The effects of parent rock on soil clay mineralogy and soil physicochemical properties: A review

Lithology stands as a fundamental determinant in soil formation processes. In this review, we aimed to synthesize the existing research on the influence of parent rock on soil clay mineralogy and soil physicochemical properties on a global scale. The majority of existing studies on soil clay mineralogy did not include information on the mineralogy of the weathered parent rock, which hinders a comprehensive understanding of the effects of lithology on soil clay mineralogy. The present review advances the notion that the dynamics of weathering environment and temporal progression ultimately supersede the influence of different parental lithologies, leading to the establishment of a “climax” soil clay mineralogy. We present a conceptual diagram that outlines the proposed relationships. Primarily, lithology influences the composition of clay minerals in the weathered parent rock, which subsequently influences the clay mineralogy of the soil. This, in turn, influences the physicochemical properties of the soil. The parent rock can also have a direct influence on soil physicochemical properties. In addition, it is pertinent to acknowledge the contribution of other soil-forming factors, such as biotic influences, in shaping soil properties.