Te-Xe法による鉱化年代測定－熱水性金鉱床を例として－

抄録

Based on the newly determined double-beta-decay half life of ¹³⁰Te ((7.0 ± 0.9_stat ± 1.1_syst) ×10²⁰ yr: Arnold et al., 2011), we have measured the direct mineralization ages on tellurium-bearing minerals from some hydrothermal gold deposits by the ¹³⁰Te-¹³⁰Xe* method. The results are as follows: Calaverite (21.9±2.3 Ma) from the epithermal Au-Te vein, Cripple Creek mining district, USA; Hessite-petzite (34.9±5.4 Ma) from the epithermal Au-Te vein, Cash mine, Boulder County, Colorado, USA; Altaite (1,040±80 Ma) from the Au-Te quartz-carbonate vein of the Mattagami Lake mine, Matagami, Quebec, Canada; Tellurobismuthite-tetradymite (9.4±1.2 Ma) from Bi-Te quartz vein, Tsushima Island, Nagasaki Prefecture, Japan; Tellurobismuthite (81.4±2.6 Ma) from hydrothermal Au-Te vein, Oya mine, Miyagi Prefecture, Japan;　Tellurobismuthite (85±18 Ma ) from the Au-Te quartz vein, Suwa mine, Ibaraki Prefecture, Japan. These ages are obviously younger than previously reported mineralization ages by K-Ar, Ar-Ar or Pb-Pb methods.