Petrographic Studies, Heavy Mineral Analysis and Pebble Morphogenesis; Implications for Sedimentary Processes of Southern Bida Basin, Nigeria.

International Journal of Research and Scientific Innovation (IJRSI) | Volume VIII, Issue VI, June 2021 | ISSN 2321–2705

Petrographic Studies, Heavy Mineral Analysis and Pebble Morphogenesis; Implications for Sedimentary Processes of Southern Bida Basin, Nigeria.

Ijaleye, O.T, Ochu, G.D. *, and Danga, O.A.
Department of Earth Sciences, Faculty of Natural Sciences, Kogi state university, Anyigba, Nigeria

Abstract: The sandstone and conglomeratic sandstone facies of Lokoja and Patti Formation, Southern Bida Basin were analysed for their mineralogical compositions and pebble morphogenesis. The identified framework grains include the dominant quartz grains, feldspars, mica and rock fragments while heavy minerals include Zircon, Topaz, Tourmaline, Staurolite, Sphene, Rutile and Olivene. The heavy minerals were used as indicators of sources of sediments; Zircon and Tourmaline suggest igneous and low grade metamorphic rocks whereas Staurolite and Rutile show high grade metamorphic rocks. The angular to sub-angular shapes of the heavy minerals and sub-angular shapes of quartz grains respectively indicate textural immaturity of the sediments. This is associated with absence or low degree of physical weathering and abrasion due to short distance of sediment transport and it implies the prevalence of chemical weathering of the source rocks. The grain to grain contacts among quartz grains, the occurrence of overgrowths and iron oxide cements are consequences of post depositional changes of the sediments. Interpretation of pebble sizes, sphericity and oblate-prolate index provided information about the paleoenvironments.

Keywords: Heavy Minerals, Pebble Morphogenesis, Bida Basin, Sedimentary Processes, Paleoenvironments.

I.INTRODUCTION

Bida Basin is an inland sedimentary basin in the central part of Nigeria. It trends in NW-SE, and perpendicular to the main axis of Benue trough. It is adjacent to the Anambra Basin at the east and Sokoto Basin at the North West. The sediment fills of the basin are upper Cretaceous clastic sequence of sandstones, shales, siltstones and ironstones. The basin is characterized laterally by different facies, so it’s geographically described as northern and southern Bida Basin.Several geological studies of the basin have been carried out by researchers and their reports published. [1] discussed the geologic development of Southern Bida Basin. [2] carried out facies analysis of Bida Sandstone.

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