de Lange, Gert J; van Os, B; Poorter, R (1992): Description and chemical composition of manganese nodules during R/V "Tyro" cruise APNAP 1 to the Madeira Abyssal Plain in 1986 [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.854707, Supplement to: de Lange, GJ et al. (1992): Geochemical composition and inferred accretion rates of sediments and managanese nodules from a submarine hill in the Madeira Abyssal Plain, eastern North Atlantic. Marine Geology, 109(1-2), 171-194, https://doi.org/10.1016/0025-3227(92)90227-9
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Abstract:
The porewater and sediment composition of two boxcores and of a small gravity core, taken on a manganese-nodule-covered hill and in the Madeira Abyssal Plain proper respectively, are compared. The pore-water study of the two boxcores indicates that oxic conditions prevail in both cores. In addition, it indicates that no detectable fluxes of Mn or Fe occur from the porewater to the ocean bottom water. Variations in the geochemical composition of the sediments can be explained by fluctuations in the amount of carbonate, which acts as a diluting agent. A clear carbonate minimum is observed at 20-22 cm depth in the two cores. This minimum is likely to be associated with the last glacial period (10-20 kyr B.P.). This association is supported by the sediment accumulation rate of 15 mm/kyr as found by extrapolation from the rate for pelagic sediments in the Madeira Abyssal Plain. The bulk composition of the manganese nodules recovered from the submarine hill is chemically almost identical to the average composition of Atlantic nodules. The trace metal and Rare Earth Elements composition indicate a hydrogenous origin for the manganese nodules of this study. On the basis of the chemical composition, and that of nodules relative to that of the adjacent sediments, an average nodule accretian rate of 2.8-3.3 mm/myr has been calculated. Although the analyses of the entire ferromanganese nodules that have been studied seem to indicate a homogenous composition, internal structures of the nodules reveal great inhomogeneity, both visually and chemically. These fluctuations may be related to variations in the fluxes of Mn and Fe, which in turn could be climate-related.
Original version:
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: 31.411985 * Median Longitude: -25.294965 * South-bound Latitude: 31.411660 * West-bound Longitude: -25.299870 * North-bound Latitude: 31.412960 * East-bound Longitude: -25.293330
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
- de Lange, GJ; van Os, B; Poorter, R (1992): Description of manganese nodules collected by R/V "Tyro" during its 1986 cruise over the Madeira Abyssal Plain. https://doi.org/10.1594/PANGAEA.854705
- de Lange, GJ; van Os, B; Poorter, R (1992): (Table 3, page 184) Chemical composition of a manganese nodule from the Madeira Abyssal Plain, R/V "Tyro" cruise APNAP 1. https://doi.org/10.1594/PANGAEA.854706