dc.date.accessioned | 2018-07-05T14:09:07Z | |
dc.date.available | 2018-07-05T14:09:07Z | |
dc.date.created | 2018-01-03T10:59:52Z | |
dc.date.issued | 2017 | |
dc.identifier.citation | Nasdala, Lutz Corfu, Fernando Blaimauer, Doris Chanmuang, Chutimun Ruschel, Katja Skoda, Radek Wildner, Manfred Wirth, Richard Zeug, Manuela Zoysa, E Gamini . Neoproterozoic amorphous "ekanite" (Ca<sub>2</sub>Th<sub>0.9</sub>U<sub>0.1</sub>Si<sub>8</sub>O<sub>20</sub>) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent leadretention performance. Geology. 2017, 45(10), 919-922 | |
dc.identifier.uri | http://hdl.handle.net/10852/62026 | |
dc.description.abstract | 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 × 1020 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 207Pb/206Pb 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. | en_US |
dc.language | EN | |
dc.publisher | Geological Society of America | |
dc.rights | Attribution 4.0 International | |
dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | |
dc.title | Neoproterozoic amorphous “ekanite” (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance | en_US |
dc.type | Journal article | en_US |
dc.creator.author | Nasdala, Lutz | |
dc.creator.author | Corfu, Fernando | |
dc.creator.author | Blaimauer, Doris | |
dc.creator.author | Chanmuang, Chutimun | |
dc.creator.author | Ruschel, Katja | |
dc.creator.author | Skoda, Radek | |
dc.creator.author | Wildner, Manfred | |
dc.creator.author | Wirth, Richard | |
dc.creator.author | Zeug, Manuela | |
dc.creator.author | Zoysa, E Gamini | |
cristin.unitcode | 185,15,22,0 | |
cristin.unitname | Institutt for geofag | |
cristin.ispublished | true | |
cristin.fulltext | original | |
cristin.qualitycode | 2 | |
dc.identifier.cristin | 1534512 | |
dc.identifier.bibliographiccitation | info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Geology&rft.volume=45&rft.spage=919&rft.date=2017 | |
dc.identifier.jtitle | Geology | |
dc.identifier.volume | 45 | |
dc.identifier.issue | 10 | |
dc.identifier.startpage | 919 | |
dc.identifier.endpage | 922 | |
dc.identifier.doi | http://dx.doi.org/10.1130/G39334.1 | |
dc.identifier.urn | URN:NBN:no-64628 | |
dc.type.document | Tidsskriftartikkel | en_US |
dc.type.peerreviewed | Peer reviewed | |
dc.source.issn | 0091-7613 | |
dc.identifier.fulltext | Fulltext https://www.duo.uio.no/bitstream/handle/10852/62026/2/Nasdala_Geology_2017_ekanite.pdf | |
dc.type.version | PublishedVersion | |