Using strain birefringence in diamond to estimate the remnant pressure on an inclusion

Raman-based geobarometry of ultrahigh-pressure metamorphic rocks: applications, problems, and perspectives

“…Barron et al [41] found that the diamond stress due to remnant pressure is proportional to the maximum strain birefringence around each inclusion. They claimed that simple birefringence measurements of diamond adjacent to inclusions can be used to estimate remnant pressures on inclusions.…”

“…However the initial pressure can partially release through fracturing of the surrounding host mineral upon heterogeneous expansion of inclusion couples [46,47]. The highest values of overpressures (up to 3.6 GPa) were documented exclusively for various inclusions in kimberlitic diamonds [5,7,41,43]. Exhumation rate of UHPM rocks is much lower (2-5 cm/year [48,49]) compared to very fast uplift of mantle xenolith by kimberlite.…”

“…Raman spectroscopy was recently used to identify minerals in isolated sealed inclusion chambers in some New South Wales (Australia) diamonds and to determine the remnant internal pressure on each inclusion with values of 3.03, 3.31, and 3.54-3.62 GPa for coesite; 0.42, 1.36, and 2.3 GPa for diopsidic omphacite; and 0.8 GPa for grossular garnet [41]. Barron et al [41] found that the diamond stress due to remnant pressure is proportional to the maximum strain birefringence around each inclusion.…”

“…So far the maximum overpressure values for fluid s ¼ sr þ 2s t ð Þ =3 ¼ ÀP stress distribution in coesite-α-quartz-pyrope system for initial conditions: T 0 =1,800 K, P 0 =3 GPa, R Coe,0 =0.01 mm, R Qtz =0.02 mm , and R Pyr =1 mm; and final conditions: T=298 K, P=10 −4 GPa, R Coe = 0.01 mm, R Qtz =0.02 mm, and R Pyr =1 mm. The elastic properties are taken from [39] inclusion even in diamond were found to be as high as 1.5-2.1 GPa [51], whereas for solid inclusions the overpressure values may exceed 3.5 GPa [5,7,41,43]. This fact implies that there are differences in behavior of UHPM fluid and solid inclusions, in particular the solid inclusions having lower-pressure polymorphs (e.g., diamond-to-graphite, coesite-to-α-quartz).…”

Mechanically‐ v. diffusion‐controlled metamorphic microstructure: a symplectite example from Rhodope Metamorphic Complex (Greece)

“…Such a view is generally valid under the assumption of constant pressure and temperature throughout the system. The preservation of grain‐scale pressure and stress gradients has been well documented for pressurized inclusions (Parkinson & Katayama, ; Enami et al ., ; Barron et al ., ; Howell et al ., ). Interestingly, residual stress (>0.3 GPa, locally up to 0.8 GPa) has been recently estimated from strain measurements in quartz fragments of a cataclasite (Chen et al ., ).…”