TEXTURAL CHARACTERIZATION OF ILLO SANDSTONE,BAGUDO LOCAL GOVERNMENT,SOKOTO BASIN,NORTH-WESTERN NIGERIA

ABSTRACT .The lithostratigraphy of Adawa Hill outcrop was described based on the essential parameters in litho-description, which include colour, composition, texture, bioturbation and structures. Illo Formation outcrop is characterized at the base by reddish bioturbated sandy claystone, overlain successively by a brown offlap structure sandy claystone, having unconformity relation with the underlying sandy claystone bed.This is followed by light brown cross laminated claystone, and white-purple bioturbated sandstone. The middle section of the outcrop is marked by successive layers of mottled red-yellow coloured sandy claystone, overlain by fractured yellow-brown claystone, and thin ferruginized claystone. The upper part is composed of reddish-yellow bioturbated and fractured medium grained sandstone, unconformably overlain by bioturbated fine sandstone with burrows and capped at the top by pebbly sandstone facies. The laboratory analyses include granulometric and heavy minerals. The materiais used in the laboratory are sieves with sizes: 2.00 μm, 1.18 μm, 0.85 μm, 0.60 μm,0.425 μm,0.30 μm, 0.25 μm,0.15 μm, 0.10 μm, 0.075 μm, and 0.063 μm of U.S standard sieve sizes including pan and cover, chemical balance (with accuracy to 0.01 g) and mechanical sieve shaker. A Granistat software was used to generate the textural statistical parameters. Textural statistical parameters derived in the mean,standard deviation (sorting), skewness and kurtosis shows that the mean values of the samples have an average of 1.520, suggestive of medium sandstone facie. Sorting values have an average of 0.849 of moderately sorted sediment deposited by medium current energy. The skewness values have an average of -0.044 indicative of coarse skewed, and the kurtosis vary from leptokurtic, very leptokurtic and mesokurtic classes. Paleoenvironment of deposition varies from -8.34 to -7.40,suggestive of marginal marine setting of an intertidal shelf deposit: The Illo Formation sandstone facies at Adawa Hili in Bagudo Área is both texturally and mineralogicaiiy immature.