QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR
INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A
COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION

J 2012

QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION

DOSBABA, Marek a Milan NOVÁK

Základní údaje

Originální název

QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION

Autoři

DOSBABA, Marek (203 Česká republika, domácí) a Milan NOVÁK (203 Česká republika, garant, domácí)

Vydání

Canadian Mineralogist, 2012, 0008-4476

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Kanada

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 1.180

Kód RIV

RIV/00216224:14310/12:00064363

Organizační jednotka

Přírodovědecká fakulta

DOI

http://dx.doi.org/10.3749/canmin.50.6.1609

UT WoS

000314295200012

Klíčová slova anglicky

quartz kerolite replacement desilicification episyenitization contamination pegmatite serpentinite Věžná

Štítky

AKR, rivok

Změněno: 11. 4. 2013 15:09, Ing. Andrea Mikešková

Anotace

V originále

Quartz replacement by kerolite (variety of talc) was examined in coarse- to medium-grained graphic intergrowths of quartz + feldspars (oligoclase An13-15Or3/orthoclase Or95-99Ab5-1) from the desilicated granitic pegmatite hosted in serpentinized apoharzburgite, at the locality Věžná I, western Moravia, Czech Republic. Pale brownish to white kerolite (Mg2.77-2.79Al0.09-010 Fe0.04 Si 4.05-4.08O10(OH)2.1.98H2O) forms aggregates, up to 2 cm in size, varying from massive fine-grained (1-10 m) to radial (needles up to ~1 mm long). Diffraction patterns exhibit a very broad peak at ~ 10 A (001) and a sharp peak at ~ 1.52 A (060). Kerolite does not swell at ethylenglycol atmosphere; cation exchange capacity (CEC) was 31+2.3 meq/100 g. Kerolite is a product of interaction between quartz and Mg-rich fluids originating from the host rock by the simplified reaction: 4SiO2 + 3MgCl2 + 6H2O = Mg3Si4O10(OH)2.2H2O + 6HCl. The process of kerolitization was evidently associated with albitization of oligoclase producing minor to trace amounts of Ba-rich K-feldspar, pectolite, analcime, natrolite, celadonite, monazite-(Ce) and niobian titanite, and possibly with vermiculitization of phlogopite. The simplified reaction including oligoclase, SiO2 released during kerolitization, and assuming immobility of Al was calculated as: 20(Na0.85Ca0.10K 0.05)Al1.15Si2.85O8 + 14SiO2 + 4.5H2O + 6NaCl = 21NaAlSi3O8 + 1KAlSi3O8 + 1NaCa2Si3O8 (OH) + 1NaAlSi2O6.H2O + 6HCl. This process likely proceeded at T ~ 100-300 C and P lt; ~ 0.5-1 kbar, under high activity of alkalis and low tectonic stress. Pseudomorphs of kerolite locally with rare relics of quartz were later almost completely removed because of surface weathering, which produced empty cavities in the graphic unit. Similar processes such as kerolitization of quartz at Věžná occur not only in granitic pegmatites but may operate in episyenites, where a direct dissolution of quartz and consequential formation of open vugs typically occurs.

Citovat

DOSBABA, Marek a Milan NOVÁK. QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION. Canadian Mineralogist. 2012, roč. 50, č. 6, s. 1609-1622. ISSN 0008-4476. Dostupné z: https://dx.doi.org/10.3749/canmin.50.6.1609.

@article{1091369,
   author = {Dosbaba, Marek and Novák, Milan},
   article_number = {6},
   doi = {http://dx.doi.org/10.3749/canmin.50.6.1609},
   keywords = {quartz kerolite replacement desilicification episyenitization contamination pegmatite serpentinite Věžná},
   language = {eng},
   issn = {0008-4476},
   journal = {Canadian Mineralogist},
   title = {QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION},
   volume = {50},
   year = {2012}
}

TY  - JOUR
ID  - 1091369
AU  - Dosbaba, Marek - Novák, Milan
PY  - 2012
TI  - QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION
JF  - Canadian Mineralogist
VL  - 50
IS  - 6
SP  - 1609-1622
EP  - 1609-1622
SN  - 00084476
KW  - quartz kerolite replacement desilicification episyenitization contamination pegmatite serpentinite Věžná
N2  - Quartz replacement by kerolite (variety of talc) was examined in coarse- to medium-grained graphic intergrowths of quartz + feldspars (oligoclase An13-15Or3/orthoclase Or95-99Ab5-1) from the desilicated granitic pegmatite hosted in serpentinized apoharzburgite, at the locality Věžná I, western Moravia, Czech Republic. Pale brownish to white kerolite (Mg2.77-2.79Al0.09-010 Fe0.04 Si 4.05-4.08O10(OH)2.1.98H2O) forms aggregates, up to 2 cm in size, varying from massive fine-grained (1-10 m) to radial (needles up to ~1 mm long). Diffraction patterns exhibit a very broad peak at ~ 10 A (001) and a sharp peak at ~ 1.52 A (060). Kerolite does not swell at ethylenglycol atmosphere; cation exchange capacity (CEC) was 31+2.3 meq/100 g. Kerolite is a product of interaction between quartz and Mg-rich fluids originating from the host rock by the simplified reaction: 4SiO2 + 3MgCl2 + 6H2O = Mg3Si4O10(OH)2.2H2O + 6HCl. The process of kerolitization was evidently associated with albitization of oligoclase producing minor to trace amounts of Ba-rich K-feldspar, pectolite, analcime, natrolite, celadonite, monazite-(Ce) and niobian titanite, and possibly with vermiculitization of phlogopite. The simplified reaction including oligoclase, SiO2 released during kerolitization, and assuming immobility of Al was calculated as: 20(Na0.85Ca0.10K 0.05)Al1.15Si2.85O8 + 14SiO2 + 4.5H2O + 6NaCl = 21NaAlSi3O8 + 1KAlSi3O8 + 1NaCa2Si3O8 (OH) + 1NaAlSi2O6.H2O + 6HCl. This process likely proceeded at T ~ 100-300 C and P lt; ~ 0.5-1 kbar, under high activity of alkalis and low tectonic stress. Pseudomorphs of kerolite locally with rare relics of quartz were later almost completely removed because of surface weathering, which produced empty cavities in the graphic unit. Similar processes such as kerolitization of quartz at Věžná occur not only in granitic pegmatites but may operate in episyenites, where a direct dissolution of quartz and consequential formation of open vugs typically occurs.
ER  -

DOSBABA, Marek a Milan NOVÁK. QUARTZ REPLACEMENT BY KEROLITE IN GRAPHIC QUARTZ-FELDSPAR INTERGROWTHS FROM THE VĚŽNÁ I PEGMATITE, CZECH REPUBLIC: A COMPLEX DESILICIFICATION PROCESS RELATED TO EPISYENITIZATION. \textit{Canadian Mineralogist}. 2012, roč.~50, č.~6, s.~1609-1622. ISSN~0008-4476. Dostupné z: https://dx.doi.org/10.3749/canmin.50.6.1609.

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