Tóm tắt
Four soils, two of which had developed from deposits with visible unconformities, served as a basis for evaluating the use of quartz, ZrO2 and TiO2 as resistant indicators in pedological studies. Contents and ratios of these components for individual size fractions, the total non-clay fraction, and the total soil were compared. Values for individual fractions serve to differentiate and characterize underlying geological strata; changes in particle size distribution and clay translocation within solum horizons necessitate the use of the total non-clay fraction for establishing the original uniformity of soil deposits. Both quartz and zirconium are reliable indices upon which to base quantitative evaluation of pedogenic changes when the total > 2 μ fraction is used, providing that original uniformity of the soil deposit has been established. The mobilization of titanium in all fractions during soil weathering limits its usefulness in this regard. Except for the surface layers, in which anomalous zirconium values were obtained, quartz and ZrO2 provided similar values of calculated losses and gains within horizons of the Orthic Gray Luvisol studied. Significant changes in particle size distribution resulting from physical breakdown in the A horizon, as well as clay translocation and formation within the solum, were recorded.
