Hydrothermal alteration of oceanic crust and consequences for geochemical cycling

Hydrothermal alteration of the oceanic crust is an important process for controlling the composition of seawater, and it also determines the quantity of seawater-derived volatiles that can be subducted into the mantle.  The halogens (F, Cl, Br, I) are a major component of seawater and sediments and each have unique and complementary behaviours.  Fluorine readily substitutes for the OH-group in hydrous minerals. Chlorine is the major anion in seawater. Bromine and iodine are essential elements for life, and iodine has relatively high concentrations in organic-rich marine sediments.  The geochemical cycles of these elements will be investigated in a deep basement IODP drill core (e.g. >500 m to 2000 m below seafloor).  The student will use a range of techinques including the electron microprobe and state of the art techniques that are only possible at the ANU (halogen determination from irradiation-produced noble gases and ion microprobe (SHRIMP)) to measure F, Cl, Br, I in rocks and minerals at the highest precision possible. The project will  provide a strong background for the candidate to pursue further study in the broad fields of geochemistry or petrology.

For more information about this potential research topic or activity, or to discuss any related research area, please contact the supervisor.

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