ABSTRACT

Oxygen isotopic compositions are determined for eleven clinopyroxenes from the Kamioka (-2.4 ∼ -0.4‰, SMOW), Tsumo (+5.0 ∼ +7.0), Yaguki (-1.5 ∼ +2.5) and Fujigatani (+10.5 ∼ +10.8) skarn deposits in Japan. Oxygen isotope values of ore-forming fluids estimated from the obtained data on clinopyroxenes are generally in good agreement with those estimated from the published data on skarn calcites. Among the studied deposits, the skarns in the Kamioka and Yaguki mines were formed under the influence of fluids with considerably low oxygen isotopic ratios.