Isotopic signatures in hydrothermal vent systems - Identifying factors controlling metal mobilization, transport and precipitation
The focus of my PhD project is to decipher the role of p-T conditions, host rock lithology and phase separation on the transport and enrichment of chalcophile metals in hydrothermal fluids and mineralization precipitating out of these fluids in a temporally stable hydrothermal vent environment. There is a broad range of chemical composition of hydrothermal vent fluids and almost every discovered vent has a different chemical fingerprint. Hence, it becomes a challenge to identify and decipher the sources and processes that modify the chemical and physical characteristics of hydrothermal vent fluids.
I will use a combination of isotopic analysis, autoclave experiments and geochemical modelling. Boron, lithium and strontium isotopes are all potential indicators of hydrothermal circulation and fluid-rock interaction, but operate on different time scales and respond differently to rock lithology, water-rock interaction, phase separation, and magmatic degassing in the magmatic hydrothermal system. Hence, each isotope system can define distinct and discrete isotopic fingerprints of hydrothermal vent processes and, in combination, provide better insights into the mobilization of elements during hydrothermal circulation. The experimentation will be used as a complementary tool to understand geochemical reaction dynamics. Finally, thermodynamic modelling using Geochemists Workbench GWB, for calculating solid-solution equilibria under specific conditions and reaction paths will be applied, using the field and experimental data as baselines and for verification.
The natural samples for the project originate from the Atlantic mid-ocean ridge hydrothermal systems and shallow and deep-sea hydrothermal systems in the Mediterranean Sea close to Milos.
