Assessment of magmatic vs. metasomatic processes in rare-metal granites: A case study of the Cínovec/Zinnwald Sn–W–Li deposit, Central Europe

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F17%3A00479233" target="_blank" >RIV/67985831:_____/17:00479233 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/17:00095003 RIV/00025798:_____/17:00000201

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.lithos.2017.08.015" target="_blank" >http://dx.doi.org/10.1016/j.lithos.2017.08.015</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.lithos.2017.08.015" target="_blank" >10.1016/j.lithos.2017.08.015</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Assessment of magmatic vs. metasomatic processes in rare-metal granites: A case study of the Cínovec/Zinnwald Sn–W–Li deposit, Central Europe

Popis výsledku v původním jazyce

The Cínovec rare-metal granite in the eastern segment of the Krušné Hory/Erzgebirge formed in the final stage of the magmatic evolution of the late Variscan volcano-plutonic system known as the Teplice caldera. The granite is slightly peraluminous, enriched in F, Li, Rb, Cs, Nb, Ta, Sn, W, Sc and U, and poor in P, Mg, Ti, Sr and Ba. The uppermost part of the granite cupola hosts a greisen-type Sn–W–Li deposit. Borehole CS-1 permits to study vertical evolution of the pluton to a depth of 1597 m. A combination of textural and chemical methods was applied to whole-rock and mineral samples to identify the extent of magmatic and metasomatic processes during the differentiation of the pluton and formation of the deposit. The following genetic scenario is proposed: the intrusion of the zinnwaldite granite magma reached subvolcanic conditions and a hem of fine-grained porphyritic granite crystallized along the upper contact. Separation of the first portion of fluid from the oversaturated melt promoted explosive degassing and the origin of breccia pipes. Subsequently, the zinnwaldite granite magma crystallized simultaneously from the upper contact and the footwall inwards. The residual melt between the two crystallizing fronts became enriched in water and volatiles to reach second saturation. Segregated fluids escaped upwards, causing hydrofracturing of the overlying granite, while the water-poor residuum crystallized in situ in the form of mica-free granite. F- and Li-rich fluids invoked greisenization and created quartz–zinnwaldite veins. Alkalis liberated from feldspars destroyed during the greisenization induced local albitization in the uppermost part of the cupola and K-feldspathisation in its deeper part. The distribution of Sn and W was controlled by fluid processes, while Nb and Ta mainly crystallized from the melt. The results from Cínovec are universally applicable to shallow-intruded rare-metal granites regardless of A- or S-types of the primary magma.

Název v anglickém jazyce

Assessment of magmatic vs. metasomatic processes in rare-metal granites: A case study of the Cínovec/Zinnwald Sn–W–Li deposit, Central Europe

Popis výsledku anglicky

The Cínovec rare-metal granite in the eastern segment of the Krušné Hory/Erzgebirge formed in the final stage of the magmatic evolution of the late Variscan volcano-plutonic system known as the Teplice caldera. The granite is slightly peraluminous, enriched in F, Li, Rb, Cs, Nb, Ta, Sn, W, Sc and U, and poor in P, Mg, Ti, Sr and Ba. The uppermost part of the granite cupola hosts a greisen-type Sn–W–Li deposit. Borehole CS-1 permits to study vertical evolution of the pluton to a depth of 1597 m. A combination of textural and chemical methods was applied to whole-rock and mineral samples to identify the extent of magmatic and metasomatic processes during the differentiation of the pluton and formation of the deposit. The following genetic scenario is proposed: the intrusion of the zinnwaldite granite magma reached subvolcanic conditions and a hem of fine-grained porphyritic granite crystallized along the upper contact. Separation of the first portion of fluid from the oversaturated melt promoted explosive degassing and the origin of breccia pipes. Subsequently, the zinnwaldite granite magma crystallized simultaneously from the upper contact and the footwall inwards. The residual melt between the two crystallizing fronts became enriched in water and volatiles to reach second saturation. Segregated fluids escaped upwards, causing hydrofracturing of the overlying granite, while the water-poor residuum crystallized in situ in the form of mica-free granite. F- and Li-rich fluids invoked greisenization and created quartz–zinnwaldite veins. Alkalis liberated from feldspars destroyed during the greisenization induced local albitization in the uppermost part of the cupola and K-feldspathisation in its deeper part. The distribution of Sn and W was controlled by fluid processes, while Nb and Ta mainly crystallized from the melt. The results from Cínovec are universally applicable to shallow-intruded rare-metal granites regardless of A- or S-types of the primary magma.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Lithos

ISSN

0024-4937

e-ISSN

—

Svazek periodika

292/293

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

20

Strana od-do

198-217

Kód UT WoS článku

000416185500013

EID výsledku v databázi Scopus

2-s2.0-85033669789