Dr David Chew from iCRAG, the Science Foundation Ireland (SFI) funded research centre in applied geosciences, has been announced as a recipient of the SFI Investigators Programme award, worth €500,000 over 5 years. The award will be used to develop a new image-based approach to dating calcite by the uranium-lead method.

SFI Investigators Programme awards support the development of world-class research capability and human capital in areas of science, technology, engineering and mathematics that demonstrably support and underpin enterprise competitiveness and societal development in Ireland. The Investigators Programme, with its focus on scientific excellence and impact will place Ireland’s researchers in a strong position to compete for Horizon 2020 research grants.

Dr Chew is a Funded Investigator in the field of hydrocarbons at iCRAG and Associate Professor at the School of Natural Sciences, Trinity College Dublin. Dr Chew’s research focusses on the thermal history of Ireland and its offshore basins, sedimentary provenance analysis and the application of geochronology and thermochronology to a variety of problems in the geosciences.

Speaking at the announcement of his award, Dr Chew outlined the work that will be undertaken through this project:  “calcite is the major rock-forming mineral in limestones, and is a common mineral in veins in zinc and lead ore systems such as the world-class Irish zinc-lead mineral province.  This project will develop a new image-based approach to dating calcite by the uranium-lead dating method, using a laser-ablation system coupled to a mass spectrometer. Laser ablation involves the use of incident light to remove material from a solid surface. When coupled with mass spectrometry it is a powerful tool for quantitative chemical analysis. Isotopic dating of calcite has important industrial applications and also permits dating of carbonate rocks from key time periods in the ancient geological record, before the appearance of hard-bodied fossils.”

 

Present approaches to U-Pb dating of calcite suffer from large age uncertainties due to low U concentrations and/or high amounts of initial Pb.  Dr Chew’s work will generate U/Pb image maps that facilitate identification of high and low U/Pb portions of the rastered area, which can be sub-sampled to yield a sufficient spread on isochrons to yield U-Pb calcite age uncertainties as low as ±1%.