The involvement of F CO2-, and As in the alteration of Zr-Th-REE-bearing accessory minerals in a the Hora Svaté Kateřiny A-type granite, Czech Republic.
|Year of publication||2009|
|Type||Article in Periodical|
|Magazine / Source||Canadian Mineralogist|
|MU Faculty or unit|
|Field||Geology and mineralogy|
|Keywords||zircon; thorite; monazite; xenotime; haleniusite; granite; solid solution; Erzgebirge ( Czech Republic)|
|Description||The assemblage of Zr(Hf)-Th(U)-REE minerals from an A-type granite from Hora Svaté Kateřiny were studied to distinguish magmatic and hydrothermal processes affected the rock. The primary accessory phases included fluorite, magnetite, zircon, xenotime, monazite, and thorite. Solid solutions of (Th+U)-, (Zr+Hf)- and REE-components formed domains within zircon and thorite crystals and are supposed to by primary. Pyrite and arsenopyrite crystallised from the first portion of hydrothermal fluid with low oxygen fugacity. Later, fluid with higher oxygen fugacity altered magnetite, sulphides, and dissolved xenotime. During this time, Th and U-bearing zircon and thorite were partially metamictised. Arsenic was oxidised to As5+ and intensively metasomatised xenotime, Y-rich zircon and thorite forming chernovite. Even later, fluid rich in CO2 dissolved metamictised thorite and partially dissolved monazite after only short transport at the contact with fluorite crystallised Th-rich bastnäsite.|