Investigation of planktonic foraminifera with ToF‐SIMS

Abstract

AbstractVarious oceanic sediment properties deliver useful information for reconstructing environmental parameters of the past. Those properties that are closely related to environmental parameters are called ‘proxies’. They are measurable descriptors for desired (but unobservable) variables. Among others, promising advances were made in the field of boron isotopes in foraminiferal shells as a palaeo‐pH recorder. The isotope ratios are typically measured with thermal ionization mass spectrometry, which requires ∼200 shells to achieve high accuracy. We have investigated the possibility of using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) for imaging single foraminiferal shells and determining their elemental and isotopic distribution. The data show that ToF‐SIMS is a useful technique for determining their elemental distribution and for measuring boron isotopic ratios with high precision in a single foraminiferal shell. The use of well‐characterized standards for calibration as well as appropriate surface cleaning procedures for foraminiferal shells should improve data accuracy. Furthermore, the data imply that the parallel detection of all masses would simplify the establishment of new proxies. Copyright © 2002 John Wiley & Sons, Ltd.