Sulfur isotope ratios of sulfide minerals were measured from fourteen Au-Ag mines in the Republic of Korea. Although δ³⁴S (CDT) values show a comparatively wide range from -0.2‰ to +9.8 ‰, 90% of the values fall in a range from +1 to 7‰. For the individual deposits the values show a small variation range usually less than three per mil. The small variation range and observed ³⁴S fractionation among sulfide minerals, indicate the precipitation of sulfides mainly from H₂S under equilibrium or nearly equilibrium conditions.
Together with the data available in previous literatures, a systematic spatial variation of δ³⁴S values for the deposits could be recognized among the deposits with different geologic environments, formation ages and workable metals. The deposits located in or near the Mugug area in the Gyeonggi massif, have ore sulfur with relatively high δ34S values, whereas the deposits in the Ryeongnam massif tend to have ore sulfur with relatively low δ³⁴S values, although some exceptional cases have been reported. It is likely that ore sulfur in the deposits was originated mainly from the host rocks prevailed in each region, and consequently that the geochemical nature of the Gyeonggi and Ryeongnam massifs is somewhat different to each other.

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The Shinyemi magnesian Fe skam-type deposit develops in carbonate rocks of the Ordovician Makkol Limestone Formation in contact with Cretaceous porphyritic rocks intruded along the NNW trending faults which could have been magmatic fluid and meteoric water inflow paths. The exoskarn is mineralogically divided into three types, magnesian, intermediate and calcic skarns, which were formed simultaneously by replacement of dolostone, dolomitic limestone and limestone, respectively.
Microthermometric analysis of primary 2-phase (liquid+vapor) NaCI-H₂O fluid inclusions in the skarn and ore minerals including forsterite, clinopyroxene, garnet, dolomite, calcite and sphalerite indicates that the fluid responsible for the Shinyemi magnesian Fe skam-type deposit is a medium-salinity (≤23 equiv.wt% NaC1) and hot fluid with little CO₂. The formation temperatures, calculated from homogenization temperatures (360°-590°C) by pressure (500 bars) correction of prograde skarns were between 510°to 620°C (at the early first stage) and 400°C to 540°C (at the late first stage). The temperature range agrees well with that (400°- 610°C) by isotopic geothermometry. The early (440°- 540°C) and late (340°- 400°C) magnetite mineralizations in magnesian skam are considered to have occurred simultaneously with early and late sulfide mineralizations in calcic skarn, respectively. The general trend of decrease in fluid salinity and tempera-ture with time, resulted from continuous fluid-rock reaction, and/or interaction and dilution of the hydrothermal fluid with more dilute fluids in retrograde skarn evolution, agrees well with the results of oxygen and hydrogen isotope study.

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Japan and USA are the major copper consuming countries, and the refined copper consumption in both countries amounted for 33 % of the free world consumption. In order to clarify the copper demand trends in Japan and USA, copper consumption data from 1960 to 1989 are analyzed by using the following intensity of use technique;
IU=C/GDP=(Q/GDP)×(C/Q)=PCI×MCP(+Embodied copper consumption/GDP) where IU : Intensity of use measures copper consumed per real GDP
C : Copper contained final product
PCI : Product Composition of Income is the proportion of consumer's total income that is spent on this final product
MCP : Material Composition of Product measures the amount of metal used to make one unit of a product The results indicate the different trends of IU, PCI, MCP and embodied copper consumption between Japan and USA, which reflects different economic and trade policy in both countries.

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Oxygen and hydrogen isotopic compositions of vein muscovite and host rocks, oxygen isotopic compositions of vein quartz and K-feldspar, and hydrogen isotopic compositions of fluid inclusions in vein quartz, drusy quartz, wolframite and scheelite from the Kaneuchi tungsten deposit, Kyoto Prefecture, are obtained in order to (1) examine the relation between the ore-forming fluid and the fluid equilibrated with host rocks at a low fluid/rock ratio, and (2) to obtain possible δ¹⁸O-δD region of the ore-forming fluid.
Oxygen isotopic compositions of vein muscovite range from 11.7 to 13.8 per mil (relative to SMOW). Based on muscovite-quartz oxygen isotope temperatures and previous works, most of vein muscovites precipitated at 400°C or above (possibly up to 600°C). The oxygen isotopic compositions of the ore-forming fluid show the-range from 10.4 to 13.7 per mil at 400° to 600°C. Host rocks show oxygen isotopic compositions ranging from 12.8 to 15.0 per mil. Using fluid-rock fractionation factors obtained from the bulk chemical compositions, oxygen isotopic compositions of the fluid equilibrated with host rocks at a low fluid/rock ratio are calculated at 300°to 600°C. These compositions show a good agreement with the estimated isotopic compositions of the ore-forming fluid either from vein quartz and vein muscovite.
The hydrothermal fluid at the earliest stage is ¹⁸O-enriched compared with a possible magmatic fluid, suggesting high temperature fluid-rock interaction. At the main stage of quartz mineralization, the ¹⁸O_fluid composition is equal to the possible magmatic fluid composition. However, the temperature of the fluid at this stage is too low (350°to 400°C), requiring significant cooling of the magmatic fluid. Simple mixing of the high-temperature ¹⁸O-enriched fluid (for the precipitation of muscovite) with the low-temperature ¹⁸O-depleted fluid (for the precipitation of calcite) does not account for the δ¹⁸O_fluid range determined from vein quartz. It is possible that the other factors, such as conductive cooling, influenced the temperature of the magmatic fluid. Otherwise, the discrepancy can be accounted for by considering fluid-rock interaction at a low fluid/rock ratio.
Hydrogen isotopic compositions of vein muscovite range from -61 to -104 per mil (relative to SMOW) and those of fluid inclusions in vein quartz and drusy quartz range from -53 to -73 per mil and from -53 to -63 per mil, respectively. Calculations of the hydrogen isotopic compositions of the hydrothermal fluid at the precipitation of muscovite show the range from around -100 to -70 per mil, suggesting relatively large variation compared with the variation in δ¹⁸O.
The hydrogen isotopic composition of the fluid from which vein and drusy quartz were deposited covers the same range as the magmatic fluid. However, the fluid responsible for muscovite precipitation is significantly depleted in deuterium. The large variation in hydrogen isotopic composition of muscovite is partly due to the temperature change of the ore-forming fluid. But the present results still suggest that the hydrothermal fluid mixed with deuterium-depleted and ¹⁸O-enriched fluid at the earliest stage of mineralization.

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The Tharsis mining area is one of the largest mining centers of the Iberian Pyrite Belt, which covers a large area in the SW part of the Iberian peninsula. Sedimentary structures in the sulfide deposits of the Filon Notrte, Tharsis mine were studied in the field and under the microscope. The sulfide deposits are classified into two types based on internal structures: (1) massive pyritic ores; (2) pyritic ores with sedimentary structures. In the latter type, several kinds of sedimentary structures are observed, such as graded bedding, parallel and cross lamination and slump structures. Distribution of the sedimentary structures indicates that slump breccias are commonly observed in the lower horizons and in the country rocks, massive ores rather in the upper horizons and cross lamination in the middle horizons. Cross lamination is also obsevable in the calst of the slump breccias. From these, depositional process is considered to be as follows. In the early stage, ore solutions flowed out in the mud on the sea-floor from the feeders and sedimentary structures were formed after the outflow. Some ores were moved by slumping before lithification. In the late stage, massive ores were rapidly precipitated on the pre-existing ores.

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