New EPMA technique using X-ray emission spectra to improve accuracy of the CHIME dating

2014 Fiscal Year Final Research Report

• Project/Area Number: 24654174
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Petrology/Mineralogy/Science of ore deposit
• Research Institution: Nagoya University
• Principal Investigator: KATO Takenori 名古屋大学, 年代測定総合研究センター, 准教授 (90293688)
• Co-Investigator(Renkei-kenkyūsha): ENAMI Masaki 名古屋大学, 年代測定総合研究センター, 教授 (20168793) ; SATO Kei 名古屋大学, 年代測定総合研究センター, 研究機関研究員 (80422533) ; SUZUKI Kazuhiro 名古屋大学, 年代測定総合研究センター, 名誉教授 (90111624)
• Research Collaborator: CHO Deung-Lyong 韓國地質資源研究院, 国土地質研究本部, 先任研究員 ; JEEN Mi-Jung 釜山国立大学, 共同実験実習館, 助教
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: CHIME年代測定 / 電子プローブマイクロアナライザー（EPMA） / discrodance / エックス線分光分析 / 状態分析 / ジルコン / モナザイト / ウラン・トリウム・鉛

Outline of Final Research Achievements

New technique for detection of possibly discordant point on zircon and monazite was developed to improve accuracy of subgrain geochronology including CHIME dating, LA-ICP-MS and SIMS dating.
Electron probe microanalysis of Si and P can detect possible broken crystal structure of zircon and monazite. Broken crystal structure implies the possibility of Pb movement, which violates the assumption of U-Pb and U-Th-Pb dating. This new technique has been applied to zircon from India and Japan, and showed that non-destructive detection of broken crystal structure is available using electron probe microanalysis.

Free Research Field

地質年代学