R7: Petrology, Mineralogy and Economic geology (Joint session with SRG)

[R7-07] Ammonium-bearing K-feldspar in the Ikutahara area, Kitami prefecture, Hokkaido, Japan

*Takuya Echigo¹, Ayaka Kawahara¹, Yasushi Watanabe¹ (1. Akita Univ. Internat. Resour. Sci.)

Keywords:ammonium ion, K-feldspar, Ikutahara, Epithermal gold deposit, Raman spectrum

Ammonium bearing K-feldspar was found in the Ikutahara area, Hokkaido during the surface exploration of epithermal gold deposits. Powder XRD, ATR-FTIR and micro-Raman analyzes revealed that potassium ion in K-feldspar is substituted by ammonium ion. The absorbance of N-H band detected by ATR-FTIR is positively correlated with the nitrogen concentration obtained by CHN analyzer and negatively correlated with the distance between the basement rock (Yubetsuso formation) and sampling location. These results suggest that ammonium ion was supplied from the basement rocks.