Sedimentary Petrology, Paleoclimatic and Tectonic Settings of Maastricthtian Sediments, Western Flank of Anambra Basin, Nigeria
Authors: Ilevbare M, Omorogieva OM
Maastricthtian Ajali formation is an exciting site for geological field study because of the rich information preserved in the strata. However, detailed sedimentary processes, paleoclimatic and tectonics setting of the formation as it occurs in Nigeria are not well understood. This study aimed at the application of geochemical and sedimentological assay in determination of the textural parameters for provenance, paleoclimate and tectonic setting of the formation to have adequate empirical knowledge of the depositional processes and paleoenvironmental conditions of the formation. A total of 51 samples were analyzed for this purpose. The textual result shows that the formation consist of an average graphic mean of 1.41Φ representing medium grain size, an average of skewness of 0.104Φ indicating near symmetry, average inclusive standard deviation of 0.92Φ indicating that the sediments are moderately sorted and an average kurtosis of 1.423Φ which typifies leptokurtic grains. The presence of quartz arenites and siliciclastic sandstone mineral suite revealed a basement rock source. This was further confirmed by the weathering indices of Al2O3/TiO2 of 3.25, Log SiO2/Al2O3 of 2.18 and SiO2/Al2O3 of 180.24. Additionally, ternary plot generated further buttress that the sediments are reworked from older sediments of igneous and metamorphic origin during a prevailing humid climate. The ternary plots for quartz feldspar lithic arkose classification scheme indicate the sandstone (quartz arenites) tectonic setting is from recycled orogeny and craton interior.
Affiliations: Department of Geology, Faculty of Physical Sciences, University of Benin, PMB 1154, Benin City, Nigeria.
Keywords: Ajali Formation, Paleoclimate, Tectonic-setting, Provenance, Sedimentary, Petrology
Published date: 2020/12/30