Controls on chemical evolution and rare element enrichment in crystallising albite-spodumene pegmatite and wallrocks: Constraints from mineral chemistry

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F20%3A00114506" target="_blank" >RIV/00216224:14310/20:00114506 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.lithos.2019.105289" target="_blank" >https://doi.org/10.1016/j.lithos.2019.105289</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.lithos.2019.105289" target="_blank" >10.1016/j.lithos.2019.105289</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Controls on chemical evolution and rare element enrichment in crystallising albite-spodumene pegmatite and wallrocks: Constraints from mineral chemistry

Popis výsledku v původním jazyce

Internal differentiation and consequent geochemical evolution in pegmatites are significant processes in the development of economically viable deposits of metal-bearing minerals. Albite-spodumene pegmatites, which represent important resources of Li and Ta worldwide, challenge the general rules of pegmatite petrogenesis as these are nearly homogeneous bodies with little or no intrusion-scale pegmatite zonation. Bulk intrusion concentrations of Li are in the uppermost range obtained by magmatic enrichment experiments, around 2 wt% Li2O, and extensive volumes of saccharoidal or platy albite are present. In Leinster, southeast Ireland, weakly zoned to homogeneous albitised spodumene pegmatites and their wallrocks were studied to compare mineral chemistry variations and understand the internal evolution of pegmatites, characteristics linked to the poor development of zonation, and links between internal evolution and pegmatite-wallrock interactions. Leinster pegmatites present mineralogical, textural and geochemical characteristics coherent with Li-saturation, and possibly supersaturation, prior to crystallisation. Weak border to centre zonation in the thickest bodies can be attributed to geochemically evolved initial melt, likely leading to nearly contemporaneous crystallisation throughout the intrusion and resulting in limited internal geochemical fractionation. Increased abundance of minerals bearing highly incompatible elements (e.g. columbite-group minerals and cassiterite) and network modifiers (e.g. phosphates) in albitite indicates it is a fractionation product from pegmatite crystallisation. Enrichment in incompatible elements B, Li, Rb, Cs and F in spodumene pegmatite exocontacts in different country rock types suggests unmixing of a hydrous fluid from the residual melt after the crystallisation of main pegmatitic assemblages, and that the H2O-rich component was mobilised into country rocks. (C) 2019 Elsevier B.V. All rights reserved.

Název v anglickém jazyce

Controls on chemical evolution and rare element enrichment in crystallising albite-spodumene pegmatite and wallrocks: Constraints from mineral chemistry

Popis výsledku anglicky

Internal differentiation and consequent geochemical evolution in pegmatites are significant processes in the development of economically viable deposits of metal-bearing minerals. Albite-spodumene pegmatites, which represent important resources of Li and Ta worldwide, challenge the general rules of pegmatite petrogenesis as these are nearly homogeneous bodies with little or no intrusion-scale pegmatite zonation. Bulk intrusion concentrations of Li are in the uppermost range obtained by magmatic enrichment experiments, around 2 wt% Li2O, and extensive volumes of saccharoidal or platy albite are present. In Leinster, southeast Ireland, weakly zoned to homogeneous albitised spodumene pegmatites and their wallrocks were studied to compare mineral chemistry variations and understand the internal evolution of pegmatites, characteristics linked to the poor development of zonation, and links between internal evolution and pegmatite-wallrock interactions. Leinster pegmatites present mineralogical, textural and geochemical characteristics coherent with Li-saturation, and possibly supersaturation, prior to crystallisation. Weak border to centre zonation in the thickest bodies can be attributed to geochemically evolved initial melt, likely leading to nearly contemporaneous crystallisation throughout the intrusion and resulting in limited internal geochemical fractionation. Increased abundance of minerals bearing highly incompatible elements (e.g. columbite-group minerals and cassiterite) and network modifiers (e.g. phosphates) in albitite indicates it is a fractionation product from pegmatite crystallisation. Enrichment in incompatible elements B, Li, Rb, Cs and F in spodumene pegmatite exocontacts in different country rock types suggests unmixing of a hydrous fluid from the residual melt after the crystallisation of main pegmatitic assemblages, and that the H2O-rich component was mobilised into country rocks. (C) 2019 Elsevier B.V. All rights reserved.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10504 - Mineralogy

Projekt

<a href="/cs/project/GA19-05198S" target="_blank" >GA19-05198S: Greisenizace a albitizace - geologické procesy s potenciálem koncentrovat některé kritické suroviny pro moderní technologie</a><br>

Návaznosti

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

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Lithos

ISSN

0024-4937

e-ISSN

1872-6143

Svazek periodika

352

Číslo periodika v rámci svazku

JAN 2020

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

19

Strana od-do

1-19

Kód UT WoS článku

000515201500023

EID výsledku v databázi Scopus

2-s2.0-85075884610