Swiss Journal of Geosciences

Table 4 Intervals of compositional variations in minerals marking different metamorphic stages of orthogneiss

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
Grt		Mg = 0
		Fe²⁺ = 0.03–0.09
		Fe³⁺ = 0.21–0.38
		Ca = 2.74–2.85
		Mn = 0.10–0.17
Jd		X_Jd = 0.87–0.99	X_Jd = 0.50–0.88
		Na = 0.92–0.99	Na = 0.84–0.99
		Fe = 0.01–0.13	Fe = 0.12–0.41
		Ca = 0.00–0.04	Ca = 0.02–0.11
		Mg = 0.00–0.04	Mg = 0.01–0.08
Wm		Si = 3.47–3.65	Si = 3.35–3.48
		Al_tot = 1.86–2.07	Al_tot = 2.05–2.22
		Ti = 0	Ti = 0.00–0.01
		Mg = 0.24–0.33	Mg = 0.28–0.33
Kfs	X_Ab = 0.02–0.04
	X_An = 0
	X_Or = 0.96-0.98

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