Authors
Scott G Johnston, Annabelle F Keene, Richard T Bush, Edward D Burton, Leigh A Sullivan, Lloyd Isaacson, Angus E McElnea, Col R Ahern, C Douglas Smith, Bernard Powell
Publication date
2011/1/24
Journal
Chemical Geology
Volume
280
Issue
3-4
Pages
257-270
Publisher
Elsevier
Description
Tidal inundation is a new technique for remediating coastal acid sulfate soils (CASS). Here, we examine the effects of this technique on the geochemical zonation and cycling of Fe across a tidally inundated CASS toposequence, by investigating toposequence hydrology, in situ porewater geochemistry, solid-phase Fe fractions and Fe mineralogy. Interactions between topography and tides exerted a fundamental hydrological control on the geochemical zonation, redistribution and subsequent mineralogical transformations of Fe within the landscape. Reductive dissolution of Fe(III) minerals, including jarosite (KFe3(SO4)2(OH)6), resulted in elevated concentrations of porewater Fe2+ (>30mmol L−1) in former sulfuric horizons in the upper-intertidal zone. Tidal forcing generated oscillating hydraulic gradients, driving upward advection of this Fe2+-enriched porewater along the intertidal slope. Subsequent oxidation of …
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SG Johnston, AF Keene, RT Bush, ED Burton… - Chemical Geology, 2011