Том 10, № 3 (2024)
- Жылы: 2024
- Мақалалар: 4
- URL: https://journals.rcsi.science/2313-545X/issue/view/18567
Бүкіл шығарылым
Minerals and mineral assemblages
About the composition and neutron activation radiography of topaz crystals from an author’s collection
Аннотация
The composition of zoned, zoned-sectorial or relatively homogeneous small topaz crystals from granite pegmatites of Ukraine (Volyn) and Russia (Ilmeny State Reserve in South Urals, Orlovskoe and Sherlovaya Gora deposits in Transbaikalia, and Zabytoe deposit in Primorye) is characterized using scanning electron microscope with energy-dispersive spectrometer and partly by laser mass spectroscopy. Photoexpositions of neutron activation radiography with data on chemical composition and possible isotopes, which form the pattern, are presented for some topaz crystals. According to the composition, the studied topaz was subdivided on three types according: 1) mostly fluoride (58%); 2) fluoride-hydroxyl (21%); 3) mostly hydroxyl (21%). The advantage of the neutron activation radiography for detecting patterns of zoned and zoned-sectorial heterogeneity of the composition of topaz crystals is shown.
5-19
Biomineralogy
Nanocomposition of hydroxylapatite from cortical bone tissue
Аннотация
Hydroxylapatite is one of the main components of bone tissue. In combination with collagen, it provides unique strength properties of the bone. The nanostructure of bone tissue (its composition) remains a matter of debate. In this work, we studied the cortical bone tissue of rats using transmission electron microscopy (TEM) and X-ray diffraction. According to the results of the Scherrer method, the size of hydroxylapatite crystallites is 8.8 × 4.0 nm. The TEM showed the presence of crystalline hydroxyapatite areas in the interfibrillary space of collagen with the sizes ranging from 10 × 5 to 50 × 10 nm. These areas are the crystalline aggregates with a subblock structure, which is expressed in different orientations of axis c. No amorphous substance in bone tissue was identified using electron nanodiffraction.
20-31
Mineralogy of ore deposits
New data on ore mineralogy of the Ak-Sug porphyry Au-Mo-Cu deposit (Northeastern Tuva)
Аннотация
New data on ore mineralogy of the Ak-Sug porphyry Au-Mo-Cu deposit (Northeastern Tuva) are presented as a result of study of ore composition using optical and scanning electron microscopy. Previously unknown minerals of Se (bohdanowiczite and berzelianite), Co (carrollite and Co-bearing pyrite), Bi (native bismuth, wittichenite, volynskite, and miharaite), Cu and Ag (mckinstryite and stromeyerite), W (scheelite), and U (brannerite) are found in ores of the deposit. The analysis of new mineral assemblages allowed us to significantly expand the list of minerals found at this deposit. The characterized minerals formed in a wide range of temperatures during several successive stages of ore formation: porphyry (carrolite and Co-bearing pyrite), epithermal and subepithermal (miharaite, volynskite, wittichenite, native bismuth, Se-bearing galena). Brannerite, berzelianite, bohdanowiczite, stromeyerite, mckinstryite, and scheelite formed at the late low-temperature stage.
32-51
Heavy concentrate gold associations in the basin of the Kukulkindzha Creek (Okhotsk region of the Khabarovsk krai)
Аннотация
This article highlights an insufficiently studied issue of a primary source of placer gold in alluvium of the basin of the Kukulkindzha Creek (Okhotsk region, Khabarovsk krai) be means of the analysis of mineralogical and geochemical features of samples. This study provides information on mineral composition of heavy concentrates and morphological characteristics and chemical composition of native gold. Native gold with lumpy morphology is dominant in heavy concentrates. The fineness of native gold varies from very low (530–689 ‰) to medium (885 ‰); native gold contains only Ag and is characterized by high-fineness rims. The minerals of the garnet group with dominant grossular-andradite composition and the minerals of the pyroxene group (diopside–hedenbergite series characteristic of contact metamorphosed rocks) are always found in heavy concentrates. Three stable mineral assemblages of native gold are identified on the basis of statistical analysis of geochemical and mineralogical data. The first assemblage is related to the presence of heavy fraction minerals in heavy concentrates, which were sourced from the entire studied area. The second assemblage mainly consists of accessory minerals of Late Cretaceous subalkali granites, which are most widespread within the studied area, and the third assemblage contains skarn minerals. A primary source is most likely related to skarns, which is evident from specific features of native gold, as well as its presence in assemblage with Ca garnets of the grossular–andradite series and pyroxenes of the diopside-hedenbergite series. The samples with the highest amount of native gold in heavy concentrates are associated with skarn source.
52-71