Iron oxides and smectites in sediments from the Atlantis II Deep, Red Sea

Chemical analyses, XRD, TEM, Moessbauer and IR spectroscopy results on an 11 m sediment core from the Atlantis II Deep are reported; iron oxides and smectites are the dominant minerals. Among the Fe oxides are nm-sized hematite with strong anisotropic XRD peak broadening in the upper part of the core, whereas well crystalline hematite prevails in the lower part; akaganeite dominates the intermediate layer. The nm-sized hematite ( approximately 5 nm) exhibits complex Moessbauer spectra. Di- and trioctahedral Fe-rich smectites make up the clay silicate fraction of the samples; the trioctahedral clays dissolved in acid oxalate and were magnetically ordered at 4.2 K.