The secondary iron oxidehydroxide mineralogy of some deep-sea and fossil manganese nodules: A Moessbauer and X-ray study.

Abstract

Mossbauer spectroscopy utilizing precise computer-based curve fitting procedures and X-ray diffrac tion methods have been used to study four deep-sea and one fossil marine manganese nodule. They have shown that X-ray amorphous goethite (a-FeOOH) and probably akaganeite (P-FeOOH) are the secondary iron oxidehydroxide phases present in the deep-sea nodules. The fossil nodule contained goethite with a larger particle size (approx. 350A) which had presumably been formed by the recrystallization of X-ray amorphous goethite and/or the alteration of the metastable akaganeite.

The distribution of rare earth, precious metal and other trace elements in Recent and fossil deep-sea manganese nodules.

“…This view is supported .by the recent work of JOHNSTON and GLASBY (1978) using Mossbauer spectroscopy which has shown that recrystallisation of the iron oxide phase of the Timor nodule has taken place since the nodule was exposed and this may have led to some element redistribution. In spite of this, the trace element composition can be recognised as being typical of that of a deep-sea nodule.…”

“…Summaries of sample locations, sample descritpions, associated sediment types, nodule mineralogy and previous element ana lyses have been given by JOHNSTON and GLASBY (1978 , Table 1). An account of the iron oxide mineralogy of the nodules has also been pres ented by JOHNSTON and GLASBY (1978).…”

M6ouml;ssbauer effect studies of iron in manganese nodules and associated marine sediments in five areas in the equatorial and S. W. Pacific

“…99 South of the Marquesas Fracture Zone in Area G) and that these spectra are identical to those obtained by JOHNSTON and GLASBY (1978) for a limited number of deep-sea nodules from the Southwestern Pacific Basin, from north of the Indian-Antarctic Ridge and from the Carlsberg Ridge, Indian Ocean. Since these nodules were chosen specifically to re present different environments of deposition (particularly in respect to the biological produc tivity of the overlying surface seawater), the data offer persuasive evidence that the iron min eralogy of all deep-sea manganese nodules is identical irrespective of location.…”

“…On the basis of the Mossbauer spectra and parameters now available, it is very difficult to distinguish fi and y-FeOOH phases. The agree ments of JOHNSTON and GLASBY (1978) and regarding the stabilisation of a-FeOOH by chloride ions in seawater, however, may still make this the preferred iron oxide hydroxide mineral in marine manganese nodules. Deep-sea nodules may therefore still consist of a mixture of a and O-FeOOH.…”

An occurrence of akaganéite (β-FeOOH ˙ C1) in Recent oxidized carbonate concretions, Norfolk, England

“…Logan et al (1976) suggested on the basis of M6ssbauer data that akagan6ite is present in some New Zealand soils. Johnston (1977) identified akagan6ite coating andesite boulders at White Island volcano, New Zealand. Johnston and Glasby (1978) reported akagan6ite as a secondary oxyhydroxide mineral in marine and fossil manganese nodules.…”