Russian Mineralogical Society
2nd International Conference "Crystallogenesis and Mineralogy"
Metasomatic alteration of zircons from potassic granites of the Kola peninsula

RMS-DPI code:  2007-1-127-0
Scientific session:  Session 5. Crystal chemistry and crystal morphology of minerals
Author listing:  Kaulina T.V., Sinay M.Yu., Savchenko E.E.
Principal author:  Kaulina Tatiana Vladimirovna
Language:  Russian
Abstract - Summary 
(short description):
Zircon is a well known and a widely used geochronometer, since it is capable in retaining radiogenic Pb during high T metamorphic events. But zircon often has a complex behavior and can transform under hydrothermal conditions, especially when interacting with CO2-rich fluid. Susceptibility of zircon to alteration can be enhanced by metamictization or mechanical fracturing during deformation. Zircons with high U and Th concentrations are more likely to be metamict and susceptible to leaching. Studied zircon from peralkaline granites of the Tanaelv belt and alkaline granites of the Keivy block (the Kola Peninsula) revealed complicated internal structure which can be well explained by a process of metasomatic substitution of crystals - synchronous process of dissolving and growth. Under the influence of fluid some parts of zircons were dissolved and completely substituted with a newly formed zircon phase. Such characteristic internal structure is similar to experimentally obtained monocrystal pseudomorphosis. Zircons from potassic granites are rich in U and Th, so their structure is damaged from decay of incorporated elements. Zircons with low U-contents from other rocks in the studied area remained nearly unaffected by the fluid.
 
RMS-DPI code:  2007-1-127-0
Proceeedings volume 
in the RMS catalogue:
 
Crystallogenesis and Mineralogy
Pages:  278-281
File of proceedings 
(PDF): 
 405 K
Status:  printed
Accepted:  25/04/2007
Published on-line:  05/01/2008
Permanent address of publication:  http://www.minsoc.ru/2007-1-127-0/
Contact author(s):  Kaulina, Tatiana Vladimirovna

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