Studie zirkonu z alkalického syenitu od Naloučan, moldanubikum

ŠKODA, Radek, Mariana KLEMENTOVÁ a Renata ČOPJAKOVÁ. Studie zirkonu z alkalického syenitu od Naloučan, moldanubikum. Acta Mus. Moraviae, Sci.geol. Brno: Moravské zemské muzeum, 2009, roč. 94, č. 1, s. 47-59. ISSN 1211-8796.

Základní údaje

• Originální název: Studie zirkonu z alkalického syenitu od Naloučan, moldanubikum
• Název česky: Studie zirkonu z alkalického syenitu od Naloučan, moldanubikum
• Název anglicky: Study of zircon from alkali syenite near Naloučany, Moldanubicum, Czech Republic
• Autoři: ŠKODA, Radek (203 Česká republika, garant), Mariana KLEMENTOVÁ (203 Česká republika) a Renata ČOPJAKOVÁ (203 Česká republika).
• Vydání: Acta Mus. Moraviae, Sci.geol. Brno, Moravské zemské muzeum, 2009, 1211-8796.

Další údaje

• Originální jazyk: čeština
• Typ výsledku: Článek v odborném periodiku
• Obor: 10500 1.5. Earth and related environmental sciences
• Stát vydavatele: Česká republika
• Utajení: není předmětem státního či obchodního tajemství
• Kód RIV: RIV/00216224:14310/09:00028621
• Organizační jednotka: Přírodovědecká fakulta
• Klíčová slova anglicky: zircon; typology; radiation damage; metamictization; fluid interaction
• Příznaky: Mezinárodní význam, Recenzováno

Anotace

The fine-grained part of alkali-feldspar syenite near Naloučany is extremely enriched in Zr, Th and U. In these parts the zircon content reach 5 percent. The zircon forms euhedral crystals 100 do 350 micrometers in size with uniform typology. Among crystal faces dominate prism (100) and pyramid (101). The prism (110) and pyramids (301), (211), and (121) are less evolved. According Pupins classification studied zircons fall into S24-S25 indicated crystallization temperature about 850 oC and confirmed high alkalinity. In the BSE four different parts of zircon were observed: i) central part with inclusions of thorite, ii) dark parts propagating along fractures, iii) homogeneous rim, and iv) bright zones between central part and rim. The dark parts contain higher concentrations of Ca, Fe, Al and Ti. Based on the U and Th content the radiation damage was calculated. The highest degree of radiation damage shows bright parts (0.38-0.66 dpa) and the lowest was recorded in the rim (0.07-0.31 dpa). The dark parts exhibit lower damage (0.11-0.38 dpa) than central parts (0.17-0.46 dpa). Metamict state was confirmed by HRTEM. The first percolation point was reached about 0.11 dpa. Low calculated radiation damage in the most altered dark parts suggest loss of U > Th during mineral-fluid interaction.

Anotace anglicky

The fine-grained part of alkali-feldspar syenite near Naloučany is extremely enriched in Zr, Th and U. In these parts the zircon content reach 5 percent. The zircon forms euhedral crystals 100 do 350 micrometers in size with uniform typology. Among crystal faces dominate prism (100) and pyramid (101). The prism (110) and pyramids (301), (211), and (121) are less evolved. According Pupins classification studied zircons fall into S24-S25 indicated crystallization temperature about 850 oC and confirmed high alkalinity. In the BSE four different parts of zircon were observed: i) central part with inclusions of thorite, ii) dark parts propagating along fractures, iii) homogeneous rim, and iv) bright zones between central part and rim. The dark parts contain higher concentrations of Ca, Fe, Al and Ti. Based on the U and Th content the radiation damage was calculated. The highest degree of radiation damage shows bright parts (0.38-0.66 dpa) and the lowest was recorded in the rim (0.07-0.31 dpa). The dark parts exhibit lower damage (0.11-0.38 dpa) than central parts (0.17-0.46 dpa). Metamict state was confirmed by HRTEM. The first percolation point was reached about 0.11 dpa. Low calculated radiation damage in the most altered dark parts suggest loss of U > Th during mineral-fluid interaction.

Návaznosti

• KJB301630801, projekt VaV: Název: Interakce metamiktních minerálů s hydrotermálnímy fluidy a její význam geologickém prostředí

Investor: Akademie věd ČR, Interakce metamiktních minerálů s hydrotermálnímy fluidy a její význam geologickém prostředí