Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Textural Characteristics of the Siliciclasts of Ajali Formation, Southwestern Nigeria
by Opeloye, Saka A. and Ogbahon, Osazuwa A.

Abstract:
Textural characteristics and petrographic assessments of siliciclasts are assessed for the purpose of establishing mechanism of sediment deposition and the rock bulk properties of the Ajali Formation in the western flank of Anambra basin in Nigeria. Outcrops of the formation are well exposed along the long reach of Orle stream in Auchi as well as road embarkments at Ayogwiri, Fugar and Othame environs in the western flank of the Anambra Basin, southwestern Nigeria. Modal composition of the siliciclasts is Q90.5-96 F0-3.1 and L1-8.4 which classified it as Quartzarenite sandstone. The sandstone is texturally homogenous as its sediments are generally medium grained, moderately sorted and non-platykurtic, indicating tidally influenced deposition. The dominant quartz minerals occurred mainly in non-undulatory, strain-free monocrystalline forms indicating bulk derivation from the basement cratonic interior. Its authigenic growth as silica precipitation from pressure solution was most evident. Nevertheless, the quartz authigenesis was retarded by Iron and chlorite grain coats and rims by blocking potential nucleation sites. Consequently, the sandstones of the study area did not experience sufficient compaction to resist intense erosion.

Keywords: Anambra basin, Ajali formation, quatzarenite, saltation, authigenesis, chlorite coats.

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