Nb-Ti-Y-HREE-W-U Oxide Minerals With Uncommon Compositions Associated With the Tungsten Mineralization In the Puy-Les-Vignes Deposit (Massif Central, France): Evidence For Rare-Metal Mobilization By Late Hydrothermal Fluids With A Peralkaline Signature

2015 ◽  
Vol 53 (4) ◽  
pp. 653-672 ◽  
Author(s):  
Matthieu Harlaux ◽  
Christian Marignac ◽  
Michel Cuney ◽  
Julien Mercadier ◽  
Rémi Magott ◽  
...  
Keyword(s):  
Rare Metal ◽  
Hydrothermal Fluids ◽  
Metal Mobilization ◽  
Massif Central ◽  
Oxide Minerals ◽  
Tungsten Mineralization

scholarly journals Geochemical Signature of Magmatic-Hydrothermal Fluids Exsolved from the Beauvoir Rare-Metal Granite (Massif Central, France): Insights from LA-ICPMS Analysis of Primary Fluid Inclusions

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-25 ◽  
Author(s):  
Matthieu Harlaux ◽  
Julien Mercadier ◽  
Wilédio Marc-Emile Bonzi ◽  
Valentin Kremer ◽  
Christian Marignac ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
Rare Metal ◽  
Hydrothermal Fluids ◽  
Raman Spectrometry ◽  
Peraluminous Granite ◽  
Geochemical Composition ◽  
Massif Central ◽  
Granite Massif ◽  
Rare Metal Granite ◽  
Primary Fluid

The Beauvoir granite (Massif Central, France) represents an exceptional case in the European Variscan belt of a peraluminous rare-metal granite crosscutting an early W stockwork. The latter was strongly overprinted by rare-metal magmatic-hydrothermal fluids derived from the Beauvoir granite, resulting in a massive topazification of the quartz-ferberite vein system. This work presents a complete study of primary fluid inclusions hosted in quartz and topaz from the Beauvoir granite and the metasomatized stockwork, in order to characterize the geochemical composition of the magmatic fluids exsolved during the crystallization of this evolved rare-metal peraluminous granite. Microthermometric and Raman spectrometry data show that the earliest fluid (L1) is of high temperature (500 to >600°C), high salinity (17–28 wt.% NaCl eq), and Li-rich (Te<−70°C) with Na/Li ratios ~5. LA-ICPMS analyses of L1-type fluid inclusions reveal that the chemical composition of this magmatic-hydrothermal fluid is dominated by Na, K, Cs, and Rb, with significant concentrations (101–104 ppm) in rare-metals (W, Nb, Ta, Sn, and Li). This study demonstrates that primary fluid inclusions preserved the pristine signature of the magmatic-hydrothermal fluids in the Beauvoir granite but also in the metasomatized W stockwork, despite the distance from the granitic cupola (>100 m) and interaction with external fluids.

scholarly journals The Distribution of Rare Metals in the LCT Pegmatites from the Giraúl Field, Angola

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 580
Author(s):  
Gonçalves ◽  
Melgarejo ◽  
Alfonso ◽  
Amores ◽  
Paniagua ◽  
...  
Keyword(s):  
Grain Size ◽  
Hydrothermal Fluids ◽  
Granitic Pegmatite ◽  
Rare Metals ◽  
Accessory Minerals ◽  
Critical Elements ◽  
Incompatible Elements ◽  
Pegmatite Body ◽  
Quartz Core ◽  
Oxide Minerals

The Giraúl granitic pegmatite field in Angola is composed of five pegmatite types, the most evolved belong to the beryl-columbite, beryl-columbite-phosphate and spodumene types. Pegmatites are concentrically zoned with increased grain size toward a quartz core; the most evolved pegmatites have well-developed replacement units. These pegmatites are rich in Nb-Ta oxide minerals and the field has a moderate interest for critical elements such as Ta and Hf. Tourmaline, garnet and micas occur as accessory minerals. The abundance of Zr and Nb-Ta minerals increases with the evolution of the pegmatites, as well as the proportions of beryl and Li-rich minerals. The Ta/(Ta + Nb) ratio in Nb-Ta oxide minerals and the Hf/(Hf + Zr) ratio in zircon also increase with the evolution of the pegmatites and within each pegmatite body from border to inner zones, and especially in the late veins and subsolidus replacements. Textural patterns and occurrence of late veins with Ta-rich minerals suggest that Nb and especially Ta can be enriched in late hydrothermal fluids exsolved from the magma, along with Hf and other incompatible elements as Sn, U, Pb, Sb and Bi.

Chemistry of the Ta-Nb-Sn-W oxide minerals from the Yichun rare metal granite (SE China): genetic implications and comparison with Moroccan and French Hercynian examples

2000 ◽  
Vol 64 (3) ◽  
pp. 507-523 ◽  
Author(s):  
M. Belkasmi ◽  
M. Cuney ◽  
P. J. Pollard ◽  
A. Bastoul
Keyword(s):  
Chemical Evolution ◽  
Fractional Crystallization ◽  
Rare Metal ◽  
Strong Increase ◽  
Moderate Increase ◽  
Rare Metal Granite ◽  
History Of ◽  
Granite Complex ◽  
Oxide Minerals ◽  
Se China

AbstractIn the Yichun granite complex (SE China), columbite group minerals, microlite and cassiterite are the main Nb, Ta, Sn-bearing minerals. They are mainly concentrated in the uppermost albite-lepidolite granite. Rutile is the only Nb, Ta-bearing phase in the geochemically primitive muscovite-zinnwaldite granite. The chemical evolution of the columbite group minerals (the most abundant and commonly zoned Nb, Ta-bearing minerals) indicates a complex crystallization history of the host granites with: (1) fractional crystallization at depth, reflected by a strong increase of Mn/(Mn+Fe) ratios with a moderate increase of Ta/(Ta+Nb) ratios from the muscovite-zinnwaldite granite to the Li-mica granite and then the most fractionated topaz-lepidolite granite; and (2) emplacement of successive magma batches corresponding to the different units of the granite complex with progressive crystallization of each unit, mainly reflected by a strong increase of Ta/(Ta+Nb) ratios with moderate variation of Mn/(Mn+Fe) ratios during the growth of the zoned crystals. The data are compared with those from the RMG of Ezzirari (Morocco), Montebras, Beauvoir and Chèdeville (France).

Relationships between granitoids and mineral deposits: three-dimensional modelling of the Variscan Limousin Province (NW French Massif Central)

2000 ◽  
Vol 91 (1-2) ◽  
pp. 283-301 ◽  
Author(s):  
C. Le Carlier de Veslud ◽  
M. Cuney ◽  
J. J. Royer ◽  
J. P. Floc'h ◽  
L. Améglio ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Spatial Relationship ◽  
Rare Metal ◽  
Geochemical Data ◽  
Fluid Circulation ◽  
Massif Central ◽  
Ore Deposit ◽  
Tectonic Regime ◽  
Regional Tectonic ◽  
Different Origins

Multidisciplinary three-dimensional modelling, involving geophysical, structural and geochemical data, has been used to study the relationships between magmatism, tectonics, fluid circulation and mineralisation in the northern Limousin, and to provide P-T-Z-t paths constrained by the available dating. The ore deposit occurrence displays little spatial relationship with granites emplaced in the 360-320 Ma period, probably because the low global permeability and tectonic regime did not allowed vertical fluid exchanges to be established. In contrast, the change in the tectonic regime induced by the delamination of the lower lithosphere (320-300 Ma), and characterised by the passage to general extension, has played a major metallogenic role. However, the ore deposit processes appear to be specific to each metal. Most of the W-Sn deposits appear to be synchronous with rare metal granites emplacement, atc.310 Ma, that allowed the focus of fluids of different origins towards the apex of plutons. In contrast, for Au and U, the whole mineralisation process covers several tens of-millions of years. It is controlled by the regional tectonic evolution of the Limousin area during the same period, and especially by a rapid exhumation of the ductile crust which occurred in the 310-300 Ma period.

Interaction Of Rare-Metal Minerals With Hydrothermal Fluids: Evidence From Quartz–Epidote Metasomatites Of The Haldzan Buragtag Massif, Mongolian Altai

2015 ◽  
Vol 53 (6) ◽  
pp. 1015-1034 ◽  
Author(s):  
Ray MacDonald ◽  
Bogusław Bagiński ◽  
Pavel M. Kartashov ◽  
Dmitry Zozulya ◽  
Piotr Dzierżanowski
Keyword(s):  
Rare Metal ◽  
Hydrothermal Fluids ◽  
Mongolian Altai

Lithium and trace-element concentrations in trioctahedral micas from granites of different geochemical types measured via laser ablation ICP-MS

2017 ◽  
Vol 81 (1) ◽  
pp. 15-33 ◽  
Author(s):  
Karel Breiter ◽  
Michaela Vaňková ◽  
Michaela Vašinová Galiová ◽  
Zuzana Korbelová ◽  
Viktor Kanický
Keyword(s):  
Laser Ablation ◽  
Inductively Coupled Plasma ◽  
Rare Metal ◽  
Major Elements ◽  
Massif Central ◽  
Inductively Coupled ◽  
Exchange Vector ◽  
Icp Ms ◽  
Parent Rocks ◽  
Plasma Mass Spectrometry

AbstractThe compositions of trioctahedral micas from 51 samples of granitoids with different geochemical affiliations and grades of differentiation from the Bohemian Massif, Central Europe, were analysed using electron microprobe (major elements) and laser ablation inductively coupled plasma mass spectrometry (Li, Sc, Ga, Ge, Nb, In, Sn, Cs, Ta, W, Tl). The micas form a continuous evolutionary series from phlogopite to zinnwaldite. The phlogopites and biotites from the I-type rocks are characterized by 5.5–5.7 Si, 2.4–2.6 Al, <0.1 Li atoms per formula unit [apfu] and Mg/(Mg + Fe) = 0.4–0.8. The biotites from the S-type granites usually contain 5.3–5.7 Si, 3.2–3.6 Al, 0.1–0.3 Li apfu and Mg/(Mg + Fe) = 0.15–0.4. The annites and zinnwaldites from the rare-metal granites contain 5.7–6.8 Si, 3.2–3.8 Al, 0.6–2.6 Li apfu and Mg/(Mg + Fe) < 0.1. The concentrations of F, Rb, Cs and Tl increase from the phlogopites and biotites to zinnwaldites: F 0.1 → 8 wt.%, Rb2O 0.05 → 1.7 wt.%, Tl 2 → 50 ppm and Cs 40 → 2000 ppm. The concentrations of Sn, Nb, Ta and W in phlogopites and biotites from the I- and S-type granitoids generally correlate with those of the parent rocks and reach values of (in ppm) 20–100 Sn, 20–250 Nb, 1–20 Ta and <5 W. The highest concentrations were found in the Li-annites in the relatively early facies of rare-metal granites (in ppm): 250–600 Sn, 400–600 Nb, 60–120 Ta and 50– 120 W. The zinnwaldites in the late rare-metal granites facies are impoverished in these elements, which is explained by contemporaneous crystallization of cassiterite and columbite. Lithium enters the crystal lattice of trioctahedral micas via the exchange vector Li3□Si3Fe–6Al–1up to concentrations of ∼2.5 wt.% Li2O (1.5 apfu Li). At higher Li concentrations, Li is incorporated through the exchange vector Li3Si1□–1Fe–2Al–1.

scholarly journals Multistage development of a hydrothermal tungsten deposit during the Variscan late-orogenic evolution: the Puy-les-Vignes W breccia pipe (Massif Central, France)

2021 ◽  
Author(s):  
Matthieu Harlaux ◽  
Christian Marignac ◽  
Julien Mercadier ◽  
Marc Poujol ◽  
Marie-Christine Boiron ◽  
...  
Keyword(s):  
Rare Metal ◽  
Gold Deposits ◽  
Fluid Inclusion Study ◽  
Magmatic Fluid ◽  
First Episode ◽  
Trace Element Geochemistry ◽  
Peraluminous Granite ◽  
Massif Central ◽  
Breccia Pipe ◽  
Host Rocks

The Puy-les-Vignes W deposit, located in the northwestern French Massif Central (FMC), is a rare occurrence worldwide of a wolframite-mineralized hydrothermal breccia pipe hosted in high-grade metamorphic gneisses. We present here an integrated study of this deposit aiming to characterize the ore-forming hydrothermal system in link with the Variscan late-orogenic evolution of the FMC. Based on a set of representative samples from the host rocks and mineralization, we describe a detailed paragenetic sequence and we provide the major and trace element geochemistry of the host rocks and W-Nb-Ta-Sn-Ti oxide minerals, in situ U-Pb and 40Ar/39Ar geochronology, and a fluid inclusion study in quartz and wolframite. We demonstrate that the formation of this W-mineralized breccia pipe results from a multistage development between ca. 325 and 300 Ma related to four major episodes during the late Carboniferous. The first episode corresponds to the emplacement of an unexposed peraluminous granite at ca. 325 Ma, which generated microgranite dykes exposed at the present-day surface. The second episode is the formation of the quartz-supported breccia pipe and wolframite mineralization at ca. 318 Ma at a paleodepth of 7 km. The mineralizing fluids have a H2O-NaCl-CO2-CH4-N2 composition, a moderate-salinity (<9 wt.% NaCl eq) and were trapped at high-temperatures (400-450°C) during lithostatic to hydrostatic pressure variations caused by intense hydraulic fracturing of the host rocks. Wolframite deposition is interpreted to result from the mixing between a W-rich intermediate-density magmatic fluid exsolved from an evolved leucogranite and low-salinity volatile-rich metamorphic fluids of distal origin. The third episode corresponds to a magmatic-hydrothermal Nb-Ta mineralization overprinting the W-mineralized system and related to the intrusion at ca. 314 Ma of a rare-metal granite, which is part of a regional peraluminous rare-metal magmatism during the 315-310 Ma period. Finally, the last episode corresponds to the formation of a disseminated Bi±Au-Ag mineralization at ca. 300 Ma, which shares similar textural and mineral features with orogenic gold deposits in the FMC. The Puy-les-Vignes W deposit records, therefore, a multistage and long-lived development that extends over a timespan of 25 million years in a regional setting dominated by protracted peraluminous magmatism and HT-LP metamorphism. Although the local environment of ore deposition is atypical, our results show that the mineral assemblages, alteration styles, and fluid characteristics of the Puy-les-Vignes breccia pipe are similar to those of other peri-granitic W deposits in the FMC.

Fluid migration during contact metamorphism: the use of oriented fluid inclusion trails for a time/space reconstruction

1990 ◽  
Vol 54 (375) ◽  
pp. 169-182 ◽  
Author(s):  
M. Cathelineau ◽  
M. Lespinasse ◽  
A. M. Bastoul ◽  
C. Bernard ◽  
J. Leroy
Keyword(s):  
Fluid Inclusion ◽  
Contact Zone ◽  
Crack Opening ◽  
Hydrothermal Fluids ◽  
Contact Metamorphism ◽  
Massif Central ◽  
Time Space ◽  
Peraluminous Granites ◽  
Inclusion Trails ◽  
Metamorphic Series

AbstractMicrothermometric characteristics of metamorphic to hydrothermal fluids and microfracturing were studied in a contact zone between metamorphic series and peraluminous granites, located in the southern part of the Mont Lozère pluton (Massif Central, France). Four major stages of fluid production or migration have been recognized: (1) N2-CH4 (±CO2)-rich fluids related to the metamorphism of the C-bearing shales, occurring as fluid inclusion along the quartz grain boundaries; (2) CO2-CH4-H2O vapours or liquids, with homogenization temperatures of 400 ± 20 and 350 ± 50°C respectively, related to the first hydrothermal stage produced by the late peraluminuous intrusions; (3) aqueous fluids having low salinities and Th in the range 150–330°C; (4) low-temperature aqueous fluids.It is shown that the percolation of hydrothermal fluids occurs through a dense set of microfissures on a microscopic scale. The different stages of fluid percolation have been investigated by relating the deformational events to the observed fracturing. The nature of the hydrothermal fluid has been deduced by studying the trails of fluid inclusions. Analysis of the relationships of the fluid inclusion trails (F.I.T.) with structures associated with plastic deformation show that their propagation is independent of the intracrystalline anisotropies. Combined studies of their orientation in space and their microthermometric characteristics show that: (1) according to the direction, several generations of fluids are distinguished within each sample on the basis of their physical-chemical characteristics; they correspond to different stages of the hydrothermal activity and to different directions of micro-crack opening; (2) in bulk isotropic media (granite), fluid inclusion trails are essentially mode I cracks which can be used as excellent markers of paleostress fields; however, in bulk anisotropic media (quartz lenses in mica schists) the migration directions of the fluids are mostly dependent on the local reorientations of the stress fields.The study of the contact zone between granites and a metamorphic series submitted to local abnormal heat flows shows that fluid characteristics are significantly different in the two environments. Migration of carbonic fluids from mica schists towards granites occurred but is relatively limited, whilst aqueous fluids mixed in variable amounts with carbonic fluids in the metamorphic zone.

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