1978 Volume 28 Issue 151 Pages 349-360
Filling temperatures and salinities of fluid inclusions in quartz from the bedded and stockwork siliceous orebodies of Uwamuki No.4 Orebody and No.7 Stockwork Orebody of Uchinotai Western Deposit of the Kosaka mine were studied. Filling temperatures in quartz were in a range of 260°-310°C for the bedded orebodies, and 280°-320°C for the stockwork orebodies. The temperature range of sphalerite was 200°-240°C for the bedded siliceous orebodies and 235°-280°C for the stockwork orebodies, and apparently lower than those of associated quartz. Thermal gradients in the stockwork orebodies were fairly gentle and most of temperatures concentrated around 300°C, but the data obtained from drilling cores indicate a tendency of increase in temperature at deeper levels. Salinities range from 2.5 wt. % to 5.5 wt. % and slightly increase at lower levels. From the data on fluid inclusions, it is inferred that the depth of sea floor was deeper than 1, 000 m at the Kuroko mineralization.
