Pressure sensor based on the Raman shift of the 128-cm−1 band of quartz for pressure measurements in hydrothermal diamond-anvil cells

Abstract

To interpret data collected from high-pressure (P)–temperature (T) experiments simulating geological processes, pressure information during these experiments is crucial. Traditionally, the Raman shifts of the quartz 464-cm−1 band are commonly used as a hydrostatic-pressure calibrant in such experiments, particularly in those performed using hydrothermal diamond-anvil cells (HDACs). In this study, we conducted experiments using HDAC and a Raman spectrometer to investigate the sensitivity of the quartz 128-cm−1 Raman band to changes in P and T. We found that the Raman shift of this band exhibits higher sensitivity to changes in P and T than the 464-cm−1 band at Ts above 200 °C. Changes in the Raman shift of the 128-cm−1 band with Ps and Ts are 9–16 cm−1/GPa and ~ (50–40) × 10−3 cm−1/°C, respectively, at 200–700 °C and < 1.0 GPa; the corresponding values for the 464-cm−1 band are ~9 cm−1/GPa and ~14 × 10−3 cm−1/°C, respectively. The experimental data of Ps, Ts, and the Raman shifts of the quartz 128 cm−1 band relative to that at 0.1 MPa and 23 °C (∆ω128) were fitted into an equation to express their relation: