SKŘÁPKOVÁ, Lenka, Jan CEMPÍREK and Michaela VAŠINOVÁ GALIOVÁ. Fractionation in Li-tourmaline from the Lhenice lepidolite pegmatite - "darrellhenryite loop" in F-saturation. In Tourmaline 2017. 2017.
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Basic information
Original name Fractionation in Li-tourmaline from the Lhenice lepidolite pegmatite - "darrellhenryite loop" in F-saturation
Authors SKŘÁPKOVÁ, Lenka (203 Czech Republic, guarantor, belonging to the institution), Jan CEMPÍREK (203 Czech Republic, belonging to the institution) and Michaela VAŠINOVÁ GALIOVÁ (203 Czech Republic, belonging to the institution).
Edition Tourmaline 2017, 2017.
Other information
Original language English
Type of outcome Presentations at conferences
Field of Study 10500 1.5. Earth and related environmental sciences
Country of publisher Czech Republic
Confidentiality degree is not subject to a state or trade secret
RIV identification code RIV/00216224:14310/17:00097271
Organization unit Faculty of Science
Keywords in English pegmatite; tourmaline; lepidolite; elbaite; darrellhenryite; fluorine
Tags International impact
Changed by Changed by: doc. Mgr. Jan Cempírek, Ph.D., učo 15719. Changed: 7/3/2018 09:38.
Abstract
The lepidolite-subtype pegmatite at Lhenice, South Bohemia, Czech Republic, is a moderate-sized, highly fractionated pegmatite with abundant lepidolite, elbaite, amblygonite, and cassiterite. As the first mineralogical study at the locality, we acquired EMPA and LA-ICP-MS data of pink and colorless tourmaline from the most fractionated pegmatite units. When looking in detail at the tourmaline assemblages, we can conclude that the primary tourmaline (Tur 1) crystallized from Na-rich melt that produced abundant albite. The tourmaline crystallization overlaps with emergence of the first mica n the albite zone; we suggest that the sudden drop in the tourmaline F content was caused by start of mica crystallization. The F-depleted tourmaline (darrellhenryite) in the lepidolite core is also either coeval or slightly older than the associated lepidolite. The evolution path of the early tourmaline therefore follows a “loop” of Na,F decrease and increase, turning at darrellhenryite composition. Late development of the primary tourmaline is characterized by an increase in Na, OH, F and Fe contents. The new tourmaline generation (Tur 2) is associated by late K-feldspar and muscovite, suggesting hydrothermal crystallization. Textures of latest Fe-enriched (but not Mg- or Ca-bearing) fluor-elbaite (Tur 3) indicate hydrothermal origin; we suggest that its high Fe content might reflect composition of primary hydrothermal fluid in a closed system.
Links
MUNI/A/1653/2016, interní kód MUName: Geologické, geodynamické a environmentální procesy při východním okraji Českého masívu (Acronym: Geodyn)
Investor: Masaryk University, Category A
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