R1: Characterization and description of minerals (Joint Session with The Gemmological Society of Japan)

[R1P-01] Chemical compositions and a CHIME age of monazite from the Ishikawa district, Fukushima Prefecture, Japan

*Yasuyuki BANNO¹ (1. AIST)

Keywords:Monazite, Chemical composition, CHIME dating, Granite pegmatite, Ishikawa district

Monazite in a granite pegmatite from the Ishikawa district, Fukushima Prefecture, Japan was examined in terms of U, Th, Pb, and rare earth element (REE) chemistry by electron microprobe analysis. An averaged empirical formula was (Ce_0.383Nd_0.204La_0.136Y_0.062Sm_0.061Pr_0.050Gd_0.040Dy_0.014Er_0.002Th_0.046U_0.005Ca_0.011)_Σ1.014 (P_0.952Si_0.040)_Σ0.992O₄. The CHIME monazite age is 103 ± 26 Ma (2σ).