(Tables 1-2, pages 107-108) Chemical composition of Hawaiian soil concretions and adjacent soil
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| Language: | en |
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1979
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| _version_ | 1867172334642659328 |
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| author | Glasby, Geoffrey P Rankin, P C Meylan, Maurice A |
| author_facet | Glasby, Geoffrey P Rankin, P C Meylan, Maurice A |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Manganiferous soil concretions have been located in pineapple and sugar cane plantations of the Schofield Plateau, Oahu, and black manganiferous coatings on the surface of soils have been observed on the crests of embankments next to pineapple plantations on Oahu, Molokai, and Lanai. The concretions and coatings are found inoxisols derived from volcanic parent material. The moisture regime of the soils is characterized by alternate wet and dry periods. This alternation facilitates remobilization and reprecipitation of manganese and to a much lesser extent iron and associated trace metals in the soils. Optimum conditions for manganiferous soil concretion development are encountered on the Schofield Plateau, where mean annual rainfall exceeds 1000 mm/year but where there is a net evaporation loss from the soils during the dry period (May through October). Remobilization of manganese is less pronounced in the oxisols of Molokai and Lanai, where mean annual rainfall is lower. Thin manganiferous coatings rather than concretions therefore form in these islands. The contents of Mn, Fe, Cu, and Ni of the soils on which Hawaiian concretions form are higher than those of New Zealand soils in which manganese soil concretions are found. This is reflected by the much redder color of the Hawaiian concretion-bearing soils compared with their New Zealand counterparts. Rare earths show an enrichment sequence: parent rock ---+ soil ---+ soil concretion. A small positive Ce anomaly is noted in the soil and is more marked in the concretions. This may be due to the increasing oxidation of Ce in the concretions relative to the soil, although contamination of the soil by concretionary material may also playa role. The parent rock shows no Ce anomaly. Barium and Pb are enriched in concretions relative to the surrounding soil, whereas D, Th, Hf, Nb, Zr, and As are present in similar or higher concentrations in the soil relative to the concretions. Arsenic may follow Fe in the soils. Todorokite is the predominant manganese mineral in the Hawaiian soil concretions, not pyrolusite as previously reported. Scanning electron microscope studies show the crystalline nature of the manganese oxide minerals in the concretions. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_862562 |
| institution | PANGAEA |
| language | en |
| publishDate | 1979 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Tables 1-2, pages 107-108) Chemical composition of Hawaiian soil concretions and adjacent soil Glasby, Geoffrey P Rankin, P C Meylan, Maurice A Aluminium oxide; Arsenic; Barium; Calcium oxide; Cerium; Copper; Deposit type; DEPTH, sediment/rock; Description; Dysprosium; Elevation of event; Erbium; Europium; Gadolinium; Hafnium; Hawaiian Islands, North Central Pacific; Holmium; Iron oxide, Fe2O3; Lanthanum; Latitude of event; Lead; Longitude of event; Loss on ignition; Magnesium oxide; Manganese oxide; Neodymium; Nickel; Niobium; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Oahu_K; Phosphorus pentoxide; Potassium oxide; Praseodymium; Quantity of deposit; Samarium; Sample ID; Silicon dioxide; Size; Spark Source Mass Spectrography; Terbium; Thorium; Titanium dioxide; Uranium; Wet chemistry; X-ray fluorescence (XRF); Ytterbium; Yttrium; Zirconium Manganiferous soil concretions have been located in pineapple and sugar cane plantations of the Schofield Plateau, Oahu, and black manganiferous coatings on the surface of soils have been observed on the crests of embankments next to pineapple plantations on Oahu, Molokai, and Lanai. The concretions and coatings are found inoxisols derived from volcanic parent material. The moisture regime of the soils is characterized by alternate wet and dry periods. This alternation facilitates remobilization and reprecipitation of manganese and to a much lesser extent iron and associated trace metals in the soils. Optimum conditions for manganiferous soil concretion development are encountered on the Schofield Plateau, where mean annual rainfall exceeds 1000 mm/year but where there is a net evaporation loss from the soils during the dry period (May through October). Remobilization of manganese is less pronounced in the oxisols of Molokai and Lanai, where mean annual rainfall is lower. Thin manganiferous coatings rather than concretions therefore form in these islands. The contents of Mn, Fe, Cu, and Ni of the soils on which Hawaiian concretions form are higher than those of New Zealand soils in which manganese soil concretions are found. This is reflected by the much redder color of the Hawaiian concretion-bearing soils compared with their New Zealand counterparts. Rare earths show an enrichment sequence: parent rock ---+ soil ---+ soil concretion. A small positive Ce anomaly is noted in the soil and is more marked in the concretions. This may be due to the increasing oxidation of Ce in the concretions relative to the soil, although contamination of the soil by concretionary material may also playa role. The parent rock shows no Ce anomaly. Barium and Pb are enriched in concretions relative to the surrounding soil, whereas D, Th, Hf, Nb, Zr, and As are present in similar or higher concentrations in the soil relative to the concretions. Arsenic may follow Fe in the soils. Todorokite is the predominant manganese mineral in the Hawaiian soil concretions, not pyrolusite as previously reported. Scanning electron microscope studies show the crystalline nature of the manganese oxide minerals in the concretions. |
| title | (Tables 1-2, pages 107-108) Chemical composition of Hawaiian soil concretions and adjacent soil |
| topic | Aluminium oxide; Arsenic; Barium; Calcium oxide; Cerium; Copper; Deposit type; DEPTH, sediment/rock; Description; Dysprosium; Elevation of event; Erbium; Europium; Gadolinium; Hafnium; Hawaiian Islands, North Central Pacific; Holmium; Iron oxide, Fe2O3; Lanthanum; Latitude of event; Lead; Longitude of event; Loss on ignition; Magnesium oxide; Manganese oxide; Neodymium; Nickel; Niobium; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Oahu_K; Phosphorus pentoxide; Potassium oxide; Praseodymium; Quantity of deposit; Samarium; Sample ID; Silicon dioxide; Size; Spark Source Mass Spectrography; Terbium; Thorium; Titanium dioxide; Uranium; Wet chemistry; X-ray fluorescence (XRF); Ytterbium; Yttrium; Zirconium |
| url | https://doi.org/10.1594/PANGAEA.862562 |