Stamm, FM;
Méheut, M;
Zambardi, T;
Chmeleff, J;
Schott, J;
Oelkers, EH;
(2020)
Extreme silicon isotope fractionation due to Si organic complexation: Implications for silica biomineralization.
Earth and Planetary Science Letters
, 541
, Article 116287. 10.1016/j.epsl.2020.116287.
Preview |
Text
stamm 2020 for posting.pdf - Accepted Version Download (6MB) | Preview |
Abstract
A combination of theoretical predictions and isotopic equilibration experiments using the three-isotope method have been performed to assess Si isotope fractionation among minerals, and aqueous species in the presence of dissolved catechol. Aqueous Si in abiotic ambient temperature aqueous solutions is dominated by the IV-coordinated H4SiO40 species, but the presence of aqueous catechol provokes the formation of a VI-fold Si-catechol complex. Results show an equilibrium Si fractionation factor of ∼19‰ between the VI-fold coordinated Si-catechol complex and the IV-fold coordinated aqueous silicic acid, an amplitude never previously observed for silicon. The fractionation between V-fold Si-organo complexes (with diolate, glyconate or methyllactate groups) and silicic acid has also been estimated through theoretical predictions to be about −10‰. These extreme fractionations can be used to improve our ability to interpret the Si isotope compositions of natural solids, and in particular those associated with marine silica biomineralization processes (e.g. sponge spicules).
| Type: | Article |
|---|---|
| Title: | Extreme silicon isotope fractionation due to Si organic complexation: Implications for silica biomineralization |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.epsl.2020.116287 |
| Publisher version: | http://dx.doi.org/10.1016/j.epsl.2020.116287 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | silicon, equilibrium isotope fractionation, organo-silicon complexes, first principle calculation, three-isotope method, Si coordination change |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10099570 |
Archive Staff Only
 |
View Item |
