Quantitative mapping of the ferrous to ferric ratio on a sub-micron scale using synchrotron spectromicroscopy Frazer, B. H. ; Xu, Huifang ; Waychunas, G. A. ; de Stasio, G. Abstract Publication: Geochimica et Cosmochimica Acta Supplement Pub Date: May 2005 Bibcode: 2005GeCAS..69..598F