Rock textures and mineral zoning – A clue to understanding rare-metal granite evolution: Argemela stock, Central-Eastern Portugal

The article presents an event correlation of the Permian‐Triassic granites of the Altai collision system, which are associated with industrial ore deposits and occurrences (Mo‐W, Sn‐W, Li‐Ta‐Be). The multi‐system and multi‐mineral isotope datings of igneous rocks and ore bodies (U/Pb, Re/Os, Rb/Sr, Ar/Ar‐methods) suggest the postcollisional (intraplate) formation of ore‐magmatic systems (OMS), the duration of which depended on the crustmantle interaction and the rates of tectonic exposure of geoblocks to the upper crustal levels.Two cases of the OMS thermal history are described: (1) Kalguty Mo‐W deposit associated with rare‐metal granite‐leucogranites and ongonite‐ elvan dykes, and (2) Novo‐Akhmirov Li‐Ta deposit represented by topaz‐zinnwaldite granites and the contemporary lamprophyre and ongonit‐elvan dykes. For these geological objects, numerical modeling was carried out. The proposed models show thermal cooling of the deep magmatic chambers of granite composition, resulting in the residual foci of rare‐metal‐granite melts, which are known as the petrological indicators of industrial ore deposits (Mo‐W, Sn‐W, Li‐Ta‐Be). According to the simulation results concerning the framework of a closed magmatic system with a complex multistage development history, the magmatic chamber has a lower underlying observable massif and a reservoir associated with it. A long‐term magmatic differentiation of the parental melt (a source of rare‐metal‐granite melts and ore hydrothermal fluids) takes place in this reservoir.

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CASSERITE U-Pb GEOCHRONOLOGY OF THE SANTA BÁRBARA TIN DISTRICT, RONDÔNIA TIN PROVINCE, BRAZIL

Economic Geology ◽

10.5382/econgeo.4876 ◽

2021 ◽

Author(s):

Frederico Sousa Guimarães ◽

Rongqing Zhang ◽

Bernd Lehmann ◽

Alexandre Raphael Cabral ◽

Francisco Javier Rios

Keyword(s):

Inductively Coupled Plasma ◽

Rare Metal ◽

Santa Barbara ◽

Rare Metal Granite ◽

Inductively Coupled ◽

Granite Emplacement ◽

Amazonian Craton ◽

Plasma Mass Spectrometry ◽

Granite Magmatism ◽

Intrusive Suite

Abstract The Mesoproterozoic Rondônia Tin Province of the Amazonian craton records a protracted history of about 600 m.y. of successive rare-metal granite intrusions and hosts the youngest known event of tin-granite emplacement of the craton—a rare-metal granite suite known as the Younger Granites of Rondônia intrusive suite. The ~1 Ga suite is currently interpreted as intracratonic magmatism resulting from a Grenvillian-age orogeny during the assembly of Rodinia. The Santa Bárbara massif is a tin-granite system of the Younger Granites of Rondônia intrusive suite that hosts Sn-Nb-Ta-W–bearing endogreisen and stockwork, as well as important placer deposits. The Santa Bárbara mine produces about 800 to 1,000 t Sn/year from placers and weathered greisen and represents about 20% of the tin mine output of the Rondônia Tin Province. Here, we report laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) cassiterite U-Pb ages of 989 ± 3 and 987 ± 6 Ma for the Santa Bárbara greisen and the cassiterite-quartz vein system, respectively. Alluvial cassiterite from placer mining has a U-Pb age of 995 ± 4 Ma, which is, within uncertainty, indistinguishable from those of primary cassiterite. These ages agree well with the previously published zircon and monazite U-Pb ages for the Santa Bárbara granite (978 ± 13 and 989 ± 13 Ma), which indicate a coeval relationship between hydrothermal tin mineralization and granite magmatism. The previously suggested 20- to 30-m.y. time span between granite magmatism and hydrothermal tin mineralization, which was based on mica K-Ar and Ar-Ar age data, is likely due to younger thermal disturbance of the isotopic systems.

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Geochemistry and Sr- and Nd-isotopic study on rare-metal-bearing granitic rocks, central Eastern Desert, Egypt

Precambrian Research ◽

10.1016/0301-9268(95)00099-2 ◽

1996 ◽

Vol 80 (1-2) ◽

pp. 1-22 ◽

Cited By ~ 23

Author(s):

M Hassanen

Keyword(s):

Eastern Desert ◽

Rare Metal ◽

Granitic Rocks ◽

Isotopic Study ◽

Central Eastern Desert ◽

Central Eastern

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Mineralogical Evidence for Two Magmatic Stages in the Evolution of an Extremely Fractionated P-rich Rare-metal Granite: the Podlesi Stock, Krusne Hory, Czech Republic

Journal of Petrology ◽

10.1093/petroj/38.12.1723 ◽

1997 ◽

Vol 38 (12) ◽

pp. 1723-1739 ◽

Cited By ~ 27

Author(s):

K. Breiter ◽

J. Fryda ◽

R. Seltmann ◽

R. Thomas

Keyword(s):

Czech Republic ◽

Rare Metal ◽

Rare Metal Granite ◽

Mineralogical Evidence

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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

Mineralogical Magazine ◽

10.1180/002646100549391 ◽

2000 ◽

Vol 64 (3) ◽

pp. 507-523 ◽

Cited By ~ 38

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).

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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 ◽

10.1155/2017/1925817 ◽

2017 ◽

Vol 2017 ◽

pp. 1-25 ◽

Cited By ~ 15

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.

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