Late Cretaceous (81.5 Ma) granitic rocks of the Kanamaru mine area are composed of coarse-grained biotite granite, fine-grained biotite granite and two-mica granite-aplite. They were found to be all ilmenite-series, and are high in K₂O, and low in total Fe₂O₃, MgO and CaO, as compared with the average Japanese granitoids. The Rb/Sr ratio is 0.3-1.6 in the coarse-grained biotite granite, 0.9-1.1 in the fine-grained biotite granite, 15-52 in the two-mica granite, 68-108 in the garnet-biotite rocks and higher than 76-104 in the K-feldspar pegmatite. The most-fractionated, two-mica granite appears to be genetically related to the pegmatite deposit. Biotite in the two-mica granite and garnet-biotite rocks are iron rich, as a result of fractionation of the original ilmenite-series magmas. Garnets are almandine > spessartine in composition.
The pegmatite deposit, which has a rugby-ball shape with an E-W axis, is hosted in the fine-grained biotite granite and the two-mica granite. It is leucocratic, containing a large amount of K-feldspar, some quartz and only a little mafic silicates, reflecting the K₂O-rich and Fe-poor characters of the original granitic magma. No mineralogical and textural zonings are observed in the pegmatite. Fluid inclusion study on quartz indicates low homogenization temperature and presence of CO₂-bearing fluids. K-feldspars of the two-mica granite and pegmatite have high degrees of triclinicity. These rocks may have been solidified under volatile-rich environment, which made Al-Si ordering of the K-feldspars during the sub-solidus stage.

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Asahino disseminated-type mercury mineralization probably occurred in the Pliocene Age at the same time as the late-stage of the Kitano-oh hot spring-type gold-silver mineralization.
Tokoro vein-type mercury mineralization occurred at 4.5±0.6 Ma and was probably closely related to the extrusive activity of the Maruyama-toge Lava (rhyolite) between 5.3±0.1 and 4.8±0.1 Ma.
These mercury deposits were formed at approximately the same time as the gold-silver deposits located in the vicinity, suggesting that the gold-silver and mercury mineralizations are closely related.

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Proton induced X-ray emission (PIXE) uses proton beam to excite the atoms in the specimen resulting in the emission of the characteristic X-rays of its elemental constituents. The low continuum background radiation in PIXE results in much higher sensitivity with detection limits in the ppm regime, even when the X-ray spectrum is recorded in energy-dispersive detectors. The large penetration depth (>30 microns) of 2-4 MeV energy protons typically used for PIXE also simplifies the X-ray yield calculations and self-absorption corrections, facilitating quantification of the results without resorting to standards. PIXE conducted with broad beam of protons, often referred to as bulk-PIXE, can be used effectively for trace element distribution measurements in drill cores, and for measurements of the minute quantities of elements present in geogas emanations captured on a collector foil. When the beam is focused to the order of micrometer, the method is known as micro-PIXE. Micro-PIXE is a powerful tool in its readily quantified, non-destructive, in situ multielement analytical capability, with ppm sensitivity and microns spatial resolution. It opens up new windows of opportunity as demonstrated in many applications. In mantle petrology and diamond exploration (GRIFFIN et al., 1990) it leads to the development of a single mineral thermometry resulting in a novel and powerful method of assessing diamond prospectivity. Applications to sulfide mineralogy reveal the residence of gold in refractory ores, and the general distribution of precious metal and trace elements in coexisting phases in a deposit for exploration, ore genesis studies and beneficiation purposes (SIE et al, 1989, 1991). A recent study on kuroko-analogue ore from the Okinawa Trough reveals that rare metal distribution and is dependent on the occurrence mode of ore, and within each ore, it is regulated by the crystal structure (MURAO et al., 1996). The usefulness of micro-PIXE is further demonstrated in studies of complex and fine-grained tin-polymetallic ore to delineate the distribution of high-tech and medical rare metals in the deposits (MURAO et al., 1995a). The large penetration depth of the proton beam is exploited in analysis of fluid inclusions without decrepitation (HEINRICH et al., 1992). The non-destructive nature of micro-PIXE is invaluable in studies of and small melt inclusions. The use of EDS defines some of the limitations of PIXE, specifically in detection of light elements and the REE. The development of new detectors with ultra thin windows lowers the limit of detectable atomic number. REE detection can be improved by using Ge detector or WDS detectors. One growth area for future work includes two-dimensional mapping in minerals and channeling analysis for determining the state of an impurity in crystals. The case histories within the past few years demonstrated that the benefits of PIXE far outweighs the limitations.

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The Bukok hydrothermal deposits are located in the Haenam area of the southwestern part of the Korean Peninsula. This mining area is composed of Cretaceous volcaniclastic sediments, acidic pyroclastics and rhyolite lava in ascending order. In the waning stage of acidic volcanism, low temperature hydrothermal alteration occurred by a solution related to post-volcanic activity. The hydrothermal solution ascending through the conduit of a rhyolite dome altered the parent rhyolite, pyroclastics and sediments. The alteration minerals contain quartz, barite, alunite, dickite, kaolinite, illite, chlorite, calcite and pyrite, which are classified as a mineral assemblage of the "acid sulfate type". Hydrothermal alteration resulted in the loss of major components such as Fe₂O₃, TiO₂, Na₂O, K₂O and MgO, the depletion of trace and rare earth elements and the enrichment of Au, Ag, As and Sb. The mobility of trace elements including precious and base metals took place due to gold mineralization associated with the hydrothermal alteration.
The δ34S values for sulfide (pyrite) and sulfates (alunite and barite) range from -3.4 to 3.5‰ and from 6.0 to 9.6‰, respectively. The difference of δ34S values indicates that the acid sulfate alteration is a primary hypogene origin. The δ18 OH2O and δDH2O values estimated from the data of dickite and illite are from -3.8 to -0.3 and -79.6 to -96‰, respectively, representing that the hydrothermal fluids are the mixture of magmatic and meteoric waters in origin. The homogenization temperature (Th) and salinity of fluid inclusions for quartz ranges from 127 to 361°C and from 0.33 to 7.87 wt.% NaCl, respectively.
The geochemical characteristics of the Bukok hydrothermal clay deposits described above are very similar to those of "volcanogenic-epithermal gold deposits".

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