The titanium isotope composition of seawater: a new oceanographic tracer?

Project Background
The chemistry of oceans is the result of a balance between inputs (e.g. weathering of landmasses) and outputs (e.g. hydrothermal exchange at mid-ocean ridges). Marine sediments can serve as archive of seawater chemistry and record the relative influence of the various inputs and outputs, which can then be used to test the link between ocean circulation and the evolution of climate over timescales ranging from thousands to millions of years.

Amongst all the elements of the periodic table, titanium has seldom been used as an oceanographic tracer despite its potential as a tracer of aeolian dust input and deglaciation processes. In this project, we will aim to use, for the first time, a newly designed geochemical tracer, the stable isotope composition of titanium [1], to study the controls on the Ti budget of the oceans and its potential as an oceanographic tracer.

Project Aims and Methods
In this project, the student will perform ultra-high precision titanium (Ti) isotope measurements on a range of sedimentary archives [2] to study the controls on the titanium budget of seawater and explore its variation through time. Analytical work will be carried out in the newly set up Cardiff Earth Laboratory for Trace Element and Isotope Chemistry (CELTIC) at Cardiff University.

The student will take a particular interest in ferromanganese crusts, which are oxides deposits precipitated directly from seawater and has been intensively used for palaeographic reconstructions using isotope tracers. The datasets generated will be used to constrain the sensitivity of Ti isotopes to varying continental inputs to seawater:
- Determine how variable are the Ti isotope composition of present-day oceans and how it relates to known inputs and current thermohaline circulation.
- Measure the Ti isotope composition of ferromanganese crust through time to test the sensitivity of the Ti isotope composition of seawater to the evolution of Earth climate.

Overall, this project will allow for a much clearer understanding of the potential of titanium isotopes as a paleo oceanographic tracer.

Candidate Requirements
This project would suit a candidate interested in understanding Earth System Science, palaeoceanography and isotope geochemistry.

CASE or Collaborative Partner
The CASE partner, Nu instrument, is a recognised company specialised in developing instrumentations and methods for high precision isotope ratio measurements. it will train and assist the student in setting Ti isotope measurements in very low-level samples such as water samples.

Training
The student will receive extensive training in isotope geochemistry, oceanography as well as numerical modelling by Millet, Andersen and Van der Flierdt. In addition, the student will be trained in cutting-edge analytical techniques in the newly installed geochemistry analytical facilities at Cardiff University.

In addition to project-specific training, the student will have access to the DTP training courses, as well as a range of Cardiff University Student Development courses, to maximise transferable skills. The student is also expected to present project results to national and international conferences. Finally, the student will have the opportunity to demonstrate both in the classroom and in the field.
Combined, the training package of the project will give the student an excellent basis for the rest of their career.