Barian Micas and Exotic Ba-Cr and Ba-V Micas Associated with Metamorphosed Sedimentary Exhalative Baryte Deposits near Aberfeldy, Scotland, UK
Abstract
:1. Introduction
2. Occurrence of Micas Associated with the Aberfeldy SEDEX Mineralization
Sample Name | Type | Rock Description | Mineralogy † |
---|---|---|---|
G100d | outcrop | Quartz celsian chert with sulphate pseudomorphs | CLS, QZ, ms, bt, py, rt, (sp) |
G114a | outcrop | Quartz chert with pyrite laminae | QZ, PY, cls, hyal, ms, sp, pyh |
429-5 | core | Garnet hornblende mica schist (BLS) | QZ, PL, MS, GT, HB, DOL, bt, chl, cal |
429-18 | core | Baryte rock | BRT, py, cls, qz, bt, hyal, (sp, rt, cal) |
BH9-28.6 | core * (4330) | Quartz muscovite hyalophane schist | QZ, MS, HYAL, cls, py, sp, (rt, brt) |
09-05 [BH9] | core | Muscovite dolomite schist (MB) | DOL, MS, QZ, PYH, (rt, ap) |
N81-80 | outcrop | Hyalophane chert | HYAL, QZ, bt, ms, py, rt, brt, sp, (ap) |
424-8 | core | Hyalophane biotite schist | HYAL, DOL, BT, QZ, PY, ms, pyh, rt, (sp) |
BH3-27.8 | core * (3963) | Banded baryte rock | BRT, QZ, PY, cal, mag, bt, dol |
G171 | outcrop | Baryte rock | BRT, qz, bt, cls, py, dol |
702-11 | core | Banded baryte–dolomite rock | BRT, DOL, py, qz, sp, bt, mag, cls, gn, (phy, ap) |
207-5 | core | Biotite calcite schist (MB) | BT, QZ, CAL, PL, chl, dol, py, rt, ms, ap, (ccp) |
410-31 | core | Sulphidic baryte rock | BRT, PY, QZ, sp, dol, ms, (gn, cal, ap, ccp) |
703-9 | core | Quartz chert and sulphide breccia | QZ, PY, CLS, SP, gn, ms, (ccp, ap) |
503-23 | core | Graphitic dolostone | DOL, sp, phy, qz, bt, ms, py, gn, (chl, rt, ccp, ap) |
503-27 | core | Graphitic garnet mica schist | QZ, MS, GT, pl, bt, chl, cal, ap, py, rt |
705-22 | core | Muscovite dolomite schist (metabasite) | DOL, MS, QZ, pyh, (rt, ap, ccp) |
705-28 | core | Calcareous sulphidic baryte rock | BRT, CAL, PY, qz, sp, dol, (gal, ms, ccp) |
505-14 | core | Calcareous sulphidic baryte rock | CAL, QZ, BRT, PY SP, dol, gal, (ms, ccp, ap) |
N81-43 | outcrop | Biotite calcite schist (MB) | BT, QZ, CAL, MS, (pyh, ap, ccp) |
708-4b | core | Quartz muscovite hyalophane schist | QZ, MS, HYAL, py, sp, cls, chl, rt, gn |
708-10 | core | Sulphidic quartz chert | QZ, PY, sp, hyal, dol, cls, gn, ccp, bt, ms, ap, (rt) |
708-28 | core | Calcareous sulphidic baryte rock | BRT, CAL, PY, qz, sp, dol, (gn, ms, ccp) |
3. Materials and Methods
4. Results
4.1. Muscovite and Barian Muscovite
4.2. Chromium- and Vanadium-Bearing Barian Micas
4.3. Biotite, Phlogopite, and Barian Biotite
4.4. Altered (Interlayer-Deficient) Biotite
5. Discussion
5.1. Di-Octahedral Mica Compositions and Substitution Mechanisms
5.2. Tri-Octahedral Mica Compositions and Substitution Mechanisms
5.3. Compositional Variations in Micas Coexisting in Rock Samples
5.4. Other SEDEX Ba- (±Cr ±V) Mica Occurrences and Comparisons with Aberfeldy Barian Micas
6. Conclusions
Supplementary Materials
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Barian Muscovite (Sample 504-5) | Biotite (Sample 429-5) | ||||||
---|---|---|---|---|---|---|---|
wt% | 2σ | det | wt% | 2σ | det | ||
SiO2 | 42.76 | 0.27 | 0.06 | SiO2 | 37.29 | 0.25 | 0.03 |
TiO2 | 0.59 | 0.06 | 0.04 | TiO2 | 1.76 | 0.08 | 0.04 |
Al2O3 | 31.87 | 0.17 | 0.02 | Al2O3 | 17.57 | 0.14 | 0.02 |
FeO | 0.93 | 0.06 | 0.05 | FeO | 17.71 | 0.21 | 0.05 |
MnO | 0.01 | 0.03 | 0.04 | MnO | 0.05 | 0.04 | 0.04 |
MgO | 2.33 | 0.06 | 0.02 | MgO | 11.52 | 0.11 | 0.02 |
Na2O | 0.34 | 0.02 | 0.02 | Na2O | 0.20 | 0.01 | 0.02 |
K2O | 7.70 | 0.14 | 0.03 | K2O | 8.33 | 0.14 | 0.03 |
BaO | 8.71 | 0.22 | 0.07 | ||||
F | 0.20 | 0.10 | 0.07 | ||||
Total | 95.44 | Total | 94.43 |
Sample | 429-5 | 503-27 | 09-05 | 705-22 | N81-43 | G100d | N81-80 | 705-22 | G100d | G114a |
---|---|---|---|---|---|---|---|---|---|---|
Composition expressed as weight % oxides | ||||||||||
SiO2 | 46.86 | 46.40 | 47.40 | 46.54 | 45.15 | 48.09 | 44.50 | 43.35 | 44.76 | 38.38 |
Al2O3 | 32.23 | 33.36 | 32.52 | 32.09 | 30.54 | 28.22 | 30.75 | 29.63 | 31.06 | 33.41 |
TiO2 | 0.39 | 0.44 | 0.53 | 0.62 | 0.82 | 1.56 | 1.50 | 1.40 | 1.44 | 0.69 |
V2O3 | ||||||||||
Cr2O3 | 0.09 | |||||||||
MgO | 1.78 | 1.42 | 2.35 | 3.07 | 2.35 | 3.97 | 2.16 | 3.11 | 3.22 | 1.64 |
MnO | 0.02 | 0.02 | 0.02 | 0.12 | 0.02 | 0.03 | 0.10 | 0.02 | ||
FeO * | 1.68 | 1.62 | 1.17 | 0.85 | 2.70 | 0.69 | 2.14 | 1.38 | 0.21 | 0.25 |
CaO | 0.01 | |||||||||
Na2O | 0.77 | 0.63 | 0.64 | 0.72 | 0.54 | 0.15 | 0.30 | 0.25 | 0.30 | 0.69 |
K2O | 9.54 | 9.83 | 9.21 | 9.22 | 8.73 | 8.89 | 8.64 | 7.87 | 7.75 | 6.16 |
BaO | 0.23 | 1.13 | 3.19 | 4.47 | 5.70 | 6.46 | 7.97 | 9.10 | 10.86 | |
Total | 93.27 | 93.95 | 95.06 | 96.30 | 95.30 | 97.39 | 96.48 | 94.99 | 97.94 | 92.10 |
F | 0.14 | 0.16 | 0.25 | 0.32 | 0.18 | 0.23 | 0.40 | 0.12 | ||
Atoms per formula unit on the basis of 22 positive charges | ||||||||||
Si | 3.180 | 3.135 | 3.165 | 3.125 | 3.120 | 3.245 | 3.080 | 3.070 | 3.070 | 2.845 |
Aliv † | 0.820 | 0.865 | 0.835 | 0.875 | 0.880 | 0.755 | 0.920 | 0.930 | 0.930 | 1.155 |
Alvi | 1.755 | 1.790 | 1.725 | 1.665 | 1.610 | 1.490 | 1.585 | 1.540 | 1.580 | 1.765 |
Al total | 2.575 | 2.655 | 2.560 | 2.540 | 2.490 | 2.245 | 2.505 | 2.470 | 2.510 | 2.920 |
Ti | 0.020 | 0.020 | 0.025 | 0.030 | 0.045 | 0.080 | 0.080 | 0.075 | 0.075 | 0.040 |
V | ||||||||||
Cr | ||||||||||
Mg | 0.180 | 0.145 | 0.235 | 0.305 | 0.240 | 0.400 | 0.225 | 0.330 | 0.330 | 0.180 |
Mn | ||||||||||
Fe * | 0.095 | 0.090 | 0.065 | 0.050 | 0.155 | 0.040 | 0.125 | 0.080 | 0.010 | 0.015 |
Na | 0.100 | 0.080 | 0.085 | 0.095 | 0.070 | 0.020 | 0.040 | 0.035 | 0.040 | 0.100 |
K | 0.825 | 0.845 | 0.785 | 0.790 | 0.770 | 0.765 | 0.765 | 0.710 | 0.680 | 0.585 |
Ba | 0.005 | 0.030 | 0.085 | 0.120 | 0.150 | 0.175 | 0.220 | 0.245 | 0.315 | |
Total | 6.975 | 6.975 | 6.950 | 7.020 | 7.010 | 6.945 | 6.995 | 6.990 | 6.960 | 7.000 |
∑I interlayer site | 0.927 | 0.936 | 0.898 | 0.967 | 0.963 | 0.935 | 0.978 | 0.966 | 0.962 | 0.997 |
∑M octahedral site | 3.806 | 3.836 | 3.785 | 3.715 | 3.660 | 3.502 | 3.597 | 3.567 | 3.580 | 3.766 |
Fe/(Fe + Mg) | 0.346 | 0.390 | 0.218 | 0.134 | 0.392 | 0.089 | 0.357 | 0.199 | 0.035 | 0.079 |
Sample | 708-10 | G114a | G100e a | G100e b | 505-14 | 705-28 | 410-31 a | 410-31 b |
---|---|---|---|---|---|---|---|---|
Composition expressed as weight % oxides | ||||||||
SiO2 | 46.39 | 40.53 | 42.42 | 33.94 | 37.29 | 36.66 | 36.40 | 34.77 |
Al2O3 | 27.95 | 26.30 | 27.21 | 18.42 | 16.41 | 16.59 | 13.67 | 13.77 |
TiO2 | 1.10 | 1.28 | 1.45 | 1.32 | 0.75 | 0.70 | 1.49 | 1.80 |
V2O3 | 10.82 | 10.07 | ||||||
Cr2O3 | 0.98 | 4.19 | 0.45 | 4.60 | 9.27 | 5.15 | 4.25 | 3.48 |
MgO | 3.82 | 2.62 | 3.31 | 2.14 | 1.44 | 1.55 | 3.30 | 2.13 |
MnO | 0.02 | 0.07 | 0.04 | 0.08 | 0.16 | 0.04 | 0.04 | 0.08 |
FeO * | 0.51 | 0.38 | 0.35 | 0.25 | 3.09 | 2.30 | 7.52 | 10.25 |
ZnO | 0.06 | 0.03 | ||||||
Na2O | 0.11 | 0.25 | 0.24 | 0.15 | 0.09 | 0.10 | 0.09 | 0.05 |
K2O | 8.73 | 5.82 | 7.86 | 4.78 | 6.42 | 6.10 | 6.64 | 5.83 |
BaO | 6.27 | 11.48 | 8.34 | 15.70 | 11.02 | 11.13 | 9.86 | 12.33 |
Total | 95.88 | 92.92 | 91.67 | 81.38 | 85.94 | 80.32 | 94.14 | 94.59 |
F | 0.22 | 0.05 | 0.23 | 0.07 | 0.10 | |||
Atoms per formula unit on the basis of 22 positive charges | ||||||||
Si | 3.205 | 3.030 | 3.125 | 3.095 | 3.180 | 3.295 | 2.930 | 2.870 |
Aliv † | 0.795 | 0.970 | 0.875 | 0.905 | 0.820 | 0.705 | 1.070 | 1.130 |
Alvi | 1.480 | 1.345 | 1.485 | 1.075 | 0.830 | 1.050 | 0.225 | 0.210 |
Al total | 2.275 | 2.315 | 2.360 | 1.980 | 1.650 | 1.755 | 1.295 | 1.340 |
Ti | 0.055 | 0.070 | 0.080 | 0.090 | 0.050 | 0.045 | 0.090 | 0.110 |
V | 0.700 | 0.665 | ||||||
Cr | 0.055 | 0.250 | 0.025 | 0.330 | 0.625 | 0.365 | 0.270 | 0.225 |
Mg | 0.395 | 0.290 | 0.365 | 0.290 | 0.185 | 0.210 | 0.395 | 0.260 |
Mn | 0.010 | 0.005 | ||||||
Fe * | 0.030 | 0.025 | 0.020 | 0.020 | 0.220 | 0.175 | 0.505 | 0.710 |
Na | 0.015 | 0.035 | 0.035 | 0.025 | 0.015 | 0.015 | 0.015 | 0.010 |
K | 0.770 | 0.555 | 0.740 | 0.555 | 0.700 | 0.700 | 0.680 | 0.615 |
Ba | 0.170 | 0.335 | 0.240 | 0.560 | 0.370 | 0.390 | 0.310 | 0.400 |
Total | 6.970 | 6.905 | 6.990 | 6.945 | 7.005 | 6.950 | 7.190 | 7.210 |
∑I interlayer site | 0.954 | 0.932 | 1.013 | 1.143 | 1.081 | 1.108 | 1.006 | 1.021 |
∑M octahedral site | 3.494 | 3.331 | 3.462 | 2.885 | 2.744 | 2.898 | 1.715 | 1.734 |
Fe/(Fe + Mg) | 0.070 | 0.075 | 0.056 | 0.062 | 0.546 | 0.454 | 0.561 | 0.730 |
Sample | 429-5 | 503-27 | 503-23 | N81-43 | G100d | 708-10 | 207-5 | BH3-27.8 | 424-8 | 702-11 |
---|---|---|---|---|---|---|---|---|---|---|
Composition expressed as weight % oxides | ||||||||||
SiO2 | 37.15 | 34.68 | 38.03 | 37.01 | 42.01 | 40.44 | 36.47 | 37.56 | 34.87 | 35.99 |
Al2O3 | 17.49 | 18.25 | 16.46 | 16.77 | 14.56 | 14.16 | 16.46 | 12.56 | 14.56 | 12.89 |
TiO2 | 1.84 | 1.46 | 1.10 | 2.64 | 0.54 | 0.82 | 2.36 | 0.15 | 3.36 | 1.75 |
Cr2O3 | 0.34 | |||||||||
MgO | 11.95 | 9.22 | 16.67 | 11.81 | 24.75 | 24.61 | 14.66 | 16.81 | 13.24 | 14.37 |
MnO | 0.03 | 0.26 | 0.11 | 0.09 | 0.29 | 0.07 | 0.12 | 0.05 | 0.02 | |
FeO * | 17.28 | 21.34 | 11.11 | 17.56 | 1.29 | 1.54 | 13.39 | 15.11 | 15.56 | 16.05 |
CaO | ||||||||||
Na2O | 0.18 | 0.13 | 0.10 | 0.17 | 0.19 | 0.08 | 0.17 | 0.12 | 0.16 | 0.14 |
K2O | 8.21 | 7.67 | 8.78 | 8.75 | 8.91 | 8.80 | 8.40 | 7.51 | 7.70 | 6.99 |
BaO | 0.06 | 0.07 | 1.33 | 2.81 | 2.99 | 3.08 | 4.55 | 4.54 | 5.46 | |
Total | 94.13 | 93.07 | 92.43 | 96.13 | 95.35 | 93.78 | 95.06 | 94.49 | 94.04 | 93.66 |
F | 0.24 | 0.68 | 0.09 | 2.71 | 3.08 | 0.63 | 1.62 | 0.90 | 0.97 | |
Atoms per formula unit on the basis of 22 positive charges | ||||||||||
Si | 2.805 | 2.710 | 2.850 | 2.785 | 2.965 | 2.915 | 2.735 | 2.910 | 2.735 | 2.850 |
Aliv † | 1.195 | 1.290 | 1.150 | 1.215 | 1.035 | 1.085 | 1.265 | 1.090 | 1.265 | 1.150 |
Alvi | 0.360 | 0.390 | 0.305 | 0.270 | 0.175 | 0.120 | 0.190 | 0.055 | 0.080 | 0.050 |
Al total | 1.555 | 1.680 | 1.455 | 1.485 | 1.210 | 1.205 | 1.455 | 1.145 | 1.345 | 1.200 |
Ti | 0.105 | 0.085 | 0.060 | 0.150 | 0.030 | 0.045 | 0.135 | 0.010 | 0.200 | 0.105 |
Cr | 0.020 | |||||||||
Mg | 1.345 | 1.075 | 1.860 | 1.325 | 2.605 | 2.645 | 1.640 | 1.940 | 1.550 | 1.695 |
Mn | 0.005 | 0.015 | 0.010 | |||||||
Fe * | 1.090 | 1.395 | 0.695 | 1.105 | 0.075 | 0.095 | 0.840 | 0.980 | 1.020 | 1.060 |
Na | 0.025 | 0.020 | 0.015 | 0.025 | 0.025 | 0.010 | 0.025 | 0.020 | 0.025 | 0.020 |
K | 0.790 | 0.765 | 0.840 | 0.840 | 0.805 | 0.810 | 0.805 | 0.740 | 0.770 | 0.705 |
Ba | 0.040 | 0.080 | 0.085 | 0.090 | 0.140 | 0.140 | 0.170 | |||
Total | 7.715 | 7.730 | 7.780 | 7.755 | 7.810 | 7.830 | 7.725 | 7.895 | 7.785 | 7.805 |
∑I interlayer site | 0.817 | 0.787 | 0.856 | 0.904 | 0.907 | 0.906 | 0.918 | 0.898 | 0.935 | 0.897 |
∑M octahedral site | 3.264 | 3.357 | 3.237 | 3.123 | 3.082 | 3.043 | 2.992 | 3.046 | 2.935 | 2.964 |
Fe/(Fe + Mg) | 0.448 | 0.565 | 0.272 | 0.455 | 0.028 | 0.034 | 0.339 | 0.335 | 0.397 | 0.385 |
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Moles, N.R. Barian Micas and Exotic Ba-Cr and Ba-V Micas Associated with Metamorphosed Sedimentary Exhalative Baryte Deposits near Aberfeldy, Scotland, UK. Minerals 2025, 15, 511. https://doi.org/10.3390/min15050511
Moles NR. Barian Micas and Exotic Ba-Cr and Ba-V Micas Associated with Metamorphosed Sedimentary Exhalative Baryte Deposits near Aberfeldy, Scotland, UK. Minerals. 2025; 15(5):511. https://doi.org/10.3390/min15050511
Chicago/Turabian StyleMoles, Norman R. 2025. "Barian Micas and Exotic Ba-Cr and Ba-V Micas Associated with Metamorphosed Sedimentary Exhalative Baryte Deposits near Aberfeldy, Scotland, UK" Minerals 15, no. 5: 511. https://doi.org/10.3390/min15050511
APA StyleMoles, N. R. (2025). Barian Micas and Exotic Ba-Cr and Ba-V Micas Associated with Metamorphosed Sedimentary Exhalative Baryte Deposits near Aberfeldy, Scotland, UK. Minerals, 15(5), 511. https://doi.org/10.3390/min15050511