Geology, Geophysics and Environment

Determination of catchment-scale hydrogeological parameters of fractured crystalline rocks using streamflow recession analysis – an example from south-western Poland

Tomasz Olichwer — Mon, 22 Apr 2024 00:00:00 +0200

To estimate catchment-scale hydrogeological parameters such as hydraulic conductivity (k) and specific yield (Sy), the streamflow recession analysis method proposed by Brutsaert and Nieber (1977) was used. The analysis employed the technique of fitting a theoretical recession curve to the observed data in which three points of transition between the short- and long-term flow regimes were determined. This method is a simple, fast, and cheap alternative to standard point-based hydrogeological methods using investigations carried out in hydrogeological boreholes. The study area covered the mountainous catchment of the Biała Lądecka River, located in south-western Poland and composed of metamorphic rocks. The hydrogeological environments drained by the Biała Lądecka are two zones, i.e. the zone of weathered covers and rock debris and the zone of fractured rock mass. The k values determined based on the recession analysis were in the boundary zone of the range from 10⁻⁴ to 10⁻⁵ m/s and they represented the upper range of the values reported in the literature (from 10⁻⁴ to 10⁻⁷ m/s). The Sy values at a level of 0.38–1.02%, in turn, entirely fitted the literature data. The results confirm the thesis that the recession method, despite certain limitations in terms of its applicability, can be well adapted to the conditions of a mountainous catchment composed of crystalline rocks where a cool temperate climate prevails.

The geology of the deepest Cenozoic lignite-rich grabens in Poland with particular reference to their lithostratigraphy: a comparative study

Marek Widera, Jakub Klęsk, Paweł Urbański — Mon, 29 Apr 2024 00:00:00 +0200

The thickest lignite seams in Poland are located in tectonic depressions such as the Kleszczów, Złoczew, and Lubstów grabens, as well as the Zittau (Żytawa) Basin. Their depth ranges from 220 m to 550 m, while the maximum lignite thickness ranges from approximately 90 m to over 250 m. The areas selected for this study include two Miocene lignite seams that have been exploited or prepared for mining, i.e. the third Ścinawa lignite seam (ŚLS-3) and the second Lusatian lignite seam (LLS-2). Currently, more than 95% of the Polish lignite production comes from the exploitation of these seams. Both lignite seams are accompanied by siliciclastic sediments that are lithologically very diverse. The lignite-rich grabens examined in this study form isolated structures and their individual geology is complex. Hence, apart from the Lubstów Graben, local lithostratigraphy is applied for each case, an approach that makes it difficult to compare the lithological units and their stratigraphic position with the Paleogene and Neogene lithostratigraphy used for the Polish Lowlands area. Therefore, it seems appropriate to present an outline of the geology of the Polish regions bearing most of the lignite seams, including a brief overview of their lithological and palaeotectonic characteristics. However, it is first necessary to clarify and compare the lithostratigraphy of the Cenozoic sediments that fill the studied grabens.

The effects of component rotation on H/V spectra: a comparison of rotational and translational data

Dariusz Nawrocki, Maciej Mendecki, Leslaw Teper — Mon, 20 May 2024 00:00:00 +0200

The presented investigation focused on site effect estimations, specifically resonance frequency and amplification. These estimations were carried out for both rotational and translational signals, using waveforms from mining-induced seismic events. Site effect parameters were calculated using the horizontal-to-vertical spectral ratio (HVSR) technique, which is commonly applied to translational records by comparing the spectral ratio between horizontal and vertical components. In this study, we also applied the horizontal-to-vertical (H/V) ratio to rotational records. However, due to the different orientations of motion propagation, we introduced the spectral H/V ratio for rotational motion as the torsion-to-rocking spectral ratio (TRSR). Furthermore, we analyzed
these signals according to two approaches. First, we estimated the site effect parameters for directly registered signals, and secondly, we considered rotated components by varying the angle from 0° to 180° in 5-degree increments. Generally, the H/V curves indicated two peaks for translational motions and four peaks for rotational motions. The averaged H/V spectra and spectra obtained for different angles of component rotation showed insignificant fluctuation in amplification values for both rotational and translational motions. However, when comparing each component’s spectrum for all angles, we observed changes in the site effect parameter values for both motion types. Radar plots depicting amplification values versus rotation angles for separated components revealed characteristic fluctuations, suggesting local anisotropy. Moreover, when comparing the radar plots between rotational and translational results, it was evident that rotational resonance frequencies shifted to higher frequency values, potentially indicating shallower geological layers as their source.

Ash admixtures formed during the loss on ignition (LOI) procedure and their impact on laser textural analysis results

Dmitry Tsvirko, Wojciech Tołoczko, Piotr Kittel — Fri, 07 Jun 2024 00:00:00 +0200

We present an experimental study that explores the feasibility of using the ash from biogenic deposits for laser textural analysis. The results have demonstrated that conducting ash textural analysis without prior chemical treatment can lead to unreliable results. Among other things, this is due to the “contamination” of the ash with aggregates formed by metal oxides and carbonates during ignition (LOI550 procedure) in a muffle furnace. Metal oxides and carbonates can create aggregates with silt and clay grains. As a result, the material coarsens, mainly to very coarse and coarse silt fractions. It is illustrated that the ash after LOI550 has been contaminated with oxides and carbonates of iron (Fe), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), sodium (Na), zinc (Zn), lead (Pb) and copper (Cu). Thus, we suggest a method of using 10% HCl to purify the ash from metal oxides and carbonates (so-called ash purification procedure or APP). The analysis in this paper focuses on the grain size composition of ash, both untreated and HCl-treated. The obtained results have been compared and discussed in detail.

Numerical modeling of a potential CO2-supplied enhanced geothermal system (CO2-EGS) in the Åsgard field, Norway

Thu, 20 Jun 2024 00:00:00 +0200

The principle of Enhanced Geothermal System (EGS) technology is that water injected at a sufficiently high pressure will lead to the fracturing of naturally impermeable rocks, and as a result, this will create hydraulic communication between wells. In this way, reservoirs not previously considered to be perspective can provide geothermal heat to the surface. Since nearly two decades, CO₂is considered, mostly theoretically, as a working fluid that can potentially provide higher net power output than water in EGS’s installation. In this respect, the possibility of accessing high-temperature heat from the Åre and Tilje formations located on the shelf of the Norwegian Sea was analysed. The estimated temperature at the reservoir depth of 4,500–5,000 m is not less than 165°C. For this, a 3D numerical modelling was performed in order to analyse 10 different scenarios for heat extraction using supercritical CO₂ (sCO₂) as a working fluid. Results indicate that appropriate matching of the mass flow and temperature of the injected CO₂ allows to avoid premature temperature decline in the reservoir. However, as Åre and Tilje formations are built from highly porous and relatively highly permeable rocks, the fluid entering the production well will always be a mixture of CO₂ and water. This is advantageous from the point of view that a significant part of the injected CO₂ is trapped in the reservoir, while the higher water content in the production well allows a significant temperature drop during fluid extraction to the surface to be avoided.

Capacity of surface water to reduce air multi-pollution in urbanized areas (the City of Krakow, southern Poland)

Dorota Pierri, Dorota Myszkowska, Alba Casado, Paulina Mitana — Thu, 20 Jun 2024 00:00:00 +0200

The study analyzes changes in the physico-chemical parameters in a 400 cm2 artificial water reservoir with distilled water, exposed to a 2-week (±2 days) period of atmospheric conditions in Krakow. After nearly 500 days, dry and wet deposition caused a shift from neutral to acidic pH levels (7.30–5.12, averaging 6.22 pH) and an average electric conductivity of 19.5 μS/cm (1.6–143.0 μS/cm). The study investigated chemical and biological pollutants, including pollen and fungal spores. Three distinct air quality periods were identified: (1) characterized by vehicle and combustion-related pollutants (Oct-Jan), (2) a transitional phase with increased biological particles (Feb-May), and (3) dominated by pollen and fungal spores (Jun-Sep). Despite peak air pollution in the warmest months, air temperature showed an inverse relationship with pollutant concentration, possibly due to decreased air humidity. Precipitation positively impacted air quality. The artificial reservoir received a total of 0.7 kg of air pollutants
(723.6 mg/m2 of surface water table). This corresponds to an annual load of 0.5 kg (551.4 mg) and a daily load of 1.51 mg. The reservoir’s pollutant capture capacity was estimated at 28% ±21% (mean±SD), with a critical value of 12%. The study evaluated Krakow’s surface water reservoirs’ capacity to mitigate air pollution, indicating potential benefits for urban air quality.

Front page

Fri, 28 Jun 2024 00:00:00 +0200

Editorial page

Fri, 28 Jun 2024 00:00:00 +0200

Instruction for the authors

Fri, 28 Jun 2024 00:00:00 +0200

Geology, Geophysics and Environment

Determination of catchment-scale hydrogeological parameters of fractured crystalline rocks using streamflow recession analysis – an example from south-western Poland

The geology of the deepest Cenozoic lignite-rich grabens in Poland with particular reference to their lithostratigraphy: a comparative study

The effects of component rotation on H/V spectra: a comparison of rotational and translational data

Ash admixtures formed during the loss on ignition (LOI) procedure and their impact on laser textural analysis results

Numerical modeling of a potential CO2-supplied enhanced geothermal system (CO2-EGS) in the Åsgard field, Norway

Capacity of surface water to reduce air multi-pollution in urbanized areas (the City of Krakow, southern Poland)

Front page

Editorial page

Table of contents

Instruction for the authors