White,A.F., Schulz,M.S., Stonestrom,D.A., Vivit,D.V., Fitzpatrick,J. and Bullen,T.(2008): Solute profiles in soils, weathering gradients and exchange equilibrium/disequilibrium. Mineralogical Magazine, 72(1), 149-153.

『土壌の溶質断面、風化勾配、および平衡/非平衡交換』


Abstract
 The spatial and temporal changes in hydrology and pore water elemental and87/86Sr compositions were used to determine contemporary weathering rates in a 65 to 226 ky old soil chronosequence formed from granitic sediments deposited on marine terraces along coastal California. Cl-corrected Na, K and Si increased with depth denoting inputs from the weathering of plagioclase and K-feldspar. Solute 87/86Sr exhibited progressive mixing of sea water-dominated precipitation with inputs from less radiogenic plagioclase. Linear approximations to these weathering gradients were used to determine plagioclase weathering rates of between 0.38 and 8.9×10-15 moles m-2 s-1. The lack of corresponding weathering gradients for Ca and Sr indicated short-term equilibrium with the clay ion exchange pool which requires periodic resetting by natural perturbations to maintain continuity, in spite of soil composition changes reflecting the effects of long-term weathering.』

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