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| 2. |
- Boström, Kurt, et al.
(författare)
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Geochemistry and origin of ferromanganese concretions in the Gulf of Bothnia
- 1982
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Ingår i: Marine Geology. - : Elsevier BV. - 0025-3227 .- 1872-6151. ; 50:1-2, s. 1-24
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Tidskriftsartikel (refereegranskat)abstract
- Ferromanganese concretions cover large areas of the Gulf of Bothnia. They are flat to well-rounded, the rounded ones being richer in oxyhydroxides of iron and manganese. Rounded and ellipsoidal nodules, particularly those in the northern Gulf of Bothnia, are richest in Mn, Ni, Ba and Cu, which probably coexist in a Mn oxyhydroxide phase. Flat nodules are enriched in Fe, P, rare earths and As, probably associated with an Fe oxy-hydroxide component. Aluminum, V, Cr and Ti occur in still another phase. The sediments of the gulf generally consist of a 10-50 mm-thick layer of oxidized surface sediment, enriched in Mn, Ba, P and Ni lying on top of reduced sediments which are diagenetically depleted in these elements. The remobilized elements have redeposited in the nodules, but this process cannot explain the origin of all the nodular material. Some released Mn, Ba and Ni furthermore enter into suspended phases, which eventually leave the Baltic Sea. The economic value of the nodules in the Gulf of Bothnia is probably limited at present.
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| 3. |
- Boström, Kurt
(författare)
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On the formation of magnetite-hematite-apatite "magmas" from metalliferous sediments at subduction zones
- 1982
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Ingår i: Stockholm Contributions in Geology. - 0585-3532. ; :37, s. 21-42
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Tidskriftsartikel (refereegranskat)abstract
- One interpretation of the plate tectonic theory suggests that marine sediments are brought down to large depths in the Earth and become intensely metamorphosed at subduction zones. A considerable fraction of these subducted sediments would consist of Fe, Mn and P rich exhalative-sedimentary deposits that have formed at spreading centers. A thermodynamic model for such alteration processes shows that exhalative sedimentary deposits would serve as source beds for magmatic magnetite-hematite-apatite rich ores whereas Mn would be lost due to reduction by organic matter, and subsequent removal in acid solutions, formed from interactions between clays and NaCl in pore waters. The alteration products show several similarities with the many magnetite-hematite-apatite ores which are located in the circumpacific orogenic belt
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| 4. |
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| 5. |
- Burman, Jan-Ola, et al.
(författare)
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Use of ICP-AES in marine geochemistry
- 1982
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Ingår i: ICP Information Newsletter. ; 7:10, s. 493-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
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| 7. |
- Ehlin, Per-Olov
(författare)
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Seasonal variations in metal contents of birch
- 1982
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Ingår i: Geologiska föreningens i Stockholm förhandlingar. - : Informa UK Limited. - 0016-786X. ; 104:1, s. 63-67
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Tidskriftsartikel (refereegranskat)abstract
- A two year study of the metal content of birch leaves shows that most of the major elements increase in content during the growth season, whereas Cu and Ni decrease during its beginning. All trace elements have rather constant contents after the beginning of July. Ground water changes seem to explain the differences in major element contents between samples taken from 1977 and 1978. Physiological and leaf weight changes could explain the major variations during the growth season and the physiologically influenced increases are well eliminated by normalizations. Only the 1977 Mn increase is not eliminated, probably because of unusual ground water content. The best normalizations found are those with respect to Fe + Al + Zn, Ba + Sr and Al + Ti. Irregular variations in metal contents are hardly caused by occasional weather changes; probably they are caused by occasional ground water variations.
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| 8. |
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| 9. |
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| 10. |
- Fredriksson, Sverker, et al.
(författare)
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A new diquark model for deep inelastic structure functions
- 1982
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739 .- 1431-5858. ; 14:1, s. 35-39
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Tidskriftsartikel (refereegranskat)abstract
- The bulk of data from deep inelasticep, eD, μp, μN, νp and νN scattering is fitted with a new diquark model of nucleons. The proton is found to be mostly in au(ud) 0 state, where the (ud)0 diquark has spin and isospin zero. There is hence no trace ofSU(6) symmetry among diquarks in nucleons.
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