Variation in Physical Properties and Mineral Composition of Thin Loess Deposits in the Swift Current Area of Saskatchewan1
- W. E. Souster,
- R. J. St. Arnaud and
- P. M. Huang2
The nature and distribution of thin loessial deposits occurring on the Swift Current Plateau in southwestern Saskatchewan were studied. Results of physical and mineralogical investigations confirm the eolian origin of the material and support the separation of these loessial soils from adjacent lacustrine soils for mapping purposes.
A definite thinning trend is apparent along a southeasterly transect across the area. The particle-size distribution of the material is very similar to typical loess and the phi median diameter of individual samples increases progressively with increasing distance from the source.
Mineralogical analyses provide evidence of a sorting action during deposition of loess which is controlled by particle shape. Quartz and potassium feldspars, both 3-dimensional tektosilicates, remain constant in very fine sand and silt fractions across the loess transect. In contrast, a marked concentration of platy micaceous minerals occurs in coarser fractions and their depletion is noted in finer fractions with transport distance. This sorting serves to explain previously anomalous trends in total K contents of size fractions as a function of distance reported for loessial deposits by other workers.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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