Simultaneous Determination of δ18 O and δ37 Cl Isotopic Compositions and the Concentrations of F, Cl, and S in Apatite Using SIMS

Abstract

Due to its ubiquity in rock types and ability to accommodate a wide range of trace elements, apatite is widely used to interpret magmatic evolution and track volatile elements in hydrothermal systems. Volatile elements and Cl–O isotopes make apatite an ideal mineral with which to record the chemical and textural signatures of geological processes. This study describes a new analytical procedure to obtain the F, Cl, and S contents and Cl and O isotopes simultaneously using secondary ion mass spectrometry (SIMS) within ~10 min of analysis time for each spot. The analytical precision of δ18 O (2 SD (standard deviation) ~0.30‰) and δ37 Cl (2 SD ~0.20‰) has no obvious trade-off compared with ordinary SIMS analysis. The new protocol is time-efficient and, more importantly, ensures the consistency of data sources. A set of apatite standards with different uses were determined using this new method to provide a complete set of recommended values.