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The article presents a study of the extent and rates of deep saprolite chemical weathering throughout a seaward-facing escarpment in the south-eastern coast of Australia. It mentions that spatial gradients of climatic and tectonic forcing promote various characters and extent of chemical weathering in a topographic escarpment. It imparts that the researchers used the mass balance approach, coupling past denudation rates measurement and major and trace elemental chemistry analyses using cosmogenic nuclides (10Be and 26Al), to quantify the extents of chemical weathering of the escarpment. The researchers found spatial and intensive chemical weathering of saprolite at the base of the escarpment.

Virtually all soil chronosequence studies have equated the degree of mineral weathering with the soil age, which is equal to the time since the cessation of erosion or deposition. The primary minerals from the parent material, however, enter the soil as the weathering front propagates downward and are depleted via chemical weathering. The residence time of minerals is thus a function of both the rate of conversion of parent material to soil (i.e., soil production) and the minerals' susceptibility to chemical weathering reactions. We find that mineral residence times are significantly shorter than the soil age. By mathematically considering the interactions among soil production and chemical weathering, we demonstrate that traditional estimates of mineral-specific chemical weathering rates from soil chronosequences may diverge by several orders of magnitude from the actual weathering rates. [ABSTRACT FROM AUTHOR]