A cautionary note on the use of 87Sr/86Sr sediment ages in stratigraphy studies

Depth to time conversions based on 87Sr/86Sr isotopic ratios in sediments have been used to determine depositional histories in various marine sedimentary environments. We have developed a numerical method which predicts 87Sr/86Sr values versus depth from the available data. In this paper we show how the method can detect samples which have been contaminated, usually by diagenesis or sediment reworking. Because sample contamination is often otherwise difficult to detect, the method helps to avoid incorrect age determinations and the misinterpretation of depositional histories. (author)