ALBERT

Description: We would like to announce that the latest issue of the Acta Geologica Slovaca Journal (Volume 13, Issue 2) has already been released at 19th December 2021.

Description: The presented comparative study evaluates the sensitivity of selected computational procedures to chosen parameters of solute transport and source geometry in homogeneous conditions. The computation procedures include three numerical schemes with FDI (finite difference implicit), MOC (method of characteristics), and a TVD (total variation diminishing) advection solver, while the other terms of the governing equation are computed by the FDI method. Furthermore, two analytical solutions were used: the exact solution of Newille (2005) and the approximate solution of Domenico (1987). Finally, a simplified, so-called Step-method, which is still being used in the practice, was used. The sensitivities of the individual procedures to selected physical-chemical parameters and to the geometric characteristics of the solute source were evaluated and compared. The obtained results show considerable differences between the particular procedures used. In most test cases, the numerical procedures with a TVD and MOC advection solver produced higher concentrations and were more sensitive to the transport parameters in comparison with the other methods used. Applied variations of individual parameter values caused a change of the calculated solute concentrations up to 7.1 %, whereas the substitution of calculation methods caused up to 7.7 % of C0 (the concentration in solute source). The simultaneous changes of all the examined parameter values with a synergistic effect caused the maximal change of calculated concentration up to 15.3 % of C0. A significant effect of the solute source geometry on the match between the results obtained by the selected numerical and analytical methods was also found (difference up to 57.9 % of C0). The achieved results indicate a need to solve the solute transport in homogeneous conditions using both types of calculation methods, the numerical and analytical, in order to cover possible variability of resulting concentrations. The simplified Step-method predominantly yields the lowest concentrations. At the same time, it is the least sensitive procedure to the selected parameters and can be used only for a reference point situated on the plume centerline. From a cautious point of view, it is the least suitable method for solute transport modelling among the compared methods.

Description: This research is focused on the dolines of Dobrá Voda Karst, which is situated in the Brezovské Karpaty Mts. (north-eastern part of the Malé Karpaty Mts) near the villages of Chtelnica and Dobrá Voda. 263 dolines were identified here and measured in the field, which is presumably the final count. The measured parameters of the dolines were used for morphometric analyses, as well as for finding out the relationships with the geology of the area. The karst is formed in Triassic carbonates of the Považie and Dobrá Voda nappes of the Hronic Unit. Dolines were identified in Neogene basal carbonatic conglomerates (Dobrá Voda Formation) as well. The area of karst rocks is approximately 87.2 km2. Dolines often tend to be formed in lines with tectonical or lithological predisposition. The most significant lines in the Dobrá Voda Karst are Hlboký Dol, Chtelnické Uhliská, and Cínovec. The origin of dolines can be assumed to the Quaternary Period and related to neotectonics, the development of the relief, and the formation of the river network. This is also confirmed by the trends of the maximum axes of the extension of dolines in the direction N-S, NE-SW and WNW-ESE, which partially correspond to the regional faults. New faults (Hlboký Dol, Cínovec, Bzová) were also identified on the basis of dolines in the lines.

Description: Presented research investigate the phenomenom of karstic area remarkable with specific karst landform, so-called covered karst. So far, not much attention has been paid to this particular type of karst in Slovakia, so the aim of the research is to bring new informations about it, especially about dolines formation and their origin. Study was focused on 50 dolines following the distinctive NE–SW line in the study area - the Cajla Karst located in the Malé Karpaty Mts., Slovakia. To understand the process of the formation of dolines in the covered karst and to distinguish the dolines from the pits resulted from anthropogenic processing via mining, several geophysical methods were adopted to prove the doline origin (soil radon emanometry, electric resistivity tomography and seismic refraction tomography). For identification of dolines and subsequent processing, the lidar data were used. The formation of studied dolines was controlled by lithological-tectonic properties of the bedrock, especially along the contact zone of karstic (Triassic carbonates) and non-karstic rocks composed of quartzite and crystalline basement. The resulting shape was also influenced by infiltration of surface water into the underground.

Description: An unusual assemblage of Pb-Cu-(Sb)-(Mn) supergene minerals, represented by mottramite, phosphohedyphane, mimetite, segnitite-beudantite series, anglesite, cerussite, oxyplumboroméite, brochantite, devilline, gypsum and coronadite was recently identified at the Priečna, Johan de Deo and Anna-Zubau epithermal ore veins near Rudno nad Hronom, Štiavnické vrchy Mts., Slovak Republic. Mottramite is a rare mineral at the Rudno deposit and this is the first reported occurrence in the Western Carpathians. Also phosphohedyphane occurs only rarely at the deposit. The localized Pb2+ -- Ca2+ substitution between phosphohedyphane and pyromorphite was observed. A large substitution between As and S was recognized on the T site in the beudantite – segnitite. Anglesite and cerussite are relatively abundant supergene minerals, especially in the proximity of primary galena relicts. Secondary Cu sulphates (brochantite and devilline) are only secondary minerals found also in macroscopic size. Brochantite forms dark green tabular crystals up to 0.1 mm. Devilline occurs as a light green-blue acicular crystals grown on brochantite. Gypsum was found with this assemblage. This is also first occurrence of coronadite in Western Carpathians.

Description: Assessment of hazard and disaster risk is critical for urban resilience. Given that earthquake hazard assessments will often have limitations and uncertainty, it is essential to understand the worst-case scenario of hazard possibility. Palu City is located in a disaster-prone area because it is traversed by the Palu-Koro fault, an active fault in Indonesia. In preparing the latest risk assessment for earthquakes as consideration for potential land use planning in Palu, an earthquake hazard risk assessment was carried out, including estimating earthquake hazard, vulnerability, risk, and the integration of disaster risk into land-use planning documents. This study employed the applied methods with quantitative and quantitative approaches, and the data were processed with ArcGIS tools; field observations supported primary and secondary data. The results showed that 70% of the Palu area is under high earthquake threat as located in an active tectonic area. The findings of the earthquake hazard and risk assessments were then integrated into a land-use planning document that can be used as a foundation for creating a community development plan document for the Palu City Government, known as the Palu City Spatial Plan. The spatial plan of Palu City will support the resilience of Palu in carrying out its functions as a city to eliminate impacts and risks of hazards occur. Thus, strict land-use implementation as means for disaster mitigation is urgently needed.

Description: This study aims to understand the effect of frost weathering of travertines from Spišské Podhradie in Slovakia. The application of travertine as a natural building and facing stone shows a gradually increasing trend in construction sector around the world. Travertines are commonly seen in tile sizes as façade material, wall cladding or flooring and are naturally exposed to the freeze–thaw processes. Methods of frost damage assessment in rocks are commonly based on parameters acquired mainly by destructive testing of samples, such as the uniaxial compressive strength test or Young’s modulus test. In the presented research, a nondestructive method taking advantage of selected petrophysical properties compared before and after 100 freeze-thaw (F-T) cycles, as well as recorded length change behavior and temperature development by a specially- constructed thermodilatometer (VLAP 04) with two induced linear variable differential transformer sensors (HIRT- LVDT) on vacuum-saturated samples has been conducted. Results demonstrate that travertine from Spišské Podhradie is quite heterogeneous in term of petrophysical properties. This heterogeneity can significantly affect the nature and intensity of the processes which take place during the ice crystallization within the pore space of the rock. While crystallization pressures in the macropores and the hydraulic pressure induced by the migration of water towards the advancing freeze front cause the specimen to expand, they are not sufficient to overcome the reduction of pore pressures in micro and mesopores and thus the total contraction of the specimen occurs after 100 freeze-thaw (F-T) cycles. The changes in the microstructure of the pore space of the travertine from Spišské Podhradie are not significant and so we can state that this travertine is a resistant material to the effects of frost weathering.

Description: Slovakia is rich in the Pliocene, Pleistocene travertines and Holocene tufas and travertines, which were studied in 82 localities. Travertines are developed in the spring mounds (49 %) with central orifices frequently in crater-like forms. Fissure ridges (6 %) with vertical veins were identified. A few mounds and ridges were connected to large coalesced mounds (2 %). Many tufas and travertines were formed in perched springline deposits (21 %). The mounds, ridges, and perched springline deposits have the slopes with prograding cascades, fewer included waterfalls. The dams on slopes were very rare. Most tufas were formed in dams along streams (20 %), usually with waterfalls and caves. The upper Miocene freshwater limestones in 5 localities were originated in lakes and marshes (2 %). The Slovak travertines are usually related to regionally important faults such as the N–S striking Central Slovak Fault System (17 sites). Westwards, the faults related to the travertine occurrences the NE–SW striking faults prevailed (3 sites). In northern and eastern Slovakia, the faults have generally W–E to NW–SE direction (15 sites). The travertines are often formed on the fault intersections and they are related to the extensional tectonics.

Description: We would like to announce that the latest issue of the Acta Geologica Slovaca Journal (Volume 12, Issue 2) has already been released at 11th December 2020.

Description: We would like to announce that the latest issue of the Acta Geologica Slovaca Journal (Volume 13, Issue 1) has already been released at 30th June 2021.