A precise, high‐throughput method for determining Sr/Ca, Sr/Ba, and Ca/Ba ratios in marine barite

[1] Recent evidence suggests that marine barite, an inorganic phase preserved in oxic, deep-sea sediments, may record seawater Sr and Ca concentrations. Here we describe a novel method for determining Sr/Ca, Sr/Ba, and Ca/Ba ratios of discrete marine barite separates. Marine barite, separated from deep-sea sediments, is dissolved in a basic, ethylene diamine tetra acetic acid (EDTA) solution and subsequently analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES). Since dissolution occurs within 2–5 days, and >15 samples can be analyzed on the ICP-OES per hour, data acquisition is rapid compared with other procedures. The method yields precisions of <0.7% (Sr/Ca), <0.6% (Sr/Ba), and <1.0% (Ca/Ba), which are reproducible within 1.7% (Sr/Ca), 1.7% (Sr/Ba), and 2.5% (Ca/Ba). Precise determination of trace element incorporation in marine barite has implications for paleoceanography (development of seawater Sr and Ca concentration curves) and calculation of barite solubility in both the modern and ancient ocean.