Coral Sr thermometer simplified from Sr/Ca thermometer

Cubic sub-samples obtained from a Porites coral slice collected from Xisha Islands, South China Sea, were weighed with precise microbalance. The Sr an d Ca concentrations were analyzed with isotope dilution thermal ionization mass spectrometry. Our results demonstrate that Ca concentrations in all sa mples me very uniform (mean = 9.52 mmol/g, 2 sigma = 0.02 mmol/g); Sr conce ntrations and Sr/Ca ratios are well correlated (correlation coefficient r = 0.9968). It implies that the Sr thermometer can replace Sr/Ca thermometer and the determination of Ca can he omitted. This can save up to 50% time an d cast, and more importantly, paleoclimate study using coral proxy can now be carried out in routine Sr isotope laboratories.