SAND AND CLAY MINERALOGY OF SOME ALLUVIAL SOILS WITH RELATION TO SOIL ORIGIN, UNIFORMITY AND HEAVY METALS CONTENT, ASSIUT, EGYPT. | ||
| Journal of Soil Sciences and Agricultural Engineering | ||
| Article 5, Volume 29, Issue 12, December 2004, Pages 7575-7592 PDF (4.5 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jssae.2004.243937 | ||
| Authors | ||
| M. EI-A. A. Farragallah,1; M. A. Essa2 | ||
| 1Soil and water Sci. Dept, Fac. Agric., AI-Azhar Univ., Assiut, Egypt. | ||
| 2Geology Department, Faculty of Science, Assiut Univ., Assiut, Egypt. | ||
| Abstract | ||
| 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. | ||
| Keywords | ||
| Grain size; heavy and light minerals; deposition mode; origin; uniformity and weathering ratios; heavy metals | ||
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