Balwant, S. and H. Susan. 2002), clay minerals particularly smectite are sensitive to pressure and temperature conditions and to variations in the chemical environment (sensitivity is expressed as crystallographic and mineralogical changes). Consequently, the study of clays can supply a great deal of information concerning the processes that occur in the evolution of the sequences of which they form a part such as weathering, hydrothermal alteration, digenesis, low grade metamorphism, etc. Furthermore, clay may reflect the history of the sediments better than any other component, because the characteristics of the clay minerals are to some extent subject to changes depending on the environment in which they are found (Grim 1968). The x- ray diffraction (XRD) analyses were used to identify quantitatively and semi-quantitatively the proportion of each clay mineral with respect to other clay minerals present in the tested samples. The X – Ray diffraction analyses of samples in these profiles indicates that the dominant clay minerals is Smectite with percentages ranging between 71.3 - 36.1% followed by kaolinite 46.5 - 22.2%, chlorite 6.8 - 1.2%, illite 15.32 -2.6% and Semctite Chlorite 6.9 - 1.0%. The bulk mineral analysis indicate the present quartz minerals found in all sites with percentages 69.2, 12.5, 35.1, 86.8, 31.7, 31.6, 50.1, 50.6; mica is found only in profiles except siteTE008with percentages of 16.9 and traces at TE005;Kaolinite present in sitesTE009, Te008, TE006, TE004 and ME003 with percentage of 8.9, 1.9, 2.1, traces, 0.6, 0.4; Vermiculite is found only in site TE009 with percentages of 5.6 and non-silicate minerals Magnetite exists in sites TE009, TE008, TE007 with percentages of 2.5, traces and 11.7 and Clinochlopreexist in TE007 and TE005 with percentages of 28.4 and 40.7. In aggregates this mineralogical assemblages occurring in three areas (Abbasyia,Megenis and Terter) suggest origins of parent materials derived from basic igneousmetamorphic rocks that have under gone weathering and in situ formation of clay minerals that have imposed magnitude of variations in the Pedological features." />
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
This research study was carried to identify the mineralogical properties of the cracking clay soils (Vertisols) at the upper clay plains located at the eastern parts of Nuba Mountains, Sudan. Soil samples were collected from profile pits along a toposequence in a transect stretching from Abbasyia to Megenis through Terter (64 Km).Another lowest site was selecte on the White Nile terrace adjacent to lower clay plain to investigate its clay mineralogy in relation to Nuba Mountains clays. The area is an intermountain, slightly undulating clay plain surrounded by the Nuba mountains and hills. The majority of the soils identified belong to the dark cracking clays (Ahmed, N. 1996). The huge mantle of clay rests on the basement complex but the origin of this clay is somewhat controversial, it is either transported from another place and deposited were it is or formed in situ (Vail, J.R. 1971). According to (Balwant, S. and H. Susan. 2002), clay minerals particularly smectite are sensitive to pressure and temperature conditions and to variations in the chemical environment (sensitivity is expressed as crystallographic and mineralogical changes). Consequently, the study of clays can supply a great deal of information concerning the processes that occur in the evolution of the sequences of which they form a part such as weathering, hydrothermal alteration, digenesis, low grade metamorphism, etc. Furthermore, clay may reflect the history of the sediments better than any other component, because the characteristics of the clay minerals are to some extent subject to changes depending on the environment in which they are found (Grim 1968). The x- ray diffraction (XRD) analyses were used to identify quantitatively and semi-quantitatively the proportion of each clay mineral with respect to other clay minerals present in the tested samples. The X – Ray diffraction analyses of samples in these profiles indicates that the dominant clay minerals is Smectite with percentages ranging between 71.3 - 36.1% followed by kaolinite 46.5 - 22.2%, chlorite 6.8 - 1.2%, illite 15.32 -2.6% and Semctite Chlorite 6.9 - 1.0%. The bulk mineral analysis indicate the present quartz minerals found in all sites with percentages 69.2, 12.5, 35.1, 86.8, 31.7, 31.6, 50.1, 50.6; mica is found only in profiles except siteTE008with percentages of 16.9 and traces at TE005;Kaolinite present in sitesTE009, Te008, TE006, TE004 and ME003 with percentage of 8.9, 1.9, 2.1, traces, 0.6, 0.4; Vermiculite is found only in site TE009 with percentages of 5.6 and non-silicate minerals Magnetite exists in sites TE009, TE008, TE007 with percentages of 2.5, traces and 11.7 and Clinochlopreexist in TE007 and TE005 with percentages of 28.4 and 40.7. In aggregates this mineralogical assemblages occurring in three areas (Abbasyia,Megenis and Terter) suggest origins of parent materials derived from basic igneousmetamorphic rocks that have under gone weathering and in situ formation of clay minerals that have imposed magnitude of variations in the Pedological features.