Textures and Chemical Compositions of Nb-Bearing Minerals and Nb Mineralization in the Shuangshan Nepheline Syenite Pluton, East Qinling, China
Abstract
:1. Introduction
2. Geological Setting
2.1. Regional Geology
2.2. Shuangshan Alkaline Complex
3. Samples and Analytical Methods
4. Results
4.1. Pyrochlore
4.2. Zircon
4.3. Titanite
4.4. Allanite
5. Discussion
5.1. Magma Evolution and Pyrochlore Crystallization
5.2. Hydrothermal Alteration
5.3. Quantitative Evaluation of the Migration of Niobium from Hydrothermal Zircon and Titanite
6. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
Appendix A
Standard | Element | Counting Time (s) |
---|---|---|
Pyrope | Fe, Mn, Ti, Al, Si, Ca | 15 |
Benitoite | Ba | 15 |
Orthoclase | Na, K | 15 |
Monazite | Y, La, Ce | 45 |
Apatite | F | 15 |
Anhydride | Sr | 45 |
PbS | Pb | 15 |
Cubic Zirconia 1 | Zr, Hf, Y | 15,45 |
Rutile 2 | Ti | 15 |
Diopside 2 | Ca | 15 |
Albite 3 | Na, Al, Si | 15 |
Almandine 4 | Fe | 15 |
Kaersutite 4 | Na, Ca, Ti, Al, Si, Mg, K | 15 |
MAC-Nb | Nb | 15 |
MAC-Ta | Ta | 15 |
MAC-U | U | 45 |
Sample | DZ18-02 | DZ18-06 | DZ18-08 | DZ18-09 | DZ18-18 | DZ18-21 | DZ18-28 | DZ18-30 | ZK503-6 |
---|---|---|---|---|---|---|---|---|---|
Oxide (wt%) | |||||||||
SiO2 | 57.26 | 56.70 | 60.38 | 57.53 | 56.99 | 52.66 | 56.76 | 56.81 | 56.11 |
Al2O3 | 19.17 | 21.23 | 21.37 | 17.73 | 20.10 | 16.55 | 19.75 | 19.30 | 19.82 |
TFe2O3 | 4.61 | 4.29 | 3.62 | 5.44 | 3.96 | 6.56 | 5.48 | 5.20 | 5.04 |
MgO | 0.75 | 0.72 | 0.32 | 0.55 | 0.46 | 0.85 | 0.69 | 0.71 | 0.37 |
CaO | 2.72 | 1.49 | 0.25 | 3.13 | 1.30 | 7.20 | 1.82 | 2.39 | 1.94 |
Na2O | 6.80 | 5.57 | 7.44 | 5.87 | 3.72 | 4.43 | 6.21 | 7.54 | 7.88 |
K2O | 6.00 | 6.68 | 4.12 | 7.05 | 8.87 | 6.00 | 6.70 | 5.97 | 5.27 |
MnO | 0.33 | 0.41 | 0.37 | 0.52 | 0.34 | 0.49 | 0.40 | 0.35 | 0.25 |
P2O5 | 0.05 | 0.05 | 0.05 | 0.05 | 0.09 | 0.20 | 0.04 | 0.05 | 0.05 |
TiO2 | 0.47 | 0.26 | 0.30 | 0.43 | 0.64 | 0.38 | 0.58 | 0.52 | 0.50 |
LOI | 1.51 | 1.66 | 0.99 | 1.21 | 2.62 | 3.83 | 0.68 | 0.98 | 1.67 |
Total | 99.67 | 99.07 | 99.21 | 99.51 | 99.09 | 99.15 | 99.11 | 99.83 | 98.90 |
Trace element (μg/g) | |||||||||
La | 140 | 257 | 279 | 261 | 318 | 684 | 248 | 398 | 531 |
Ce | 254 | 458 | 458 | 435 | 603 | 1431 | 358 | 627 | 791 |
Pr | 23 | 36 | 42 | 41 | 62 | 160 | 30 | 53 | 68 |
Nd | 72 | 105 | 123 | 123 | 206 | 553 | 82 | 154 | 190 |
Sm | 10 | 15 | 17 | 17 | 29 | 80 | 11 | 20 | 25 |
Eu | 1 | 1 | 2 | 2 | 3 | 9 | 1 | 2 | 3 |
Gd | 9 | 13 | 15 | 15 | 24 | 63 | 11 | 18 | 23 |
Tb | 2 | 2 | 2 | 2 | 3 | 9 | 2 | 3 | 3 |
Dy | 12 | 11 | 16 | 15 | 19 | 51 | 11 | 17 | 20 |
Ho | 3 | 3 | 4 | 3 | 4 | 10 | 2 | 4 | 4 |
Y | 84 | 69 | 120 | 108 | 120 | 285 | 79 | 118 | 137 |
Er | 8 | 8 | 12 | 11 | 12 | 29 | 8 | 12 | 14 |
Tm | 1 | 1 | 2 | 2 | 2 | 4 | 1 | 2 | 2 |
Yb | 8 | 12 | 15 | 14 | 13 | 24 | 8 | 14 | 15 |
Lu | 1 | 2 | 2 | 2 | 2 | 3 | 1 | 2 | 2 |
Zr | 1143 | 3447 | 2529 | 2305 | 1748 | 1230 | 2109 | 2568 | 3642 |
Nb | 232 | 531 | 787 | 546 | 511 | 729 | 451 | 582 | 703 |
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Pyrochlore Type | Type-1 Pyrochlore | Type-2 Pyrochlore | Overgrown Pyrochlore | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Sample No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
Nb2O5 | 56.17 | 54.39 | 49.70 | 50.53 | 60.63 | 59.06 | 59.44 | 59.78 | 55.74 | 56.82 | 59.34 |
Ta2O5 | 2.56 | 2.83 | 2.31 | 2.17 | 1.86 | 2.39 | 2.49 | 2.05 | 2.62 | 2.57 | 2.08 |
TiO2 | 8.06 | 7.88 | 7.28 | 7.30 | 8.54 | 8.61 | 7.71 | 8.61 | 8.09 | 8.45 | 8.39 |
SiO2 | 4.62 | 5.88 | 8.83 | 7.52 | - | 0.13 | - | 0.12 | 2.61 | 1.16 | - |
Al2O3 | 0.94 | 1.31 | 2.60 | 1.89 | - | 0.06 | 0.05 | 0.12 | 0.75 | 0.17 | 0.05 |
FeO | 0.74 | 0.77 | 0.12 | 0.46 | - | - | 0.25 | - | - | - | 0.10 |
MnO | 0.59 | 0.53 | 0.04 | 0.76 | 0.03 | - | - | 0.03 | 0.15 | 0.06 | - |
Na2O | 0.64 | 0.16 | 1.42 | 1.58 | 5.12 | 4.70 | 5.29 | 4.67 | 3.92 | 4.50 | 5.75 |
Y2O3 | 0.20 | 0.13 | 0.30 | 0.40 | 0.37 | 0.39 | 0.25 | 0.39 | 0.51 | 0.46 | 0.33 |
SrO | 1.14 | 1.19 | 0.40 | 0.40 | 0.06 | 0.09 | 0.28 | 0.04 | 0.07 | 0.18 | 0.04 |
K2O | 0.60 | 0.42 | 0.58 | 0.32 | - | - | - | 0.02 | 0.12 | 0.02 | - |
CaO | 14.97 | 14.00 | 13.89 | 15.07 | 17.88 | 17.79 | 18.79 | 17.69 | 16.27 | 15.95 | 17.70 |
UO2 | 1.59 | 1.99 | 2.38 | 1.68 | 1.84 | 1.79 | 1.65 | 1.93 | 2.42 | 2.35 | 1.85 |
PbO | 0.41 | 0.32 | 0.37 | 0.58 | 0.44 | 0.39 | 0.38 | 0.45 | 0.49 | 0.37 | 0.44 |
F | 1.27 | 1.08 | 1.53 | 1.42 | 2.75 | 2.61 | 3.43 | 2.43 | 1.83 | 2.03 | 3.39 |
H2O* | 2.24 | 2.39 | 2.31 | 2.22 | 1.27 | 1.31 | 0.87 | 1.42 | 1.79 | 1.59 | 0.93 |
F=O | 0.53 | 0.45 | 0.64 | 0.60 | 1.15 | 1.10 | 1.44 | 1.02 | 0.77 | 0.85 | 1.42 |
Total | 96.19 | 94.80 | 93.45 | 92.08 | 99.66 | 98.25 | 99.45 | 98.72 | 96.63 | 95.84 | 98.96 |
Structural Formulae | |||||||||||
Nb | 1.34 | 1.27 | 1.11 | 1.18 | 1.60 | 1.57 | 1.61 | 1.58 | 1.42 | 1.51 | 1.59 |
Ta | 0.04 | 0.04 | 0.03 | 0.03 | 0.03 | 0.04 | 0.04 | 0.03 | 0.04 | 0.04 | 0.03 |
Ti | 0.32 | 0.31 | 0.27 | 0.28 | 0.37 | 0.38 | 0.35 | 0.38 | 0.34 | 0.37 | 0.37 |
Si | 0.24 | 0.30 | 0.44 | 0.39 | - | 0.01 | - | 0.01 | 0.15 | 0.07 | - |
Al | 0.06 | 0.08 | 0.15 | 0.12 | - | - | - | 0.01 | 0.05 | 0.01 | - |
Fe | 0.03 | 0.03 | 0.01 | 0.02 | - | - | 0.01 | - | - | - | 0.01 |
Mn | 0.03 | 0.02 | - | 0.03 | - | - | - | - | 0.01 | - | - |
Na | 0.07 | 0.02 | 0.14 | 0.16 | 0.58 | 0.54 | 0.61 | 0.53 | 0.43 | 0.51 | 0.66 |
Y | 0.01 | - | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.02 | 0.01 | 0.01 |
Sr | 0.04 | 0.04 | 0.01 | 0.01 | - | - | 0.01 | - | - | 0.01 | - |
K | 0.04 | 0.03 | 0.04 | 0.02 | - | - | - | - | 0.01 | - | - |
Ca | 0.85 | 0.78 | 0.74 | 0.84 | 1.12 | 1.12 | 1.21 | 1.11 | 0.98 | 1.00 | 1.12 |
U | 0.02 | 0.02 | 0.03 | 0.02 | 0.02 | 0.02 | 0.02 | 0.03 | 0.03 | 0.03 | 0.02 |
Pb | 0.01 | - | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 |
F | 0.21 | 0.18 | 0.24 | 0.23 | 0.51 | 0.49 | 0.65 | 0.45 | 0.33 | 0.38 | 0.63 |
OH | 0.79 | 0.82 | 0.76 | 0.77 | 0.49 | 0.52 | 0.35 | 0.55 | 0.67 | 0.62 | 0.37 |
No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ZrO2 | 63.46 | 64.63 | 63.65 | 64.78 | 64.05 | 63.69 | 64.99 | 63.63 | 63.05 | 64.63 | 63.44 | 62.43 | 62.83 | 63.32 | 64.36 | 64.36 | 63.77 | 64.21 | 64.57 | 64.13 |
Nb2O5 | 0.09 | 0.10 | 0.39 | 0.12 | 0.05 | 0.07 | 0.16 | 0.11 | 0.09 | 0.09 | 0.21 | 0.14 | 0.13 | 0.15 | 0.16 | 0.08 | 0.07 | 0.06 | 0.02 | 0.06 |
CaO | 0.02 | 0.05 | 0.08 | 0.03 | 0.02 | 0.04 | 0.08 | 0.02 | 0.04 | 0.03 | 0.02 | 0.02 | 0.08 | 0.01 | 0.02 | 0.01 | 0.04 | 0.04 | 0.03 | 0.01 |
Y2O3 | - | - | 0.19 | - | 0.08 | 0.17 | - | 0.01 | - | - | 0.21 | 0.23 | 0.15 | 0.06 | 0.15 | - | - | 0.10 | - | - |
SiO2 | 33.55 | 33.66 | 33.43 | 33.82 | 33.63 | 33.88 | 33.58 | 33.41 | 33.46 | 33.40 | 33.94 | 34.02 | 34.12 | 34.07 | 33.96 | 33.63 | 33.65 | 33.26 | 33.92 | 33.80 |
La2O3 | - | - | - | - | - | - | 0.06 | - | 0.04 | - | - | - | - | 0.05 | - | - | - | 0.06 | - | - |
Ce2O3 | - | - | - | - | - | 0.03 | - | - | 0.03 | - | - | - | - | 0.05 | 0.03 | - | - | 0.03 | - | - |
HfO2 | 1.39 | 1.34 | 1.31 | 1.43 | 1.35 | 1.36 | 1.41 | 1.37 | 1.39 | 1.46 | 1.12 | 1.08 | 1.28 | 1.34 | 1.27 | 1.40 | 1.25 | 1.25 | 1.43 | 1.23 |
Total | 98.51 | 99.78 | 99.05 | 100.18 | 99.18 | 99.24 | 100.28 | 98.55 | 98.1 | 99.61 | 98.94 | 97.92 | 98.59 | 99.05 | 99.95 | 99.48 | 98.78 | 99.01 | 99.97 | 99.23 |
Structural Formulae | ||||||||||||||||||||
Zr | 0.953 | 0.960 | 0.952 | 0.959 | 0.956 | 0.949 | 0.963 | 0.956 | 0.951 | 0.964 | 0.946 | 0.937 | 0.938 | 0.943 | 0.953 | 0.959 | 0.954 | 0.963 | 0.956 | 0.955 |
Nb | 0.001 | 0.001 | 0.005 | 0.002 | 0.001 | 0.001 | 0.002 | 0.002 | 0.001 | 0.001 | 0.003 | 0.002 | 0.002 | 0.002 | 0.002 | 0.001 | 0.001 | 0.001 | - | 0.001 |
Ca | 0.001 | 0.002 | 0.003 | 0.001 | 0.001 | 0.001 | 0.003 | 0.001 | 0.001 | 0.001 | 0.001 | 0.001 | 0.003 | - | 0.001 | - | 0.001 | 0.001 | 0.001 | - |
Y | - | - | 0.003 | - | 0.001 | 0.003 | - | - | - | - | 0.003 | 0.004 | 0.002 | 0.001 | 0.002 | - | - | 0.002 | - | - |
Si | 1.033 | 1.026 | 1.026 | 1.026 | 1.030 | 1.035 | 1.020 | 1.029 | 1.035 | 1.021 | 1.038 | 1.048 | 1.045 | 1.041 | 1.031 | 1.027 | 1.033 | 1.023 | 1.030 | 1.033 |
La | - | - | - | - | - | - | 0.001 | - | - | - | - | - | - | 0.001 | - | - | - | 0.001 | - | - |
Ce | - | - | - | - | - | - | - | - | - | - | - | - | - | 0.001 | - | - | - | - | - | - |
Hf | 0.012 | 0.012 | 0.011 | 0.012 | 0.012 | 0.012 | 0.012 | 0.012 | 0.012 | 0.013 | 0.010 | 0.009 | 0.011 | 0.012 | 0.011 | 0.012 | 0.011 | 0.011 | 0.012 | 0.011 |
No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
---|---|---|---|---|---|---|---|---|---|---|
Nb2O5 | 1.12 | 1.57 | 1.63 | 1.51 | 1.52 | 1.22 | 1.39 | 1.10 | 1.03 | 1.53 |
TiO2 | 27.71 | 27.68 | 28.43 | 28.35 | 29.03 | 28.31 | 31.21 | 28.26 | 29.91 | 29.30 |
Al2O3 | 7.41 | 7.35 | 6.94 | 6.75 | 6.40 | 7.15 | 4.87 | 7.15 | 6.05 | 6.33 |
Y2O3 | 0.40 | 0.35 | 0.35 | 0.34 | 0.38 | 0.34 | 0.56 | 0.32 | 0.25 | 0.39 |
SiO2 | 30.85 | 30.85 | 30.71 | 30.76 | 30.74 | 30.83 | 30.38 | 30.71 | 30.81 | 30.59 |
Fe2O3 | 1.12 | 1.10 | 1.08 | 1.09 | 1.06 | 1.12 | 1.39 | 1.12 | 1.10 | 1.05 |
CaO | 28.20 | 28.13 | 27.91 | 28.21 | 28.21 | 28.33 | 27.69 | 28.32 | 28.26 | 27.96 |
MnO | 0.23 | 0.23 | 0.22 | 0.21 | 0.20 | 0.25 | 0.16 | 0.22 | 0.23 | 0.17 |
F | 2.36 | 2.09 | 2.33 | 2.05 | 1.90 | 2.00 | 1.69 | 2.28 | 1.73 | 1.77 |
F=O | 0.99 | 0.88 | 0.98 | 0.86 | 0.80 | 0.84 | 0.71 | 0.96 | 0.73 | 0.74 |
Total | 98.41 | 98.47 | 98.61 | 98.41 | 98.65 | 98.70 | 98.62 | 98.51 | 98.65 | 98.33 |
Structural Formulae | ||||||||||
Nb | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 | 0.01 | 0.02 |
Ti | 0.67 | 0.67 | 0.69 | 0.69 | 0.70 | 0.68 | 0.76 | 0.68 | 0.72 | 0.71 |
Al | 0.28 | 0.28 | 0.26 | 0.26 | 0.24 | 0.27 | 0.19 | 0.27 | 0.23 | 0.24 |
Y | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | - | 0.01 |
Si | 0.99 | 0.99 | 0.99 | 0.99 | 0.99 | 0.99 | 0.98 | 0.99 | 0.99 | 0.99 |
Fe | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | 0.08 | 0.06 | 0.06 | 0.06 |
Ca | 0.97 | 0.97 | 0.96 | 0.97 | 0.97 | 0.97 | 0.96 | 0.97 | 0.97 | 0.97 |
Mn | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | - | 0.01 | 0.01 | - |
F | 0.24 | 0.21 | 0.24 | 0.21 | 0.19 | 0.20 | 0.17 | 0.23 | 0.18 | 0.18 |
(O,OH) | 0.76 | 0.79 | 0.76 | 0.79 | 0.81 | 0.80 | 0.83 | 0.77 | 0.82 | 0.82 |
Temperature | 600 °C | 500 °C | |
---|---|---|---|
Total Content of Nb2O5 in Nepheline Syenite (ppm) | |||
Initially in melt | 1000 | 1000 | |
At pyrochlore saturation | 1000 | 150 | |
Nb2O5 Content of Minerals (ppm) | DNb * | ||
K-feldspar (60%) | 18.00 | 2.70 | 0.03 |
Albite (10%) | 3.00 | 0.45 | 0.03 |
Nepheline (20%) | 6.00 | 0.90 | 0.03 |
Amphibole (4%) | 3.76 | 0.56 | 0.094 |
Biotite (2%) | 64.00 | 9.60 | 3.2 |
Titanite (1.23%) | 200.49 | 30.07 | 16.3 |
Magnetite (1%) | 1.10 | 0.17 | 0.11 |
Zircon (0.72%) | 28.08 | 4.21 | 3.9 |
Pyrochlore | 675.57 | 951.34 | |
Nb2O5 in other minerals (ppm) | 324.43 | 48.66 | |
Nb as pyrochlore (% of total) | 67.56 | 95.13 |
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Wang, H.; Tang, Y.; Xu, Y.-S.; Zhang, H.; Lv, Z.-H.; Qin, S.-X.; Song, Y.-W. Textures and Chemical Compositions of Nb-Bearing Minerals and Nb Mineralization in the Shuangshan Nepheline Syenite Pluton, East Qinling, China. Minerals 2021, 11, 1163. https://doi.org/10.3390/min11111163
Wang H, Tang Y, Xu Y-S, Zhang H, Lv Z-H, Qin S-X, Song Y-W. Textures and Chemical Compositions of Nb-Bearing Minerals and Nb Mineralization in the Shuangshan Nepheline Syenite Pluton, East Qinling, China. Minerals. 2021; 11(11):1163. https://doi.org/10.3390/min11111163
Chicago/Turabian StyleWang, Hong, Yong Tang, Yu-Sheng Xu, Hui Zhang, Zheng-Hang Lv, Shan-Xian Qin, and Ying-Wei Song. 2021. "Textures and Chemical Compositions of Nb-Bearing Minerals and Nb Mineralization in the Shuangshan Nepheline Syenite Pluton, East Qinling, China" Minerals 11, no. 11: 1163. https://doi.org/10.3390/min11111163