From molecular dynamics to gold deposits - Volker Haigis - 2 novembre 2015

Volker Haigis - ENS, Département de Chimie – UPMC, IMPMC – CNRS

Lundi 2 novembre 2015 à 10 h 30

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de conférence, 4^e étage, Tour 22-23, Salle 1

Abstract

The mobility of metals in fluids of the Earth's crust and precipitation of metals in ore forming processes depend strongly on the speciation of the metal in hydrothermal fluids. In the case of gold, current speciation models focus on hydrogen sulfide (HS-) as the most important ligand [1]. However, this picture is challenged by the discovery that the radical ion S3 - is a stable sulfur species in aqueous solution at elevated pressures and temperatures and forms stable complexes with gold [2]. This species is therefore expected to play a crucial rôle in the extraction of gold from magma or rocks, in the transport by crustal fluids and in the focused precipitation of gold ore. I will show how molecular dynamics simulations, laboratory experiments and geological insight can be combined into a coherent picture of the relevant processes.

[1] Seward (1973), Geochim. Cosmochim. Acta 37, 379-399
[2] Pokrovski et al. (2015), PNAS, doi: 10.1073/pnas.1506378112