Schwertmann, U; Carlson, L; Murad, E (1987): Description and chemical and mineral composition of iron oxide samples from two Finnish lakes [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.854200, Supplement to: Schwertmann, U et al. (1987): Properties of iron oxides in two Finnish lakes in relation to the environment of their formation. Clays and Clay Minerals, 35(4), 297-304, https://doi.org/10.1346/CCMN.1987.0350407
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Abstract:
Fifteen iron oxide accumulations from the bottoms of two Finnish lakes ("lake ores") were found to contain as much as 50% Fe. Differential X-ray powder diffraction and selective dissolution by oxalate showed that the samples consisted of poorly crystallized goethite and ferrihydrite. The crust ores of one lake had higher ferrihydrite to goethite ratios than the nodular ores of the other lake. The higher ferrihydrite proportion was attributed to a higher rate of Fe2+ supply from the ground water and/or a higher rate of oxidation as a function of water depth and bottom-sediment permeability. Values of Al-for-Fe substitution of the goethites determined from unit-cell dimensions agreed with those obtained from chemical extraction if the unit-cell volume rather than the c dimension was used. In very small goethite crystals a slight expansion of the a unit-cell dimension is probaby compensated by a corresponding contraction of the c dimension, so that a contraction of the c dimension need not necessarily be caused by Al substitution. The goethites of the two lakes differed significantly in their Al-for-Fe substitutions and hence in their unit-cell sizes, OH-bending characteristics, dehydroxylation temperatures, dissolution kinetics, and Mössbauer parameters. The difference in Al substitution (0 vs. 7 mole %) is attributed to the Al-supplying power of the bottom sediments: the silty-clayey sediments in one lake appear to have supplied A1 during goethite formation, whereas the gravelly-sandy sediments in the other lake did not. The compositions of the goethites thus reflect their environments of formation.
Source:
Grant, John Bruce; Moore, Carla J; Alameddin, George; Chen, Kuiying; Barton, Mark (1992): The NOAA and MMS Marine Minerals Geochemical Database. National Geophysical Data Center, NOAA, https://doi.org/10.7289/V52Z13FT
Further details:
Warnken, Robin R; Virden, William T; Moore, Carla J (1992): The NOAA and MMS Marine Minerals Bibliography. National Geophysical Data Center, NOAA, https://doi.org/10.7289/V53X84KN
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Coverage:
Median Latitude: 61.963640 * Median Longitude: 28.032335 * South-bound Latitude: 61.483330 * West-bound Longitude: 25.900000 * North-bound Latitude: 62.443950 * East-bound Longitude: 30.164670
Comment:
From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.
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Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
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Datasets listed in this publication series
- Schwertmann, U; Carlson, L; Murad, E (1987): (Table 1, page 298) Description of iron oxide samples from the Finnish lakes. https://doi.org/10.1594/PANGAEA.854198
- Schwertmann, U; Carlson, L; Murad, E (1987): (Table 2, page 299) Chemical and mineral compositions of the samples (air-dry basis). https://doi.org/10.1594/PANGAEA.854199