Table 1.

Elemental compositions of apatites, carbonates and silicates obtained from EDS and WDS analyses

Apatites analysed by WDS in the EPMA
Target:TVA294-659.6TVA294-659.6TVA294-659.6TVA294-659.6
Element wt%/spot:312144
CaO55.154.555.055.1
P2O541.241.540.640.9
F3.23.23.33.2
Cl0.00.00.00.0
FeO0.50.61.00.4
MnO0.20.30.20.2
Na2O0.00.00.00.0
MgO0.00.00.00.0
SiO20.00.00.00.0
Ce2O30.10.10.00.1
Y2O30.00.00.00.0
Total99.198.898.898.7
FluorapatiteFluorapatiteFluorapatiteFluorapatite
Fe-silicates analysed by EDS in the TEM (on FIB lamellae; spots shown in inset of Fig. 4e)
Target:TVA294-656.9TVA294-656.9
Element wt%/spot:01b01a
O K48.649.9
Mg K0.40.4
Al K0.80.5
Si K36.939.6
Ca K0.70.8
Mn K0.40.2
Fe K12.28.6
Total100.0100.0
Ca–Mn-stilpnomelaneCa–Mn-stilpnomelane
Ferric–ferrous silicates analysed by EDS in the SEM
Target:TVA294-622.1TVA294-622.1TVA294-622.1TVA294-622.1TVA294-622.1TVA294-622.1TVA294-622.1
Element wt%/spot:1258746
C K14.313.0
O K36.236.136.337.139.939.237.8
Mg K5.95.24.15.65.55.14.0
Al K11.28.98.2
Si K26.926.219.525.612.613.910.1
K K1.4
Mn K2.31.81.92.7
Fe K28.830.724.029.130.831.526.9
Total100.0100.0100.0100.0100.0100.0100.0
Proto-Mn,Fe-anthophyliteMn,Fe-anthophyliteMn,Fe-anthophyllite + graphiteGruneriteChloriteChloriteGraphite with chlorite
Sulphides and oxides with graphitic carbon analysed by EDS in the SEM
Target:TVA294-622.1TVA294-622.1TVA294-622.1TVA294-622.1
Element wt%/spot:1392
C K22.48.8
O K11.522.9
S K34.726.722.3
Fe K65.350.966.268.3
Total100.0100.0100.0100.0
PyrrhotitePyrrhotite + graphiteoxidized pyriteMagnetite + graphite
Carbonates analysed by EDS in the SEM
Target:TVA294-656.9TVA294-656.9TVA294-622.1TVA294-622.1TVA294-622.1TVA294-622.1
Element wt%/spot:124563
C K15.513.613.613.611.763.2
O K43.034.443.243.245.120.9
Mg K9.89.86.16.16.72.2
Cl K1.4
Ca K26.024.821.421.420.77.9
Si K1.11.10.6
Mn K4.54.96.56.55.42.5
Fe K11.09.29.29.22.8
Total99.999.6100.0100.0100.0100.0
Mn-dolomiteMn–Fe-dolomiteMn–Fe-dolomiteMn–Fe-dolomiteMn–Fe-dolomiteGraphite in dolomite