Stable isotope (B, H, O) and mineral-chemistry constraints on the magmatic to hydrothermal evolution of the Varuträsk rare-element pegmatite (Northern Sweden)

Siegel, Karin; Wagner, Thomas; Trumbull, Robert B.; Jönsson, Erik; Matalin, Gabriella; Wälle, Marküs; Heinrich, Christoph A.

doi:10.1016/j.chemgeo.2015.11.025

Cited by 59 publications

(19 citation statements)

References 79 publications

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“…Pegmatites could, as such, potentially hold a record of the transition from magmatic to hydrothermal conditions (e.g. Siegel et al, 2016) as they can be viewed on a petrological systemic level as intermediates between a magmatic, (leuco)granitic end-member and a hydrothermal quartz vein endmember (Černý et al, 2005;Hulsbosch et al, 2017;Jahns and Burnham, 1969;Varlamoff, 1972). The origin of granitic pegmatites and their distinctive petrological features, including but not limited to giant crystal sizes or typical crystal textures (e.g.…”

Section: Introductionmentioning

confidence: 99%

Tracing fluid saturation during pegmatite differentiation by studying the fluid inclusion evolution and multiphase cassiterite mineralisation of the Gatumba pegmatite dyke system (NW Rwanda)

Hulsbosch

Muchez

2020

Lithos

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 Multiphase SnO2 mineralisation reflects increasingly magmatic-hydrothermal conditions  Saline, NaCl-KCl-rich fluid present during saturation of SnO2 in wall zone  Saline, NaCl-LiCl-rich fluid present during saturation of SnO2 in quartz-phosphate core  Saline, NaCl-rich fluid formed greisens causing saturation of SnO2 by fluid-rock reactions  Disequilibrium mineral growth caused local water-saturated melt conditions

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Section: Introductionmentioning

confidence: 99%

Tracing fluid saturation during pegmatite differentiation by studying the fluid inclusion evolution and multiphase cassiterite mineralisation of the Gatumba pegmatite dyke system (NW Rwanda)

Hulsbosch

Muchez

2020

Lithos

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“…Nevertheless, the consensus is that the main Ta mineralization stage appears late in the pegmatite-forming process. Most researchers agree that fluid exsolution occurs during pegmatite formation, which is documented by miarolitic cavities, fluid inclusions, as well as stable isotope (H, B, O) fractionation (Thomas et al, 2012;Thomas and Davidson, 2013;London, 2014;Siegel et al, 2016;Thomas and Davidson, 2016). However, the timing of fluid release is still debated.…”

Section: Introductionmentioning

confidence: 99%

“…However, the timing of fluid release is still debated. Furthermore, the significance of melt-melt immiscibility and fluid exsolution for rare-element mineralization in pegmatites remains contentious (Thomas et al, 2012;Siegel et al, 2016) Characterizing the chemical variation in zoned minerals using modern in-situ microanalytical methods can yield important constraints on changes in crystallization conditions in magmatic, metasomatic and hydrothermal systems (Ginibre et al, 2007). Micas are ideal for this type of approach.…”

Section: Introductionmentioning

confidence: 99%

The magmatic–hydrothermal transition in rare-element pegmatites from southeast Ireland: LA-ICP-MS chemical mapping of muscovite and columbite–tantalite

Kaeter

Barros

Menuge

et al. 2018

Geochimica et Cosmochimica Acta

102

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The processes involved in the magmatic-hydrothermal transition in rare-element pegmatite crystallization are obscure, and the role of hydrothermal mechanisms in producing economic concentrations of rare elements such as tantalum remains contentious. To decipher the paragenetic information encoded in zoned minerals crystallized during the magmatichydrothermal transition, we applied SEM-EDS and LA-ICP-MS chemical mapping to muscovite-and columbite-group minerals (CGM) from a rare-element pegmatite of the albite-spodumene subtype from Aclare, southeast Ireland. We present a three-stage model for the magmatic-hydrothermal transition based on petrography, imaging and quantification of rare-element (Li, B, Rb, Nb, Sn, Cs, Ba, Ta, W, U) zoning, integrated with geochemical modeling and constraints from published literature. Stage I marks the end of purely magmatic crystallization from a peraluminous granitic melt.

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“…In this hydrothermal-magmatic transition a deuteric silicate liquid was described as a transitional phase between a magma and an aqueous fluid [88]. The hydrogen isotopic composition of micas from the Varuträsk rare-element pegmatite was also used as an argument to the occurrence of mica-rich metasomatic replacements by an aqueous fluid exsolved from the magma [89].…”

Section: Mechanisms Of Concentration Of Nb and Tamentioning

confidence: 99%

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

et al. 2019

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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.

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Stable isotope (B, H, O) and mineral-chemistry constraints on the magmatic to hydrothermal evolution of the Varuträsk rare-element pegmatite (Northern Sweden)

Cited by 59 publications

References 79 publications

Tracing fluid saturation during pegmatite differentiation by studying the fluid inclusion evolution and multiphase cassiterite mineralisation of the Gatumba pegmatite dyke system (NW Rwanda)

Tracing fluid saturation during pegmatite differentiation by studying the fluid inclusion evolution and multiphase cassiterite mineralisation of the Gatumba pegmatite dyke system (NW Rwanda)

The magmatic–hydrothermal transition in rare-element pegmatites from southeast Ireland: LA-ICP-MS chemical mapping of muscovite and columbite–tantalite

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

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