New calcite growth experiments for a better understanding of paleoclimates and biomineralization

A great deal of what we know about the Earth’s past climate and environment over geologic timescales was inferred from the isotopic composition (d¹⁸O and d¹³C) of calcium carbonate minerals (CaCO₃). For example, the pace and magnitude of glacial/inter-glacial cycles over the past 3 millions years was discovered in the late 1960s by measuring the d¹⁸O of carbonate shells (i.e. foraminifers) found in marine sediment cores. Since then, hundreds of marine and terrestrial isotope records have been produced and are used to evaluate past temperatures, sea level, precipitation and other environmental parameters.

Despite the wide usage of carbonate isotopic records in Earth Sciences, a full understanding of isotopic fractionation between carbonate minerals and water is still lacking. This is a significant problem because it limits the accuracy of environmental reconstructions based on carbonate isotopic proxies.

In parallel, new knowledge on the isotopic fractionation mechanisms will contribute to elucidate how biologic calcifiers (such as corals, molluscs and calcifying planktic species) build their shells. Such knowledge is critical for predicting how marine life will respond to ocean acidification as well as for the Earth’s global carbon budget.

The proposed master project aims at closing a significant knowledge gap in our understanding of isotopic fractionation between carbonate minerals and water. Specifically, you will grow calcium carbonate minerals under controlled conditions and measure their isotopic composition using mass spectrometric techniques. A successful completion of this project is expected to result in a scientific publication in a prestigious journal such as Earth and Planetary Science Letters or Geochimica et Cosmochimica Acta.

Requirements

We are looking for a highly motivated MSc student. This 6 to 9 months project consists of conducting experiments, processing samples and isotope analyses, requiring some autonomy, knowledge of chemistry and/or geochemistry. The student will gain experience in the field of isotope geology, mass spectrometry, mathematical modelling and reporting scientific research.