Potential Reference Materials for Hematite Oxygen Isotope Analysis

Abstract

Hematite is a potential mineral for reconstructing the oxygen isotope composition and paleotemperature of paleowater. A highly accurate analysis of oxygen isotopes is essential. However, relative to other oxygenated minerals, we lack hematite reference materials that allow for internationally comparable analyses between different laboratories. To address this issue, we attempted to perform bulk rock oxygen isotope analysis on five hematite reference materials (GBW07223a, GBW07825, YSBC28740-95, YSBC28756-2008, Harvard 92649). Meanwhile, the oxygen isotope ratios of iron oxides (GBW07223a, GBW07825, YSBC28740-95, YSBC28756-2008) were obtained by mass balance involving other oxygen-bearing minerals such as quartz and silicates. In addition, the oxygen isotope ratios of iron oxides in an oolitic hematite (ca. 1.65 billion years ago) are consistent with the results of previous analyses of this class of minerals.

LM-19 lawsonite: a potential reference material for in situ oxygen isotope determination in lawsonite by ion microprobe

“…Laser fluorination oxygen isotope analysis at IGGCAS was conducted using a New Wave Research MIR10-30 laser coupled to a vacuum extraction system. We mainly followed the protocol described by Feng et al 26 Samples (each of ca. 1.5 mg) reacted with purified BrF 5 in the sample chamber to liberate oxygen.…”

Chromite Reference Materials and Matrix Effects in SIMS Oxygen Isotope Measurements

“…The samples were analysed by laser fluorination at the Laboratory for Stable Isotope Geochemistry, IGGCAS, using a New Wave Research MIR10‐30 laser (Feng et al . 2020). About 3–4 mg of handpicked chromite grains were reacted with reagent BrF 5 .…”

Beryl Reference Materials for In Situ Oxygen Isotope Determination

“…The oxygen isotopes of the BS1-BS6 beryl crystals were acquired using the laser-based fluorination oxygen extraction line at the Stable Isotope Laboratory. A New Wave Research MIR10-30 laser was coupled to a vacuum extraction system [27]. Each analysis consumed ~2 mg.…”