Uranium–niobium-rich alteration products after “písekite”, an intimate mixture of Y, REE, Nb, Ta, Ti-oxide minerals from the Obrázek I pegmatite, Písek, Czech Republic

ŠKODA, Radek, Milan NOVÁK and Jaroslav CÍCHA. Uranium–niobium-rich alteration products after “písekite”, an intimate mixture of Y, REE, Nb, Ta, Ti-oxide minerals from the Obrázek I pegmatite, Písek, Czech Republic. Journal of Geosciences. Praha: Česká geologická společnost, 2011, vol. 56, No 3, p. 317-325. ISSN 1802-6222.

Basic information

• Original name: Uranium–niobium-rich alteration products after “písekite”, an intimate mixture of Y, REE, Nb, Ta, Ti-oxide minerals from the Obrázek I pegmatite, Písek, Czech Republic
• Authors: ŠKODA, Radek (203 Czech Republic, guarantor, belonging to the institution), Milan NOVÁK (203 Czech Republic, belonging to the institution) and Jaroslav CÍCHA (203 Czech Republic).
• Edition: Journal of Geosciences, Praha, Česká geologická společnost, 2011, 1802-6222.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10500 1.5. Earth and related environmental sciences
• Country of publisher: Czech Republic
• Confidentiality degree: is not subject to a state or trade secret
• Impact factor: Impact factor: 1.279
• RIV identification code: RIV/00216224:14310/11:00049545
• Organization unit: Faculty of Science
• UT WoS: 000298138300007
• Keywords in English: uranium; polycrase-(Y); samarskite-(Y); fergusonite-(Y); kahlerite; smectite
• Tags: AKR, rivok
• Tags: International impact, Reviewed

Abstract

An improperly described association, further called "pisekite" aggregate, of fine-grained, mostly metamict U, Th-enriched Y, REE, Nb, Ta, Ti-oxide minerals from Obrazek I pegmatite, Pisek, forms an intimate mixture of polycrase-(Y), samarskite-(Y) and fergusonite-(Y). It underwent a low-temperature hydrothermal alteration the products of which are depleted in Y and REE>U and significantly enriched in Si, As and P. Two distinct assemblages of secondary phases were recognized to be associated with "pisekite" aggregate, namely (i) that developed within the central parts of the aggregate and (ii) pocket assemblage in albite adjacent to it. Both assemblages are dominated by Fe-rich smectite. "Pisekite" aggregate is intensively replaced by U, Nb, Ti, Fe, As, P-rich phases of variable chemical composition: phase A (Nb>Ti>Fe>U>As) from the first assemblage, as well as phases B (U similar to Nb>Ti>As>P>Fe) and C (U>Nb>As>Fe>Ti) from the second assemblage. Associated pharmacosiderite and kahlerite/metakahlerite as well as Fe-rich smectite indicate a low temperature of the alteration processes (less than 150-200 degrees C). Whereas the "pisekite" aggregate was the likely source of U, Nb and Ti, arsenopyrite of the host pegmatite yielded As with Fe. The textural features show that the Fe-rich smectite replacement by the U, Nb-rich phases A, B and C took place on a micrometer scale, and these highly heterogeneous U, Nb-rich phases likely represent a mixture of nanoscale, possibly amorphous hydrated oxides, phosphates-arsenates as well as silicates of U, Fe and Ca.

Links

• KJB301630801, research and development project: Name: Interakce metamiktních minerálů s hydrotermálnímy fluidy a její význam geologickém prostředí

Investor: Academy of Sciences of the Czech Republic, The interaction of metamict minerals and hydrothermal fluids and its significance in the geological environment

• MSM0021622412, plan (intention): Name: Interakce mezi chemickými látkami, prostředím a biologickými systémy a jejich důsledky na globální, regionální a lokální úrovni (INCHEMBIOL) (Acronym: INCHEMBIOL)

Investor: Ministry of Education, Youth and Sports of the CR, Interactions among the chemicals, environment and biological systems and their consequences on the global, regional and local scales (INCHEMBIOL)