R6: Plutonic rocks, volcanic rocks and subduction factory

[R6P-05] Cathodoluminescence oscillatory zoning of anhedral K-feldspar from equigranular Toki granite

*Mai Nonaka¹, Takashi Yuguchi¹, Satoshi Suzuki¹, Takumi Iuura¹, Kazuo Nakashima¹, Tadao Nishiyama² (1. Yamagata Uni. Sci., 2. Kumamoto Uni.)

Keywords:cathodoluminescence, K-feldspar, oscillatory zoning, Toki granite

We focused on the anhedral K-feldspar of the equigranular Toki granite, we newly observed cathodoluminescence (CL) oscillatory zoning of the anhedral K-feldspar. The crystal cores displayed in the CL images reflect the nucleation parts of magmatic K-feldspar. The CL intensities are positively correlated with titanium and barium concentrations, indicating that the CL variations depend on two factors: 1) titanium concentration as a CL activator and 2) density of Al-O⁻-Al structural defects.