A Sedimentologic And Stratigraphic Study Of The Maastrichtian-Pateocene Sediments In Yuil Area, Bauchi State

ABSTRACT

The Maastrichian-Paleocene sediments in Yuli area me composed of the Gombe Sandstone and the Kerri-Kerri Formation. They cover 400 square kilometres have a thickness of more than 100 metres. Six stratigraphic sections were studied, representing the entire stratigraphic succession of the Gombe Sandstone in the Yuli area, The formation has a thickness of about 30 metres in the studied area. The Gombe Sandstone consists of folded beds of sandstone, siltstone and mudstone. The sandstone consists of well consolidated, texturally immature, feldspathic wacks which have iron oxide cement. Cross-bedding, ripple marks, bioturbations, parting lineations and laminations are the structural features present. The sandstone varieties include the ferruginous, bioturbated and cross-bedded sandstones. Dark red slabby sandstones are also present. Texturally the sandstones are G medium grained, subrounded, poorly to moderately sorted, positively skewed and leptokurtic. Based on an integrated analysis of the stratigraphic, petrographic, textural, faunal and structural data, three environments of deposition may be suggested, namely fluvial, estuarine , and deltaic. The Kerri-Kerri Formation consists of horizontal to near horizontal strata of sandstone, siltstone and clay. The formation overlies the Gombe Sandstone. It attains a thickness of about 70 metres. laterite capping is very common.