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Southern Cross GeoScience

Schwertmannite stability in wetland soils

NEWS FLASH
PhD positions are currently available in this research area.

Research summary

Schwertmannite is a ferric-oxyhydroxysulfate mineral that forms in acidic, iron- and sulfate-rich waters. As a consequence, it is a very common secondary mineral resulting from sulfide oxidation in rocks, soils and sediments. It has been widely recognized in environments impacted by acid-mine drainage and acid-sulfate soils, where schwertmannite plays a key role in determining water quality trends.

Schwertmannite


Schwertmannite is a common feature of acid-sulfate soil landscapes.

A research stream within Southern Cross GeoScience aims at understanding the stability of schwertmannite in acid-sulfate soil environments. Work completed so far has discovered that the production of ferrous iron by ferric iron-reducing bacteria can catalyse fast transformation of schwertmannite to goethite - a common iron(III) (hydr)oxide. This process has been documented in drain sediment profiles and in re-flooded wetlands, and its rate has been quantified in laboratory-based experiments.

Research activities include in-situ studies on an array of schwertmannite-bearing systems. For example, we have described the in-situ transformation of schwertmannite to goethite in the benthic sediments of acidified coastal waterways. In addition, a range of controlled laboratory-based experiments have been completed, which range from simple closed-system to more complex column-type studies.

Field Studies


Geoscience research integrates field studies with controlled experiments to unravel the controls on schwertmannite stability.

PhD opportunity

If you are interested in collaborating or undertaking a PhD project on this topic, please contact Associate Professor Ed Burton ed.burton@scu.edu.au.

Publications

Burton, E. D., Bush, R. T., Sullivan, L. A., Mitchell, D. R. G. (2008) Schwertmannite transformation to goethite via the Fe(II) pathway: Reaction rates and implications for iron-sulfide formation. Geochimica et Cosmochimica Acta 72, 4551 - 4564.

Burton, E. D., Bush, R. T., Sullivan, L. A., Mitchell, D. R. G. (2007) Reductive transformation of iron and sulfur in schwertmannite-rich accumulations associated with acidified coastal lowlands. Geochimica et Cosmochimica Acta 71, 4456 - 4473.

Burton, E. D., Bush, R. T., Sullivan, L. A. (2006) Sedimentary iron geochemistry in acidic waterways associated with coastal lowland acid sulfate soils. Geochimica et Cosmochimica Acta 70, 5455 - 5468.