Zoeken
Zoeken kan via de modus 'eenvoudig zoeken' (één veld) of uitgebreid via 'geavanceerd zoeken' (meerdere velden). Zo kan je bv. zoeken op een combinatie van een auteursnaam (auteur), een jaartal (jaar) en een documenttype.
Boekenmand
Nuttige resultaten kan je aanvinken en toevoegen aan een mandje. De inhoud hiervan kan je exporteren of afdrukken (naar bv. PDF).
RSS
Op de hoogte blijven van nieuw toegevoegde publicaties binnen uw interessegebied? Dit kan door een RSS-feed (?) te maken van jouw zoekopdracht.
nieuwe zoekopdracht
Riverine silicon isotope variations in glaciated basaltic terrains: implications for the Si delivery to the ocean over glacial-interglacial intervals
Opfergelt, S.; Burton, K.W.; Pogge von Strandmann, P.A.E.; Gislason, S.R.; Halliday, A.N. (2013). Riverine silicon isotope variations in glaciated basaltic terrains: implications for the Si delivery to the ocean over glacial-interglacial intervals. Earth Planet. Sci. Lett. 369-370: 211-219. dx.doi.org/10.1016/j.epsl.2013.03.025
In: Earth and Planetary Science Letters. Elsevier: Amsterdam. ISSN 0012-821X; e-ISSN 1385-013X
|  |
| Trefwoord |
|
| Author keywords |
basalt weathering; silicon isotopes; glacial rivers; direct runoffrivers; Iceland |
| Auteurs | | Top |
- Opfergelt, S.
- Burton, K.W.
- Pogge von Strandmann, P.A.E.
|
- Gislason, S.R.
- Halliday, A.N.
|
|
| Abstract |
Marine primary production is dominated by diatoms and these are dependent upon the riverine delivery of silicon (Si) to the ocean. In paleoreconstruction of silicic acid utilisation by diatoms, it is assumed that the isotopic composition of the Si that is delivered from the continent to the oceans remains constant. In this study it is shown that glacier-fed Icelandic rivers differ from those directly draining basaltic catchments in their dissolved Si isotope compositions. Lighter values (d30Si=+0.17±0.18‰) are associated with the high physical erosion rates in glacial rivers, and heavier values (d30Si=+0.97±0.31‰) are associated with lower physical erosion rates and enhanced formation of secondary minerals in direct runoff rivers. The Si isotopic compositions correlate with those of Li and provide evidence of a climatic dependence that is likely to have led to glacial–interglacial differences. Based on existing d30Si measurements from diatoms in a sediment record from the Southern Ocean, the interpretation of changes in Si utilisation between the Last Glacial Maximum (LGM) and the early Holocene is revisited taking into account changing isotopic compositions of the river water delivered to the ocean over glacial–interglacial intervals. During the LGM, Si utilisation values are higher when allowing for changing Si isotope input to the ocean (59±5%), than when a constant Si isotope input is assumed (42–47±5%). This reduces but does not eliminate the difference relative to the Holocene (88±5%). Therefore, changes in Si isotope delivery to the ocean need to be taken into account in the precise reconstruction of ocean Si utilisation and primary productivity over glacial–interglacial timescales. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
