The Progress of the CHIME monazite dating on JXA-8530F FE-EPMA equipped with R = 100 mm spectrometers

Shimizu, Mayuko   ; Shibata, Kenji; Suzuki, Kazuhiro; Sueoka, Shigeru   ; Niwa, Masakazu   

The CHIME dating has been performed on JEOL JXA-8530F FE-EPMA introduced in Tono Geoscience Center of JAEA. The R = 100 mm spectrometer is desirable for quantitative determination of trace Pb, giving an intrinsic response 3 to 5 times higher than that of the conventional R = 140 mm spectrometer. JXA-8530F equipped with three R = 100 and two R = 140 mm spectrometers significantly shortens an analyzing time. The age values by this advanced procedure of monazites from the Cooma granodiorite and the Kojaku granite correspond to the values of the previous researches within the error range. In our presentation we also show the CHIME age of the Steenkampskraal monazite, which was dated by SHRIMP as 1033 Ma. In addition, a quick heavy mineral identification method, which has been established as well, is introduced.