Deposits of critical metals and related carbonatite-alkaline rock systems

46 Pages·2012·1.19 MB·English

Laboratory of Orogenic Belts and Crustal Evolution, Peking University, China
Institute of Geology, Chinese Academy of Geological Sciences, China
Mendel University in Brno, Czech Republic
Tescan, a.s., Czech Republic

Deposits of critical metals
and related carbonatite-alkaline rock systems

Jindrich Kynicky
Anton Chakhmouradian
Hana Cihlarova
Zengqian Hou
Lifei Zhang
Cheng Xu

(Eds.)

2012
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Deposits of critical metals and related carbonatite-alkaline rock systems

Critical metals are metals whose availability is essential for high-technology, green
and defense applications, but prone to supply restrictions. At present, this designation applies
particularly to the rare-earth elements (REE), whose supply market has been undergoing
major changes in the past several years; a range of other metals (e.g., niobium and tantalum)
are also considered critical.
The first workshop on deposits of critical metals and related alkaline-carbonatite rock
systems was organized during September 4-7, 2012, at Peking University, China. The meeting
will address the origin and evolution of these deposits and specifically REE-bearing systems
(carbonatites and associated alkaline rocks, hydrothermal, metasomatic and residual deposits)
with a particular emphasis on their mineralization and economic potential. A special session
will be held on the localities of alkaline rocks and carbonatites in China, Mongolia and
Russia. Geologists, petrologists, mineralogists, geochemists, explorationists, technologists
and market specialists are all welcome to contribute to this cutting-edge workshop.
CM2012 was financially supported by the Tescan, a.s., (Czech Republic); Laboratory
of Orogenic Belts and Crustal Evolution (Peking University); IGCP-600 program (Institute of
Geology, Chinese Academy of Geological Science); Chinese National Science Foundation
(Nos. 40973040, 41173033); Mendel University in Brno (Czech Republic) and CEITEC
CZ.1.05/1.1.00/02.0068.
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Workshop Program
Day 1, Tuesday 04 September –Yifu 2nd Building, Peking University
15:00-18:00 Registration at Yifu 2nd Building, School of Earth and Space Sciences
18:00- Icebreaker party at Xihua hotel
Day 2, Wednesday 05 September – Peking University, International Center for
Mathematical Research
8:20-8:30 Opening address
Host Zengqian Hou
Keynote: Prof. Frances Wall, University of Exeter, UK
8:30-9:00 Report title: Rare earth deposits associated with carbonatite complexes – where are the
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heavy rare earths?

Session 1: Carbonatites and alkaline rocks: Magmatic evolution, subsolidus
hydrothermal overprint, and processes leading to deposits of critical metals
Prof. Cheng Xu, Peking University, China
9:00-9: 25
Report title: Crustal recycling vs. rare Mo mineralization related with carbonatites
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Prof. Pavel Uher, Comenius University, Slovakia
9:25-9:50
Report title: The REE-Ti-Nb-Ta oxide minerals: from crystal chemistry to ore deposits
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9:50-10:10 Tea break

Prof. Daniel Harlov, Helmholtz-Zentrum Potsdam, Germany
10:10-10:35
Report title: Reprecipitation textures and REE redistribution in REE mineral associations
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Prof. Martin Ondrejka, Univerzita Komenského, Slovakia
10:35-11:00 Report title: Destabilization of REE bearing accessory minerals under rock-fluid
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interaction conditions

Dr. Martin Smith, University of Brighton, UK
11:00-11:25
Report title: Hydrothermal process in REE enrichment and fractionation
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Dr. Mihoko Hoshino, National Institute of Advanced Industrial Science &
Technology, Japan
11:25-11:50
Report title: Crystallization process of zircon and fergusonite during hydrothermal
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alteration in Nechalacho REE deposit, Thor Lake, Canada

Masterate student Lize Wang, Peking University, China
11:50-12:10 Report title: The genesis of ion adsorption type REE+Y deposits of Granitoids in Dingnan
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region, Jiangxi Province, Southern China
12:10-2:00 Lunch break
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Session 2: New analytical methods and HT experiments for carbonatites-
alkaline rocks and associated deposits
Host Anton Chakhmouradian
Dr. Ilya V. Veksler, GFZ German Research Centre for Geosciences, Germany
Report title: Experimental data on element partitioning between immiscible silicate and
2:00-2:25 UUU
carbonate liquids with implications for the origin of rare metal deposits in carbonatites and
alkaline rocks

Associated Prof. Shuangmeng Zhai, Peking University, China
2:25-2:50
Report title: Trace elements in tuite experimentally decomposed from natural apatite
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Associated Prof. Qiong Liu, Peking University, China
2:50-3:15 Report title: Equation of state for carbonate liquids and implications to deep earth carbon
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recycle

Dr. Veronika Králová
3:15-3:40 Report title: TIMA – TESCAN Integrated Mineral Analyzer: New approach for rapid
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evaluation of critical elements ore samples
3:40-4:00 Tea break

Dr. Ekaterina Reguir, University of Manitoba, Canada
4:00-4:25 Report title: The importance of trace-element analysis for petrogenetic studies and mineral
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exploration (as exemplified by carbonatites)

Prof. Liang Qi, Chinese Academy of Sciences, China
4:25-4:50 Report title: A new type of Carius tube for the determination of Re-Os and PGE in
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geological samples

Prof. Yan Liu, Chinese Academy of Geological Sciences, China
4:50-5:15 Report title: Himalayan mountains and south Tibetan plateau: a larger reservoir for
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atmospheric CO since Late Miocene
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Doctoral student Hongming Zhang, China University of Geosciences, China
5:15-5:35
Report title: Isotope tracing deep carbon cycle
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Masterate student Yi Sun, Peking University, China
Report title: REE and rare metal element mobility and mineralization during magmatic
5:35-5:55 UUU
and fluid evolution in alkaline granite system: Evidence from In-Situ LA-ICP-MS study of
melt inclusions in Baerzhe granite

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Day 3, Thursday 6 September - Peking University, International Center for Mathematical
Research
Host Jindrich Kynicky
Keynote: Prof. Anton Chakhmouradian, University of Manitoba, Canada
8:30-9:00 Report title: Postorogenic carbonatites and their significance for rare-metal
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exploration and geodynamic analysis

Session 3: Strategic REE deposits in China, Mongolia and Russia
Prof. Xiangkun Zhu, Chinese Academy of Geological Sciences, China
9:00-9:25
Report title: Genesis of the Bayan Obo REE-Fe-Nb deposit
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Prof. Tiegeng Liu, Chinese Academy of Sciences, China
9:25-9:50 Report title: Geological and geochemical characteristics and genesis of “dolomite” at
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Bayan Obo, China

9:50-10:10 Tea break

Dr. Ulf Kempe, TU Bergakademie Freiberg, Germany
10:10-10:35 Report title: The genesis of Zr-Nb-REE mineralisation at Khalzan Buregte (NW
Mongolia) reconsidered

Dr. Jindrich Kynicky, Mendel University, Czech Republic
10:35-11:00
Report title: REE deposits of Mongolia
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Dr. German S. Ripp, Russian Academy of Sciences Geological, Russia
11:00-11:25
Report title: Sr- and REE carbonatite deposits of the West Transbaikalia, Russia
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Dr. Anna Doroshkevich, Russian Academy of Sciences Geological, Russia
11:25-11:50 Report title: New mineralogical and isotopic data on Nb- and REE carbonatite deposit
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Belaya Zima, Russia
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Dr. Yan Liu, Chinese Academy of Geological Sciences, China
11:50-12:10 Report title: Some progresses for the study of Dalucao LREE deposit, Sichuan, SW China

12:10-2:00 Lunch break
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Session 4: The global picture: critical metals deposits worldwide.
Host Cheng Xu
Dr. Clint Cox, Anchor House, Chicago, America
2:00-2:25 Report title: Some Economic Factors to Consider in Mining and Processing Rare
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Earths - past, present and future of REE mining

Dr. Milan Hauser
2:25-2:50 Report title: Introduction of the TESCAN Company and Product Line useful in quick
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analyse of ores and associated minerals
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Doctoral student Wenlei Song, Peking University, China
2:50-3:15 Report title: Geological and geochemical guidebook for fieldtrip in Huanglongpu Mo
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deposit
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3:15- Tea break and Photo

7-10th
Fieldtrip in Huanglongpu Mo deposit
September
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TIMA – TESCAN Integrated Mineral Analyzer: New approach for rapid evaluation of
critical elements ore samples

Veronika Kralova1, David Motl1, Jindrich Kynicky2

1TESCAN, a.s., Czech Republic; 2 Department of Geology and Pedology, Mendel University, Czech Republic

The Czech company TESCAN is one of the global suppliers of scientific instruments. Within
20 years of its existence, the TESCAN brand has built its reputation particularly in designing
and manufacturing scanning electron microscopes, system solutions for micro- and
nanotechnology, and a wide range of other applications.
For analytical work in the fields of mineralogy and geology, TESCAN has developed a new
automated mineralogy solution, which enables fast and effective data acquisition and accurate
and reliable data analysis. TESCAN Integrated Mineral Analyzer (TIMA) combines BSE and
EDX data to automatically measure mineral abundance, mineral liberation and association,
particle and grain sizes, and bright particles, on multiple samples of grain mounts, thin
sections or polished sections. TIMA can find its application in ore characterization, search for
precious metals and rare earth minerals, remediation, and many other areas.
TIMA has been tested and used for the examination of various samples. The most important
of them were samples of fresh and metasomatically modified carbonatites from the Lugiin
Gol (a.k.a. Lugingol’skiy) complex in the South Gobi, Mongolia. The samples chosen
represent not only rare carbonatite outcrops, but also drill-core material (down to a depth of
1200 m) that had not been previously studied. The carbonatites are represented predominantly
by coarse-grained sövite, consisting of magmatic calcite and a plethora of rare-earth
carbonates whose modal content locally reaches 30 %. The latter group is paragenetically
diverse and includes both primary carbonates (burbankite–calcioburbankite series and REE
fluorocarbonates) and hydrothermally or metasomatically formed phases associated with
strontianite, ankerite and fluorite. The primary fluorocarbonates are represented by zoned
synchysite-(Ce) and parisite-(Ce).
Using scanning electron microscope together with various detectors helps to identify mineral
species in detail and is a powerful tool for better understanding of ores and ore deposits in
general. TIMA, additionally, allows acquiring data automatically with high data acquisition
speed and processing them in the same time, providing various types of analyses depending
on required results.
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Crustal recycling vs. rare Mo mineralization related with carbonatites

Cheng Xu 1, Jindrich Kynicky2, Anton R. Chakhmouradian 3

1Department of Geology, Peking University, China; 2 Department of Geology and Pedology, Mendel University, Czech; 3Department of
Geological Sciences, University of Manitoba, Canada

Collision-related carbonatites are rare and raise questions about the role of crustal recycling in
their genesis. Most carbonatites are very poor in Mo, whose levels are at or below the limit of
detection. In this work, we report a new type of carbonatite-related Mo deposit. At
Huanglongpu (HLP), economic molybdenite mineralization is associated with calcite
carbonatites emplaced in the Lesser Qinling orogenic belt. The deposit has an ore reserve of >
0.18 million tons of MoS . The HLP carbonatites are characterized by unusually high levels of
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heavy rare-earth elements (HREE: e.g.,> 30 ppm Yb) and flat to weakly light-REE-enriched
chondrite-normalized patterns [(La/Yb)n=1.0-5.5], which is in marked contrast with mostk
nown carbonatites. Their C and O isotopic compositions are consistent with a mantle source,
and do not indicate any secondary processes that could lead to HREE enrichment. The
carbonatites intrude a variety of Archean and Mesoproterozoic wall-rocks, but are
characterized by remarkably similar isotopic compositions [(87Sr/86Sr) = 0.7048-0.7057; ε =
i Nd
-4.3 to -10.1; 207Pb/206Pb = 0.878-0.889 and 208Pb/206Pb = 2.136-2.160], which approach, and
trend toward slightly less radiogenic Sr and Nd values than, the enriched mantle component
of type 1 (EM1). This feature distinguishes the HLP rocks from anorogenic carbonatites
worldwide. We consider that delaminated and recycled lower-crust material is the most
probable source of the HLP carbonatites. This interpretation is supported by the following
evidence:
(1) The North China block (NCB) hosts a world-class Mo mineralization belt, and its
lower crust has a high Mo content (Gao et al., 1998);
(2) Subduction of oceanic crust beneath the NCB resulted in amalgamation between
the Qinling and NCB in the Mesoproterozoic (Zhang et al., 2002);
(3) Fractionation of REE in the lower crust could explain HREE enrichment in
magmas derived from mantle sources affected by crustal recycling.
Recycling of carbonated oceanic crust through deep mantle over 1 Ga (or longer) can produce
an EM1-type carbonate reservoir. The HLP carbonatite emplacement at 221 Ma followed the
collision between the SCB and Qinling. The NCB was underthrust by crustal material derived
from the Qinling during the collision, contributing to thickening of the lower crust beneath the
NCB and its conversion to dense eclogite. This process culminated in brittle delamination of
the eclogitized material into the mantle and its metasomatic reworking. Involvement of
recycled lower-crust material in magma generation explains an enriched HREE and Mo
signature of the HLP carbonatite magma.
References
Gao, S., Luo, T.C., Zhang, B.R., et al., 1998. Geochimica et Cosmochimica Acta 62, 1959-1975.
Zhang, B.R., Gao, S., Zhang, H.F., 2002. The Geochemistry of the Qinling Orogenic Belt. Science Press, Beijing.
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The nature of the Mo-bearing carbonatitic fluids from Huanglongpu deposit, Shaanxi,
China: Evidence from fluid inclusions and stable isotope research
Song Wenlei1, Xu Cheng1, Jindrich Kynicky2

1Department of Geology, Peking University, China; 2 Department of Geology and Pedology, Mendel University, Czech

We report new microthermometric data for primary and pseudosecondary fluid
inclusions of calcite and quartz from the Huanglongpu deposit. The fluid inclusions can be
divided into 7 types, namely pure vapour including H O-enriched gases or CO (V),
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aqueous(L), two-phase aqueous-carbonic(VL), three phase aqueous-carbonic (LLV), solid-
bearing aqueous(LVS), and solid-bearing aqueous-carbonic(LLVS). Note that most of the
solid phase commonly occurs in LLVS-type inclusions. According to the crystal habits and the
analyses of microraman spectroscopy the transparent solid phase are halite, sylvite, calcite,
anhydrite, K-feldspar and the opaque solid inclusions represents probably molybdenite and
Pb-bearing minerals.
Th of the VL, VL and LLV are 147-425 ℃, 13.2-15.5 ℃and 247-308 ℃respectively.
Homogenization temperatures were not determined for LVS or LLVS. However, the nature of
the trapped minerals and the phase behavior of inclusions indicate that original fluids must
have had even higher concentrations of SO 2-, CO 2- besides NaCl and KCl than was
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previously expected.
The C and O isotopic data for rock-forming calcite from carbonatites has uniform
isotopic compositions with δ13C and δ18O values ranging from -6.36 to -6.90‰ and 7.22 to
9.19‰ respectively. Meanwhile, the absence of 18O-rich carbonates and consistently low δ18O
values of quartz from the orebodies (8.8–10.2‰) also suggesting a magmatic origin. S
isotopic data for sulphides and barite from Huanglongpu carbonatites show that different S-
bearing minerals have different S isotopic compositions deviate from the meteoritic mean
δ34S(0‰) due to the S isotopic fractionation between sulphides and sulfate. Molybdenite
displays δ34S values from -6.69 to -7.68‰ (mean -7.27‰), galena and pyrite range from -8.87
to -10.54‰ (mean -9.86‰) and -6.55 to -7.15‰ (mean -6.9‰) respectively in addition with
4.61 to 5.12(mean 4.75‰) for Sr-bearing barite. It also has been estimated that the δ34S
ΣS
interval of the ore fluids is about 1-2‰, suggesting a mantle-derived source.
We propose that the parental ore forming fluid of the Huanglongpu exhibit moderate to
high salinity, CO -dominanted system enriched in Mo, Pb, S, REE, and other ions expelled
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from fractionated carbonatite magma of mantle source. The unique sulphide bearing
carbonatites of Huanglongpu deposit rapidly crystallized from carbonatite magma and
associated brines of high salinity in very low pressures of shallow level.

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