Sedimentology And Palynology Models Of Sedimentary Sections Along Lemna Section Of The Benin Formation, Cross River- Southern Nigeria

The paleodepositional environment and age of sedimentary outcrops along Lemna Road, northeast of Calabar Town, Cross River State, were determined using sedimentological and palynological studies. The sediments are primarily made up of sand gravel, carbonaceous shale with plant roots, and clays. Sedimentological and Palynological analyses were performed with the goal of determining the textural properties, age, and depositional environment of the sediments. Graphic mean grain sizes, sorting, skewness, and kurtosis are the grain size factors. Sorting of coarse-grained sediments deposited in a river setting was low to extremely poor as a result of graphic mean estimated coarse-grained sediments. The overall skewness is well formed, with a platykurtic kurtosis. Scatter plots of the coefficient of flatness vs sphericity and sphericity versus the oblate-prolate index show that pebbles formed in a highly energetic system (beach). According to the results of pebble morphometric indices, the sandstones are in an extremely energetic (beach) environment. Bivariate plots of sand textural metrics including graphical skewness vs graphical standard deviation and second moment skewness versus second moment standard deviation confirmed the high intensity (beach) origin of the sandstones. In the palynological analysis it was observed that there was absence of foraminifera’s while index taxa such as Magnstriatites howardii, Zonocostites ramonae, Verrucatosporitea lienus and Psilatricolporites sp. Were identified inferring early to late Miocene in age of sediments exposed in the study area.