Abstract
Although there have been numerous studies about the rise of atmospheric oxygen level during the Paleoproterozoic, the quantitive pattern of the oxygen rise is still not fully understood. Recently, Murakami et al. (2011) showed Fe(III)/Fe(II) rations recorded in paleosols can give quantitive information about oxygen levels at the time of their formation when kinetically analyzed. As the same kinetical approach, Yokota et al.(2008; in prep.) constructed the weathering model which predicts Fe(III)/Fe(II) ratios as a function of atmospheric oxygen level, revealing the ratio of Fe(III)/Fe(II) is mainly determined by Fe(II) oxidation rate and sweep-out rate of Fe(II) by groundwater flow. Taking Parameters for Fe(II) oxidation rate from recent reports and estimating those for sweep-out rate of Fe(II) by groundwater by focusing Si behavior in paleosols, the model was improved.
