Canadian Field Soils II. Modeling of Quartz Occurrence

The measured mineral composition data (XRD/XRF) of 40 Canadian soils were modeled for the presence of quartz as a function of soil texture. Preliminary modeling revealed a lack of strict correlation between quartz content and mass fraction of sand. For that reason, the occurrence of quartz content was modeled as dependent on a combined fraction of sand and silt, which produced an improved correlation for all tested soils. Then, all soils were modeled separately for five assigned provinces/regions of Canada and strong correlations of quartz versus combined sand and silt fractions were obtained. Estimates of quartz content and an average thermal conductivity of other minerals were also obtained by the reverse analysis of the weighted geometric mean model applied to the experimental thermal conductivity data of saturated soils. In general, quartz estimates followed XRD/XRF data sufficiently well. The thermal conductivity of the remaining soil minerals was about 2.13 W · m^?1 · K^?1 on average and did not depend on the soil texture.