|Schwimmeisen has been observed in wetlands, iron-rich seeps, and seasonally reduced soils. It forms when Fe(II)-rich groundwater oxidizes to Fe(III) at the air-water interface. The natural films are 100 to 300 nm thick and contain both Fe(III) and Fe(II) as well as Si. Energy-filtered electron diffraction patterns (EFED) show three diffraction rings at ~4.5, 2.6, and 1.4 Å. |
`We synthesized films using Cornell and Schwertmann's (2000) recipe for Green Rust with and without the addition of humic acid and with surface oxidation using introduced air or photo-oxidation with 7% UVB light over periods of 8 to 600 hours. The few films that formed without organic acids were crystalline under TEM. The films that formed using 0.2% humic acid solutions appeared poorly crystalline as did the natural samples. Many of the synthesized films show similar diffraction rings and contain a similar ratio of Fe(II):Fe(III)as the natural films.
General Geochemistry and Clay Minerals Society Poster Session
6:00 PM-8:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster