The element ratio and the isotopic composition of trace elements in calcareous microfossils (e.g. foraminifers) as well as corals and mussels are used for the reconstruction of the climate in the past.
In the so-called Proxy Laboratory samples are prepared and measured. A metal free cleanroom allows preparation of extremely small samples for ultra-trace element analysis.
Measurements are carried out on ICP mass spectrometers. According to the requirements element ratios (e.g. B/Ca, Mg/Ca, Sr/Ca) are measured by either high resolution ICP-MS (Nu Attom, Nu Instruments) or by another mass spectrometer with a lower resolution, which allows simultaneous detection of the whole mass spectrum from lithium to uranium (m/z 6 - 238) (Spectro MS, SPECTRO).
Isotope ratios of selected trace elements (e.g. δ11B) are determined by a multicollector-ICP-MS (Nu Plasma II, Nu Instruments).