pdf № 368, August

DOI: 10.19110/geov.2025.8.1

Crystal structure of a high calcium eudialyte group member from the Tamazert massif, Morocco, with the following stoichiometry (calculated on 26 atoms Si + Nb, Z = 3): Na_8.1K_0.45Ln_0.6Ca_7.2Mn_2.2Fe_1.5Zr_3.1Nb_0.8—0.9Si_25.1—25.2Cl_0.3(CO₃)_0.4 by X-ray has been studied. The studied mineral is a fragment of a crystal of potentially new high calcium mineral with a complex growth zoning studied earlier. It differs from the latter by higher contents of Ca, Na and Nb. The unit-cell parameters are:
a = 14.1530(1) Å, c = 30.0801(2) Å, V = 5218.1(5) ų, space group P3. The structural model characterized by 163 crystallographic sites is refined to R = 5.48 % using 4644 independent reflections with с F > 3s(F). The cation distribution over the key sites in the frame of the low symmetry (space group P3) is more detailed as compared to the classical model with rhombohedral R-symmetry.

Keywords: eudialyte group, crystal structure, key positions, primitive cell, Tamazert massif, Morocco

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DOI: 10.19110/geov.2025.8.2

The development, adaptation, and improvement of methods and algorithms for obtaining, processing, and integrated use of near-Earth remote sensing data using unmanned aerial vehicles (UAVs) and modern software (SW) is an urgent task in the development of information models for monitoring potential hazards. This study demonstrates the implementation of digital methods for monitoring hazardous natural processes in a mountain riverbed. As a result of data processing, orthophotos and digital models of the study area have been created. The study quantifies of denudation and soil accumulation caused by the passage of a mudflow through the riverbed. The results are used in the development of measures to protect settlements and infrastructure facilities from the negative effects of hazardous natural processes

Keywords: Unmanned aerial vehicle, mudflow, riverbed, orthophotoplane, digital model, landscape

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DOI: 10.19110/geov.2025.8.3

A novel study of fossil resin from Yakutia has been conducted using infrared spectroscopy and differential thermal analysis. The resins are exclusively gedanites, although retinite may also be found. Gedanites are more oxidized than retinites.

For the first time, we analyze information on coniferous plant remains within the location of the studied fossil resins. This analysis confirms that conifers from the families Cupressaceae and Taxodiaceae can really be the main botanical sources of the formation of gedanite, while the Pinaceae family — of retinite.

Keywords: fossil resins, retinite, gedanite, Yakutia

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DOI: 10.19110/geov.2025.8.4

Recrystallisation processes in carbonates can affect the chemical and isotopic composition, the preservation of organic matter and fossils, change the filtration-capacity properties of the rock. Consideration of these processes seems to be critical for correct interpretation of the results of a wide range of analytical studies. On the basis of computer vision and machine learning technology the models for qualitative and quantitative express estimation of the degree of recrystallisation of sedimentary carbonate rocks are developed on the basis of thin-section images. The models have been trained on the basis of 300 images and 45000 fragments of thin-section images. The achieved accuracy of the models exceeds 90 %. The results of application of models and software based on them can be used for comparison of geochemical and isotopic information, as well as for express selection of the least recrystallised samples for analytical studies.

Keywords: carbonate rocks, thin-sections, recrystallisation, machine learning, image classification

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