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 (276 Německo), Fernando CORFU (756 Švýcarsko), Doris BLAIMAUER (40 Rakousko), Chutimun CHANMUANG (40 Rakousko), Katja RUSCHEL (40 Rakousko), Radek ŠKODA (203 Česká republika, garant, domácí), Manfred WILDNER (40 Rakousko), Richard WIRTH (276 Německo), Manuela ZEUG (40 Rakousko) a E. Gamini ZOYSA (144 Šrí Lanka)

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

Kód RIV

RIV/00216224:14310/17:00100314

Organizační jednotka

Přírodovědecká fakulta

DOI

http://dx.doi.org/10.1130/G39334.1

UT WoS

000411705800019

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://dx.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 = {http://dx.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://dx.doi.org/10.1130/G39334.1.

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