Senegalinium sp., Lejeuncysta diversiforma and Paleocystodinium golzowense indicative of marginal marine, while deeper marginal marine forms of gonyaulacacean phytoplanktons present are Micrhystridium sp., Canningia capillata and Dinogymnium sp. There are similarities in palynomorph assemblages of this study and Tunga Buzu Valley section in terms of age and similarity to Gwandu Formation though varied in paleoenvironment in the valley litho-section, marked by continental to marginal marine settings. Field relationship suggests that the Tunga Buzu Hill is stratigraphically overlying the Tunga Buzu Valley, separated by a fault. The Tunga Buzu Hill section represents the footwall while the Tunga Buzu Valley is situated within the hanging wall of a normal fault structure.