Table 1
Compilation of substrates and products of experiments containing Mnz-(Ce)
| Sample (experiment number) | P (MPa) | T (°C) | Time (days) | Components/water fluid with | Products (new phases) |
|---|---|---|---|---|---|
| CF-8 | 200 | 600 | 26 | Cvk, Q, Ab, Byt, Fap, FeS2, CaCO3/NaF, H2O | Bri, Ttn, Px(NaFe), Mnz |
| CF-12 | 200 | 500 | 63 | Cvk, Q, An (glass), Ca3(PO4)2/NaF, H2O | Ab, Mnz, Pl |
| CF-15 | 200 | 550 | 84 | Cvk, Q, Ab, Ca3(PO4)2/NaF, H2O | Mnz, Bri, Px, Ab, Flr, Aes/Nar, Thr |
| CF-17 | 200 | 550 | 84 | Cvk, Q, Ab, Fap/NaF, H2O | Bri, Px, Mnz, Ab, Flr, Nar, |
| CF-19 | 200 | 600 | 42 | Cvk, Q, An (glass), Al2O3/Ca(OH)2, H2O | Pl, Bri, Ttn, Wo, Mnz, Thr* |
| CF-24 | 200 | 600 | 32 | Cvk, Q, Byt, KFs, CaF2, FeO/Ca(OH)2, Mg(OH)2, H2O | Bri, Ttn, Px, ESM, Pl, Mnz, Flr, Thr, Bt |
Abbreviations according to Warr (2021): Ab – albite, Aes – aeschynite, An – anorthite, Bri – britholite, Bt – biotite, Byt – beryllite, Cvk – chevkinite, Fap – fluorapatite, Flr – fluorite, Mnz – monazite, Nar – narsarsukite, Pl – plagioclase, Px – pyroxene, Q – quartz, Thr – thorite, Ttn – titanite, Wo – wollastonite.
*Thorite may also occur as huttonite and in amorphous forms (Bagiński et al., 2023; Stachowicz et al., 2024).
Figure 1
BSE images of Mnz-(Ce) formed as a result of Cvk-(Ce) alteration. Samples from experiments CF-08, CF-12, CF-15, and CF-24.
Figure 2
EDS mapping of Ce distribution in the CF-15 sample. False colours Mnz-(Ce) on the edges of the big Cvk-(Ce) crystals (yellow arrows). a) slightly altered czewkinit-(Ce) b) heavily altered czewkinit-(Ce).
Figure 3
Triangular diagram in REEPO4-CaTh(PO4)2-ThSiO4 system showing the composition of the samples from the experiments. (a) Results of Mnz from the CF-8 analyses, (b) CF-12, (c) CF-15, (d) CF-17, (e) CF-21, and (f) CF-24.
Compiled from Linthout (2007).
Table 2
EPMA analyses of Mnz-(Ce)
| CF-8-mon | CF_12_5_Mnz1 | CF_15_D_Mnz | CF_17_A_Mnz | CF19_Mnz_A1_01 | CF24_C2_Mnz | |
|---|---|---|---|---|---|---|
| SO3 | 25.84 | 28.66 | 25.48 | 23.29 | 28.58 | 27.76 |
| P2O5 | 25.84 | 28.66 | 25.48 | 23.29 | 28.58 | 27.76 |
| V2O5 | 0.05 | 0.04 | 0.07 | 0.01 | n.d. | 0.01 |
| Nb2O5 | n.d. | n.d. | n.d. | 0.01 | 0.07 | n.d. |
| Ta2O5 | 0.13 | n.d. | 0.04 | 0.09 | n.d. | 0.18 |
| SIO2 | 1.38 | 0.94 | 3.67 | 4.61 | 1.04 | 1.05 |
| TiO2 | 0.06 | 0.58 | 0.17 | 3.16 | 0.11 | 0.30 |
| ZrO2 | 0.07 | 0.10 | 0.09 | 0.15 | 0.22 | 0.11 |
| HfO2 | 0.10 | 0.01 | n.d. | n.d. | 0.15 | n.d. |
| ThO2 | 1.95 | 1.17 | 4.78 | 2.68 | 1.09 | 1.05 |
| UO2 | 0.02 | 0.05 | 0.01 | 0.10 | 0.05 | n.d. |
| Sc2O3 | 0.02 | 0.02 | 0.03 | 0.02 | 0.01 | 0.04 |
| Cr2O3 | n.d. | 0.03 | n.d. | 0.01 | n.d. | n.d. |
| As2O3 | 0.07 | 0.01 | n.d. | 0.07 | 0.03 | 0.06 |
| Y2O3 | 0.07 | 0.03 | 0.01 | n.d. | 0.01 | 0.02 |
| La2O3 | 17.54 | 15.22 | 19.11 | 17.91 | 15.23 | 16.11 |
| Ce2O3 | 34.60 | 33.99 | 33.45 | 32.48 | 35.19 | 34.18 |
| Pr2O3 | 3.58 | 3.26 | 2.92 | 2.93 | 4.06 | 3.48 |
| Nd2O3 | 10.07 | 11.33 | 8.10 | 9.16 | 11.06 | 10.80 |
| Sm2O3 | 0.85 | 1.08 | 0.49 | 0.56 | 0.84 | 0.88 |
| Eu2O3 | 0.23 | 0.41 | 0.12 | n.d. | 0.05 | 0.14 |
| Gd2O3 | 0.38 | 0.26 | 0.34 | 0.02 | 0.38 | 0.38 |
| MgO | 0.06 | 0.10 | 0.03 | 0.01 | 0.09 | 0.02 |
| CaO | 0.42 | 0.62 | 0.13 | 0.30 | 0.39 | 0.83 |
| MnO | n.d. | 0.06 | n.d. | 0.07 | n.d. | n.d. |
| FeO* | 0.06 | 0.26 | 0.06 | 1.47 | n.d. | 0.33 |
| SrO | 0.04 | n.d. | n.d. | 0.01 | 0.24 | 0.16 |
| BaO | 0.02 | 0.09 | 0.07 | 0.05 | 0.19 | n.d. |
| PbO | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. |
| Na2O | 0.03 | 0.05 | 0.03 | 0.08 | n.d. | 0.04 |
| K2O | 0.01 | n.d. | n.d. | n.d. | 0.01 | 0.01 |
| Cl | n.d. | 0.01 | n.d. | n.d. | 0.01 | n.d. |
| O═Fl | — | — | — | — | — | — |
| Σ | 98.31 | 98.38 | 99.23 | 99.24 | 99.74 | 98.67 |
| S6+ | 0.12 | n.d. | n.d. | n.d. | 0.11 | 0.11 |
| P5+ | 2.24 | 2.40 | 2.16 | 1.95 | 2.37 | 2.33 |
| SI2+ | 0.06 | 0.04 | 0.15 | 0.18 | 0.04 | 0.04 |
| Ti4+ | n.d. | 0.02 | 0.01 | 0.09 | n.d. | 0.01 |
| U2+ | 0.02 | 0.01 | 0.04 | 0.02 | 0.01 | 0.01 |
| Ce3+ | 0.27 | 0.22 | 0.28 | 0.26 | 0.22 | 0.24 |
| Pe3+ | 0.52 | 0.49 | 0.49 | 0.47 | 0.50 | 0.50 |
| Nd3+ | 0.05 | 0.05 | 0.04 | 0.04 | 0.06 | 0.05 |
| Sm3+ | 0.15 | 0.16 | 0.12 | 0.13 | 0.15 | 0.15 |
| Eu3+ | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 |
| Gd3+ | n.d. | 0.01 | n.d. | n.d. | n.d. | n.d. |
| Ca3+ | n.d. | 0.01 | n.d. | n.d. | 0.01 | n.d. |
| Mn3+ | 0.02 | 0.03 | 0.01 | 0.01 | 0.02 | 0.04 |
| Sr2+ | n.d. | 0.01 | n.d. | 0.05 | n.d. | 0.01 |
| Ba2+ | n.d. | n.d. | n.d. | n.d. | 0.01 | n.d. |
| K+ | n.d. | n.d. | n.d. | 0.01 | n.d. | n.d. |
| Σ | 3.42 | 3.45 | 3.42 | 3.33 | 3.45 | 3.45 |
* - indicates the presence of iron in both the +2 and +3 oxidation states (Fe2+ and Fe3+).
Figure 4
Normalization of REE concentration to chondrite (Nakamura, 1974) for all Cvk-(Ce) (left diagram) and Mnz-(Ce) (right diagram) analyses derived from experiments. Performed using GCDkit 6.2 (Janoušek et al., 2006).
Figure 5
Triangular diagram in the REEPO4-CaTh(PO4)2-ThSiO4 system, showing samples from Saveleva and Karmanov (2008).
Compiled by the authors based on Linthout (2007).
Table 3
A list of components and products from other experiments similar to those involving Mnz-(Ce) but not producing Mnz-(Ce)
| Sample | P (MPa) | T (°C) | Time (days) | Components/water fluid with | Products |
|---|---|---|---|---|---|
| CF-6 | 200 | 600 | 26 | Cvk, Q, Ab, Byt, Fap, FeS2, CaCO3 | Bri, Ttn, Wo, Ab, Thr*, Ap |
| Ca(OH)2, H2O | |||||
| CF-11 | 200 | 500 | 63 | Cvk, Q, An (glass), Ca3(PO4)2 | ESM, Bri, |
| Ca(OH)2, CaF2, H2O |
*Thorite may also occur as huttonite and in amorphous forms (Bagiński et al, 2023; Stachowicz et al, 2024). Abbreviations according to Warr (2021). Abbreviations according to Warr (2021): Ab – albite, An – anorthite, Bri – britholite, Bt – biotite, Byt – beryllite, Cvk – chevkinite, ESM – epidote supergroup minerals Fap – fluorapatite, Flr – fluorite, Q – quartz, Thr – thorite, Ttn – titanite, Wo – wollastonite.