Determination of pressure from measured Raman frequency shifts of anhydrite and its application in fluid inclusions and HDAC experiments

作者：Yuan, Xueyin; Mayanovic, Robert A.; Zheng, Haifei^*

来源：Geochimica et Cosmochimica Acta, 2016, 194: 253-265.

DOI：10.1016/j.gca.2016.09.002

• Anhydrite
• Raman spectroscopy
• Geobarometry
• HDAC
• Fluid inclusions

A new geobarometry was derived from the quantified relationships among Raman vibrational frequencies of anhydrite, pressure and temperature, as determined from in-situ micro-Raman spectroscopy of natural anhydrite crystals measured at p-T conditions up to 560 degrees C and 1400 MPa by using a hydrothermal diamond anvil cell (HDAC). With this geobarometry, the pressure in HDAC experiments and in anhydrite-bearing fluid inclusions can be determined directly from the nu(1), (1016), nu(3), (1128) and nu(3), 1160 Raman frequency shifts of anhydrite at high p-T conditions relative to their values measured at ambient conditions. The pressure can be determined to an accuracy of better than 30 MPa based on the attainable accuracy of +/- 0.1 cm(-1) for the fitted nu(1) Raman peak positions, provided the measured spectra are calibrated using the emission peak of an external fluorescent light source. The feasibility and reliability of this geobarometry were verified by rebuilding the p-T history of two fluid inclusions from the m1 frequency shifts of anhydrite daughter minerals from room to high temperatures, and by measuring the phase-transition pressures of calcite-CaCO3(II)-CaCO3(III) sequence at ambient temperature in a HDAC experiment using anhydrite as a Raman pressure sensor.

• 出版日期2016-12-1
• 单位中国地质科学院矿产资源研究所; 北京大学