TY  - EJOU
AU  - 
T1  - Granulometric Study of the Lokoja Sandstone, Mid Niger Basin, Nigeria
T2  - Review of Environment and Earth Sciences

PY  - 2017
VL  - 4
IS  - 1
SN  - 2313-8440

AB  - Grain size studies of the Campanian-Maastrichtian Lokoja Formation have 
been investigated. The sand particles exhibit low sphericity which are 
angular to sub-angular. Histograms showed unimodal and bimodal trends 
and is predominantly asymmetrical with varying modal class, which may be
 due to variation in transporting medium energy. The graphic mean ranges
 from 0.1ф (coarse grained) to 1.35ф (medium grained) while the is 
average 0.81ф (coarse grained). The dominance of coarse grained 
particles and dearth of fine sands implies strong to moderate energy 
conditions during deposition. The standard deviation ranges from 
0.08ф-0.60ф (very well sorted to moderately well sorted); average of 
0.40ф (well sorted), which may be due to rapid back and forth movement 
of the depositing medium. The skewness ranges between -0.39 and 0.59 
(strongly coarse skewed to strongly fine skewed), while the graphic 
kurtosis ranges between 0.77 and 2.5 indicating playtykurtic to very 
leptokurtic and this variation may be due to some of the deposits being 
sorted in high-energy environment elsewhere. A Bivariate plot (simple 
skewness vs. standard deviation) shows the samples plotting mainly in 
the river sand zone. Another plot of mean size vs. standard deviation 
also shows the samples appearing in the river sand zone; other 
granulometric parameters that discriminates between river channel 
deposits, overbank deposits and overbank-pool deposits shows that the 
Lokoja sandstones plotted in the river channel zone. Linear discriminant
 analyses signpost a shallow marine beach environment. From the Passega 
diagram, majority of the samples plotted outside the featured fields, 
only three samples plotted within the diagnostic parameter zone around 
the uniform suspension-SR zone.
KW  - Lokoja sandstone
KW  - Granulometric
KW  - Standard deviation
KW  - Skewness
KW  - Kurtosis
KW  - Graphic mean
KW  - Passega diagram.
DO  - 10.18488/journal.80.2017.41.12.26