The Sambo Pb-Zn-barite mine is composed of fissure-filling quartz-barite veins within Proterozoic biotite schist which are related genetically to Jurassic granitic intrusions. Ore mineralization consists of three distinct stages of quartzbarite veins which were separated by tectonic fracturing and brecciation events. Ore textures of stage II indicate rhythmic deposition, containing five successive mineralization cycles, each with up to seven nearly monomineralic bands. Detailed oxygen isotope studies of stage II rhythmic mineralization reveals patterns both among and within cycles which can be interpreted in terms of two processes: (1) increasing involvement of unexchanged meteoric waters in the ore fluids, resulting in an overall decrease in δ ¹⁸Owate, values (from +0.9 to -6.8‰) among cycles; and (2) periodic boiling, resulting in small positive changes in δ ¹⁸Owater values within cycles. Hydrogen and oxygen isotope compositions of the Sambo ore fluids may represent mixing of magmatic or highly exchanged meteoric water with less exchanged meteoric water, or exchange of meteoric water with granitic or gneissic rocks at elevated temperatures and moderate to high water/rock atom ratios (0.1 to 0.5). Using either a mixing or exchange model, it is evident that the hydrogen and oxygen isotopic compositions of fluids in the Sambo hydrothermal system were controlled predominantly by local meteoric waters.

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Gold mineralization at the Mount Leyshon mine, located about 24km south of Charters Towers, eastern Queensland, Australia, is hosted mainly by breccia and quartz porphyry. The quartz porphyly has a Rb-Sr isotope age of 283±19Ma. The Rb-Sr data, combined with lead and K-Ar isotope systematics, reveal that the intrusive phases and related gold mineralization were essentially continuous from latest Carboniferous to earliest Permian, and occurred over a short time period at high levels in the crust. Using the isochron age, the following initial Sr and Nd ratios are obtained: εSr=9.9 to 12.0, εNd=-1.3 to -1.5 for a trachyandesite dike (post-ore and latest magmatic event) ; εSr=86.0 to 100.0, εNd=-7.1 to -13.0 for hydrothermal calcite associated with ores in the breccia; εSr =40.0 to 110.0, εNd=-2.2 to -3.3 for quartz porphyry (related to the mineralization); εSr=138.0 to 162.0, εNd =-14.0 to -15.0 for metasedimentary basement; and εSr=264.0, εNd=-11 for granitic basement. These isotope characteristics are consistent with a two-component mixing model where the bulk earth component is mixed with a limited amount of recycled crustal component.
Based on field relationships and textural evidence, the mineralization and related alteration are divided into two stages, early and late. Ores in the early stage occur as veins and veinlets up to 3 cm wide mainly in quartz porphyry, metasediment and breccia (Main Pipe breccia), while those in the late stage occur as matrix replacement, cavity fillings, disseminations and veins up to 1.5m wide mainly within the Mount Leyshon breccia and tuffisite. The early stage is characterized by Mo and ore fluids of high salinity (40 to 52 eq.wt% NaCl) and higher pH (potash feldspar and biotite), while the late stage fluid is characterized by Cu-Pb-Zn-Bi-Au-Ag, low salinity (3 to 17 eq.wt% NaCl) and lower pH (muscovite, chlorite and kaolinite).
Using available solubility data, gold at the Mount Leyshon deposit can best be interpreted as having precipitated from the breakdown of a thio complex (Au(HS)₂-) at about 300°C possibly due to a decrease of pH in the pyrites table region.

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Diopsidic to hedenbergitic clinopyroxenes are major constituent minerals both in the country rocks called Inishi Migmatite and skarn ore in the Kamioka Pb-Zn deposits embedded in intercalated marble beds within the Hida gneisses, central Japan. Clinopyroxenes in the Inishi Migmatite generally vary from Hd (hedenbergite molecule percent) 40 to 70, mostly 50 to 60 in composition, and those in the skarn ore called Mokuji ore range from Hd70 to larger than 90 with higher johannsenite molecule (10 to 20%) than the former (generally less than 3%). The replacement of marble beds by the hedenbergitic skarn requires significant enrichment of iron, however, there can be found no systematic compositional change in clinopyroxenes of the country rocks around orebodies, in any scale of investigations from regional to an outcrop. Clinopyroxenes vary randomly in composition from a specimen to specimen, and the increase of Hd-molecule is limited in the narrow zone of hydrothermally altered part nearest the orebody, such as called "Yopparai". The composition of clinopyroxenes in the country rocks is essentially controlled by the difference of bulk chemistry, not by the mineralization, and it is likely that the Inishi Migmatite did not directly relate to the mineralization.

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Okawame mine, located in the northeastem area of the Kitakami massif, was hetherto recognized as a peculiar skarn type molybdenum deposits in the Japanese Islands. The detailed observation of the occurrences of molybdenite clari-fied that the Okawame deposits, is a vein type and the occurrences can be classified into four types, i. e., Type I: molybdenites occurring in the quartz vein, Type II: occurring sporadically in the country rocks accompanied with discontinuous quartz vein, Type III: those filling the joint without quartz and Type IV: those occurring in the oriented fracture along grain bounda-ries of skarn minerals. Types II, III and IV are evidences for misapprehention of the occurrences of molybdenite to be a disseiminated and a stockwork deposits in skarn. Four types are closely related with each other, i. e., Types II and III are deri-vated from Type I and II, respectively. Since the quartz veins and joints evidently cut the metamorphosed and skarnized country rocks, the molybdenum mineralization took place after the contact metamorphism and skarnization.
The directions of the quartz veins and joints with and without molybdenite are dominated by N-S to NNE-SSW in trends and vertical in dips. The quartz veins and joints are considered to have formed under the stress field with horizontal maximum principal stress axis trending N-S-NNE-SSW (=σHmax). The studies on the relationship between directions and radiometric ages of the granite bodies in the northern Kitakami massif show that vein-type molybdenum deposits in the northern Kitakami massif were formed under the stress field with horizontal maximum principal stress axis trending N-S-NNW-SSE in the last stage of the granitic magma activity, which was slightly earlier than Okawame mineralization.

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