Geologica Macedonica

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2023-12-13T10:09:43+00:00

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MINERALOGICAL AND CHEMICAL CHARACTERISTICS OF PHOSPHATES FROM THE DJEBEL ONK DEPOSITS

2023-12-06T08:27:52+00:00

Algeria has important phosphate reserves (2 billion tons) located in the east of the country at Djebel Onk. This mining district, located in the northwestern part of the Algerian Sahara near the Algerian-Tunisian border, is composed of five sectors: Kef Essennoun, Djemi Djema, Bled El Hadba, Djebel Onk North and Oued Betita. Kef Essennoun and Bled El Hadba were selected for this study. The knowledge of the petro-mineralogical and chemical characteristics as well as the dimensions of the main existing minerals in the two types of phosphate ores is necessary to guide the choices of upgrading treatments and understand the reaction processes. The physico-chemical studies applied to the light and dark phosphates, respectively from the deposits of Bled El Hadba and Kef Essennoun revealed significant differences on the chemical and mineralogical level, with however a great similarity in terms of size and shape phosphate grains. The Kef Essennoun phosphate ore rich in P2O5 with a content of 28.23 % and the grain release mesh characterized by the slice of 800 to 125 microns. On the other hand, the Bled El Hadba ore less rich in P2O5 with a content of 23.90 % and the grain release mesh characterized by the slice of 500 to 100 microns. This study constitutes a criterion for assessing the quality and behavior of the two types of ore on the processing chain.

HYDROTHERMAL HALITE IN THE Pb-Zn MINERAL ASSOCIATION OF THE SASA DEPOSIT (NORTH MACEDONIA)

2023-12-19T07:20:28+00:00

The present study was performed to describe an occurrence of hydrothermal halite in the Sasa ore field. The occurrence of halite in hydrothermal systems is not a rare occurrence, considering the different types of hydrothermal processes. Тhe occurrence of hydrothermal halite embedded in calcite crys-tals has not been established so far. In the Sasa ore field calcite is the most important of all non-ore minerals. It occurs together with dolomite, rhodochrosite, siderite, barite, quartz, calcedony, opal, and so on. Halite crystals are in form of dendrites. The morphology of natural halite is largely dominated by the cube {100}; the {110} and {111} forms are rarely present. When crystals grow by evaporation from aqueous solution the perfection of the cube faces is usually lost. Оwing to the high values of the supersaturation appear dendritic branches developing in the <111> directions. Dendrite forms when water rich in NaCl flows be-tween microscopic layers of calcite. Halite crystals are long from 4.08 to 22.35 and widе from 1.24 to 2.42 μm.

COMPARISON BETWEEN TRADITIONAL AND CONTEMPORARY METHODS FOR DATA RECORDING IN STRUCTURAL GEOLOGY

2023-12-06T08:35:36+00:00

3D modeling has become a favored way of analyzing 3D data, where users can collect more data with high accuracy in less time than other surveying methods. Technologies capable of providing 3D data such as Terrestrial Laser Scanners (TLS) are often expensive; thus, encouraging users to seek affordable alternatives while achieving the desired accuracies. Characterization of a rock mass requires data from the intact rock along with the discontinuities. The geometrical analysis of the surface enables the calculation of the parameters to characterize the discontinuities and receive other geological and geotechnical data. Remote sensing techniques, such as Terrestrial Laser Scanning (TLS) and Structure from Motion (SfM) technique, provide 3D point clouds that enable the geometrical analysis. The scientific community has been testing both techniques since the 2000s, and companies are introducing their use in their workflows. Today, mobile phones are becoming more capable of 3D modeling, and the most recent iPhone 12/13/14 Pro and iPad Pro provide an integrated LiDAR sensor. In this paper, we explore the digitalization of a rocky slope via the SfM technique generated using drone surveying and via iPhone-13 pro as a comparison to the “old school” data collected from the compass survey. The target of this work is one outcrop of Mica-schist in the north-east part of Macedonia. To capture the surface, compass surveying is used, SfM drone imaging, and two iPhone con-figurations of LiDAR scanner. The data is analyzed using Pix4D and CloudCompare software. The results of iPhone LiDAR and drone SfM scanning show a highly promising match when compared to the compass measurements.

SPATIAL DISTRIBUTION OF CHEMICAL ELEMENTS IN SOILS FROM THE SOUTHEASTERN PART OF NORTH MACEDONIA (GEVGELIJA, VALANDOVO, BOGDANCI AND DOJRAN MUNICIPALITIES)

2023-12-06T08:37:09+00:00

In this work, the contents and spatial distributions of 18 elements (Ag, Al, Ba, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Sr, V, Zn) in the soils of the southeastern part of North Macedonia (Gevgelija–Valandovo–Bogdanci–Dojran region) are presented. For this purpose, a total of 86 soil samples were collected from 43 locations (43 samples of topsoil and 43 samples of subsoil). All samples were analyzsed by inductively coupled plasma with atomic emission spectrometry (ICP-AES) after complete digestion with four acids (HNO3, HF, HClO4, and HCl). The obtained results were statistically evaluated and spatial distribution maps for all analysed elements were also prepared. Factor analysis was performed to reduce the number of data used and new synthetic variables (factors) were identified. Through the application of factor analysis, three geochemical associations were identified: Factor 1 (Fe, V, Mn, Cu, Ni, Zn, and Pb), Factor 2 (Ba, Li, and K), and Factor 3 (Mg, Al, Ca, and Sr). From the obtained data and the maps of spatial distribution, it could be concluded that the occurrence of the analyzed elements is related to the lithology of the region. Namely, it was found that the content of elements of Factor 1 is higher in soils dominated by Mesozoic volcanic rocks, Quaternary alluvial sediments, and Proterozoic gneisses and Paleozoic shales; the content of elements of Factor 2 is higher in soils in the north (where Mesozoic felsic plutonites dominate) and east (where Proterozoic gneisses and Paleozoic shales dominate) of the study area; and that elements of Factor 3 are present in soils from the area dominated by Quaternary alluvial sediments, Paleozoic carbonates and shales, and Mesozoic mafic plutonites. The only exception is the fact that the P content in the topsoil from the Gevgelija and Valandovo valleys along the Vardar and Anska rivers is higher than in the subsoil samples, which is probably due to the use of phosphate artificial fertilisers in agriculture.

GEOMAGNETIC RESEARCHES IN THE EASTERN PART OF NORTH MACEDONIA

2023-12-06T08:38:37+00:00

Republic of North Macedonia, according to current knowledge, has deposits of gold that were exploited in the past. Existence of contemporary geophysical methods, especially high precision magnetometers, gives relatively easy and very efficient possibility for defining the area of alluvial terraces, not only on the existing rivers but, also, in the old riverbeds. To define the most prospective areas for detailed research, bearing in mind that the gold and accompanying heavy precious metals are non-magnetic, which are of exploitation interest, almost always, paragenetic, magnetite is present with them. Magnetite as a mineral have the highest magnetic level, according to that is easy de-tectable. Areas with registered anomalies should be investigated with this method and core drilling in order to define depth of the ore.

RADON AND RADIUM CONCENTRATION IN WATER FROM PUBLIC FOUNTAINS AT THE CENTRAL PARTS OF THE KRATOVO-ZLETOVO VOLCANIC AREA, REPUBLIC NORTH MACEDONIA

2023-12-06T09:21:05+00:00

The paper presents information about our latest study of radon and radium in drinking water from the public water fountains situated in central parts of the Kratovo-Zletovo volcanic area. Results for the radon in water measurements were as follows: Fountain 1 to Fountain 4 samples, ranged from 6.63 up to 157.73 Bq L-1. Obtained results for the radium in water, Fountain 1 to Fountain 4 samples, ranged from 0.20 up to 1.08 Bq L-1. Both, radon and radium measurements, in water samples from certain fountains have shown significantly higher values than the strictest standards given by the United States Environmental Protection Agency (USEPA) and World Health Organization (WHO), respectively. The committed effective doses for the population consuming the water directly from the fountains or as self-bottled waters from the Kratovo-Zletovo volcanic area were estimated using the concentration of 222Rn and 226Ra in water samples, ranged from 45.47 mSv y-1 to 709.36 mSv y-1, which once again for some fountains were higher than the WHO recommended values of max. 100 mSv y-1.