Open AccessChemical and mineralogical composition of clay fraction found in Podillia upland haplic chernozems
Author(s) -
Igor Papish,
Oleksii Telehuz
Publication year - 2017
Publication title -
vìsnik lʹvìvsʹkogo unìversitetu. serìâ geografìčna
Language(s) - English
Resource type - Journals
eISSN - 2415-7201
pISSN - 2078-6441
DOI - 10.30970/vgg.2017.51.8866
Subject(s) - clay minerals , chernozem , kaolinite , weathering , geology , illite , chlorite , loess , feldspar , mineralogy , soil horizon , soil water , geochemistry , silicate , soil science , quartz , chemistry , geomorphology , paleontology , organic chemistry
The article presents data on gross chemical and mineralogical composition of clay faction found in typical chernozems occurred within the Podillia Upland. Geographical regularities of formation as regards clayey profile of Chernozems pertaining to the same genetic series are revealed. The relationship between conditions and Chernozem development stage, character of vertical differentiation of basic mineral phases of clayey plasma and its chemical and mineralogical composition are shown. Izoclayey profile of hydromicas is the consequence of their relative accumulation as a result eluviation of colloid-dispersible mica-smectite minerals. The character of clay profile observed in Chernozems is determined by the correlation of intensity of carbonates leaching, lessivage and soils argillisation. Typical Podolian Chernozems are characterised with the like weathering crust of silicate type. The modern Chernozem clayey profile originated mainly during a wetter stage of soil formation. In the ploughable layer a high content of clastic minerals (quartz, potassium feldspar, sodium plagioclase) is observed. Random mixed and stratified mica-smectite minerals with a high content (>50 %) of smectite packets (33–63 %), hydromica (33–52 %), and kaolinite plus chlorite (4–15 %) are present in the profile. The mineralogical composition of soils clay fraction indicates obvious signs of smectite eluviation and relative illite accumulation. Clayey profile of the Bug upstream plateau located within the Podillia Upland is atypical for Chernozems found in the eastern forest-steppe and steppe areas. The distribution character of layered silicates, especially smectite, is even more contrastive. Clayey plasma redistributes differentially through leaching and lessivage processes. Accumulative type of sludge deposits formed in Chernozems of the Dniester plateau located within the Podillia Upland, even profile distribution of basic oxides and molar ratios of SiO2 : Al2O3 and SiO2 : Fe2O3 against the background of decreased downward smectite content indicate weakened eluviation of fine-grained clays towards the Dniester. The prevalence of smectite over hydromicas within the entire profile indicates argillisation of Chernozems.Key words: Chernozem, chemical-mineralogical composition, clayey minerals, hydromica, smectite, kaolinite, leaching, lessivage, argillisation.