Zr- Hf Fractionation During Water-Rock Interaction

Pierpaolo Zuddas (1) , C. Inguaggiato (2, 3) , P. Censi (2) , W. D’alessandro (4)

1 BES - Biominéralisations et environnements sédimentaires
2 Dipartimento DiSTeM
3 iSTeP - Institut des Sciences de la Terre de Paris
4 Istituto Nazionale di Geofisica e Vulcanologia

Zr and Hf are two elements having same ionic charge and similar ionic size at a given coordination number. Despite the Zr/Hf ratio is considered to be quite constant in meteorites and lithospheric rocks, seawaters collected from the surface down to varying depths of several Pacific Ocean stations reveal that the Zr/Hf ratio increases by one order of magnitude. Very recent studies have shown that, in both ground waters and lake waters, the Zr/Hf ratio is either higher or lower compared to the interacting minerals displaying a large variability in the distribution of these twin elements. In this communication the possible processes responsible for such a large fractionation are discussed but further work is needed to test the validity of these interpretations. This basic problem of scientific significance needs more attention from the water-rock interaction community.

Keywords: Zr/Hf ratio; natural waters

Domains: Earth Sciences

Pierpaolo Zuddas, C. Inguaggiato, P. Censi, W. D’alessandro. Zr- Hf Fractionation During Water-Rock Interaction. Procedia Earth and Planetary Science, 2017, 17, pp.670 - 673. ⟨10.1016/j.proeps.2016.12.179⟩. ⟨hal-01440534⟩