Monazite-(Ce) formation as a product of hydrothermal chevkinite-(Ce) alteration: Experimental constraints

Kacper M. Urbanik; Bogusław Bagiński; Daniel E. Harlov; Ray Macdonald; Marcin Stachowicz

doi:10.2478/mipo-2026-0003

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Monazite-(Ce) formation as a product of hydrothermal chevkinite-(Ce) alteration: Experimental constraints

Mineralogia

Volume 57 (2026): Issue 1 (January 2026)

By: Kacper M. Urbanik , Bogusław Bagiński, Daniel E. Harlov, Ray Macdonald and Marcin Stachowicz

Open Access

|Jul 2026

Figures & Tables

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.

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).

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.

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).

Triangular diagram in the REEPO4-CaTh(PO4)2-ThSiO4 system, showing samples from Saveleva and Karmanov (2008).

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

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

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
CF-6	200	600	26	Ca(OH)₂, H₂O	Bri, Ttn, Wo, Ab, Thr*, Ap
CF-11	200	500	63	Cvk, Q, An (glass), Ca₃(PO₄)₂	ESM, Bri,
CF-11	200	500	63	Ca(OH)₂, CaF₂, H₂O	ESM, Bri,

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DOI: https://doi.org/10.2478/mipo-2026-0003 | Journal eISSN: 1899-8526 | Journal ISSN: 1899-8291

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Language: English

Page range: 48 - 57

Submitted on: Mar 4, 2026

Accepted on: Jun 8, 2026

Published on: Jul 30, 2026

Published by: Mineralogical Society of Poland

In partnership with: Paradigm Publishing Services

Publication frequency: Volume open

Keywords:

Chevkinite-(Ce),

Hydrothermal alteration,

Related subjects:

© 2026 Kacper M. Urbanik, Bogusław Bagiński, Daniel E. Harlov, Ray Macdonald, Marcin Stachowicz, published by Mineralogical Society of Poland
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 57 (2026): Issue 1 (January 2026)

Monazite-(Ce) formation as a product of hydrothermal chevkinite-(Ce) alteration: Experimental constraints

Figures & Tables

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

EPMA analyses of Mnz-(Ce)

Compilation of substrates and products of experiments containing Mnz-(Ce)

A list of components and products from other experiments similar to those involving Mnz-(Ce) but not producing Mnz-(Ce)

Paradigm

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