IMPROVING PRESSURE ESTIMATION IN HIGH PRESSURE TERRANES WITH RAMAN SPECTROSCOPY: NEW CALIBRATION AND AN IMPLEMENTATION ON BLUESCHISTS FROM SIFNOS, GREECE
The relationship was tested on quartz- and garnet-bearing blueschists from Sifnos, Greece. Care was taken to select those inclusions completely encapsulated by garnet in 3D which have the highest chance of preserving the PT conditions at which they were included in garnet. Garnet growth was estimated to start c. 460°C and end at 560°C (Dragovic et al., 2012), with P between 20–22 kbar. We estimate P to be 18.1 kbar at 460°C and 19.7 kbar at 560°C (Δu206 = 20.97 cm-1). Differences in calculated P could result from partial relaxation of the garnet that surrounds the inclusion and cracks/surface-exposure. Thus we suggest that calculated pressures are minimum values. Further experimental work at high-P conditions could better refine the relationship between T, P and Δu at these high-P conditions.