Four soil profiles were selected to represent the Nile alluvial soils; that lies
between the Nile River and EI-Ibrahimya Canal, northwest of Assiut city.
Representative soil samples were collected from various layers of each profile to
examine the mineralogy of the fine sand and clay fractionS and also to evaluate the
supplying power of these soils for some heavy metals. This study reveals that the
mean-size values (Mz) of the sand fraction of the studied soil samples vary between
fine and very fine sand-sized fraction. These fractions are characterized by being very
well to poorly sorted and are very coarse skewed. This suggests that the deposition
mode was by one source, namely, Nile river water. The amounts and distributions of the heavy minerals in the fine sand fraction
range between 0.73 and 12.01%. Generally, the heavy mineral fraction increases with
depth. The mineralogical examination shows that the non-opaque minerals are the
most abundant with a range between 71.3 and 84.71 %, including amphiboles,
epidotes, biotite, pyroxenes, zircon, sphene, garnet, rutile, tourmaline, lemonite and
apatite in a decreasing order of abundance. Opaque minerals are less abundant in the
studied samples. The light minerals constitute the main part ranging between 87.99
and 99.27% in the fine sand fraction. They are represented mainly by quartz with small
amounts of feldspars (plagioclase, microcline and orthoclase). Assemblages of the
constituent minerals, resistant minerals and weathering ratios reflect that these soils
are derived from different provenances and are recently deposited with a weak
weathering changes. Ratios between zircon, rutile and tourmaline were evaluated. The
data indicated some clear variations between various layers of each soil profile;
indicating variable origin and heterogeneous nature. Generally, low positive correlations are found between extractable Mn, Zn,
Cu, Ni and Pb and their bearing-minerals, while low negative correlation with Fe and B
is shown. This reflects the young nature of these soils. Smectites are the most dominant clay minerals in the studied c!lay fraction
«2iJ) of the soil samples followed by interstratified minerals namely mica-vermiculite
and mica-smectite. Also, sepiolite, palygorskite, vermiculite, kaolinite, mica, chlorite,
pyrophyllite, feldspars and quartz are present in a decreasing order of abundance.
This assemblage of clay minerals emphasizes the concept that these studied soils are
young, less weathered and are derived as detritals from the older Nile sediments and
the calcareous deposits of the western plateau.