Swiss Journal of Geosciences

Table 2 Intervals of compositional variations in minerals marking different metamorphic stages of garnet-bearing 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-1a	pre-1b	M1	M2
Grt	Mg = 0.28–0.56	Mg = 0.09–0.28	Mg = 0.03–0.08	Mg = 0.02–0.04
	Fe²⁺ = 2.02–2.31	Fe²⁺ = 2.24–2.51	Fe²⁺ =1.37–1.67	Fe²⁺ = 1.18–1.53
	Fe³⁺ = 0.00–0.07	Fe³⁺ = 0.01–0.07	Fe³⁺ =0.00–0.08	Fe³⁺ = 0.00–0.10
	Ca = 0.08–0.22	Ca = 0.09–0.31	Ca = 1.08–1.40	Ca = 1.24–1.48
	Mn = 0.15–0.34	Mn = 0.22–0.36	Mn = 0.09–0.28	Mn = 0.12–0.31
Jd/Cpx			X_Jd = 0.84–0.97
			Na = 0.89–0.98
			Fe = 0.00–0.05
			Ca = 0.01–0.04
			Mg = 0.00–0.03
Wm	Si = 3.07–3.07		Si = 3.37–3.58	Si = 3.35–3.52
	Al_tot = 2.85–2.85		Al_tot = 1.88–2.23	Al_tot = 2.02–2.25
	Ti = 0.02–0.02		Ti = 0.00–0.01	Ti = 0.00–0.01
	Mg = 0.04–0.05		Mg = 0.24–0.30	Mg = 0.23–0.30
Ep			Fe³⁺ =0.38–0.65	Fe³⁺ =0.33–0.52
			Al_tot = 2.36–2.64	Al_tot = 2.47–2.7
			Mn = 0.00–0.01	Mn = 0.00–0.01
Gln				Na = 1.88–1.96
				Al_tot = 1.77–1.93
				Fe²⁺=1.58–2.04
Pl				X_Ab = 0.93–0.96
				X_An = 0.02–0.06
				X_Or = 0.01–0.03

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