Planktonic foraminifera, stable isotope record and temperature reconstruction of sediment core MD95-2040

Stable isotope measurements were generally made on 30 specimens of the planktonic foraminifera species Globigerina bulloides picked from the 250-355 µm size fraction. Before analysis, the forams were treated with a 3 % solution of hydrogen peroxide to remove traces of organic contaminants, crushed and cleaned using an ultrasonic generator, rinsed in acetone and oven dried at 50°C. Depending on the sample size, they were analysed using different mass spectrometers and preparation systems. The larger samples were reacted with 100 % orthophosphoric acid at 90oC using a VG Isotech Isocarb common acid bath system, and the carbon dioxide produced during this reaction was then analysed by a VG Isotech SIRA - Series II mass spectrometer. For the smaller samples (less than100 micrograms) analyses were performed using a PRISM mass spectrometer with a Micromass Multicarb sample preparation system. The results were calibrated to VPDB using the repeated analysis of an internal carbonate standard (Carrara Marble). The analytical precision was better than 0.08 per mil (1s ) for oxygen and 0.06 per mil (1s ) for carbon (internal standard). The standard deviation of the analysis for replicate samples is s = 0.14 per mil for the d18O and s = 0.08 per mil for the d13C.