Applicability of oxygen isotope geothermometers to sulphate minerals from the Kuroko deposits has been discussed by utilizing oxygen isotope fractionation factors determined for the anhydrite-water and baryte-water systems, together with the existing isotopic data and models. The depositional T of the anhydrite- gypsum orebody at the Shakanai mine is estimated to be approx 200oC, assuming direct precipitation of anhydrite from sea-water. At these T approx 50% of calcium sulphate originally dissolved in the Miocene sea-water was precipitated to form the orebody. The total volume of sea-water required to produce a known amount of the anhydrite- gypsum orebody was calculated. Baryte in the black ore from the Shakanai mine may have been precipitated at T considerably lower than 250oC which is widely accepted as the depositional T of the black ores based on the sulphur isotopic data. However, this discrepancy remains to be studied in the future, because the number of oxygen isotopic data from the baryte and ore solutions is very limited.- H.S.
|Number of pages||8|
|Publication status||Published - Jan 1 1979|
ASJC Scopus subject areas
- Environmental Science(all)
- Earth and Planetary Sciences(all)