Mössbauer Spectroscopic Study of the Iron Mineralogy of Post-Glacial Marine Clays

Abstract

Abstract--Three post-glacial marine clays from eastern Canada and one marine clay from Japan have been studied by M6ssbauer spectroscopy to ascertain their iron mineralogy. Small amounts of hematite (in two samples) and magnetite (in one sample) were found in the Canadian clays, and hematite was detected in the Japanese clay. The major spectral components were ferrous and ferric doublets, consistent with X-ray powder diffraction results that show chlorite, mica, and amphibole in the Canadian samples and smectite in the Japanese sample. Citrate-dithionite extraction removed hematite and most of the magnetite from these samples. Acid-base extraction also removed chlorite and some mica from the Canadian samples. Samples treated by these extractions had appreciably lower geotechnical yield stresses at given water contents.

Particle Interaction and Rheology of Illite-Iron Oxide Complexes

“…Response of the yield stress of illite by addition of iron oxides confirms the role of iron oxides in natural clays previously studied by Yong et aL (1979), Torrance (1984), and Torrance et al (1986). They have indicated that citrate-dithionite and acid-base extractions of iron oxides decrease the shear strength and the yield stress for remolded post-glacial marine clays.…”

“…A decrease in the yield stress following citrate-dithionite and acid-base extraction of iron oxides has been demonstrated. (Torrance, 1984;Torrance et al, 1986).…”

Identification of newly generated iron phases in recent anoxic sediments: 57Fe Mössbauer and microRaman spectroscopic studies

“…The d and D values are very similar to those reported for marine clays such as chlorite. 52 If the relative areas are taken as relative percentages of the Fe components, FeIII and FeII then account for 63È79 and 29È37% of the total absorption area, respectively (Table 1). It is worth noting that lower percentages of iron(II) (ca.…”

Moessbauer spectroscopy

“…The combination of Mossbauer spectroscopy with sequential extraction helped clarify the interpretation of the deceptively simple spectra and showed that not only ferric oxides but easily oxidizable amorphous Fe2+ also contributed appreciably to the original spectra. Postglacial marine clays from eastern Canada have been studied by Torrance et al (258). These were examples of so-called "quick clays" which have the property of becoming fluid when subjected to remolded shear.…”