A RAPID MASS-SPECTROMETRIC METHOD FOR THE SIMULTANEOUS ANALYSIS OF BARIUM, CADMIUM, AND STRONTIUM IN FORAMINIFERA SHELLS

Recent developments in inductively coupled plasma mass spectrometry (I CP-MS) make it possible to simultaneously measure a suite of trace ele ments of paleoceanographic interest in foraminifera shells from deep-s ea sediments. Here we present an ICP-MS method that allows determinati on of precise Cd/Ca, Ba/Ca, Sr/Ca, and Mn/Ca ratios in purified forami nifera shell samples as small as 25 mu g. The method utilizes a combin ation of isotope dilution for Ba and Cd determination and internal sta ndardization for Ca and Sr determination. Long term reproducibility of the method is 2-3% for the elemental ratios. The principal advantages of the method are that all four elemental ratios of paleoceanographic interest are generated simultaneously for a single sample of purified foraminiferal carbonate, minimizing sample size requirement, reducing analysis time, and improving correlation between proxies.