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The mineral parageneses and succession of their formation are considered for the first time for the Zverevsky, Orekhovy, and Vodonosny ore lodes of the Lebediny gold deposit and the Radostny prospect in the Central Aldan ore district, which are genetically related to the epoch of Mesozoic tectonomagmatic reactivation. The orebodies, represented by two morphological varieties—ribbonlike lodes and steeply dipping veins—are hosted in lower part of the Vendian–Cambrian dolomitic sequence, which is cut through by Mesozoic subalkaline intrusive bodies. The chemistry of fahlore and rare minerals, including native gold and bismuth, altaite, aikinite, tetradymite, and sulfosalts of lillianite series, has been studied. Native gold is related to the late hydrothermal process and occurs in skarn and in quartz–tremolite–sulfide and quartz–carbonate–sulfide veins. The data on stable sulfur (δ34S) isotopes of sulfides, oxygen (δ18O) and carbon (δ13C) isotopes of carbonates, as well as on fluid inclusions in various generations of tremolite and quartz, provide evidence for the heterogeneity of ore-bearing solutions, their relationships to magmatism, the depth of the source feeding each specific lode, and different sources of ore-forming hydrothermal solutions.

The Dal’negorsk borosilicate skarn deposit (44° 34′ N and 135° 37′ E), located in the center of the ore field bearing the same name, is referred to the category of giant deposits. The currently predominant genetic concept assumes that ore mineralization at this deposit is related to a mantle source and that boron and ore-bearing alkaline fluids are derivatives of a juvenile source as well. The alternative model considered in this paper suggests that sedimentary sequences, probably, evaporites of a local basin, were immediate boron sources and hot subsurface water served as an agent of ore deposition. The authors’ conclusions are based on (1) mineralogical and geochemical features of alteration of premineral dikes as evidence for the composition of percolating ore-bearing fluids, (2) results of fluid inclusion study, and (3) boron and oxygen isotopic compositions of datolite.

Unusual intergrowths of sphalerite, chalcopyrite, and stannite have been described in two samples from the St. Agnes (Cornwall) and Sinancha (southern Primorye) tin deposits. Possible origins of these sulfide intergrowths and their implications for understanding the formation conditions of the deposits are discussed on the basis of ore microscopy and analytical data. At the St. Agnes deposit, the intergrowths appeared due to the breakdown of a high-temperature solid solution with formation of a Zn-stannite matrix, chalcopyrite lamellae, and rounded drop-shaped inclusions of sphalerite. At the Sinancha deposit, the rare myrmekite stannite-sphalerite intergrowths are interpreted as eutectic textures of mutual penetration that resulted from ore metamorphism at the contact of a dike.

The mineralogy and PT formation conditions of the Dzhimidon Pb-Zn deposit in the Sadon ore district are considered. The deposit is localized in metamorphic rocks of the Buron Formation, which pertain to the pre-Jurassic basement (lower structural stage) and are cut through by Upper Paleozoic granitoids, and in the Lower Jurassic terrigenous sequence (upper structural stage). Orebodies as quartz-sulfide veins are mainly hosted in the metamorphic rocks. Galena, sphalerite, chalcopyrite, pyrite, pyrrhotite, and arsenopyrite are the most abundant sulfides, while quartz, carbonates, chlorite, sericite, and feldspar are gangue minerals. The bismuth mineralization identified at this deposit for the first time is represented by diverse phases of the Ag-Pb-Bi-S system. Five stages of the ore deposit formation are recognized: a premineral stage (quartz-feldspar), three ore-bearing stages (pyrite-arsenopyrite, pyrrhotite-chalcopyrite-sphalerite, and arsenopyrite-sphalerite-galena), and a postmineral stage (quartz-calcite); each stage comprises one or several mineral assemblages. The study of fluid inclusions in quartz, calcite, and sphalerite of the premineral, ore-forming, and postmineral stages has shown that the ore was deposited mainly from Na chloride solution with a salinity varying from >22 to

Distribution of cadmium and manganese, fractionation of sulfur isotopes between coexisting galena and sphalerite, and filling temperatures in sphalerite have been studied as a test of sphalerite-galena geothermometers in samples from more then 30 deposits. The distribution patterns of cadmium range from linear to scattered. Scattered distribution patterns of manganese are typical of most samples studied, although there is a small tendency for linear distribution in samples from a few deposits. The relationship delta 34 S ZnS 250 degrees C). Its applicability for low-temperature deposits is doubtful. The assumption that coexisting sphalerite and galena equilibrated with respect to cadmium distribution at the majority of deposits studied seems to be reasonable. Several samples studied gave a good agreement between temperatures based on manganese distribution and those estimated from filling and the cadmium galena-sphalerite geothermometer. However, most of the samples gave rather unreliable temperatures. From these results it is concluded that geothermometry based on manganese distribution between galena and sphalerite is not useful. The isotopic sphalerite-galena geothermometer yielded temperature ranges from 90 degrees to 690 degrees C. Approximately 30 percent of the samples gave unrealistic values. Most of samples studied display Delta (sub ZnS-PbS) values which seem to be much smaller then the expected equilibrium values and therefore give unrealistic temperatures. Part of the filling temperatures are within 100 degrees C of the sulfur isotope curves, but in some cases the discrepancies are larger. An important result is that no samples for which all three geothermometers were employed have given concordant temperatures. This is evidence of chemical and isotopic disequilibria at least on the scale of the volumes sampled.

Chalcopyrite inclusions in sphalerite, once considered to be only exsolution poducts, have been suggested to be replacements of Fe-rich sphalerite. This study reveals that (1) chalcopyrite inclusions were found in sphalerite with different iron contents: both Fe-poor varieties from 0.5 to 2 wt percent and Fe-rich, from 8 to 14 wt percent; (2) chalcopyrite inclusions were produced by replacement as the result of interaction of sphalerite with solutions, which transported both copper and iron; and (3) coprecipitation of sphalerite and chalcopyrite is an alternative mechanism of formation of the chalcopyrite inclusions in the ore deposits studied.

The All-Union Research Institute of Medical Instrumentation has recently developed a series of endoscopes with fiber-optic elements and with better characteristics than endoscopes fitted with incandescent lamps. A feature of these instruments is that, because they use fiber-optic light guides, the cavity to be examined can be illuminated with "cold light~" thus preventing heating or burning of the mucous membranes, and a much greater intensity of illumination of the object to be examined is possible. This, in turn, provides better conditions for still and motion-picture photography in conjunction with endoscopy.

(1982). Murunskite, K2Cu3FeS4, a new sulfide of potassium, copper, and iron. International Geology Review: Vol. 24, No. 9, pp. 1109-1114.

(1988). THE CONNECTION BETWEEN STRATIFORM LEAD-ZINC DEPOSITS IN CARBONATE ROCKS AND OIL-PRODUCING AND SALINE SEQUENCES. International Geology Review: Vol. 30, No. 6, pp. 597-612.