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Table 3 Intervals of compositional variations in minerals marking different metamorphic stages of garnet-free gneiss

From: Blueschist mylonitic zones accommodating syn-subduction exhumation of deeply buried continental crust: the example of the Rocca Canavese Thrust Sheets Unit (Sesia–Lanzo Zone, Italian Western Alps)

Mineral pre-1 M1 M2/D2 M3/D3
Jd   XJd = 0.87–0.99 XJd = 0.66–0.83 XJd = 0.09–0.2
   Na = 0.92–0.99 Na = 0.85–0.96 Na = 0.58–0.87
   Fe = 0.02–0.10 Fe = 0.13–0.32 Fe = 0.55–0.81
   Ca = 0.01–0.05 Ca = 0.04–0.14 Ca = 0.15–0.35
   Mg = 0.00–0.04 Mg = 0.03–0.11 Mg = 0.11–0.24
Cpx   XJd = 0.43–0.43   
   Na = 0.55–0.56   
   Fe = 0.26–0.27   
   Ca = 0.41–0.45   
   Mg = 0.27–0.28   
Wm   Si = 3.44–3.53 Si = 3.39–3.44  
   Altot = 1.97–2.07 Altot = 2.07–2.13  
   Ti = 0.00–0.01 Ti = 0.00–0.01  
   Mg = 0.28–0.32 Mg = 0.28–0.33  
Ep   Fe3+ =0.61–0.78 Fe3+=0.54–0.59  
   Altot = 2.22–2.39 Altot = 2.40–2.45  
   Mn = 0.00–0.01 Mn = 0.01–0.02  
Bt Ti = 0.00–0.01    
  AlVI = 0.60–1.02    
  XMg = 0.41–0.56    
Pl     XAb = 0.95
     XAn = 0.02
     XOr = 0.03