1. SATPAYEV INSTITUTE OF GEOLOGICAL SCIENCES
Mineralogical laboratory Satpaev Institute of Geological Sciences
SATPAYEV INSTITUTE OF GEOLOGICAL SCIENCES
Rare earth minerals from the Verkhnee Espe rare element deposit (East Kazakhstan)
PhD student Baisalova A.

2. Geology of the Verkhnee Espe deposit
Mineralogical laboratory Satpaev Institute of Geological Sciences
Geology of the Verkhnee Espe deposit
The rare metal mineralization at the Verkhnee Espe deposit is related to altered alkaline granitic rocks of the Greater and Lesser cupolas and to the exo-contact altered host rocks. The host rocks are represented by the thin-bedded grey sandstone, siltstone, tuffite and carbonaceous materials. The host rocks are cut by pre-granitic dikes of diorite and diabase porphyry. The outcrops are composed of the following granitic rocks;
- porphyritic biotite granite developed in the south-western part of the Greater Cupola;
the medium-coarse- grained riebeckite and pegmatoid granite composed about 70-80% of both outcrops;
the fine-grained riebeckite granite, which forms minor intrusions in inner parts of the Creater and Lesser Cupolas.
Geological structure of the Verkhnee Espe deposit
Biotite granite
coarse- grained
riebeckite
Pegmatoid granite
fine-grained riebeckite
granite

3. Rocks of Verkhnee Espe deposit
Mineralogical laboratory Satpaev Institute of Geological Sciences
Rocks of Verkhnee Espe deposit
The rare pegmatite veins are concentrated mostly within the Greater Cupola. The microcline-astrophyllite and albite-pegmatite facies are recognized. These facies are enriched in zircon minerals, more minerals of REE and Nb. The specific feature of the Verkhnee Espe deposit consists in the alkaline metamorphic alteration that has affected both granitic and host rocks and gave rise to the increased Li2O contents in micas, amphibole and to the enrichment of granite in Li, Rb, REE, Y, Nb, Zr.
Pegmatite veins
microcline-astrophyllite rock
Albitized granite
Metacrystalls of narsarsukite
in fenitized slate
Metasomatic alteration
slate of exo-contact
riebeckite-albite apogranite
Phenocryst crystals of
Narsarsukite in fenitized siltstone.

4. Classification of rare metal minerals
Mineralogical laboratory Satpaev Institute of Geological Sciences
Classification of rare metal minerals
Mineral composition of deposit characterized by great diversity and include of 120 minerals. Among them are rare, very rare and re-discovered mineral types and species.
The minerals are distributed by classes as follows;
fluorides: gagarinite, fluorite-(Y), fluocerite;
phosphates: xenotime, monazite, fluorapatite;
fluorocarbonates: bastnesite - (Ce), bastnaesite - (Y), synchusite – (Y)
niobates: pyrochlor group minerals and fergusonite;
silicates: natrotitanite, gadolinite, yftisite, rowlandite

5. Group of fluorides Gagarinite NaCaYF6 Fluorite-(Y) (Ca,Y)(F,O,OH)2
Mineralogical laboratory Satpaev Institute of Geological Sciences
Group of fluorides
Gagarinite NaCaYF6
Fluorite-(Y) (Ca,Y)(F,O,OH)2
An aggregate of gagarinite in
phenite rocks
BEI (compo) of an aggregate of gagarinite (grey), zircon (dark
grey), quartz (black).
BEI (compo) of an aggregate of bastnaesite-(Ce) (white) and fluorite-(Y) (black).
The chemical composition of fluorite-(Y)
The chemical composition of gagarinite
Constituent
(1) F
43.14 Na
2.17 Si
0.64 K
0.30 Ca
19.32 Fe
0.18 Co
0.13 Y
28.44 Ce
0.96 Nd
0.67 Sm
0.24 Gd
1.01 Dy
1.43 Er
0.81 Yb
0.93 Σ
100.36
Constituent
Wt.%
(1)
(2) F
42.13
41.85 Na
6.16
4.51 Ca
10.97
10.85 Y
18.21
17.92 La
1.43
1.92 Ce
6.03
6.69 Pr
0.74
1.24 Nd
4.41
4.66 Sm
2.15
2.55 Eu
0.00
0.52 Gd
2.72
2.86 Tb
0.70
0.87 Dy
3.27 Ho
0.27 Er
1.73
1.53 
100.66
101.50
Constituent
Wt.%
(1)
(2)
(3)
Mean F
30.33
30.50
30.90
30.58 Y
0.96
1.50
1.08
1.18 La
11.15
11.89
9.39
10.81 Ce
36.95
35.53
35.81
36.10 Pr
4.25
3.94
4.27
4.15 Nd
14.93
14.14
15.30
14.79 Sm
2.18
2.03
2.27
2.16 
100.75
99.53
99.02
99.77
The empirical formula, calculated on the basis of REEs+Ca+Na=3 apfu:
1. (Y0.68Ce0.14Nd0.10Dy0.07Gd0.06Sm0.05La0.03Er0.03Pr0.02Tb0.01)1.19Ca0.91Na0.89F6.28
2. (Y0.71Ce0.17Nd0.11Dy0.07Gd0.06Sm0.06La0.05Er0.03Pr0.03Tb0.02Eu0.01Ho0.01)1.33Ca0.96Na0.70F6.61.

6. Group of phosphates Xenotime YPO4 Monazite CePO4
Mineralogical laboratory Satpayev Institute of Geological Sciences
Group of phosphates
Xenotime YPO4
SEI of an aggregate of xenotime (dark grey) and Y-bearing fluorite (grey).
SEI of xenotime.
The chemical composition (wt.) of xenotime
BEI (compo) of an aggregate
of aegirine with inclusions:
K- feldspar (black) and REEs-bearing fluorapatite. N O P Y Gd Dy Ho Er Yb Lu Ta 
(1)
30.87
15.26
25.00
0.70
5.13
1.25
7.15
12.51
1.41
0.84
100.13
(2)
31.26
15.86
23.78
0.76
4.93
1.17
7.67
12.49
1.72
0.80
100.45
(3)
30.48
15.50
23.70
0.74
5.03
1.33
7.14
12.32
1.53
0.36
98.13
Average of 3 analyses the empirical formula, calculated on the basis of P=1 apfu: (Y0.54Yb0.14Er0.09Dy0.06Ho0.02Lu0.02Gd0.01Ta0.01)0.89 ( P 1.00O3.85) .
Monazite CePO4
The chemical composition (wt.) of monazite N
SiO2
P2O5
La2O3
Ce2O3
Pr2O3
Nd2O3
ThO2 
(1)
1.16
30.28
19.43
34.78
2.33
6.26
5.85
100.08
(2)
1.00
30.16
19.67
34.92
1.42
6.24
6.50
99.91
(3)
0.88
30.43
21.16
35.81
1.31
5.34
3.51
98.43 M
1.02
30.29
20.09
35.17
1.69
5.95
5.28
99.48
The average of 3 analyses the empirical formula, was calculated on the basis of REEs+Th+Si=1 apfu: (Ce0.53La0.31Nd0.09Pr0.03Th0.05)1.00(P1.06Si0.04)1.10O4.25.
BEI (compo) of mineral-host monazite (white) with inclusions - crystals of zircon (grey).

7. Group of fluorocarbonates
Mineralogical laboratory Satpaev Institute of Geological Sciences
Group of fluorocarbonates
Bastnesite - (Ce)
Bastnaesite-(Y) (Y,Сe)(CO3)F·nH2O
The empirical formula of bastnaesite-(Y) was calculated on the basis
of REEs+Co+Ca = 1 (formula number corresponds to the number of analysis):
(Y0.21Ce0.18Nd0.16Dy0.09Gd0.08Sm0.08La0.04Pr0.04Er0.02Yb0.02Ho0.01Co0.01Ca0.03Si0.02)0.99(CO3)F0.98;
BEI (compo) of an aggregate of
bastnaesite-(Ce) (grey) and
bastnaesite-(Ce) with high Ca
content (dark grey).
BEI (compo) of an aggregate of bastnaesite-(Y) (white) and rowlandite-(Y) (grey).
The chemical composition of bastnaesite-(Ce)
Synchusite-(Y) СаY(CO3)2F
Constituent
Wt.%
(1)
(2)
(3)
Mean F
7.27
7.21
6.83
7.10
CaO
0.12
0.22
0.23
0.19
La2O3
20.20
17.89
17.63
18.57
Ce2O3
37.52
37.19
37.30
Pr2O3
1.92
2.04
2.33
2.10
Nd2O3
5.87
7.59
7.74
7.07
Sm2O3
1.13
0.80
1.46
ThO2
1.29
1.47
1.39
1.38 
75.32
74.41
74.80
74.84
The empirical formula of synchusite-(Y) was calculated on the basis
(Ca0.82Y0.83Dy0.12Er0.08Yb0.04Gd0.03Ho0.02Sm0.01Si0.05)2.00(CO3)2(O0.23OH0.40F0.36Cl0.01)1.00;
BEI (compo) of an aggregate of synchusite-(Y) (white) and quartz (black) in the rim of mineral “porridge”.
Average of 3 analyses the empirical formula of Bastnaesite
(Ce) was calculated on the basis of REEs+Th+Ca = 1: (Ce0.55La0.28Nd0.10Pr0.03Sm0.02Th0.01Ca0.01)1.00(CO3)(F1.91OH0.09).

8. Group of silicates Natrotitanite Rowlandite-(Y) Gadolinite-(Y)
Mineralogical laboratory Satpayev Institute of Geological Sciences
Group of silicates
Natrotitanite
(Na0.5Y0.5)Ti(SiO4)O
Gadolinite-(Y)
Y2Fe[BeSiO4]2(O,OH)2
Rowlandite-(Y)
Y4Fe2+Si4O14F2
BEI (compo) of rowlandite with variation of chemical composition.
BEI (compo) of zones of gadolinite-(Y) with different Y content.
BEI (compo) of an aggregate of wedge-shaped crystals of (Na,Y,REE)-bearing titanite (dark grey) and natrotitanite (grey). The polished section is approximately parallel to the direction of elongation of the crystals.
BEI (compo) of an aggregate of rowlandite-(Y) (light grey) and fluorothalenite-(Y) with microinclusions of bastnaesite (white) and fluorite-(Y) (black).
BEI (compo) of gadolinite-(Y) (grey) and gadolinite-(Y) with lower Y content (dark grey), in which inclusions of albite are black.
Average of 8 analyses the empirical formula of gadolinite-(Y) was
calculated on the basis of REEs+Y+Si = 4:
(Y1.07Yb0.18Er0.16Dy0.15Ce0.06Ho0.04Gd0.03Tm0.03Nd0.03La0.02Sm0.02Lu0.02Tb0.02Eu0.01
Pr0.01Th0.01Si0.14)2.00(Fe0.69Ca0.21)0.89(Si2O8)Be2[О1.89(OH)0.11]2.00.
BEI (compo) of an aggregate of natrotitanite (light grey), fluorite-(Y) (grey) and elpidite (dark grey).

9. Thank you for your attention
Mineralogical laboratory Satpayev Institute of Geological Sciences
Thank you for your attention