Tourmaline, an indicator of external Mg-contamination of granitic pegmatites from host serpentinite; examples from the Moldanubian Zone, Czech Republic

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F17%3A00095537" target="_blank" >RIV/00216224:14310/17:00095537 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1007/s00710-017-0512-4" target="_blank" >http://dx.doi.org/10.1007/s00710-017-0512-4</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00710-017-0512-4" target="_blank" >10.1007/s00710-017-0512-4</a>

Result language

angličtina

Original language name

Tourmaline, an indicator of external Mg-contamination of granitic pegmatites from host serpentinite; examples from the Moldanubian Zone, Czech Republic

Original language description

Dominant primary solidus and minor subsolidus tourmalines from a variety of granitic pegmatites enclosed in serpentinites of the Moldanubian Zone, Czech Republic were examined, mainly by electron probe micro-analyser, to reveal the degree of external Mg(Ca)-contamination from their host rocks. The rocks include: (i) homogeneous to slightly heterogeneous nests of plagioclase-tourmaline rocks (group A) of anatectic or metasomatic origin, (ii) subhomogeneous to simply zoned barren pegmatite dikes (group B), and (iii) Li-bearing zoned pegmatite dikes of rare-element class (group C). The plagioclase-tourmaline rocks (group A) show spatial relation to pegmatites of the group B. Mostly black primary tourmalines (dravite, oxy-dravite, uvite, schorl, oxy-schorl, fluor-schorl) show extensive Mg- and Ca-contamination (group A), moderate Mg- and locally minor Ca-contamination (group B plus the locality Věžná I of the group C) and weak Mg-contamination of the tourmaline solely from outermost pegmatite units (group C); tourmalines from internal units of the pegmatites are typically Mg-free. Both Mg- and Ca-contamination events were very likely contemporaneous. The extent of contamination is higher in small and texturally simple plagioclase-tourmaline rocks (group A). Larger and more highly evolved Li-bearing pegmatites (group C) with zoned internal structure show a high degree of undercooling; consequently, rapid crystallization of outer zones with biotite and/or tourmaline depleted melt in almost all Mg and isolated the pegmatite body from further external contamination during solidus crystallisation. The granitic pegmatites (group B and group C) were open to the host serpentinite during early solidus crystallization immediately after emplacement of melt and then in early and/or late subsolidus crystallization (hydrothermal stage); in plagioclase-tourmaline rocks (group A) the system was likely continuously open to host serpentinite. This study affirms tourmaline as a very useful indicator of external contamination and elevated contents of Mg in tourmaline or in other minerals are the most reliable sign of external contamination in granitic rocks.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10504 - Mineralogy

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Publication year

2017

Confidentiality

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

Name of the periodical

Mineralogy and Petrology

ISSN

0930-0708

e-ISSN

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Volume of the periodical

111

Issue of the periodical within the volume

4

Country of publishing house

AT - AUSTRIA

Number of pages

17

Pages from-to

625-641

UT code for WoS article

000407743900013

EID of the result in the Scopus database

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