Recent isotopic study of Mesozoic ore leads from the Korean Peninsula revealed two major dates for the source regions, 2.5 and ca. 2.0 b.y. The leads seem to have evolved in the Precambrian basement with rather little disturbance till extraction and mineralization during Jurassic to Cretaceous granitoid activities. Leads of the Japanese Islands have their roots basically in nearby continental crusts, albeit their evolutionary system went through a series of mixing and homogenizing processes prior to mineralization and a certain amount of mantle lead may have also been incorporated.

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High grade gold ores were intersected in 1981 by a scout drill carried out by the Metal Mining Agency of Japan during a reconnaissance drilling programme at Hishikari, Kagoshima Prefecture. The original aim of the hole was to explore a deep target where geophysical anomalies overlapped the abandoned old drifts (gravity-high, resistivitylow by airborne EM, and resistibity-low near the surface and high at the depth by the schlumberger deep-sounding).
Subsequently, a follow-up drilling programme was commenced by the Sumitomo Metal Mining Co., Ltd, the property owner, and all the 18 holes intersected high tirade ores.
The underground development was started in January 1983, and the first crosscut intersected the ore body at 100 mL (a.s.l.) in July 1985.
The deposit is of an epithermal gold-siver bearing quartz-adularia vein with unusually high gold content. The overall Au: Ag ratio is about 1: 0.6. The deposit has a "semi-blind" nature, as the top of the present high grade portions occur some 120 m underneath the abandoned old drifts.
Several major veins and numerous veinlets have so far been encountered in an area some 800 m by 100 m.
Veins strike in N45°to 70°E and dip 70°N to 90°, and their widths vary from a few cm up to 8 m. They occur in both andesitic volcanics of Pleistocene and sedimentary rocks of late Cretaceous to early Palaeogene. The K-Ar ages of mineralization are 0.78±0.07 and 1.04±0.07 m.y. (vein adularia).
The major constituent ore minerals are electrum, naumannite, and chalcopyrite, with minor amounts of pyrite, sphalerite, galena, stibnite, and marcasite. Quartz, adularia, montmorillonite, and a minor amount of calcite, chlorite, and truscottite are so far identified as gangue minerals.
Large volumes of hotwater with a temperature of 59-65°C occur within the vein system. The original static water level was as high as 200 m a.s.l.

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The Nakatenjo lead and zinc deposit, 3.5 kilometers south of the Nakatatsu mine, belongs to the pyrometasomatic type, embedded in the Akiu Formation of middle Permian age.
The formation of the deposit appears to be controlled by the inferred fault with N-S trend, and syncline, anticline and related fissures with E-W trend. The main mineralized zone is formed at the boundary between the limestone and sandstone-slate members on the south flank of anticline.
The nickel content and chemical composition of the country rocks and skarns suggest the followings. Limestone is replaced to clinopyroxene skarn, and sandstone, slate and schalstein to epidote skarn causing the exchange of CaO, CO₂, SiO₂, Fe₂O₃, FeO and MnO. Furthermore, clinopyroxene skarn is partly altered to rhodonite skarn resulting from the ascension of fCO₂ and concentration of MnO.
The metal elements are arranged in the deposit as the followings. Ag, Pb, Zn and Co contents of ores increase toward the depth of deposit, while Mn content decreases. Thulite (Mn₂" (Al, Fe "')₃Si₃O₁₂(OH)) mol% in epidote and quantity of rhodonite vary in accord with Mn content. From the viewpoint of zonal arrangement, the deposit may be divided into a part of surface (the Mn zone), a part of anticline and syncline (the transitional zone into the Pb-Zn zone), and a part of south flank of anticline (the Pb-Zn zone).

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The Mount Isa deposit is either regarded as sediment-hosted stratiform deposit or as submarine exhalative deposit by many mining geologists. To investigate this problem from the geochemical point of view, chalcopyrite (7 samples), pyrite (6 samples), sphalerite (1 sample), and pyrrhotite (1 sample) from the copper orebody of the Mount Isa deposit have been analyzed for minor elements by atomic absorption spectroscopy. The comparison of the minor element distribution in pyrites from the Mount Isa deposit, the kuroko deposits, the Kieslarger type deposits and the Lower Jurassic black shale of Yorkshire, England, shows that the Co and Ni contents of pyrite from the Mount Isa ores are almost same with those of the Kieslarger type deposits.
The other features of the minor element contents in pyrite from the Mount Isa deposit include comparatively enriched Bi and poor Mn, compared with those of the kuroko and Kieslarger type deposits. The same tendencies are also observed in chalcopyrite from the Mount Isa deposit.

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Homogenization temperatures and salinities of fluid inclusions in quartz, scheelite, clinopyroxene, and garnet from the Akemidani and Gosento ore bodies of the Fujigatani deposit and the Suo ore body of the Kuga deposit are measured in order to compare the formation temperatures of anhydrous skarns, quartz veins, and scheelite.
Homogenization temperatures and salinities of primary fluid inclusions in vein quartz from the Fujigatani deposit range from 361°to 191°C and 14 to 1 wt% (NaCl eq.), respectively. Primary fluid inclusions in scheelite show the homogenization temperatures ranging from 308° to 233°C, and the salinities ranging from 9 to 1 wt% (NaCl eq.), respectively. Homogenization temperatures and salinities of primary fluid inclusions in clinopyroxene range from 361°to 251°C and 11 to 3 wt% (NaCl eq.), respectively.
Primary fluid inclusions in vein quartz from the Kuga deposit show the homogenization temperatures ranging from 373°to 196°C, and the salinities ranging from 12 to 2 wt% (NaCl eq.), respectively. Homogenization temperatures and salinities of primary fluid inclusions in scheelite range from 376°to 242°C and 9 to 1 wt% (NaCl eq.), respectively. Homogenization temperatures of primary fluid inclusions in clinopyroxene and garnet range from 370°to 263°C and from 339°C to 275°C, respectively. Salinities of primary fluid inclusions in these minerals range from 11 to 2 wt% (NaCl eq.).
It is indicated for both deposits that the formation of quartz veins occurred at lower temperatures than that of skarns. Skarn scheelite precipitated at lower temperatures than clinopyroxene and/or garnet, whereas vein scheelite precipitated at higher temperatures than vein quartz. The temporal relationship between quartz veins and skarns, tex-tural relations of scheelite and other skarn minerals, and the fluid inclusion data suggest that the precipitation of scheelites occurred at the late stage of the formation of skarns, and at the early stage of the formation of quartz veins.
Difference in salinity of inclusion fluid is not observed between scheelites in skarns and in quartz veins. Homogenization temperature data show that vein scheelite from the Fujigatani deposit was formed at higher temperatures than skarn scheelite. On the other hand, vein scheelite from the Kuga deposit was formed at the same temperature with skarn scheelite. There is a possibility that the temperatures of hydrothermal solutions for these deposits die not decrease monotously, but fluctuated during the course of the mineralization of the Fujigatani deposit.
No apparent difference in formation temperature is observed between molybdenite and scheelite in quartz veins of the Fujigatani deposit.

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To understand the mode of differentiation of the granitic magmas of Southwest Japan, neutron activation analyses have been made to measure the REE abundance of the granitic rocks. We employed the Rayleigh fractionation model to simulate the crystallization of the granitic melts. Since the model calculations fit the observed REE data for the granitic rocks well, it is suggested that the granitic rocks of Southwest Japan were mainly differentiated by fractional crystallization. On the basis of the model calculations, it is also suggested that the granitic rocks with a large negative Eu anomaly found near some tungsten deposits are residues of an extremely differentiated magma.

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