J 2015

Boralsilite and Li,Be-bearing “boron mullite” Al8B2Si2O19, breakdown products of spodumene from the Manjaka pegmatite, Sahatany Valley, Madagascar.

NOVÁK, Milan, Jan CEMPÍREK, Petr GADAS, Radek ŠKODA, Michaela VAŠINOVÁ GALIOVÁ et. al.

Basic information

Original name

Boralsilite and Li,Be-bearing “boron mullite” Al8B2Si2O19, breakdown products of spodumene from the Manjaka pegmatite, Sahatany Valley, Madagascar.

Authors

NOVÁK, Milan (203 Czech Republic, guarantor, belonging to the institution), Jan CEMPÍREK (203 Czech Republic, belonging to the institution), Petr GADAS (203 Czech Republic, belonging to the institution), Radek ŠKODA (203 Czech Republic, belonging to the institution), Michaela VAŠINOVÁ GALIOVÁ (203 Czech Republic, belonging to the institution), F. PEZZOTTA (380 Italy) and L.A. GROAT (124 Canada)

Edition

Canadian Mineralogist, Ottawa, MAC, 2015, 0008-4476

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10500 1.5. Earth and related environmental sciences

Country of publisher

Canada

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 0.862

RIV identification code

RIV/00216224:14310/15:00081647

Organization unit

Faculty of Science

DOI

UT WoS

000362880900013

Keywords in English

boralsilite;boron mullite;spodumene;replacement;granitic pegmatite;Manjaka;Madagascar

Tags

Tags

International impact, Reviewed
Změněno: 29/3/2016 14:14, Mgr. Michaela Vašinová Galiová, Ph.D.

Abstract

V originále

Boralsilite Al16B6Si2O37 and Li, Be-bearing "boron mullite" Al8B2Si2O19 were discovered as breakdown products of spodumene from the elbaite-subtype Manjaka granitic pegmatite, Sahatany Valley, Madagascar. Boralsilite assemblages are closely associated with prismatic spodumene crystals, up to 10 cm long, mostly as narrow albite ; K-feldspar zones (albite; K-feldspar; boralsilite; "boron mullite"), up to similar to 0.5 mm thick, or rarely as inclusions in the central parts of spodumene crystals. Long prismatic crystals and fibers of boralsilite, and rare elongated grains of "boron mullite" Al8B2Si2O19, are mostly enclosed in albite and rarely in K-feldspar. The EMP and LA-ICP-MS data yielded relatively variable Al/Si ratios (similar to 5.4-9.8; similar to 3.2-4.6) and concentrations of B (similar to 48500-59500; similar to 24000-28000 ppm), Li (688-1433; 3339-4287 ppm), and Be (288-1082; 1017-2728 ppm), in boralsilite and "boron mullite", respectively. Fluid/melt with very high a(B2O3), a(Na), and low a(H2O), along with high a(CO2) indicated by the absence of significant amount of hydrous phases, very minor extent of exocontact reactions along the pegmatite, and secondary rhodochrosite, are responsible for the origin of boralsilite. Very late solidus or early subsolidus conditions at temperature similar to 350-450 degrees C and pressure similar to 2-3 kbar, estimated for the crystallization of the assemblage albite + boralsilite, are significantly lower than those given for fibrous boralsilite at other localities of mostly anatectic granitic pegmatites (Larsemann Hills, Antarctica; Almgjotheii, Norway; and Horni Bory, Czech Republic).

Links

ED1.1.00/02.0068, research and development project
Name: CEITEC - central european institute of technology
GA14-13347S, research and development project
Name: Variabilita lehkých prvků (Li, Be, B) ve vybraných horninotvorných a akcesorických minerálech z felsických magmatických a metamorfovaných hornin
Investor: Czech Science Foundation