Electron microprobe petrochronology of monazite-bearing garnet micaschists in the Oetztal-Stubai Complex (Alpeiner Valley, Stubai)

Swiss Journal of Geosciences

Table 3 microprobe analyses (cations p.f.u.) of garnet (Grt), biotite (Bt), muscovite (Ms) and plagioclase (Pl) in micaschists and gneisses from the Schrankogel complex in the Austroalpine Oetztal-Stubai basement, Alpeiner Valley around Franz-Senn-Hütte, normalized to 12 oxygen (garnet), 11 oxygen (biotite, muscovite) and 8 oxygen (plagioclase). Almandine (Alm), anorthite (An), grossular (Grs), pyrope (Prp), spessartine (Sps) contents in mole%*100. Mineral analyses combined for geothermobarometric calculations are as follows: Sample RZ33: Grt31c–Bt119–Pl73; Grt4r–Bt108–Pl170/Pl73: Sample RZ42: Grt245c–Bt161–Ms187–Pl171; Grt104c–Bt161–Ms187–Pl171; Grt84r–Bt247–Ms187–Pl203; Grt77r–Bt247–Ms187–Pl203. c core, r rim

	Bt119	Bt108	Bt161	Ms187	Bt247	Ms187
Si	2.727	2.737	2.636	3.152	2.654	3.152
^IVAl	1.273	1.263	1.364	0.848	1.346	0.848
^VIAl	0.349	0.368	0.419	1.821	0.387	1.821
Ti	0.095	0.090	0.045	0.008	0.095	0.008
Fe	1.261	1.183	1.155	0.092	1.229	0.092
Mn	0.003	0.003	0.005	0.001	0.005	0.001
Mg	1.186	1.240	1.443	0.096	1.255	0.096
Ca	0.000	0.000	0.002	0.001	0.001	0.001
Na	0.024	0.028	0.027	0.131	0.030	0.131
K	0.922	0.919	0.692	0.839	0.793	0.839
Tot	7.840	7.831	7.787	6.990	7.796	6.890
XMg	0.48	0.51	0.56	0.51	0.51	0.49
Pl	73	76	171	173	203	204
Si	2.859	2.784	2.847	2.842	2.779	2.805
Al	1.129	1.203	1.150	1.152	1.220	1.190
Ca	0.153	0.226	0.152	0.163	0.222	0.205
Na	0.849	0.788	0.846	0.846	0.762	0.798
K	0.013	0.002	0.008	0.002	0.013	0.004
Tot	5.006	5.008	5.003	5.005	4.996	5.001
An	15.0	22.2	15.1	16.1	22.3	20.3