Study on Chemical Weathering Index for Rocks

Abstract

The chemical weathering indices, being one of the measures for the degree of weathering, have been proposed by many researchers since WPI (Weathering Potential Index) by Reiche (1943) . In case of using these indices, it is necessary not only to systematically classify and arrange them but also to understand the property of each index.
In this paper, the comparison among each index was attempted by applying their indices to the same weathering profile, using the papers which indicate the chemical composition of rocks. The rock type are granitic rock, andesite, shale, and mudstone.
And some weathering indices, being both more accurate and easy to use, such as ss2, A. D. F., ba1, ba2, ff etc., were selected.
Furthermore, the authors propose a new chemical weathering index: SIW (Simple Index of Weathering) =Na₂O/Al₂O₃+Ig. loss (molecular proportion) and prove its effectiveness.