Neoproterozoic amorphous

J 2017

Neoproterozoic amorphous "ekanite" (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance

NASDALA, Lutz; Fernando CORFU; Doris BLAIMAUER; Chutimun CHANMUANG; Katja RUSCHEL et al.

Základní údaje

Originální název

Neoproterozoic amorphous "ekanite" (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance

Autoři

NASDALA, Lutz; Fernando CORFU; Doris BLAIMAUER; Chutimun CHANMUANG; Katja RUSCHEL; Radek ŠKODA; Manfred WILDNER; Richard WIRTH; Manuela ZEUG a E. Gamini ZOYSA

Vydání

Geology, BOULDER, Geological Society of America, 2017, 0091-7613

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10504 Mineralogy

Stát vydavatele

Spojené státy

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 5.073

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/17:00100314

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova anglicky

PB ZIRCON AGES; RADIATION-DAMAGE; ALTERED ZIRCON; GEOCHRONOLOGY; DISSOLUTION; METAMORPHISM; MICROPROBE; ACCURACY; URANIUM; SYSTEMS

Štítky

NZ, rivok

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 9. 4. 2018 15:44, Ing. Nicole Zrilić

Anotace

V originále

A rare gemstone form of "ekanite" from Okkampitiya, eastern Sri Lanka, has a chemical composition of Ca2Th0.9U0.1Si8O20, corresponding to that of the tetragonal mineral ekanite. The Okkampitiya material, however, has undergone amorphization and is found in a fully metamict state, which is ascribed to the long-term accumulation of high levels of self-irradiation damage (1.38 x 10(20) alpha decay events per gram). The "ekanite" nevertheless does not show any post-growth chemical alteration, and the radiogenic Pb has been retained. The Okkampitiya "ekanite" yielded a Neoproterozoic Pb-207/Pb-206 age of 562.1 +/- 0.8 Ma (uncertainty quoted at the 95% confidence level) that is concordant within the uncertainties of decay constants. The remarkable Pb-retention performance of "ekanite" contradicts the common hypothesis that metamictization in minerals results in U-Pb discordance. The exceptional chemical durability of the heavily radiation-damaged geological material described here has also implications for materials-science research. High radiation resistance, a key criterion in the search for advanced nuclear waste forms, may not be a prerequisite for high aqueous durability of a solid.

Návaznosti

MUNI/A/1653/2016, interní kód MU

Název: Geologické, geodynamické a environmentální procesy při východním okraji Českého masívu (Akronym: Geodyn)

Investor: Masarykova univerzita, Geologické, geodynamické a environmentální procesy při východním okraji Českého masívu, DO R. 2020_Kategorie A - Specifický výzkum - Studentské výzkumné projekty

Citovat

NASDALA, Lutz; Fernando CORFU; Doris BLAIMAUER; Chutimun CHANMUANG; Katja RUSCHEL; Radek ŠKODA; Manfred WILDNER; Richard WIRTH; Manuela ZEUG a E. Gamini ZOYSA. Neoproterozoic amorphous "ekanite" (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance. Geology. BOULDER: Geological Society of America, 2017, roč. 45, č. 10, s. 919-922. ISSN 0091-7613. Dostupné z: https://doi.org/10.1130/G39334.1.

@article{1410920,
   author = {Nasdala, Lutz and Corfu, Fernando and Blaimauer, Doris and Chanmuang, Chutimun and Ruschel, Katja and Škoda, Radek and Wildner, Manfred and Wirth, Richard and Zeug, Manuela and Zoysa, E. Gamini},
   article_location = {BOULDER},
   article_number = {10},
   doi = {https://doi.org/10.1130/G39334.1},
   keywords = {PB ZIRCON AGES; RADIATION-DAMAGE; ALTERED ZIRCON; GEOCHRONOLOGY; DISSOLUTION; METAMORPHISM; MICROPROBE; ACCURACY; URANIUM; SYSTEMS},
   language = {eng},
   issn = {0091-7613},
   journal = {Geology},
   title = {Neoproterozoic amorphous "ekanite" (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance},
   volume = {45},
   year = {2017}
}

TY  - JOUR
ID  - 1410920
AU  - Nasdala, Lutz - Corfu, Fernando - Blaimauer, Doris - Chanmuang, Chutimun - Ruschel, Katja - Škoda, Radek - Wildner, Manfred - Wirth, Richard - Zeug, Manuela - Zoysa, E. Gamini
PY  - 2017
TI  - Neoproterozoic amorphous "ekanite" (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance
JF  - Geology
VL  - 45
IS  - 10
SP  - 919-922
EP  - 919-922
PB  - Geological Society of America
SN  - 00917613
KW  - PB ZIRCON AGES
KW  - RADIATION-DAMAGE
KW  - ALTERED ZIRCON
KW  - GEOCHRONOLOGY
KW  - DISSOLUTION
KW  - METAMORPHISM
KW  - MICROPROBE
KW  - ACCURACY
KW  - URANIUM
KW  - SYSTEMS
N2  - A rare gemstone form of "ekanite" from Okkampitiya, eastern Sri Lanka, has a chemical composition of Ca2Th0.9U0.1Si8O20, corresponding to that of the tetragonal mineral ekanite. The Okkampitiya material, however, has undergone amorphization and is found in a fully metamict state, which is ascribed to the long-term accumulation of high levels of self-irradiation damage (1.38 x 10(20) alpha decay events per gram). The "ekanite" nevertheless does not show any post-growth chemical alteration, and the radiogenic Pb has been retained. The Okkampitiya "ekanite" yielded a Neoproterozoic Pb-207/Pb-206 age of 562.1 +/- 0.8 Ma (uncertainty quoted at the 95% confidence level) that is concordant within the uncertainties of decay constants. The remarkable Pb-retention performance of "ekanite" contradicts the common hypothesis that metamictization in minerals results in U-Pb discordance. The exceptional chemical durability of the heavily radiation-damaged geological material described here has also implications for materials-science research. High radiation resistance, a key criterion in the search for advanced nuclear waste forms, may not be a prerequisite for high aqueous durability of a solid.
ER  -

NASDALA, Lutz; Fernando CORFU; Doris BLAIMAUER; Chutimun CHANMUANG; Katja RUSCHEL; Radek ŠKODA; Manfred WILDNER; Richard WIRTH; Manuela ZEUG a E. Gamini ZOYSA. Neoproterozoic amorphous ''ekanite'' (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance. \textit{Geology}. BOULDER: Geological Society of America, 2017, roč.~45, č.~10, s.~919-922. ISSN~0091-7613. Dostupné z: https://doi.org/10.1130/G39334.1.

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