The Nature of K‐Feldspars of Selected Soils in the Canadian Prairies

Abstract

AbstractThe nature of K‐feldspars of four soils developed from glacial till deposits and lacustrine sediments in Saskatchewan, Canada was studied. The K‐feldspars from the size fractions 20‐2,000µ were concentrated by heavy liquid separation at a specific gravity of 2.59. X‐ray diffraction analysis was used to identify orthoclase and microcline, to estimate the proportion of orthoclase to microcline, and to determine the obliquity of microcline. The K‐feldspars in the size fractions 50 to 2,000µ of certain soils were further studied by optical microscope and electron microprobe methods.The proportion of orthoclase to microcline increased with decrease in particle size. In the comparable size fractions of the soils developed from the glacial till deposits, the proportion of orthoclase to microcline increased from north to south in the region under study. The proportion of orthoclase to microcline was higher in the Orthic Black soil developed from the lacustrine sediments than in the Orthic Black soil developed from glacial till deposits. The data obtained show the bearings of soil parent material on the relative abundance of orthoclase to microcline. The obliquity values range from 0.81 to 0.89, indicating a high degree of exsolution. The presence of perthite, as revealed by X‐ray data, optical microscope, and electron microprobe studies, further elucidate the nature of exsolution.