Microthermometry study of fluid inclusions in quartz veins of the Maletoyvayam deposit (Koryak Highland, Russia) was carried out. This epithermal gold deposit contains unique Au compounds including maletoyvayamite, which has not been reported anywhere else. Two paragenetic mineral associations (pyrite-quartz and maletoyvayamite-quartz) with quartz of different generations corresponding to different pulses were also described. Only early generations of quartz (Q1) include ore minerals: pyrite for the first mineral assemblage, and in Au-bearing minerals, sulfosalts, bismuthinite, and others—for the second assemblage. A study on fluid inclusions in quartz showed a salinity (mainly NaCl + KCl) range from 0.2 to 4.3 wt.% NaCl eq., increasing from the first mineral association to the second due to boiling fluids. The obtained temperature variations for quartz crystallization were 295–135 °C, the fluid pressure ranged from 79 to 4 bar. On the other hand, the range of conditions obtained for the gold productive ore association is more narrow: salinity of the fluid inclusions is 4.3 wt.% NaCl eq., the temperatures vary from 255 °C to 245 °C, and the pressure from 39 to 32 bar. These physicochemical characteristics of the Maletoyvayam ore deposit greatly coincide with other HS-type epithermal deposits; however, within the Central Kamchatka Volcanic Belt it is so far the only deposit of this type reported.
This study concerns the simultaneous detection of five rare-earth elements (REEs) – Ce, La, Nd, Pr, Sm – in ores and nodules using two X-ray fluorescence techniques (XRF): total reflection...
This study was performed to search for the possibility of assessing the FeO/Fe 2 O 3 tot ratio in rocks using K-and L-series of the X-ray fluorescence (XRF) spectrum. The uncertainty in the determination of the FeO/Fe 2 O 3 tot ratio was compared from the obtained ratios of Kβ 2,5 -/Kβ 1,3 -and Lβ-/Lα 1,2 -line intensities. The measurements were implemented by a conventional XRF spectrometer, S4 Pioneer. The assessment of the uncertainty in FeO/Fe 2 O 3 tot determination in mineral powder fractions proved that the Kβ 2,5 /Kβ 1,3 ratio of lines could be selected as the analytical signal. A relative standard deviation of FeO content in the collection of 48 reference materials of igneous rocks varies within the range of 5-16%, depending on the range of the FeO/Fe 2 O 3 tot ratio and the FeO content. The best accuracy was attained for FeO/Fe 2 O 3 tot >0.45 with FeO contents varying within 5-15%. In the andesite and basalt samples, the relative standard deviation was <4%. In granite rocks, the error reached 23% at fairly low content of FeO <3%. For the igneous rock samples at a ratio FeO/Fe 2 O 3 tot >0.25, the XRF determination of FeO content can be performed at an accuracy comparable with that of wet chemical analysis. The XRF method is preferred because it is fast and convenient for sample preparation. It could be used as an analytical technique in routine geochemical investigations.
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