I recently interpreted some XRF data on samples of a granodiorite which were classified under three different types of physical characteristics: very little, mild and significant levels of weathering. I plotted ratios between $Al_2O_3$ for $CaO$ and $K_2O$ and noticed $CaO$ had a much lower correlation coefficient, i.e., it was more clumped. I know it's about which of these elements go into clay compounds but I need a bit more help understanding.
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